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Simulation of peanut plant growth and the effect of defoliation on growth and yield

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Simulation of peanut plant growth and the effect of defoliation on growth and yield
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Wilkerson, Gail G., l946-
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English
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xi, 210 leaves : ill. ; 28 cm.

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Subjects / Keywords:
Branches ( jstor )
Defoliation ( jstor )
Leaves ( jstor )
Modeling ( jstor )
Peanuts ( jstor )
Plant growth ( jstor )
Planting ( jstor )
Plants ( jstor )
Stems ( jstor )
Vegetation canopies ( jstor )
Dissertations, Academic -- Entomology and Nematology -- UF
Entomology and Nematology thesis Ph. D
Peanuts -- Diseases and pests ( lcsh )
Peanuts -- Growth ( lcsh )
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bibliography ( marcgt )
non-fiction ( marcgt )

Notes

Thesis:
Thesis--University of Florida.
Bibliography:
Bibliography: leaves 206-209.
General Note:
Typescript.
General Note:
Vita.
Statement of Responsibility:
by Gail G. Wilkerson.

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SIMULATION OF PEANUT PLANT GROWTH AND THE EFFECT
OF DEFOLIATION ON GROWTH AND YIELD












By

Gail G. Wilkerson


A DISSERTATION PRESENTED TO THE GRADUATE COUNCIL OF
THE UNIVERSITY OF FLORIDA
IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE
DEGREE OF DOCTOR OF PHILOSOPHY



UNIVERSITY OF FLORIDA


1980













ACKNOWLEDGEMENTS


I wish to express my sincere appreciation to Dr. S. L. Poe for

serving as chairman of my supervisory committee during the major portion of my graduate program, and for providing aid and advice when needed. I also thank Dr. S. H. Kerr for assuming the role of supervisory chairman upon Dr. Poe's departure from the University of Florida, and for providing editorial assistance in the preparation of this manuscript.

To Dr. J. W. Jones I extend my sincere thanks for his invaluable assistance in all phases of this research. I would also like to thank Dr. K. J. Boote for his help in designing the field experiments, and Drs. T. R. Ashley and R. C. Littell for their advice, encouragement, and manuscript review. My appreciation also is extended to Dr. C. S. Barfield for reviewing the manuscript.

I especially want to thank Dr. W. G. Duncan for so kindly allowing me to use his PENUTZ model and for discussing it with me.

To John Mangold, Carol Lippincott, Randy Stout, and Gail Childs I

express my heartfelt thanks for their help with the field work, for without their assistance this research would not have been possible.

I wish to thank Mary Jermann for her help in typing the final

copy of this dissertation, and I especially want to thank Barbara Lemont for her excellent work on the graphs contained in this dissertation.

Above all, I thank my son, Trevor, for putting up with a grouchy mom on many occasions.


ii

















TABLE OF CONTENTS


PAGE


ACKNOWLEDGEMENTS. . . . . .

LIST OF TABLES. . . . . . .

LIST OF FIGURES . . . . . .


ABSTRACT. . . . . . .


I INTRODUCTION. . . . . . . .

I1 GROWTH OF NON-DEFOLIATED PEANUT PLANTS.


Introduction. . . .
Effect of Temperature Photosynthesis. . Methods and Materials .
Crop Management . .
First Experiment. .
Second Experiment
Results .. .. .
First Experiment. .
Second Experiment .


on PI


ant Growth


III THE EFFECTS OF DEFOLIATION ON PEANUT PLANT GROWTH

Introduction . .. .. .. . . . .
Methods and Materials . . . . . . . .
First Defoliation . . . . . . . .
Second Defoliation. . . . . . . . .
Third Defoliation . . . . . . . .
Fourth Defoliation. . . . . . . . .
Results . . . *. . *. . . . . . .
First Defoliation . . . . . . . .
Second Defoliation. . . . . . . . .
Third Defoliation . . . . . . . .
Fourth Defoliation. . . . . . . . .


IV THE SIMULATION MODEL. . . . .


Introduction. . . . Description of the Model.
Initiation of New Leaves


. . . . . .
. . . . . .
and Branches . .


Calculation of the Day's Net Photosynthate. .


CHAPTER


Sii


. . . . . . . X


6


6
8
8
10 10
11 13 14 14 17

29

29
35 35 37 38 38 39 39
44
48 52


. . . . . . 57


57 60
64 66


I












CHAPTER PAGE

Calculation of Increases in Total Dry Weight per
Unit of Carbohydrate. . . . . . . . 72
Inactivation of Vegetative Growing Points. . . 73 Cessation of Peg and Pod Initiation. . . . . 74 INSECT Subroutine. . . . . . . . . 75
Subroutine ATTAC . . . . . . . . . 77
Results and Discussion . . . . . . . . 79
Comparison of Model Predictions with Growth of Nondefoliated Plants in the Field. . . . . . 79
Comparison of Model Predictions with Results of
the Field Defoliations. . . . . . . . 90
Simulation of Insect Cohort Entering the Field . 110

V SUMMARY AND CONCLUSIONS. . . . . . . . . 115

APPENDICES

I WEATHER DATA FOR THE 1978 GROWING SEASON . . . . 118

2 FLOW CHARTS OF THE MAJOR SUBROUTINES IN PMINUS . . 123

3 COMPUTER PRINTOUT OF PMINUS. . . . . . . . 151

4 DESCRIPTION OF MODEL PARAMETERS. . . . . . . 193

5 INPUT PARAMETERS AND VARIABLES DESCRIBING DYNAMICS
OF PEANUT PLANT GROWTH. . . . . . . . . 198


REFERENCES CITED . . . . . . . . . . 206

BIOGRAPHICAL SKETCH. . . . . . . . . . 210


iv
















LIST OF TABLES


TABLE PAGE

1 Average leaf growth for 4 Florunner peanut plants
marked weekly and harvested at 16 weeks. . . . 15

2 Average numbers and weights of pods of various
size categories from 4 Florunner peanut plants
marked on a weekly basis during 1978 and harvested at 16 weeks of age. . . . . . . . 16

3 Average leaf growth for Florunner peanut plants
during the 1978 growing season, as indicated by
weekly plant samples . . . . . . . . 18

4 Average stem growth for Florunner peanut plants
during the 1978 growing season, as indicated by
weekly plant samples . . . . . . . . 19

5 Average numbers and weights of pods present on
the Florunner peanut plants harvested each week
during the 1978 growing season. . . . . . 20

6 Number of new leaves per branch during the 1978
growing season, as indicated by weekly plant
samples. . . . . . . . . . . . 21

7 Estimation of leaf loss by Florunner peanut plants
during the 1978 season, as indicated by weekly
plant samples. . . . . . . . . . . 22

8 Comparison of specific leaf weights for leaves
initiated at the same time but harvested within
a week or at week 16. . . . . . . . . 24

9 Results of linear correlations of stem size to
plant age and plant size for Florunner peanuts. . 26

10 Average size of stem internodes during the 1978
season, as indicated by weekly plant samples. . . 27

11 Summary of the defoliation experiments performed
during the 1978 growing season on Florunner peanut plants. . . . . . . . . . . 40


v











TABLE PAGE

12 The effect of various levels of defoliation at
41 weeks upon plant size at 7 weeks. . . . . 41

13 Estimated leaf and stem gains in the 21 weeks .
following defoliation at 4i- weeks. . . . . . 43

14 Summary of light interception by plants 7 weeks
of age which had been defoliated at 4i weeks. . 45

15 The effect of 50% defoliation at week 9 upon
plant size at week 11. . . . . . . . . 46

16 The effect of 50% defoliation at week 9 upon
plant size at week 15. . . . . . . . . 47

17 Summary of light interception by plants
defoliated at 9 weeks of age. . . . . . . 49

18 The effect of 50% defoliation at week 12 upon
plant size at 14 weeks. . . . . . . . 50

19 The effect of 50% defoliation at week 12 upon
plant size at week 16. . . . . . . . . 51

20 Summary of light interception by plants
defoliated at week 12. . . . . . . . . 53

21 The effect of defoliation at 16 weeks upon
plant size at 18 weeks. . . . . . . . 54

22 Summary of light interception by plants
defoliated at 16 weeks. . . . . . . . 56

23 A brief description of the user-written subroutines included in PMINUS. . . . . . . 61

24 Root growth during the 1978 growing season, as
indicated by weekly plant samples. . . . . . 69

25 Comparison of leaf growth in the field with
model predictions. . . . . . . . . . 89

26 Comparison of model predictions with field
results for plants defoliated at 4 weeks and
harvested at 7 weeks. . . . . . . . . 91

27 Comparison of model predictions with field
results for plants defoliated at 9 weeks and
harvested at 11 weeks. . . . . . . . . 94











TABLE PAGE

28 Comparison of model predictions with field
results for plants defoliated at 9 weeks and
harvested at 15 weeks. . . . . . . . . 95

29 Comparison of model predictions with field
results for plants defoliated at 9 weeks and
harvested at 14 weeks. . . . . . . . . 98

30 Comparison of model predictions with field
results for plants defoliated at 12 weeks and
harvested at 16 weeks. . . . . . . . . 99

31 Specific leaf weights and average size of new
leaves grown in the 2 weeks following defoliation. .104

32 Comparison of model predictions with field
results for plants defoliated at 16 weeks and
harvested at 18 weeks. . . . . . . . .106

33 Comparison of simulated and experimental (Mangold,
1979) growth of Florunner peanuts in the 2 weeks
immediately following defoliation at 8 weeks. . .108

34 Comparison of simulated and experimental (Mangold,
1979) yields for Florunner peanuts defoliated at
various points in the season. . . . . . .109


vii















LIST OF FIGURES


FIGURE PAGE

I Relationship between leaf area index and percent
light interception for Florunner peanuts planted
on 24 May 1978. . . . . . . . . . 28

2 Simulated and experimental leaf area index for
Florunner peanuts planted on 24 May 1978. . . . 80

3 Simulated and experimental change in leaf numbers
for Florunner peanuts planted on 24 May 1978. . . 81

4 Simulated and experimental leaf growth for
Florunner peanuts planted on 24 May 1978. . . . 82

5 Simulated and experimental stem growth for
Florunner peanuts planted on 24 May 1978. . . . 83

6 Simulated and experimental changes in pod numbers
for Florunner peanuts planted on 24 May 1978. . . 84

7 Simulated and experimental pod growth for Florunner
peanuts planted on 24 May 1978. . . . . . 85

8 Simulated and experimental change in number of
fully expanded pods for Florunner peanuts planted
on 24 May 1978. . . . . . . . . . 86

9 Simulated and experimental growth of fruit filling
seeds for Florunner peanuts planted on 24 May 1978. 87

10 The simulated and experimental effect of 50% uniform defoliation at 9 weeks after planting on LAI
(a) and pod dry weight (b). . . . . . . 96

11 The simulated and experimental effect of removal
of all leaves from the outer 50% of the canopy at
9 weeks after planting on LAI (a) and pod dry
weight (b). . . . . . . . . . . 97

12 The simulated and experimental effect of 50% uniform defoliation at 12 weeks after planting on
LAI (a) and pod dry weight (b). . . . . . 100


viii













13 The simulated and experimental effect of removal of
all leaves from the outer 50% of the canopy at 12 weeks after planting on LAI (a) and pod dry weight
(b). . . . . . . . . . . . 10 1

14 The simulated and experimental effect of 50% uniform and 100% defoliation at 16 weeks after planting
on LAI (a) and pod dry weight (b). . . . . .107

15 The simulated effect of 10 larvae/plant entering the
field on day 35 after planting and feeding for 26 days
at an increasing rate. . . . . . . . .

16 The simulated effect on LAI (a) and pod dry weight
(b) of 10 larvae/plant entering the field on day 56
and feeding for 26 days at an increasing rate. . .113

17 The simulated effect on LAI (a) and pod dry weight
(b) of 20 larvae/plant entering the field on day 35
and feeding for 26 days at an increasing rate. . .114


PAGE


F IGURE


i X

















Abstract of Dissertation Presented to the Graduate Council of
the University of Florida in Partial Fullfillment of the Requirements
for the Degree of Doctor of Philosophy



SIMULATION OF PEANUT PLANT GROWTH AND THE EFFECT
OF DEFOLIATION ON GROWTH AND YIELD


By


Gail G. Wilkerson


June 1980


Chairman: S.H. Kerr
Major Department: Entomology



Field experiments were performed to produce information necessary for modification and expansion of an existing peanut plant growth model so that the effects of insect defoliation could be simulated. In order to provide a baseline for normal growth, several plants were selected at the beginning of the season and their growth followed until the end of the season. In addition, plants were harvested weekly. Plants were defoliated mechanically at 4f', 9, 12, and 16 weeks after planting and were harvested 2, 4, or 6 weeks following treatment.

Early season defoliations (at 4!' weeks) resulted in reductions in weights of all plant parts; whereas later defoliations resulted in significantly lower stem weight to length ratios, lower pod numbers and weights, and equal or higher leaf numbers and weights. Apparently

x











this peanut cultivar (Florunner) accumulates reserves in the stem during the course of the season which can be utilized to grow new leaves or to fill pods in the event of defoliation.

PMINUS is the simulation model developed on the basis of these experiments. Plant growth depends upon physiological time and intercepted radiation. The model keeps track of the number and weight of leaves, internodes, and pods initiated each day. New vegetative and reproductive branches are initiated according to the branching pattern of the plant. Light interception (calculated on the basis of leaf area index) is used to determine amount of photosynthesis each day. Carbohydrate supply and demand are balanced each day based on a system of priorities which changes during the course of the season. The model successfully describes the growth of both defoliated and nondefoliated plants. PMINUS is designed so that it can be easily coupled to either a plant disease or an insect development model, as is demonstrated by the introduction of a theoretical insect population.


xi
















CHAPTER I
INTRODUCTION



Peanuts are an important food and oil crop. During the period 1967-1969, an average of nearly 45 million acres of peanuts was grown annually throughout the world and over 1.4 million acres were grown in the United States (McGill, 1973). The peanut agroecosystem is complex, in that there are numerous arthropods, weeds, and diseases which attack peanut plants and affect crop growth and yield. In addition, growth and yield are influenced by soil and weather conditions, and by crop management practices. The effects of many of these factors are dynamic--for example, final yield may be less affected by a given level of moisture stress or defoliation at one time in the season than at another. Furthermore, there is interaction between factors; a plant that has been weakened by disease may be less able to withstand insect defoliation. Linker (1980), working in north Florida, noted an interaction between a crop management practice (date of planting) and numbers of fall armyworm, Spodoptera frugiperda (J.E. Smith), and corn earworm, Heliothis zea Boddie, larvae obtained in his field samples. As a result of this interaction, in 1975 and 1976 the later in the season the crop was planted, the more insecticide treatments were required for crop protection.

Given the dynamic nature of the different factors involved in determination of final yield, and the difficulty of designing and


I







2


performing experiments to directly determine the effects of interactions between the various factors, modeling and computer simulation can be effectively used in pest management programs for studying crop management decisions on the basis of overall costs and gains. In addition, the modeling approach can be used to evaluate various hypotheses of how particular processes in pest management systems are controlled and function. For example, there is much about plant growth that is still not fully understood, and any model of plant growth contains many explicit or implicit assumptions about the operation of the various processes. Although simulation cannot be used to prove that a particular process operates in a certain manner, it can be used to separate hypotheses that warrant further experimentation from those that are inoperable.

The purpose of my research was to develop a computer simulation model of peanut plant growth containing the necessary mechanisms for coupling it to an insect development model. As this research was part of an interdisciplinary pest management project concerned with the effects of diseases as well as insects, a model structure of sufficient complexity to allow for the incorporation of both was needed.

There has been at least one research effort aimed at modeling the effect of foliage-consuming insects on peanut yield (Smith and Kostka 1975). These investigators fitted a response surface of yield to plant defoliation and plant phenology. This method of modeling has the disadvantage that it does not allow for interactions of the various components of the crop system which account for the final yield, and was therefore unsuitable for the purposes of this study. There were 2 peanut plant growth models available for consideration: that developed by Young et al. (1979) and that developed by Duncan (1974). There were






3


problems involved with using either of these models for simulation of insect and disease damage. PENUTZ, the model developed by Duncan (1974), does not include leaf and stem components explicitly, only as vegetative top weight. Photosynthesis each day is based on percent ground cover which is calculated by considering the plant canopy as expanding circles which eventually overlap and achieve 100% ground cover. The rate of expansion is determined by temperature (Duncan et al. 1978). Insects eat leaves and the translation of feeding into changes in canopy geometry would be difficult, if not impossible. Duncan's model therefore could not be used without modification.

The model developed by Young et al. (1979) does separate leaf from stem mass and it does store the amount of leaf mass added each day so that leaf material of a given age can be removed from the system. This ability to separate plant material by age is important for simulation of either insect or disease damage. For this reason, the model of Young and his co-workers would have been used if it had not had one serious disadvantage. The model requires values for a large number of empirical parameters. In order to find values for these parameters, Young et al. fitted data for 9 planting dates each year. In many cases a parameter value changed radically from one year to the next. There were insufficient data available for determination of realistic values of these parameters for Florida growing conditions in 1978. Duncan's model was developed largely from data obtained in Gainesville, Florida, and I therefore anticipated fewer problems in fitting growth of my non-defoliated plants to his model. Thus a decision was made to modify his model for this study.






'4


Of the 3 general approaches for partitioning growth into crop components discussed by Jones and Smerage (1978), the morphogenetic approach seemed the most applicable for the purposes of this study. In this view of growth, individual plant organs (such as leaves and pods) are initiated and grow for a finite time. Potential growth rates of individual organs are calculated, sink demand is calculated for each crop component, and growth is limited by substrate availability. A tobacco model (Hackett 1972) and several cotton models (Stapleton and Meyers 1971, McKinion et al. 1975, and Jones et al. 1980) have used the morphogenetic approach to partitioning.

Duncan's PENUTZ model is based on the philosophy that the peanut

plant partitions a certain amount of the available photosynthate to the reproductive portion of the plant and that this amount varies with cultivar. Since it calculates pod demand each day, it was only necessary to add the initiation of vegetative organs and the calculation of vegetative demands each day to develop the morphogenetic model, PMINUS, from PENUTZ. As there were insufficient data available in the literature to do this, experiments were designed to provide information on initiation and rate of growth of leaves and branches and the weight and area of individual leaves throughout the season on plants without insect damage. The development of stems, roots, and pods was also followed in these experiments so that model predictions of plant growth could be verified. Since Florunner is the most commonly grown cultivar in the United States (Duncan et al. 1978), it was used in all experiments. These experiments dealing with the normal growth of non-defoliated plants are discussed in Chapter 11.






5


There were some indications in the literature that defoliation might have a more complex effect on peanut plant growth than simply reducing leaf area, light interception, and therefore photosynthesis. Experiments were designed to investigate the effect of different kinds and levels of mechanical defoliation upon plant growth--in particular upon the plant branching pattern and the partitioning of available photosynthate into the various plant organs. These experiments are discussed in Chapter 11i.

A computer simulation model was developed, using the results of the experiments discussed in Chapters I and 1I1, information contained in the literature, and portions of PENUTZ. As there were many elements of peanut plant growth for which there was no information available for determination of model structure and parameters, various hypotheses were tested until a model structure and parameters were developed which successfully described growth of both defoliated and non-defoliated plants. Defoliation experiments performed by Mangold (1979) were then simulated to partially validate the model. A theoretical insect population was introduced at various points in the growing season, at 2 population levels, to demonstrate the usefulness of the model and to investigate the importance of time and location of damage to final yield. Chapter IV deals with this simulation model.
















CHAPTER 11
GROWTH OF NON-DEFOLIATED PEANUT PLANTS



Introduction


The Florunner cultivar of peanuts used in this study is a prostrate member of the Virginia varietal group (Arachis hypogaea L. var. hypogaea), according to the classification system given by Gregory et al. (1951). As such, it is characterized by indeterminate growth and a branching system which consists of a central stem axis and variable numbers of lateral axes, including 2 prominent cotyledonary laterals. All branches directly off the mainstem are vegetative, and all lateral branches are vegetative in the first node and predominantly vegetative in the second node. Nodes on vegetative branches of all orders generally occur in alternating vegetative and reproductive pairs. Malagamba (1976) found that the number of primary, secondary, and tertiary branches produced by Florunner is related to planting density. In his experiments, the number of primary branches/m2 increased linearly with increasing plant density, while number of secondary branches reached a peak at approxi2
mately 30 plants/m and then declined. The number of tertiary branches decreased with increasing plant density--there being no tertiary branches at the higher densities.

In Florida, growth of Florunner typically proceeds in the following manner: plants begin to emerge ca. 5 days after planting; 100% ground cover is reached 8 to 9 weeks after planting when the LAI (leaf area


6






7


index I) reaches ca. 3.0; leaf area continues to climb until week 11 or 12; and stems increase in weight until week 13. Flowering starts at day 30 to 35, reaches a peak at 8 to 9 weeks, then declines to zero by week 13. Pegs2 appear 1-2 weeks after the first flowers, reach a maximum about 6 weeks later, then decrease in number. Pegs start to swell about a week after they first appear; the number of pods increases until about week 12, when it plateaus; and seeds begin to fill around day 70. Harvest occurs between 19 and 20 weeks after planting (McGraw 1977, McCloud 1974, Duncan et al. 1978).

The time required to reach 100% ground cover varies with planting density, as do the maximum LAI achieved and the number of pegs and pods per plant (Malagamba 1976). Final yield per unit ground area is much less affected by density, however, Cahaner and Ashri (1974), working with 4 Virginia-type varieties, found equal yields of mature pods for the 3 planting densities investigated. Malagamba (1976) found a fast increase in yield was obtained, then a slow decline phase starting at 20
2
to 22.5 plants/m

Many flowers bloom and fail to produce pegs and many pegs fail to develop into mature pods. Smith (1954), investigating reproductive efficiency in a Virginia Runner variety, found 93.3% of the egg cells in all ovules were fertilized but only 63.5% actually elongated as pegs. Of the pegs which did elongate, only one-third reached the stage of pod enlargement, and a third of these pods failed to reach maturity. Only



ILeaf area index is the ratio of leaf area to ground area. 2The ovary elongates as a peg and enters the ground before enlargement of the pod commences.






8


11.4% of the ovules present at anthesis became seeds. Smith noted that the ovaries of pollinated peanut- flowers can remain dormant for several weeks without losing their ability to resume active fruit development and that flowering resumes when fruits are removed. Bolhuis (1958) found that continuous removal of flowers (thus preventing fruit development) resulted in not only a prolonged flowering period but also a greater than normal number of flowers per plant per day. Gupton et al. (1968) found that the order of pegging is related to the branching pattern of Virginia type peanuts and that the order of peg development is essentially the same as the order of peg placement. Effect of Temperature on Plant Growth

Temperature has an important effect on peanut plant development.

Bolhuis and DeGroot (1959) found that a temperature of 330C was too high for normal development and a temperature of 2)C was too low. In their study of 3 varieties they noted that tolerance to different temperatures increased as the latitude from which the varieties originated increased. Jacobs (1951) found that vegetative and gynophore (peg) growth reacted differently to various temperature combinations. In a study of Florigiant peanut plants, Cox (1979) determined that early growth was optimum at a weighted mean temperature of 27.50C and no growth occurred at 15.50 C. Treatments 40C above or below the optimum 30/260C temperature resulted in less dry weight. The optimum temperature for fruit growth (240C) was lower than that for top growth. Photosynthesis

In a study of 5 genotypes, including 2 cultivars of Arachis hypogaea L. and 3 wild species of Arachis, Florunner was found to have the highest







9


rate of photosynthesis by Bhagsari and Brown (1973). In an expanded study of 31 peanut genotypes, Bhagsari and Brown (1976) again found Florunner to have the highest photosynthetic rates. Pallas and Samish (1974) also found Florunner to have one of the highest rates of photosynthesis of the extensively cultivated varieties. Even though their plants were grown at low light intensity, they did not photosaturate at the highest light intensity tested, which was slightly less than full sunl ight.

Pallas and Samish (1974) noted that the photosynthetic rate of an

individual peanut leaf dropped after it was 3 or 4 weeks of age. Henning et al. (1979) obtained similar results, with younger leaves exhibiting higher apparent photosynthetic (AP) rates. In addition, they noted that the mean AP rate decreased in a nearly linear fashion with increasing plant age from 80 to 140 days. Trachtenberg (1976) found that leaf net photosynthetic rates increase with leaf age until peanut leaves are less than 2 weeks old, then decline with leaf age. The Pmax (theoretical maximum photosynthesis) for individual peanut leaves in his experiment was calculated at 77 mg CO2 dm-2 hr~I and the Pmax for leaves over 6 weeks old was 43.5 mg CO2 dm-2 hr-1.

Gautreau (1973) found that differences in climatic factors greatly affected the growth of all plant parts. He felt that differences in light intensity were particularly responsible for differences in length of stem internodes and of the mainstem and other branches. Cox (1978) determined that mainstems were quite elongated under low light treatments and the number of flowers was markedly reduced. Hang An (1978) found that shading affected flowering, pegging, and size of fruit load.






10


Yield was most reduced by shading during the pod filling period (83 to 104 days after planting).

The experiments discussed in this chapter were designed to provide basic information on normal peanut plant growth, necessary for modification of PENUTZ. In the first experiment the growth of several plants was followed throughout the course of the season to give a unified view of addition and loss of leaves, addition of vegetative branches, and development of pods of a known age. The second experiment was planned to furnish weekly estimates of LAI, the number of new leaves/branch, the weight, specific leaf weight, and area of new leaves, the size of stem internodes, and changes in weight of other plant parts. Plant maps were made so that the time and order of initiation of vegetative and reproductive branches could be determined. Light interception was measured periodically throughout the season and was correlated to LAI. The calculation of photosynthesis each day in the model could then be based upon LAI, rather than canopy geometry, as it was in PENUTZ.



Methods and Materials


Crop Management

Florunner peanuts were hand planted 2 per hill on 24 May 1978 at the University of Florida agronomy farm, Alachua County, Florida. The plants were thinned to I per hill after emergence. Rows were 76.2 cm apart and there were 13.8 cm between plants, giving a plant population of 9.5 plants per m2. This is within the plant density range for maximum yield (Malagamba 1976).







11


The soil type at the site was Arredondo fine sand. The field was well-irrigated prior to planting and irrigated again briefly the day after planting. A tensiometer was installed in the field to measure soil water tension at different depths and the plot was irrigated as needed to prevent significant water stress. Rainfall and maximum and minimum temperatures were recorded daily.

Rhibozium innoculum was added to the furrows at planting, and gypsum was applied by hand at the rate of 1700 kg/ha on 26 June. Weeds were controlled with preplant and cracking time herbicides. Ethylene dibromide was injected into the soil 5 days before planting for nematode control. The fungicide chlorothalonil was applied from 22 June until 22 September at 7-10 day intervals. Insecticides were applied as needed to minimize damage by foliage-feeding lepidopterous larvae. On 24 August, fensulfothion RCNB granules were hand-broadcast to slow the spread of white mold, Sclerotium rolfsii. Further details of the pesticide applications can be found in Mangold (1979). First Experiment

For the first experiment, in which the growth of several plants was to be followed throughout the season, 7 plants were selected on 14 June, 3 weeks after planting. These plants were marked once a week until 9 August, when 2 plants were harvested. The remaining 5 were harvested on 13 September, 16 weeks after planting. The experimental plants were all surrounded by healthy plants which were left undisturbed throughout the season.

Once a week each new, fully expanded leaf on the selected plants was marked by placing a colored surgical wound clip around the petiole.







12


A leaf was considered fully expanded if the next leaf on the branch was starting to unfold. New vegetative branches were marked by placing a spot of acrylic paint on the axil of the leaf at the node from which the branch was emerging. Pegs that had entered the ground during the preceding week also were marked with colored surgical wound clips. The color of paint and clips was different each week so that at the end of the experiment the age of each leaf, stem, and pod could be determined. The numbers of marked pegs, leaves, and stems were recorded each week.

When the plants were brought in from the field, the location and age of leaves, stems, and pods were mapped. The leaves were separated by age and counted; leaf area was determined by use of a Lambda3 leaf area meter; and after drying the leaves were weighed. Marked pods also were separated by age and further divided into categories of P3, P4, and P5. A P3 pod is defined as one that is slightly swollen; a P4 as one that is fully expanded but which shrinks when dried; and a P5 is one that is fully expanded which does not shrink when dried (Hang An 1976). The pods in the various categories were counted, then dried and weighed.

All plant parts in all experiments were dried at 600C for at least 48 hr prior to weighing. Data were analyzed using the Statistical Analysis System on an Amdahl 470 V/6-1l with OS/MVS Release 3.8 and JES2/NJE Release 3. Computing was done using the facilities of the Northeast Regional Data Center of the State University System of Florida, located on the campus of the University of Florida in Gainesville.



3Lambda Instruments Corporation, Lincoln, NE.











Second Experiment

in this experiment 11 rows of plants were used. Sample plants

were selected from rows 2, 4, 6, 8, and 10. The other rows were left undisturbed. Three weeks after planting, healthy plants which had a healthy plant on each side were selected, numbered, and marked with a flag. There were always at least 2 plants between sample plants. A random number table was used to select the plants to be harvested each week. Nine or 10 plants were harvested 3, 4, 5, 6, 7, 8, 9, 10, 12, 13, and 20 weeks after planting. On weeks 11, 14, 15, 16, and 18 the control plants from the defoliation experiments performed in the same field were used in determination of plant growth for those weeks. Each week 3 plants were marked in a manner similar to that described in the first experiment, and the plants were harvested the following week so that number of new leaves, stems, and pods could be determined on a weekly basis. These 3 plants were mapped as to location of branches, both reproductive and vegetative, old and new leaves, and pegs and pods. Old and new leaves were counted and weighed. A 50 or 100 leaflet sample was measured for determination of specific leaf weight.

All the plants harvested each week were taken apart and leaves, Pl-P5, and growing points were counted. All stems were measured and dry weights were obtained for leaves, stems, roots, vegetative growing points, reproductive branches and pegs, petioles, P3-P5, and kernels.

Beginning when the plants were 6 weeks old, canopy interception of photosynthetically active radiation (PAR) was measured periodically in the following manner: a metal track 3 cm wide with 3 cm sides was inserted perpendicular to the row between plants and a pyranometer4


4
Lambda Instruments Corporation, Lincoln, NE.







14


(LI-COR 2005) was pulled by its cord manually along the track at a constant rate for 1 minute. The pyranometer was connected to a quantumradiometer-photometer5 (LI-COR 185) and printing integrator (LI-COR 550). PAR measurements were made on days of clear skies between 9001500 hours EST and an ambient full-sun reading above the canopy was recorded within 1-2 minutes of the canopy reading.



Results


First Experiment

One of the 5 plants which were harvested 16 weeks after planting had been attacked by white mold and thus had to be discarded. Data obtained on leaf growth are summarized in Table 1; that for pod growth in Table 2. The number of new leaves per plant per week was at a maximum during weeks 9, 10, and 11, and fell sharply after week 12. By week 16, approximately 80% of the leaves grown during the first 3 weeks following planting had been lost, but only 34% of the leaves grown between weeks 3 and 4 had been lost. Most of the leaves grown after week 5 were still present at 16 weeks. There was a sharp drop in specific leaf weight after week 5. No new vegetative branches were initiated after week 13.

Pegs first entered the ground between weeks 6 and 7, as can be

seen in Table 2. Some of these earliest pods failed to mature by week 16. The greatest number of pods appeared to be added between weeks 9 and 10, although about 27% of all pods escaped marking and many of



5Lambda Instruments Corporation, Lincoln, NE.









Table 1. Average leaf growth for 4 Florunner peanut plants marked weekly and harvested at 16 weeks.

No. Leaves No. Leaves Still Leaf Specific Leaf Weight per No. New Veg.
Week Marked Present at 16 Weeks Area, cm2 Wt., mg/cm2 Leaf, mg Growing Pts.

3 8.5 1.8 24.3 5.48 73.9 4.6

4 11.0 7.3 50.8 5.96 41.5 3.2

5 21.0 15.5 129.7 5.42 45.4 8.6

6 34.2 31.2 484.9 4.11 63.9 10.4

7 34.8 33.0 777.5 3.82 90.0 5.8

8 34.2 33.0 941.4 3.74 106.7 6.0

9 44.8 39.8 1220.8 3.98 122.1 5.4

10 42.8 40.8 1097.3 4.04 108.7 1.8

11 39.5 39.0 995.3 4.10 104.6 5.0

12 34.8 34.8 833.6 4.23 101.3 1.4

13 25.2 25.0 492.3 4.27 84.1 1.2

14 18.2 16.5 280.7 4.24 72.1 0.0

15 10.5 10.5 164.6 4.12 64.6 0.0

16 10.2 10.2 167.4 4.17 68.5 0.0









Table 2. Average numbers and weights of pods of various size categories from 4 Florunner peanut plants
marked on a weekly basis during 1978 and harvested at 16 weeks of age.

Week Peg Total Pods Present
Entered P3 at Harvest P4 at Harvest P5 at Harvest at Harvest Kernel Weight
Ground Number Weight, g Number Weight, g Number Weight, g Number Weight, g at Harvest, g

6-7 0.0 --- 0.6 0.1 2.4 3.0 3.0 3.0 2.5

7-8 0.2 0.0 1.2 0.7 5.0 6.7 6.4 7.4 5.5

8-9 0.8 0.0 1.2 0.4 6.0 6.5 8.0 6.9 5.4

9-10 2.0 0.1 3.6 1.7 11.4 11.7 17.0 13.4 9.6

10-11 1.8 0.1 3.8 1.8 6.8 5.5 12.4 7.4 4.3

11-12 1.2 0.0 2.0 0.7 2.0 1.6 5.2 2.4 1.2

12-13 0.0 --- 0.6 0.1 0.4 0.3 1.0 0.4 0.3

13-14 0.2 0.0 0.2 0.0 0.0 --- 0.4 0.1 0.0

14-15 0.0 --- 0.0 --- 0.0 --- 0.0 --- --15-16- 6.8 0.2 2.2 0.5 11.4 12.5 20.4 13.2 10.2


*Actually pods that were not marked.


a'







17


these were early pods close to the base of the plant with little or no peg visible above ground. Very few pods were added after week 12. Weather data for the growing season are summarized in Appendix 1.


Second Experiment

Leaf, stem, and pod growth are summarized in Tables 3, 4, and 5, respectively. Based on the number of new leaves and the ratio of stem weight to length, both leaf and stem growth seemed essentially to cease after week 14. As can be seen in Table 3, specific leaf weight and weight per leaf of new leaves changed rather abruptly twice during the season--between weeks 5 and 6 and again between weeks 10 and 11. Number of new leaves per active vegetative meristem also decreased between weeks 10 and 11 (Table 6). The number of active vegetative growing points was derived from a study of the plant maps made of the 3 marked plants harvested weekly. From week 9 on, some growing points were being inactivated even as new ones were being initiated closer to the exterior of the canopy. Presumably this was due to a lack of light penetration to the interior of the canopy.

No consistent pattern of leaf loss could be determined from the available data (Table 7). Even though an attempt was made to minimize size differences between plants of the same age by hand planting the seeds and by selecting only plants which met certain criteria at week 3, large differences still existed in plant size each week, and thus larger samples would have been necessary to separate leaf loss from sample variability. It appears in Table 7 that some stress between weeks 7 and 8 caused the plants to lose about 20 leaves and then more leaves were not lost until week 13.









Table 3. Average leaf growth for Florunner peanut plants during the 1978 growing season, as indicated by
weekly plant samples.

Week Growth of Leaves During the Preceeding Week Total
From No. New Wt. New Specific Leaf Weight per Number of Total Leaf Weight per
Planting LAI* Leaves Leaves, g Wt., mg/cm2 Leaf, mg Leaves Weight, g Leaf, mg

3 0.04 10.8 0.2 4.66 20.4 10.8 0.2 20.4
4 0.08 7.4 0.2 4.92 28.4 16.8 0.4 25.6
5 0.16 11.8 0.6 5.05 50.0 28.0 0.9 31.1
6 0.73 24.0 2.0 3.66 81.2 60.8 3.3 54.6
7 1.49 36.5 3.6 4.00 99.3 80.7 6.5 80.3
8 2.05 41.8 3.4 3.68 80.4 109.7 8.7 79.3
9 3.62 50.8 5.0 3.73 98.1 164.1 15.0 91.7
10 3.49 30.7 2.6 3.78 84.1 162.7 13.8 85.1
11 4.97 35.5 2.6 3.27 72.1 223.1 17.6 79.0
12 6.55 50.0 3.5 3.09 69.2 277.8 25.0 89.9
13 5.68 20.7 1.5 3.39 71.1 280.3 21.7 77.4
14 6.23 20.7 1.6 4.02 76.4 261.5 24.8 94.7
15 6.43 3.0 0.2 3.17 50.0 276.5 24.7 89.3
16 6.09 3.3 0.2 3.51 60.0 229.7 22.8 99.3
17** 6.75 0.3 --- --- --- 306.0 26.7 87.2
18 6.24 0.0 --- --- --- 286.0 25.4 88.7
20 5.15 0.0 --- --- 226.7 24.3 107.2


.'Leaf area index.
*Only 3 plants harvested this week.






19


Table 4. Average stem growth for Florunner peanut plants during the 1978 growing season, as indicated by weekly plant samples.

Mainstem Total Stem Stem Ratio of Stem Weight
Week Length, cm Length, cm Weight, g to Length, mg/cm

3 5.0 13.5 0.1 9.4

4 5.9 21.5 0.2 8.0

5 7.1 35.1 0.4 9.9

6 9.9 101.2 1.5 13.7

7 12.0 199.5 2.9 14.4

8 18.1 403.8 7.0 16.1

9 23.9 609.2 13.2 18.7

10 29.1 787.4 14.9 18.4

11 35.7 1051.3 22.7 21.1

12 38.9 1267.4 27.4 19.6

13 44.6 1403.4 31.0 23.1

14 43.1 1245.0 30.1 24.9

15 49.2 1483.8 33.6 22.2

16 46.4 1218.6 28.6 23.2

17* 38.8 1408.0 28.7 20.4

18 52.3 1471.7 35.0 22.5

20 40.1 1081.4 26.7 24.8


*Only 3 plants harvested this week.






20


Table 5. Average numbers and weights of pods present on the Florunner
peanut plants harvested each week during the 1978 growing
season.

No. No. No. No. P4 No. P5 Kernel
Week PI P2 P3 P4 Wt., g PS Wt., g Wt., g

7 2.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

8 3.3 6.3 1.6 0.0 0.0 0.0 0.0 0.0

9 12.8 13.9 11.1 2.3 0.6 0.8 0.3 0.4

10 18.6 13.2 16.4 8.8 1.9 1.0 0.4 0.4

11 20.3 27.9 34.4 10.4 1.9 18.9 9.3 5.6

12 17.8 44.0 46.7 17.2 2.3 23.0 14.1 9.7

13 16.0 24.3 47.6 20.1 4.6 31.2 24.9 18.3

14 15.9 23.5 30.7 21.9 6.6 30.3 27.4 20.9

15 7.6 20.4 34.4 17.5 5.4 43.0 40.3 31.3

16 6.4 19.3 17.5 14.5 5.9 42.3 48.0 37.3

17* 16.3 22.3 43.7 30.3 11.0 58.3 61.5 49.1

18 9.6 17.5 26.3 22.4 6.5 57.1 63.7 51.4

20 7.7 14.3 14.3 17.6 6.0 55.4 63.6 49.8


*Only 3 plants harvested this week.






21


Table 6. Number of new leaves per. branch during the 1978 growing season,
as indicated by weekly plant samples.

Estimated Number of Active Estimated Number of New Leaves/ Week Veg. Growing Points/Plant Active Veg. Growing Point

3 --- ---


4

5

6

7


8

9


10

11

12

13


7.8


16.4 26.8 30.1

34.6 28.0 31.3 39. 1 17.8


14 20.7


1.6 1.5

1.5

1.4 1.4 1.5 1.6 1.1 1.3 1.2 1.0






22


Table 7. Estimation of leaf loss by Florunner peanut plants during the 1978 season, as indicated by weekly plant samples.

Week No. of New Sum of Actual Mean No. of Estimated
from Leaves Grown Leaves Added Leaves Present per No. of Leaves
Planting During Week Each Week Plant 2 SE Lost to date*

3 --- 10.8 10.8 + 2.2 --4 7.4 18.2 16.8 + 2.7 1.4

5 11.8 30.0 28.0 + 6.2 2.0

6 24.0 54.0 60.8 + 12.5 6.8

7 36.5 90.5 80.7 + 17.2 9.8

8 41.8 132.3 109.7 + 28.0 22.6

9 50.8 183.0 164.1 + 36.5 18.9

10 30.7 213.7 162.7 + 40.2 51.0

11 35.5 249.2 223.1 + 66.2 26.1

12 50.0 299.2 277.8 + 48.4 21.5

13 20.7 319.9 280.3 + 64.6 39.6

14 20.7 340.6 261.5 + 63.8 79.1

15 3.0 343.6 276.5 + 49.0 67.1

16 0.0 343.6 229.7 + 33.8 113.9

17 0.0 343.6 306.0 + 45.6 37.6

18 0.0 343.6 286.0 + 72.4 57.6

20 0.0 343.6 226.7 + 38.1 116.9


*Column 3 Column 4






23


Leaves continued to add weight for a time after they were considered fully expanded in this study. The specific leaf weight of the new leaves each week (Experiment 2) is compared in Table 8 with that of leaves marked during the same week but not harvested until week 16 (Experiment 1).

Pegs were first present on plants harvested at week 7 (Table 5). Pods first started to swell at week 8 and there were fully expanded pods (P4's and P5's) present by week 9. The number and weight of pods in the largest size category (P5's) continued to increase until week 17. The number of aerial pegs (P1's) decreased after week 14.

The branching pattern of Florunner turned out to be more variable than the literature indicated for Virginia peanuts (Gregory et al. 1951, Wynne 1975). According to Gregory et al. (1951), the branching pattern should be vegetative in the first node, mostly vegetative in the second node, then have alternating pairs of reproductive and vegetative nodes. In a study of the first 2 nodes on the 2 cotyledonary laterals and the first 4 branches off the mainstem on 20 plants mapped when leaf and stem growth had essentially stopped, only 72.5% of these branches were vegetative in the first node, and 29.2% in the second node. For the most part, however, the cotyledonary laterals and first 4 branches off the mainstem had more vegetative nodes than expected. There were frequently 3 or 4 vegetative nodes in a row, and sometimes as many as 6. A common pattern was 1 vegetative node, I reproductive node, then

3 or 4 vegetative nodes, then alternating pairs of reproductive and vegetative. Later branches for the most part exhibited the expected branching pattern. This variation had the effect of making most early







24


Table 8. Comparison of specific leaf weights for leaves initiated at
the same time but harvested within a week or at week 16.

Specific Leaf Weight, mg/cm2
Interval of Leaves Marked at End
Leaf Initiation, Leaves Harvested at of Week but Harvested
Weeks End of Week at Week 16

0-3 4.66 5.48

3-4 4.92 5.96

4-5 5.05 5.42

5-6 3.66 4.11

6-7 4.00 3.82

7-8 3.68 3.74

8-9 3.73 3.98

9-10 3.78 4.04

10-11 3.27 4.10

11-12 3.09 4.23

12-13 3.39 4.27

13-14 4.02 4.24

14-15 3.17 4.12






25


nodes vegetative, and this perhaps contributes to the high-yielding capability of Florunner.

Although there was a large amount of variation between plants of the same age in stem length and weight, the ratio of stem weight to length was closely correlated to plant age; in fact, there was a much higher correlation between this ratio and plant age than between it and plant size, when total length of all stems was used as the measure of plant size (Table 9). Internode length and weight also depended more on plant age than on plant size (Table 9). Table 10 is a summary of week versus internode length and internode weight. Both length and weight per internode remained constant for the first 5 weeks after planting, then began to increase. Weight increased steadily until week 16, but average length was somewhat more variable from week to week.

Figure 1 is a graph of the measured canopy light interception versus LAI. The fitted equation has an R2 value of 0.98.

The results of these experiments as they relate to the development of the plant growth model will be discussed in greater detail in Chapter IV.







26


Table 9. Results of linear correlations of stem size to plant age and
plant size for Florunner peanuts.

Dependent Variable Independent Variable(s) R2

Ratio of stem weight to length Week of the season 0.78

Ratio of stem weight to length Total stem length 0.40

Ratio of stem weight to length Week of the season, 0.78
total stem length

Internode weight* Week of the season 0.80

Internode length-* Week of the season 0.67

Internode weight* Number of leaves 0.46
(internodes)


*Internode weight was estimated by dividing total stem weight by the number of leaves on the plant.

**Internode length was estimated by dividing total stem length by the number of leaves on the plant.






27


Table 10. Average size of stem internodes during the 1978 season, as
indicated by weekly plant samples.

Week Internode Length, cm* Internode Weight, mg**

3 1.25 12.3

4 1.27 10.0

5 1.21 12.7

6 1.58 22.1

7 2.31 33.4

8 3.49 57.5

9 3.94 77.0

10 4.43 85.1

11 4.62 97.4

12 5.15 101.1

13 4.96 112.9

14 4.64 114.9

15 5.36 119.3

16 5.46 125.8

17 4.58 93.3

18 5.12 114.8

20 4.70 116.7


*Average internode length for each plant was estimated by dividing the total stem length by the number of leaves (internodes) on the plant.

*,Average internode weight for each plant was estimated by dividing the total stem weight by the number of leaves (internodes) on the plant.








100


90


80


70 00
CL
0D60



50


40
C2
Y = 11.767 + 27.167 X 2.192 X 30
a

20


10

0 f
0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0
Leaf Area Index Figure 1. Relationship between leaf area index and percent light interception for Florunner peanuts planted
on 24 May 1978.















CHAPTER III
THE EFFECTS OF DEFOLIATION ON PEANUT PLANT GROWTH



Introduction


There have been several studies on the effect of various degrees of defoliation upon final yield in peanuts. There is little in the literature about the physiological response of peanut plants to leaf removal.

Greene and Gorbet (1973) defoliated Florunner peanuts with a mowing machine, approximating 10-15, 20, 33, and 50% defoliation by changing wheel settings. They found that 33% defoliation at several growth stages decreased yields. Since their method of defoliation also removed petioles, stems, and pegs and cut across major trunks of the vascular system of the plant, their results are not applicable in determining the effect of foliage-feeding insects upon the plant.

Enyi (1975), working in Africa, performed defoliation experiments on the Dodoma edible variety of peanuts. In this experiment, flowering began 4 weeks after sowing, pegging at 8 weeks, and podding at 11. He removed either 50% (2 of the 4 leaflets on each leaf) or 100% of the foliage at weekly intervals (plants were defoliated only once). Plants were harvested at the end of the season and dry weights for stems, pods, and seeds determined. Complete defoliation significantly reduced kernel weight and pod number, the greatest reduction occurring when leaves were removed 12 weeks after sowing. Complete defoliation also reduced weight of pods, dry weight of stems, and individual kernel size. Half


29






30


defoliation at 8 and 12 weeks significantly reduced the weight of 1000 kernels, while half defoliation at any time between 4 and 14 weeks (the extent of the experiment) significantly reduced pod number per plant and dry weight of stems. In fact, in correlating pod number (N) to stem dry weight (S) he found that a variation in S accounted for about 80% of the variation in N between treatments (R=0.896). A similar correlation existed between pod dry weight and stem dry weight (R=0.913). Defoliation always significantly increased shelling percentage. Enyihypothesized that defoliation reduced pod number by depressing growth of stems and consequently reducing the number of flowering nodes, the number of pegs formed, and hence the number of pods per plant.

Nickle (1977), working in Gainesville, Florida, defoliated the Florunner variety of peanut from 25 to 100% by removing from I to 4 leaflets from each leaf. He defoliated plants at 3, 6 (beginning of flowering), 9 (pegging), 12 (beginning of pod filling), and 15 weeks of age. Some plots were defoliated 50% 2 or more times. For example, 50% of the leaves were removed at 3 weeks and 50% of the new foliage was removed 3 weeks later. He obtained dry weights for the leaves removed at each treatment period, and dry weight and quality of nuts per treatment plot at harvest. For all single defoliation levels he found greatest yield reduction at 9 weeks, followed by 12 weeks. A single defoliation at 3 or 6 weeks resulted in a delay of flower production by as much as 2 weeks. Defoliation at 9-12 weeks inhibited floral production or, if severe, caused flower drop and cessation of flower production. It also resulted in a delay or cessation of the pegging






31


process. Yields from single defoliations of 50% or more at 9, 12, and 15 weeks had a higher percentage of split and damaged nuts than the controls, but the percentage of sound, whole nuts from multiple defoliation treatments was significantly higher than that from the control.

A comparison of leaf biomass removed in single defoliations with that removed in multiple defoliations indicates that defoliated plants probably put on greater new leaf mass between treatments. For example, 35.6 g/plant total leaf weight was removed from plants defoliated at

9 and 12 weeks, whereas only 30.1 g was removed from plants defoliated at 12 weeks.

Williams et al. (1976) studied the influence of defoliation and pod removal on growth and dry matter distribution of the Makulu Red variety of peanuts in Rhodesia. Normal growth of this variety in Rhodesia, as reported by Williams et al. (1975), proceeds as follows: flowering begins 55 days after planting, continuing until 100 days. Stems increase in weight until 18 weeks after sowing, as does the plant as a whole. Leaf area reaches a maximum at 16 weeks, kernels start to form at 12 weeks, and pegs reach a maximum number at 20 weeks, as do the pods. Kernel number is set at 22 weeks. In their defoliation and depodding experiments, Williams et al. (1976) defoliated 0, 50, or 75% and depodded either 0 or 50% at 3 stages of growth (17, 19, and 21 weeks). They defoliated by removing leaflets from each leaf and depodded by severing at ground level all pegs on one half of the plant. The plants were harvested and measured 2 weeks after the treatment. Defoliation at all periods greatly increased leaf growth rate over the control. At 17 and 19 weeks, defoliation of 75% increased leaf growth rate more than 50% defoliation did. The reverse occurred at 21 weeks.







32


Stem growth rate was correspondingly slowed by defoliation. In plants that were both depodded and defoliated, stem growth rate was not as severely decreased as in plants with only defoliation. The results also indicated that few if any pods were initiated when the plants were depodded at 21 weeks--in fact the plants appeared to abort pods at this stage if they were defoliated but not depodded. Williams et al. (1976) hypothesized that the increased leaf growth with defoliation and corresponding decrease in stem growth could be accounted for by increased mass per unit area of leaf, due possibly to greater accumulation of assimilated material in leaves no more completely illuminated.

Differences in branching patterns between varieties of peanuts

may affect the response to leaf removal. Smith and Jackson (1974) found that defoliation of Florunner decreased final yeild less than did an equal percentage of defoliation of Starr peanuts (a Spanish variety). This difference might be explained by the determinate branching system of Spanish peanuts (Gregory et al. 1951) as opposed to an indeterminate branching pattern in Florunner and the consequent ability of Florunner to put on more new leaves when defoliated. Fehr et al. (1977) found that defoliated determinate cultivars of soybeans had significantly greater yield reduction than did indeterminate cultivars similarly defoliated. They also found that the indeterminate cultivars put on more new leaves following defoliation than did the determinate ones. In addition, the number of new leaves produced after defoliation significantly exceeded the number for the untreated check at some growth stages. Rudd et al. (1980), in modelling soybean growth, found that their model overestimated the damage done to final yield by 1 mechanical






33


defoliation just prior to pod appearance unless they allowed the plant to "compensate" for leaf loss by using photosynthate destined for temporary storage in the stems to produce extra leaves instead.

The experiments discussed in this chapter were designed to determine the effects of mechanical defoliation on certain aspects of plant growth. Severe uniform defoliation (50% or more) appears to have the effect of increasing growth of leaves (Nickle 1977, Williams et al. 1976) and decreasing stem growth (Enyi 1975, Williams et al. 1976), at least until fairly late in the season. This could happen if leaves left on the plant gain in weight (as suggested by Williams and his coworkers) and stems stop or slow down growth (as suggested by Enyi). Alternatively, the plants might grow leaves at an increased rate at current growing points and/or initiate new growing points at previously inactive vegetative nodes. New growing points might be initiated only in places where light penetrates due to the defoliation. This increased growth of leaves when photosynthetic supply has been decreased could be accomplished by depletion of storage reserves (probably in the stems) or by a change in the partitioning of available photosynthate to the various plant organs.

It appeared likely that defoliation at different times in the season would have different effects on plant growth. Early in the season with the plants growing at a maximum rate, defoliation was expected to have the effect of slowing down vegetative growth of the plant and thus delaying the time of full ground cover, and podsetting during pegging and podsetting. It was hypothesized that defoliation would decrease the number of fruit set, due to a decrease in available photosynthate and a shift in photosynthate partitioning to new leaves at a






34


time when vegetative growth would normally be decreasing. After the pod load is set, defoliation was expected to result in the plant filling fewer pods.

There are indications that defoliating caterpillars may attack younger leaves or terminal buds (vegetative growing points) preferentially (Huffman 1974, Arthur et al. 1959, Morgan 1979). I anticipated that the type of defoliation would make at least some difference in the plant response. Most prior defoliation experiments on peanuts have dealt with uniform defoliation (removing a certain number of leaflets from each leaf). It appeared likely that this would change light interception and plant growth in a different manner than an equal amount of non-uniform defoliation (removing an outer layer of leaves, for example).

Four defoliation experiments were performed to investigate these questions about plant response to defoliation. The purpose of the early season defoliations was to determine the effect of several levels of defoliation and the effect of removal of vegetative meristems alone or in combination with partial or complete defoliation. The second and third defoliations investigated the effect on subsequent plant growth of severe defoliation (50%) by 2 different methods (removing 2 leaflets from each leaf, or removing 100% of the leaves from the outer 50% of the canopy) at the pegging and podsetting stages of growth. The final experiment dealt with the effect of 50% uniform and total defoliation late in the season. The 50% defoliation treatment was for comparison with the earlier experiments; the 100% defoliation was intended to reveal the presence or absence of storage reserves in the stems, as







35


vegetative growth should have ceased prior to defoliation time. All the experiments were designed to determine growth of new leaves, growth of pods, and growth of stems, as indicated by changes in length, weight, and length to weight ratio, following defoliation.



Methods and Materials


First Defoliation

The first defoliation plot was planted on 22 May with a row and intrarow spacing identical to that described in Chapter 11. Other aspects of crop management were identical also. The plants were defoliated on 23 June, 41 weeks after planting.

The experiment consisted of 7 treatments applied to 5 blocks. Plants were blocked by row. Seven treatment plots were selected in each row with at least 2 plants between treatments. Each treatment plot consisted of 5 plants, but only the 3 interior plants were included in the sample.

The 7 treatments were:

1. Check

2. 25% uniform defoliation 3. 50% uniform defoliation

4. 100% uniform defoliation

5. 50% uniform defoliation + 100% of the vegetative growing

points

6. 100% defoliation + 100% of the vegetative growing points

7. 0% defoliation + 100% of the vegetative growing points.







36


Uniform defoliation refers to removing the same number of leaflets from each 4-leaflet leaf on the plant. Only leaves which had another leaf starting to open above them on the branch were defoliated or marked. Growing points were removed by snapping off newly forming leaves as far down within the stem as possible.

Plants in treatments I and 7 were marked with surgical wound clips and acrylic paint as discussed in Chapter II. A surgical wound clip was placed around the petiole of each fully expanded leaf, and all stems were marked with a spot of paint. The stems of treatments 2 6 plants were also marked with paint and the defoliation process itself adequately marked the leaves. Removed leaflets from each treatment were measured and then dried and weighed.

The plants were harvested 7 weeks after planting--2i weeks following treatment. One plant from each treatment plot was selected for mapping. This plant was the "average" plant in that it was intermediate in size between the other 2 sample plants contained in the plot. The positions of new and old leaves and branches were noted and each stem was given a code number and measured. Each harvested plant was broken down into the following parts: old leaves, new leaves, petioles, stems, vegetative growing points, pegs and reproductive branches, and pods. Leaves were counted and a subsample was measured for leaf area. The numbers of new and old stems and number of pegs were obtained. All stems were measured. The various plant parts were then dried and weighed.

Canopy light interception was measured for each treatment plot in 2 rows just before the plants were harvested, in the manner discussed in Chapter 11.







37


Second Defoliation

Plants for this experiment were in the same field as those in Chapter II, and all crop management practices were identical. The plants were defoliated 9 weeks after planting, and half were harvested

2 weeks after treatment; the other half 6 weeks post treatment. The experiment consisted of 6 treatments applied to 4 blocks. Plants were again blocked by row, there being a buffer row between treatment rows and at least 2 plants between treatment plots in a row. Again there were 5 plants per treatment plot, but only the interior 3 were included in the sample. Plants were dug up by shovel to save as many pods and roots as possible.

The 6 treatments were:

1. Check--harvested at 11 weeks

2. 50% uniform defoliation--harvested at 11 weeks

3. Removal of all leaves from the outer 50% of the canopy-harvested at 11 weeks

4. Check--harvested at 15 weeks

5. 50% uniform defoliation--harvested at 15 weeks

6. Removal of all the leaves from the outer 50% of the canopy-harvested at 15 weeks.

For treatments 3 and 6 the outer 50% of the canopy was determined on a volume basis. Several measurements were made to determine the average height and width of the canopy and the cross-sectional area was calculated using the formula for an ellipse. The proper height and width were then calculated to obtain a canopy with only 1 the original crosssectional area. Wires were bent across the canopy delineating this






38


area and all leaves falling outside of the wires were removed; those inside were left alone.

Leaves and stems were marked in a manner similar to that of previous experiments except only the last 2 leaves on each branch were marked. Pegs that had entered the ground also were marked with wound clips. In this experiment any newly emerging leaf also was removed if the petiole was extended sufficiently for a wound clip to be placed around it.

When the plants were harvested, plant parts were separated, weighed, counted, and measured as in the other experiments and 1 plant from each treatment plot was mapped. This time pods were divided into marked versus unmarked and then into size categories P3-P5. After drying and weighing, nuts in the P5 category (fully expanded shell which did not shrink upon drying) were shelled and weighed.

Canopy light interception measurements were made in the treatment plots the day after defoliation and just before the 2-week harvest. Third Defoliation

The third defoliation was performed when the plants were 12 weeks old. This experiment was identical to the second defoliation except that pegs were not marked and plants were harvested 2 and 4 weeks after treatment.


Fourth Defoliation

The last series of defoliations took place when the plants were 16 weeks of age. As it was late in the season, the treatments were 50% uniform and 100% defoliation. All plants were harvested 2 weeks later.






39


As there was little vegetative growth at this late stage, no plant maps were made.

Table 11 is a summary of the times and types of defoliations made during the course of the season.



Results


First Defoliation

The results are summarized in Table 12. All plant parts appeared to be affected equally by defoliation, i.e., if stem weight was reduced, so were stem length and leaf number and weight (Table 13). The fact that the average values for the 50% defoliation treatment were generally higher than those for the 25% defoliation treatment (Table 12) is perhaps due to the higher initial LAI for the 50% defoliation plots. Mean LAI for the 25% defoliation plots was 0.10 just prior to defoliation, whereas that for the 50% defoliation plots was 0.16. The unevenness of planting depth caused some problems in that plants emerged at different times and this had an effect upon plant size throughout the season. Blocking by row partially overcame this problem as is indicated by significant differences (a= .05) between rows in average cotyledonary lateral length, total stem length, root weight, and the number of old leaves. There was variation in plant emergence and size within rows too and this resulted in the plants in some treatment plots being larger on average than those in other treatment plots prior to defoliation.

Plant response to growing tip removal was quite uniform. Removing the apical meristem destroyed apical dominance. If either of the first










Summary of the defoliation experiments performed during the 1978 growing season on Florunner peanut plants.


Week from Treatment Week
Planting Number Treatment Type Harvested


Check
25% uniform 50% uniform 100%
50% uniform + veg. growing pts. 100% uniform + veg. growing pts. 0% + vegetative growing points


2
3
4
5
6
7


2
3
4
5
6


the canopy the canopy the canopy the canopy


7
7
7
7
7
7
7


11 11 11 15
15 15 14 14 14 16
16 16

18 18 18


Table 11.


Check
50% uniform Outer 50% of Check
50% uniform Outer 50% of Check
50% uniform Outer 50% of Check
50% uniform Outer 50% of

Check
50% uniform 100%


12


1
2
3
4
5
6

1
2
3


16


40








Table 12. The effect of various levels of defoliation at 41 weeks upon plant size at 7 weeks.


Treatment


Check

25% uniform 50% uniform 100%

0% + vegetative growing points 50% + vegetative growing points 100% + vegetative growing points


Mainstem Length, cm*z

17.5 (0.7)

14.8 (0.7) 16.7 (0.8) 13.9 (0.9)

12.4 (0.9) 12.2 (0.5) 10.8 (0.5)


;'Number in parentheses is standard error of the mean.


Stem
Length, cm*

298.5 (32.2) 216.8 (28.3) 250.0 (31.6) 192.2 (26.8) 206.3 (24.6)


143.8 (16.2)


94.6 (10.8)


Avg. Cot. Lat.
Length, cm*

23.1 (1.1) 18.7 (1.5) 21.5 (1.2) 16.5 (1.6) 14.8 (1.1)


13.6 (1.1) 10.8 (0.7)


Stem
Weight, g*

4.0 (0.6) 2.8 (0.5) 3.5 (0.5) 2.3 (0.4) 2.5 (0.4)


1.6 (0.2)


0.9 (0.1)


Ratio of Stem Wt. to Length, mg/cm.

12.9 (0.4) 12.5 (0.4) 13.4 (0.5) 11.6 (0.4) 11.3 (0.7) 10.8 (0.5) 9.6 (0.5)








Table 12. Continued


Treatment

Check

25% uniform 50% uniform 100%

0 + vegetative growing points 50% + vegetative growing points 100% + vegetative growing points


-'Number in parentheses is standard error of the mean.


X3rNj


Number of Veg. Growing Points*

31.8 (3.2) 28.5 (2.0) 30.9 (3.0) 28.7 (3.4) 25.7 (1.4) 24.5 (2.6)


18.7 (2.1)


Number of New Leaves* 72.2 (6.4) 57.4 (4.7) 61.4 (6.0) 54.1 (5.6) 52.6 (5.2)


45.5 (4.2) 32.6 (3.0)


Weight of New Leaves, g*

5.2 (0.7) 3.9 (0.5) 5.0 (0.6) 3.4 (0.5) 3.0 (0.4) 2.1 (0.3) 1.0 (0.1)


Root
Weight, g*

0.6 (0.1) 0.6 (0.1) 0.6 (0.1) 0.5 (0.1) 0.5 (0.1) 0.4 (0.1)


0.3 (0.0)


Total Plant
Weight, g*

14.4 (1.9) 10.8 (1.5) 13.0 (1.6) 8.3 (1.2) 9.2 (1.3) 6.4 (0.9)


3.4 (0.4)









Estimated leaf and stem gains in defoliation at 4' weeks.


the 2' weeks following


Estimated Estimated
Original Gain in Gain in ALeaf
Treatment Stem Wt., g: Stem Wt., g Leaf Wt., g ALeaf+lStem

Check 3.0 3.7 5.2 0.58

253 uniform 2.8 2.6 3.9 0.60

50% uniform 3.6 3.1 5.0 0.62

100% 3.6 1.9 3.4 0.64

0% + tips 3.5 2.1 3.0 0.58

50% + tips 3.2 1.3 2.1 0.62

100% + tips 4.8 0.4 1.0 0.70


originall stem weight was estimated by dividing the original leaf weight by 0.70 to find stem weight + leaf weight. Subtracting leaf weight from this gave original stem weight. (The ratio of leaf weight to leaf + stem weight averaged 0.70 for non-defoliated plants until week 8.)


Table 13.


43







44


2 nodes below the destroyed tip was vegetative, a new branch would grow out of the end of the former branch, with only a scarred stub over to one side to mark the end of the original branch and the beginning of the new. The branching pattern of this new stem was that expected for a vegetative branch, there being no leaf at the first node. If the 2 nodes directly below the destroyed tip were both reproductive then a flower would emerge at both nodes, but there would be no vegetative growth.

Table 14 is a summary of the light interception results for this experiment. The weather was unsuitable for taking measurements for several days prior to harvest and it was therefore not possible to make as many readings as necessary to obtain an accurate picture of LAI versus percent light interception.


Second Defoliation

Tables 15 and 16 are summaries of the results for plants harvested at 11 and 15 weeks, respectively. In the removal of all the leaves from the outer 50 of the canopy in treatments 3 and 6, more than 50% of the leaf matter by weight was removed. Two weeks after treatment, plants defoliated 50% uniformly had as many new leaves as non-defoliated plants, and the ratio of stem weight to length was significantly reduced. Plants from which the exterior 50% of the canopy was removed had significantly more leaves than non-defoliated plants. They also had significantly more new vegetative growing points and a significantly reduced stem weight to length ratio. Weight of new leaves was also significantly higher. A study of the plant maps indicated that the new






45


Table 14. Summary of light interception by plants 7 weeks of age which
had been defoliated at 41 weeks.


Treatment Type

Check



25% uniform 50% uniform 100%



50% uniform + tips 100% + growing tips 0% + growing tips


Row

B
E

B
E

B
E

B
E

B
E


B
E

B
E


LAI

1.89 1.80 1.53
0.62 1.06 1.78 0.77 0.68 0.66
0.42 0.27 0.35

0.82 1.39


Percent Light Intercepted

46.9
50.8

48.4 29.6 33.3 36.9 32.0
36.6

44.7 22.7

20.2 20.6 26.9
24.7










Table 15. The effect of 50%
week 11.


defoliation at week 9 upon plant size at


Plant Variable

Number of new leaves Weight of new leaves, g Ratio of stem weight to length, mg/cm Number of vegetative growing points Number of new vegetative growing points Number of Pl* Number of P5 P5 weight, g Kernel weight, g*


Check

52.9b

4. 4b 21 .3a


49.6b 14.4b


19.3b 19.8a 9. 9a 6. Oa


Treatment


Treatment
50. Uniform Outer

56.7b

5.3ab

18.lb


58.1lab


I I. 1 b


27.lab 13.9ab

7.Oa

4.2ab


Note: Means in a row followed by the same letter are not significantly different according to a t-Test (a = 0.05 except for plant variables marked with an z, in which case a = 0.10).


50% of Canopy

86.8a 7.Oa 18.7b


72.2a 25.9a


35.la 7.7b

4.Ob 2.6b






47


Table 16. The effect of 50% defoliation at week 9 upon plant size at
week 15.


Plant Variable

Number of new leaves'. Ratio of stem weight to length, mg/cm Mainstem length, cm Average cotyledonary lateral length, cm Number of new vegetative growing points Number of P1 Number of P3* Weight of P3, g* Number of P5* Weight of PS, g Kernel weight, g


Treatment
Check 50' Uniform Outer 50 of Canopy

105.2b 107.3b 138.8a

22.8a 20.9b 18.2c


51 .9a

71 .3a 12.4b 4.6b 38.6a 1. Oa 47. la 44.8a 35.Oa


44.6b 61 .6b 16. 8ab 8.2ab

27. 2ab 0.6ab 36. lab 34.3ab 27.2ab


44.3b

60.7b 21 .8a 12.2a

20.0b 0.5b 31.6b

28.3b 22.6b


Note: Means in a row followed by the same letter are not significantly
different according to a t-Test (a = 0.05 except for plant variables marked with an :';, in which case c = 0.10).











vegetative growing points arose toward the exterior of the canopy, frequently in the axils of defoliated leaves.

The results for plants harvested at week 15 were similar to those for plants harvested at Il weeks. By this time, mainstem length and average cotyledonary lateral length were significantly lower for defoliated plants.

There was a significant effect (Ot=.05) of block (row) on mainstem length, number of P2 (pegs in ground), number of P5 (fully expanded pods which did not shrink when dried), P5 weight, kernel weight, and weight of all pods (P3-P5) at 11 weeks. This was probably due again to the difference in emergence times of different rows. By week 15, row had a significant effect only on root weight and the ratio of stem weight to length.

Light interception by plants harvested at week 11 is summarized in Table 17. Average light interception immediately following defoliation by plants defoliated uniformly was 83% of that of the check plants; average light interception by plants defoliated non-uniformly was 69% of that of the check plants at the same time. There was no difference in light interception 2 weeks after treatment between defoliated and non-defoliated plants.


Third Defoliation

The response of plants defoliated at week 12 was similar to that of plants defoliated at week 9 in that the plants from which leaves were removed had an equal or greater growth of leaves, as indicated by number and weight of new leaves per plant, and a reduction in stem weight to length ratio as compared to the check plants (Tables 18 and 19). More than half of the leaf material by weight was removed in









Table 17. Summary of 1


Treatment

Check


Row

F

G

H


ight interception by plants defoliated at 9 weeks of age.

Estimated LAI 5 Light Interception
Immediately Immediately
After Defoliation After Defoliation

2.8 82.2

4.7 59.1


LAI at I 1 weeks

4.0

6.3 3.3


Y Light Interception at 11 weeks

90.1 97.2

77.1


50% uniform







Outer 50% of canopy


F

G

H


F

G

H


2.3

1.5




1.0 1.7


56.6

56.8




56.0

42.2


4.1

2.9




2.7 3.9 2.9


91.0

96.0 71.5


94.4 96.1 79.9






50


Table 18. The effect of 50% defoliation at week 12 upon plant size at
14 weeks.

Treatment
Plant Variable Check 50' Uniform Outer 50 of Canopy

Number of new leaves 10.lb 15.lb 32.Oa

Weight of new leaves, g 0.9b 1.3b 2.la

Ratio of stem weight to 25.3a 22.5b 20.5c
length, mg/cm

Number of vegetative 45.5b 41.7b 60.6a
growing points

Number of new vegetative 6.2b 4.2b 10.8a
growing points

Number of P3 26.9b 29.9b 49.3a


Note: Means in a row followed by the same letter are not significantly different according to a t-Test (a = 0.05).






51


Table 19. The effect of 50%
week 16.


defoliation at week 12 upon plant size at


Plant Variable

Number of new leaves Weight of new leaves, g Ratio of stem weight to length, mg/cm Average cotyledonary lateral length, cm Number of new vegetative growing points Number of PI Number of P5 Weight of P5, g Kernel weight, g Total plant weight, g-'z


Treatment


Check

22.3b 1 .6b 23.4a


67.9a


5.2b


5.7b

44.4a

51 .8a 40.5a

125.6a


Note: Means in a row followed by the same letter are not significantly different according to a t-Test (a = 0.05 except for plant variables marked with an c, in which case a = 0.10).


Treatment
50% Uniform Outer

26.5b

1.9b

21.8ab 65.9ab


3.8b


13.Oa

39.9ab 46.9ab 36.7 ab 110.5ab


50/ of Canopy

55.0a

3.7a 20.6b


60.6b 8.9a 13.9a 28.2b 33.8b 27.2b 90.5b







52


Treatment 6, but in Treatments 2 and 3 essentially identical amounts of leaf material were removed. Of the plants harvested at 14 weeks, plants which were defoliated non-uniformly had an increase in number of growing points and in number of small pods (P3). By 16 weeks, defoliated plants had significantly more aerial pegs, but the number and weight of mature pods (P5) were lower, although the difference between check and 50% uniform defoliation plants was not significant.

For the plants harvested at 14 weeks, block (row) had a significant effect only on weight of P4's (fully expanded pods which shrivel). For those removed at 16 weeks, there was a significant difference between rows for number of new growing points and leaf weight prior to treatment.

Light interception data are summarized in Table 20. Average light interception immediately following defoliation by plants defoliated uniformly was 86% of that by the check plants; average light interception by plants defoliated non-uniformly was 81% of that of the check plants at the same time. Again, there was no appreciable difference in light interception between check and defoliated plots 2 weeks post treatment, although LAI was much less in the defoliated plots than in the check plots.


Fourth Defoliation

There was a significant difference between treatments for only 3 of the variables considered in this late season experiment. As can be seen in Table 21, the only discernible differences were in number and weight of new leaves and ratio of stem weight to length. The order of response was the same as in the previous experiments--the more serious








Table 20. Summary of light interception by plants defoliated at week 12.

% Light % Light
LAI Immediately Interception LAI at Interception
Treatment Row After Defoliation After Defoliation 14 Weeks at 14 Weeks

Check J 4.8 90.7 5.1 91.6
K 3.1 85.2 3.3 75.2
L 7.3 92.9 7.5 92.6
M 7.1 92.6 7.3 90.6

50% uniform J 2.3 69.9 2.5 84.9
K 2.2 81.1 2.5 94.3
L 3.7 87.7 3.9 85.9
M 2.5 72.9 3.0 88.8

Outer 50% of J 2.8 62.2 3.4 91.1
canopy K 2.5 86.2 2.8 90.9

L 2.6 68.2 3.3 79.5
M 2.5 76.3 3.1 85.4






54


Table 21.


The effect of defoliation at 16 weeks upon plant size at 18 weeks.


Number of New Weight of Ratio of Stem Weight
Treatment Leaves New Leaves,g to Length, mg/cm

Check 6.lb O.lb 22.5a

50% uniform 13.9b 0.3ab 21.2ab

100% 33.Oa 0.6a 19.2b


Note: Means in a column followed by the same letter are not significantly different according to a t-Test (at = 0.05).







55



the level of defoliation, the more new leaves were grown and the more the stem weight to length ratio was reduced. Plants defoliated 50% intercepted 80% as much light immediately following defoliation as did the check plants (Table 22). Plants from which all leaves had been removed still intercepted 46% as much light as the check plants. Plants did not put on sufficient new leaf matter following defoliation for canopy light interception to recover.









Table 22. Summary of light interception by plants defoliated at 16 weeks.


Light Intercep- % Light
LAI Immediately tion Immediately LAI at Interception
Treatment Row After Defoliation After Defoliation 18 Weeks at 18 Weeks

Check R 6.7 94.0 6.7 93.4
S 4.3 90.9 4.3 93.5
T 8.1 95.5 8.1 -U 6.0 96.0 6.0 98.5

50% Uniform R 3.3 75.4 3.4 89.1
S 3.0 73.1 3.0 90.2
T 3.7 84.4 3.8 -U 2.6 68.6 2.6 80.0

100% R 0.0 40.8 0.1 33.1
S 0.0 51.8 0.3 61.1
T 0.0 41.5 -- -U 0.0 40.1 0.03 49.2


ON















CHAPTER IV
THE SIMULATION MODEL



Introduction


The experiments discussed in Chapters I and Ill yielded much of the information necessary for modification of Duncan's (1974) PENUTZ model. From the experiments dealing with the normal growth of nondefoliated plants, I was able to establish the branching pattern of an average plant, the rate of initiation of leaves and vegetative and reproductive branches at different times in the season, the average size of individual leaves and internodes at different times in the season, and the relationship between LAI and percent light interception by the canopy.

My overall conclusions from the defoliation experiments were that the Florunner cultivar of peanuts does accumulate stem storage reserves, and that defoliated plants draw upon these reserves and continue to grow leaves of the same size as non-defoliated plants at active vegetative nodes. If the level of defoliation is severe enough to expose to the light inactive vegetative nodes that would normally be shaded, some of these nodes are activated. Severe defoliation during the pegging and podsetting stages of growth results in fewer pods of the largest size category. When the defoliation occurs early in the pod filling period, expansion of small pods (P3's) is curtailed. When defoliation occurs late in the season after vegetative growth has almost ceased,


57






58


stem reserves are apparently used for seed growth, as very little new leaf material is added.

The morphogenetic approach to crop modeling is based on the assumption that individual plant organs have maximum potential growth rates or sink strengths which may vary with temperature and may not be achieved on any given day if substrate is limiting. In order to construct a morphogenetic model, it is necessary to estimate the maximum potential growth rates for the various plant organs, such as leaves and pods, and to provide rules for the division or partitioning of the available carbohydrate and nitrogen on any day when there are insufficient amounts to fill all demands.

From the results of the experiments dealing with normal plant

growth, an estimate of maximum average leaf size could be obtained. Dividing this by the number of days required for growth of the leaf provided an estimate of the maximum potential growth rate for leaves. PENUTZ contained estimates of the maximum growth rates for seeds and shells. An estimate of maximum growth rate for individual stem internodes was somewhat more difficult to obtain. In order to do so, I assumed that the ratio of leaf weight to stem weight of 2.15, which held for the first 7 weeks of plant growth, was equal to the ratio of maximum growth rate for an individual leaf to that for an individual stem internode. Estimates were therefore available for maximum growth rates of individual leaves, shells, seeds, and stem internodes.

Many small roots are lost when plants are harvested, and root

nodules require carbohydrate for nitrogen fixation. This makes calculation of root demands difficult. A decision was made to exclude roots from the daily balancing of potential growth versus available substrate






59


in the model being developed. The handling of root growth and nitrogen fixation in the model will be discussed later in this chapter.

Establishing rules for the division of carbohydrate and nitrogen each day was less clearcut than determining potential growth rates for the various plant organs. Although it was clear from the field data (Table.2) that the pod load was set by the end of week 12, it was not clear by what mechanism the size of the pod load was determined. Nor was it obvious by what means the gradual inactivation of growing points could be programmed, especially in view of the increased leaf growth following defoliation. My overall approach to balancing supply and demand was to assume that leaf demands were given higher priority than most other demands when LAI, as an indicator of canopy light interception, was low; but that this priority was moderated by increasing pod demands later in the season. Several different sets of priority rules were tried before one which produced realistic simulations for both normal and defoliated plants was found.

Insofar as possible, parameter values used in PENUTZ were used initially in PMINUS, the morphogenetic model derived from PENUTZ. The results of the experiments dealing with normal plant growth were used for estimation of new parameters involved in computation of leaf and stem growth. When there was no experimental information available for estimation of a particular parameter value, such as the length of time a peg could remain in the ground before becoming incapable of swelling into a pod, a value was chosen which gave a good visual fit between simulated and experimental plant growth. Changes were necessary in some model parameters taken from PENUTZ in order for simulated plant growth to match that observed in the field. New estimates for these parameters






60


were obtained from the results of the experiments dealing with normal plant growth. After the model simulated normal plant growth satisfactorily, the defoliation experiments were simulated. These simulations produced some unrealistic results, such as too much pod growth and too little stem growth following defoliation, and thus further changes were made in the model so that it satisfactorily simulated not only the growth of the non-defoliated plants, but that of all defoliated plants as well. The changes generally pertained to parameters or processes for which there were no data available for direct calculation of values.



Description of the Model


PMINUS is programmed in GASP IV, a combined continuous/discrete

FORTRAN based simulation language (Pritsker 1974). The short main program reads the climate cards for the growing season (which contain daily values for radiation, maximum and minimum temperatures, and rainfall and irrigation) and then calls the executive subroutine GASP, which handles the calling of the other subroutines. A brief description of the userwritten subroutines included in PMINUS is given in Table 23. PHZDAZ and RUTNOD are the same as their counterparts in PENUTZ except for minor changes. The subroutines PTOTAL, PLTGRO, DIVIDE, and FRUFIL are adapted from subroutines of the same name in PENUTZ but differ in some major respects. INTLC, EVNTS, SCOND, STATE and OTPUT were added to convert PENUTZ from straight FORTRAN to GASP IV. BEGIN, LEAVES, GRPTS, STEMS, and PNTLAI are new subroutines which calculate the growth of the vegetative portions of the plant. INSECT and ATTAC simulate the effect






61


Table 23. A brief description of the user-written subroutines included
in PMINUS.

Subroutine Description

INTLC Initializes some model variables

EVNTS Computes changes in system status which occur whenever an
event occurs

SCOND Checks state variables at the end of each time step to
determine if any of them crossed a specified threshold,
thereby triggering a state event

BEGIN Called at time of plant emergence to initialize plant
variables

STATE Each day calls the subroutines which calculate environmental changes and plant growth

WATERX Calculates water stress factor--at present a dummy subroutine

PTOTAL Calculates carbohydrate and nitrogen available to each
plant each day

PLTGRO Calculates sink demand for various plant organs, initiates
new leaves, branches, and pegs and calls the subroutines
which divide the available carbohydrate and nitrogen LEAVES Calculates daily growth of leaves

DIVIDE Calculates amount of carbohydrate and nitrogen available
for pod growth and calls FRUFIL FRUFIL Calculates daily growth of pods

GRPTS Initiates new vegetative growing points

STEMS Calculates daily growth of stems

PNTLAI Calculates percent light interception for use in photosynthetic equations

PHZDAZ Calculates number of physiological days in each calendar
day

RUTNOD Calculates daily growth of roots and nitrogen manufacture

ATTAC Describes time and type of insect invasion or mechanical
defoliation and calls INSECT

INSECT Calculates effect of defoliation each day on leaf area,
leaf weight, and canopy light interception and initiates
special growing points if damage is severe enough






62



Table 23. Continued OTPUT Prints results of the simulation

BLK DATA Provides initial values for many model variables






63


of an insect invasion and defoliation on the plant. Flow charts of the major subroutines are contained in Appendix 2. A complete listing of PMINUS is given in Appendix 3, a description of model parameters in Appendix 4, and a glossary of input parameters and variable names in Appendix 5.

PMINUS computes growth on a square meter basis. The growth of an average plant is calculated each day and this is multiplied by the number of plants/m2 to determine growth/m2. In actuality, program storage and model structure are such that up to 7 plant types may be simulated. Growth/m2 is then calculated by multiplying the amount of growth of plants of a given type (1-7) by the number of plants of that type/m2, and then summing over all 7 plant types. This structure was originally devised so that seedling emergence could be spread over several days, giving plants of different sizes. It could also be used to simulate the effect of uneven defoliation over a field.

Subroutine STATE is called by GASP on a daily basis and it in turn calls the other subroutines to calculate plant growth each day. Most plant growth processes are dependent upon physiological time, which is calculated each day by PHZDAZ. The daily minimum and maximum temperatures are used to compute the number of physiological days in a given calendar day. One physiological day equals 750F. If the average of the maximum and minimum temperature is greater than 750F then there is more than 1 physiological day in that calendar day. There are an average of 1.2 physiological days per calendar day during the summertime in this part of Florida.






64


Initiation of New Leaves and Branches

Plants emerge 11 physiological days after planting with a fully expanded leaf on the mainstem, 3 partially developed leaves on the mainstem, and 2 partially developed leaves on each cotyledonary lateral. In the field experiments, plant emergence began on the fifth day following planting, and plants continued to emerge for more than 2 weeks, although the plants used in the experiments were those that emerged during the first 9 days of the emergence period. The earliest leaves expanded more quickly than later leaves. It was easier to simulate this by having the plants emerge later than they did in actuality with some leaves already forming, than by having the earliest leaves grow more rapidly than later ones and draw upon seed reserves.

The program keeps track of the number of branches, both vegetative and reproductive, on each plant, and the date of initiation of the last

2 leaves on each vegetative stem. When the first leaf on a branch is half-grown, a new leaf is initiated on that stem. When a leaf completes development then a new leaf is initiated, and a new branch, either vegetative or reproductive, may be initiated 2 nodes back on the stem. Whether the new branch is vegetative or reproductive depends on the fixed branching pattern of the plant. Suppose, for example, that the stem in question is the first lateral off the mainstem and that it has 1 node with no attached leaf, 4 fully developed leaves at nodes 2-5, a leaf completing development at node 6, and a halfgrown leaf at node 7 on day K. There should already be a vegetative branch at node 1, a reproductive branch at node 2, and another vegetative branch at node 3. On day K the leaf at node 6 completes development, and a branch can be initiated at node 4. This branch will be







65


vegetative according to the plant's branching pattern. A new leaf is also set to start development the next day at node 8.

Each leaf grows for a set number of physiological days. This

number depends on the stage of development of the plant. Up until 82 physiological days (about 68 calendar days) after planting, a leaf takes 10.8 physiological days (about 9 calendar days) to develop. This rate of growth yields about 1.4 leaves/branch/week, in keeping with the field results for weeks 4-10 presented in Table 6. Late in the season (after day 82), leaves take 14.4 physiological days to complete development. This yields approximately 1.1 leaves/branch/week, again in accordance with the results in Table 6. The underlying cause for this apparent decrease in growth rate could not be determined, and it may have been due to non-linearity in the leaf growth versus temperature response curve.

In the model a maximum of 333 vegetative growing points/m2 are

allowed. In the field there may be many more than this present, but in my plot this was the maximum number of active ones present at any one time (35/plant, on the average). It was simpler to stop the initiation of growing points when the maximum/m2 was reached, rather than to program the simultaneous initiation and shutdown of branches.

The length of time between nodes on a reproductive branch is set

at 6.0 physiological days in the model. A maximum of 4 nodes is allowed per reproductive branch. In the field there are occasionally more than

4 nodes per branch. The model does not keep track of flowers and pegs separately; rather, once a reproductive node has been activated, a pod may start to swell at that node 27.0 physiological days later.






66


Calculation of the Day's Net Photosynthate

The photosynthetic equations used in PMINUS are essentially the

same as those used in PENUTZ. First, gross photosynthate is calculated by the following equation:

PTS = PLTLAI CLIMAT(NOW,l) PSLOPE ; PTSFAC (I)

where PLTLAI is a measure of canopy light interception, CLIMAT(NOW,l) is total radiation in langleys, PSLOPE is the slope of the photosynthetic equation (0.0836g/langley), and PTSFAC is a factor which changes with cultivar, as some cultivars have higher photosynthetic rates than others. Photosynthate is then reduced as follows: PTS = PTS STRESF DECFCT (2)

where STRESF denotes reduction in photosynthesis due to water stress and DECFCT represents lost photosynthetic efficiency of an aging canopy. Net photosynthate/m2 is then calculated by the equation PTS = PTS PTS RESPFC BMETFC STLFRT (3)

where RESPFC is a growth respiration factor (0.30), BMETFC is the maintenance respiration coefficient (0.01), and STLFRT is the dry weight of stems, leaves, and petioles. This calculation of net photosynthate differs from Duncan's in that it is calculated on a square meter rather than per plant basis. PLTLAI is also calculated in a different manner. In PENUTZ, PLTLAI is the ground area covered by I plant. In PMINUS, PLTLAI is a measure of percent light interception and it is determined from the LAI versus percent light interception equation developed in Chapter II:

PLTLAI = (11.767 + 27.167 SS() 2.192 SS(1) SS(l))/100 (4) where SS(l) is the state variable representing ''effective'' leaf area






67


index. Generally speaking, "effective" LAI is the same as LAI, but after defoliation it may differ from real LAI. This will be explained in the description of the INSECT subroutine.

Equation (4) was derived from light interception readings made when the plants were 6 or more weeks of age and cannot be used for younger plants, as it has a Y-intercept of 0.11767; i.e., plants with zero leaf area intercept nearly 12% of the incident radiation, according to this equation. Light interception for young plants was assumed to equal LA!, or,

PLTLAI = SS(l) (5)

until an LAI of 0.16. (Equations (4) and (5) intersect at an LAI of 0.16.) In essence this assumes that in young plants all leaves are fully exposed to the light with no shading. When the LAI is above 0.16, shading causes light interception to be lower than LAI. I changed PTSFAC in equation (1) from the 1.05 used for Florunner in PENUTZ to

1.10 to correct for the fact that the maximum value for PLTLAI in equation (4) is about 0.95 rather than the 1.00 maximum for PLTLA! used in PENUTZ.

The amount of photosynthate going to any one plant is calculated by dividing the plant's leaf area by the total leaf area/m2. For the purpose of calculating leaf area index and thus light interception and photosynthesis, leaves are not counted as leaves until they are fully grown. Not until a leaf has completed development is its area computed by dividing its weight by the specific leaf weight of new leaves at that point in the season. Specific leaf weight is 4.98 until physiological day 40 (calendar day 34), 3.77 from day 41 to day 82 (calendar day 68), and 3.28 for the remainder of the season. These were the







68


average specific leaf weights for weeks 3-5, 6-10, and 11-16 (excluding week 14), respectively (Table 3). These specific leaf weights are used for defoliated as well as non-defoliated plants.


Division of Day's Net Photosynthate

The amount of carbohydrate allocated to the roots each day for

root growth and nitrogen fixation depends on time in the growing season. The roots receive 15% of the day's net photosynthate for nitrogen fixation for the first 82 physiological days, and 13% thereafter. The additional amount allocated for root growth is 28% until week 4, 15% from week 4 until week 7, and 0% thereafter. The decision to allocate 15% to roots from week 4 until week 7 for root growth rather than the lower amount indicated in Table 24 was based on balancing top growth during this time period against photosynthetic supply. Allocating at least 12% of the net carbohydrate to roots for nitrogen fixation prevents any nitrogen shortage from occurring, if 100% efficiency of conversion is assumed.

The remainder of each day's photosynthate is apportioned according to demand from leaves, stem internodes, seeds, and expanding pods. Leaf demand for carbohydrate is based on the number of developing leaves and the amount each leaf can add on a given day. Demands for the attached petiole and internode are also calculated and included in the leaf demand variable, WANTLF. Maximum new leaf size is set at 88 mg, the average weight per leaf for new leaves for weeks 6 10 (Table 3). Leaves grow for either 10.8 or 14.4 physiological days, depending on the point in the season, and thus leaves and petioles only demand carbohydrate for that length of time. Stem internodes continue to









Table 24.


Root growth during the 1978 growing season, as indicated by weekly plant samples.


Week from Root Weight, Root Growth as % of
Planting g/m2 Total PNant Growth


1.3

3.3

4.2 5.3


12.2 17.7 11.5 13.1


25.3 28.1 7.0

2.2 9.2

11.4


3


5

6


7


8

9


10






70


grow and demand carbohydrate until 32.4 physiological days (27 calendar days) after initiation.

Shell demand is calculated according to the formula

WANT = (10.0 + 0.25 ; PODWGT(J,K)) 7 DAYINC (6)

where PODWGT(J,K) is the weight of an individual pod initiated on day K on plant J and DAYINC is the number of physiological days in the given calendar day. About 85% of this demand is for carbohydrate (McGraw 1977). When the pod reaches 17% of its capacity it is considered to be fully expanded and shell growth stops and seed growth begins. If there is no shortage of carbohydrate it takes approximately 8 calendar days for the first pods to become fully expanded.

In this model, as in PENUTZ, pods that are filling seeds may grow at a maximum rate of 22 mg/physiological day. Since more energy is expended in making kernels than in making other plant parts, 35.9 mg of carbohydrate are required to produce this 22 mg of kernel dry weight. This is a result of the higher oil and protein concentration in seeds than in other plant parts (McGraw 1977). Each developing pod that is filling seeds thus demands 35.9 mg/day until it reaches 80% of its capacity. It then continues to grow at half this rate until fully grown. Schenk (1961) noted that pod growth rate declines in the later stages of seed enlargement. In both PMINUS and PENUTZ, the later in the season a pod is initiated, the smaller is its capacity.

If there is a surplus of carbohydrate after all growth demands are filled on any day, then the excess is sent to stems for storage. If there is a shortage, then allocation of the available photosynthate is determined on a priority basis. The system of priorities is based







71


partially on canopy LAI, as an indicator of light interception. Developing seeds have priority over all other plant parts, and after podset, they may draw from stem storage, if necessary, to fill their demands. This is based on my own field results and the observations of Hang An (1978) who performed plant shading experiments. There is a limit to the amount of photosynthate which seeds assimilate on any day. In PMINUS, this limit is 65% of the day's net photosynthate or, after podset, 65% of the maximum 5-day-average net photosynthate. Thus, once the pod load is set, pods may get more than 65% of the day's net photosynthate if it is less than the maximum 5-day-average. In PENUTZ, a maximum was set in a similar manner on amount of photosynthate allocated to all pods, rather than to seeds. On any day when there is insufficient carbohydrate available for seeds to satisfy total seed demand, priority is given to older pods.

If the effective LAI (ELAI) is less than 2.5, then developing leaves and their attached petioles and internodes have priority over all plant parts except seeds. If ELAI is less than 2.0, the leaves which are more than half-grown may draw from stem storage, if necessary, to meet their demands. If there is excess carbohydrate after leaf demand is met (ELAI < 2.5), then the initiation of new vegetative branches has next priority.

Early in the season (before LAI reaches 0.16 for the first time) vegetative growing points become active automatically without carbohydrate and nitrogen availability being taken into account. Once LAI reaches 0.16 for the first time, growing points are initiated only if there is excess carbohydrate left after root, seed, and leaf demands







72


are filled. The model keeps track of potential new growing points each day and each one is allowed 3 days to be activated. If there is insufficient photosynthate to activate it within this time, then it is relegated to the permanently inactive file of growing points. Once there are 333 vegetative branches, no new growing points may become active, except in the event of severe defoliation. Growing point initiation is cut off when ELAI reaches 2.5, even if there are fewer than 333 vegetative branches.

Any carbohydrate left after new branches are initiated goes to

meet stem internode and expanding pod demand. When ELAI is above 2.5, any shortage in carbohydrate supply is allocated uniformly to leaves, stems, and expanding pods. Older pods have priority over younger ones, although PENUTZ and PMINUS are set up so that older pods can be given from 0 to 100% priority.

PENUTZ was structured so that if a nitrogen shortage occurred, at any time, the rest of the day's carbohydrate supply would be allocated to the roots to fix nitrogen. This feature was retained in PMINUS, but the amount of carbohydrate allocated to roots is set sufficiently high that a nitrogen shortage never occurs.


Calculation of Increases in Total Dry Weight per Unit of Carbohydrate

The ratio of carbohydrate to nitrogen and the proportion of total weight which is either carbohydrate or nitrogen are different for different plant structures. In PENUTZ, Duncan assumed that 12% of leaf, stem, and shell dry weights was protein, 85% was carbohydrate, and 3% was other constituents. For nuts he assumed that 25% of total dry weight was protein, 50% was oil, 20% was carbohydrate, and 5% was







73


other constituents. He further assumed that it required 2.85 units of carbohydrate to produce 1 unit of oil. The same assumptions are made in PMINUS.

Once the amount of carbohydrate available for leaf, stem, or shell growth on a given day has been calculated, the total dry weight added to that portion of the plant is calculated by dWv =(dCv + dNv
__ =( v) / 0.97 (7)
dt dt dt

where dC v/dt is the change in carbohydrate for the given plant structure, dNv/dt is the change for nitrogen, and the subscript v refers to either leaf, stem, or shell. The amount of nitrogen needed is calculated by assuming a nitrogen:carbohydrate ratio of 12:85.

For nut growth, the total dry weight added on a given day is calculated by the equation

dWn = (dCn + dOn + dNn) / 0.95 (8)
dt dt dt dt

where dCn/dt is the weight of carbohydrate added to nuts, dOn/dt is the weight of oil, and dNn/dt is the weight of nitrogen in the form of protein. The ratio of carbohydrate:oil:nitrogen used is 20:50:25, and

2.85 units of carbohydrate are used to produce I unit of oil.


Inactivation of Vegetative Growing Points

The cessation of active growth by any branch is controlled by

time in the growing season and the size of the last leaf on the branch. No stem may stop growing until after day 82, when leaf development time is increased from 10.8 to 14.4 days. Maximum leaf size remains 88 mg, but daily demand/leaf is reduced at this point due to the increased







74


development time. Lack of sufficient carbohydrate to meet total demands from pods, stems, and leaves on any given day may result in leaves that are smaller than the maximum size. After day 82, the weight/leaf of all leaves completing development on day K is checked against SIZMIN (70.0 mg). If WTLEAF(J,I), the weight of a single leaf initiated on day I on plant J, is greater than SIZMIN, then no growing points are inactivated. If WTLEAF(J,I) is less than SIZMIN, growing points are shut down in the proportion of WTLEAF(J,I)/SIZMIN; i.e., the smaller the leaves that are just completing development, the greater the number of growing points which are shut down.


Cessation of Peg and Pod initiation

Reproductive nodes continue to be activated and pegs continue to grow until the time the pod load is set. This point is reached when seeds have demanded more photosynthate than is available to them for 5 days. When this occurs, flowering ceases and all pegs which have not developed to the point that they can expand as pods (i.e., they are less than 27.0 physiological days old) are removed from the system. On any day from the time the first pod starts to swell until podset, no new reproductive nodes are activated if there is no photosynthate available on that day for stem growth and pod expansion. This was based on the observation by Hang An (1978) that 75% shade (and the resulting shortage of photosynthate) reduced flowering and reduced peg formation after 7 days.

If a peg has not started swelling (i.e., its weight is still zero) after 32 physiological days as a potential pod, then it is deleted from







75


the system. A shell that is not fully expanded after 42 physiological days ceases to grow and make demands for carbohydrate.


INSECT Subroutine

INSECT is the subroutine developed to link PMINUS to an insect

development model. Each day that simulated insect damage occurs, it is called to compute changes in leaf weight and area and in canopy light interception due to defoliation. The type of defoliation must be specified. At present, INSECT can simulate the effects of 3 types of defoliation: 1) removal of the same proportion of leaf material from each leaf on the plant; 2) removal of whole leaves, starting with the youngest; and 3) removal of portions of leaves as in 1) plus removal of some or all of the active vegetative growing points on the plant. Only minor changes would be required to combine leaf removal as in 2) with

removal of growing points.

The effect of defoliation on canopy light interception and photosynthesis is handled differently in the model depending on the type of defoliation. The data collected by Jones et al. (1980 and personal communication) were used to estimate the effect of uniform defoliation on photosynthesis. The regression line
2
Y = 99.45 0.0715 DEFPER 0.00816 DEFPER (9)

with an R2 value of 0.96 relates DEFPER, percent defoliation, to Y, percent of photosynthesis of defoliated versus non-defoliated plants. (For the purposes of the regression, only readings that were made 1-3 days after defoliation or that were made after week 15, when leaf growth had essentially stopped, were used.) For example, a plant which is defoliated 50% on a given day will have, immediately after







76


defoliation, a photosynthetic rate 75.48% of its rate before defoliation, according to the equation. This value (Y) is multiplied by PLTLAI (proportion of the available light intercepted by the canopy prior to defoliation) to find the effective canopy light interception (Y'). This value

(Y') is then inserted into equation (4) to find the normal canopy LAI which photosynthesizes at the same rate as the defoliated plants now do. This becomes the "effective' LA! for the defoliated plants and is used as the baseline for any increases or decreases in LA! in the future. Going back to the example of the plants defoliated 50% on a given day, if the plants had an LAI of 2.15 and were intercepting 60% of the available light just prior to defoliation, then they would now intercept 45.28% of the available light (75.48 0.60) and have an effective LAI of 1.39. In actuality, the LAI is half of 2.15, or 1.08, but these plants are photosynthesizing at the same rate as normal, non-defoliated plants with an LAI of 1.39. In summary, effective LA! is a variable to relate percent interception of defoliated canopies to percent interception of non-defoliated canopies.

The removal of leaves from the outer portion of the canopy was

equated with removal of the youngest leaves. Since there were no data to relate light interception by plants defoliated in this manner to rate of photosynthesis, the assumption was made that the photosynthetic rate of plants defoliated in this manner is the same as the photosynthetic rate of non-defoliated plants with an LAI equal to the reduced LA!. For example, if 50% of the total leaf area is removed in this manner from a plant with an initial LAI of 3.0, then, after treatment, the plant will photosynthesize at the same rate as a normal plant with an LA! of 1.5. By removal of the outer envelope of leaves from the







77


canopy, the canopy is effectively returned to the size of a normal canopy with the lower LAI, as photosynthesis by bare stems is negligible (Jones et al. 1980).

If the level of defoliation is severe enough that percent light interception is reduced by more than 40% from its level when INSECT is first called, new vegetative growing points may be initiated, if there are any potentially active ones present. These growing points are of a special type in that they may only grow I leaf before shutting down. I assume that the normal maximum number of active growing points is 333/m2 and that only when stems are exposed to light may this number be temporarily exceeded until the canopy closes over again. The selection of 40% as the trigger point for this reaction was based on the fact that the 50% uniform defoliations (which reduced light interception by 25%) caused no increase in vegetative growing points, whereas the literature indicates (Mangold 1979, Williams et al. 1976) that 75% defoliation (50% decrease in light interception) resulted in increased leaf growth, which was probably due to an increase in the

number of growing points.

If growing points are destroyed, then the last 2 nodes on the affected branch are checked to determine if they are vegetative or reproductive. If either of them is vegetative, then a new branch is initiated to replace the one destroyed. Subroutine ATTAC

This is the subroutine which simulates insect entry into the system. It may do nothing more than call the subroutine INSECT on a given day to remove a certain portion of the leaves on that day, or it may be considerably more complicated.






78


Each of the defoliation experiments was simulated by calling

INSECT on the day the plants were defoliated, and by specifying the percent and type of defoliation. For the simulations of removal of leaves from the outer portion of the canopy, a sufficient amount of defoliation was specified to bring the simulated LAI down to the same level as that of the experimental plants after treatment.

I also simulated defoliation experiments performed by Mangold (1979) in a field adjacent to mine. His peanuts were planted I or 2 days earlier than mine but the plant spacing and crop management were identical. The defoliations simulated were as follows:

1. 75% uniform at week 8

2. 75% uniform at week 8 plus 75% defoliation of new leaves for

the next 7 days

3. 75% uniform at week 11

4. 75% uniform at week 11 and 75% defoliation of all new leaves

at week 15.

In order to demonstrate the coupling of PMINUS to an insect development model, I constructed a simplistic model of an insect cohort entering the system, growing and eating for a certain number of days, and then leaving the system. One of the power curves derived by Huffman (1974) for consumption of peanut foliage by the bollworm, Heliothis zea (Boddie) was used in calculation of leaf material eaten each day: Y = 0.011 X2.995 (10)

where X is the age of the larva in days and Y is the cumulative foliage consumption to date, in cm2. I assumed all larvae emerged on the same day; the same number attacked each plant; they grew and fed for 26 days;






79


no mortality occurred; and they all left the system after 26 days. The simulated attacks were as follows:

1. 10 larvae per plant, entering the field on day 21, and feeding randomly on the plant (the effect of this on light interception was assumed to be the same as uniform defoliation)


2. 10 larvae per plant, entering

on the youngest leaves

3. 10 larvae per plant, entering

randomly on the plant

4. 10 larvae per plant, entering

randomly

5. 10 larvae per plant, entering

randomly

6. 10 larvae per plant, entering

on the youngest leaves

7. 20 larvae per plant, entering

randomly

8. 20 larvae per plant, entering

on the youngest leaves.


the field on day 21, and feeding the field on day 35, and feeding the field on day 35, and feeding the field on day 56, and feeding the field on day 56, and feeding the field on day 35, and feeding the field on day 35, and feeding


Results and Discussion


Comparison of Model Predictions with Growth of Non-defoliated Plants in the Field

Figures 2 through 9 are graphs of time versus LAI, number of

leaves, leaf dry weight, stem dry weight, number of pods, pod dry weight, number of fully expanded pods (P4's and P5's), and weight of fully expanded pods, according to the weekly plant samples and according to the










9.0 8.0


7.0- simulation

6.0- mean + 2 SE for
field samples

5.0


<~ 4.0


3.0


2.0


1.0


01
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Weeks from Planting Figure 2. Simulated and experimental leaf area index for Florunner peanuts planted on 24 May 1978.
















3000 -


E
2000

a)

0 E 1000-


0


simulation


mean + 2 SE for
field samples











"1







I I I I I I I


0


I


I I I I I I I I


o 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Weeks from Planting

Figure 3. Simulated and experimental change in leaf numbers for Florunner peanuts planted on 24 May 1978.


4


4


I



















- simulation


mean + 2 SE for
field samples


0 1 2 3 __L I 7 01i 2 34 5 6 78


I I I I I I I I


9


10 iI 12 13 14 15 16 17 18 19 20


Weeks from Planting
Simulated and -experimental leaf growth for Florunner peanuts planted on 24 May 1978.


300


N-\
E


U)


0 ci)
3:


200k-


100


0


Figure 4.


_j 0 1 1 0
1 t I


I I I I I I I


-


0


i i i




















- simulat ion


mean + 2 SE for field samples


0 1 2 3 4 5 6 7 8 9 10 1


I I I I I I 1
[1 12 13 14 15 16 17


I I I
18 19 20


Weeks from Planting


Simulated and experimental stem growth for Florunner peanuts planted on 24 May 1978.


400


300t-


I~I


N\
E



Ci)

E

(I)


200


h -


I


100


I


I


0


Figure 5.


. .... .......



L




















- s imulat ion


16II


12 10


8


~1


I


I I I I I I I I I I


0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20


Weeks frorn Planting


Figure 6. Simulated and experimental changes in pod numbers for Florunner peanuts planted on 24 May 1978


mean + 2 SE for field samples









i i i i i i i riI


6


0


C\j
E
a)
OL VI)
_0




E
z


2 -


0


-


I


0


I


-







































0 1


- simulation


1000 r


mean + 2 SE for
field samples
















I I I I I i ii ii i i


71


4


Figure 7. Simulated and experimental pod growth for Florunner peanuts planted on 24 May 1978.


900


8001-


700 600 500


N
E

N,






0
a-


400k


7
4



L -


300


200


100


0


2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Weeks from Planting


I I I I


I







10


9


8


7


6


5


a
0


E
7C3 ~0 a

C: C3


LLJ


0 EQ
E
z


1~~I I I I I I I I


I I I I I I I I I


0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Weeks from Planting

Figure 8. Simulated and experimental change in number of fully expanded pods for Florunner peanuts planted
on 24 May 1978.


- simulation


mean + 2 SE for field samples


I7


K


F-


0


CO
a-'


I I I I I I I I I


0


4


I


3


2-

















- simulation


900800700600500


400 300


200


1001-


I I I I I I I


0 1 2 3 4 5 6 7


4


N'
E



0 ~0



0
-C

CP


8 9 10 it 12 13 14 15 16 17 18 19 2


Weeks from Planting


Simulated and 24 May 1978.


experimental growth of fruit filling seeds for Florunner peanuts planted on


0


-I


mean + 2 SE for field samples


0


Figure 9.


I







88


model predictions. For all variables the average plant means from the weekly sampels were converted to a square meter basis by multiplying by
2
9.5 plants/m2. Simulated leaf, stem, and pod dry weights are within the 95% confidence intervals for the experimental means at all times during the season.

Simulated and experimental leaf area indexes match until the very end of the season, when LAI of the field plants declines, but that of the model plants does not. Rather than model leaf loss, I chose to use the results of Jones et al. (1980), obtained in a plot adjoining mine, to model the decrease in gross photosynthesis late in the season. They noted a 40% drop in P1500 (gross photosynthesis at a light intensity of 1500 PE/m2) between weeks 17 and 19; a drop that was due to the combined effects of decreased LAI and decreased efficiency of aging leaves.

The fact that the model does not deal with loss of leaves due to age or stress conditions leads to another difference between simulation and field results, as shown in Figure 3. Number of leaves/m2 is overestimated by the model after week 7 since at this point in the season plants in the field started to lose leaves. The model does a fairly good job of matching field results for the growth of new leaves each week (Table 25), except between weeks 8 and 9. Simulated leaf weight and LAI match those of the sample plants because the model adds less weight to new leaves many weeks than do the sample plants (Table 25). If leaf loss were to be included in the model, it would be necessary to increase the photosynthate available for vegetative growth to account for the extra leaf weight.

There are 3 points in the season when simulated pod numbers do not correspond to those of the sample plants--at weeks 12, 16, and 17






89


Table 25. Comparison of Period of Time, Weeks from Planting

0 -3 3 -4 4 -5 5 -6 6 -7 7 -8 8 -9 9 -10*

10 -11 11 -12 12.-13 13 -14 14 -15 15 -16 16 -17


*Leaves were marked 2 days late this week, weight of leaves grown in a 5-day period.


so this is the number and


leaf growth in the field with model predictions. No. of New Leaves/mz Wt. of New Leaves,g/m2
Field Model Field Model

102.6 104.5 2.1 1.9

70.3 47.5 2.0 2.0

112.1 142.6 5.6 9.0

228.0 142.5 18.5 13.1

346.8 370.6 34.4 30.3

397.1 323.1 31.9 26.7

482.6 627.2 47.3 53.5

291.6 370.6 24.5 28.9

337.2 332.6 24.3 20.6

475.0 465.7 32.9 28.5

196.6 199.5 14.0 8.4

196.6 114.1 15.0 6.8

28.5 38.0 1.4 2.8

31.4 19.0 1.9 1.0

2.8 0.0 -- --




Full Text
SIMULATION OF PEANUT PLANT GROWTH AND THE EFFECT
OF DEFOLIATION ON GROWTH AND YIELD
By
Gail G. Wilkerson
A DISSERTATION PRESENTED TO THE GRADUATE COUNCIL OF
THE UNIVERSITY OF FLORIDA
IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE
DEGREE OF DOCTOR OF PHILOSOPHY
UNIVERSITY OF FLORIDA
1980


This dissertation was submitted to the Graduate Faculty of the
College of Agriculture and the the Graduate Council, and was accepted
as partial fulfillment of the requirements for the degree of Doctor
of Philosophy.
June 1980
coJ\ X.
i cu 1 tyr
Deany College of Agr
Dean, Graduate School


8
11.4$ of the ovules present at anthesis became seeds. Smith noted that
the ovaries of pollinated peanut flowers can remain dormant for several
weeks without losing their ability to resume active fruit development
and that flowering resumes when fruits are removed. Bolhuis (1958)
found that continuous removal of flowers (thus preventing fruit devel
opment) resulted in not only a prolonged flowering period but also a
greater than normal number of flowers per plant per day. Gupton et al.
(1988) found that the order of pegging is related to the branching pat
tern of Virginia type peanuts and that the order of peg development is
essentially the same as the order of peg placement.
Effect of Temperature on Plant Growth
Temperature has an important effect on peanut plant development.
Bolhuis and DeGroot (1959) found that a temperature of 33C was too high
for normal development and a temperature of 21C was too low. In their
study of 3 varieties they noted that tolerance to different temperatures
increased as the latitude from which the varieties originated increased.
Jacobs (1951) found that vegetative and gynophore (peg) growth reacted
differently to various temperature combinations. In a study of Flori-
giant peanut plants, Cox (1979) determined that early growth was optimum
at a weighted mean temperature of 27.5C and no growth occurred at 15.5
C. Treatments 4C above or below the optimum 30/26C temperature re
sulted in less dry weight. The optimum temperature for fruit growth
(24C) was lower than that for top growth.
Photosynthesis
In a study of 5 genotypes, including 2 cultivars of Arachis hypogaea
L. and 3 wild species of Arachis, Florunner was found to have the highest


REFERENCES CITED
Arthur, B.W., L.L. Hyche, and R.H. Mount. 1959. Control of the
red-necked peanutworm on peanuts. J. Econ. Entomol. 52: 468-70.
Bhagsari, A.S., and R.H. Brown. 1973. Photosynthesis in peanut
genotypes. Amer. Peanut Res. Ed. Assoc. J. 5: 194.
Bhagsari, A.S., and R.H. Brown. 1976. Photosynthesis in peanut
(Arachis) genotypes. Peanut Sci. 3: 1-5.
Bolhuis, G.G. 1958. Observations on the flowering and fructification
of the groundnut, Arachis hypogaea L. II. Neth. J. Agrie. Sci.
6: 245-8.
Bolhuis, G.G., and W. DeGroot. 1959. Observations on the effect of
varying temperatures on the flowering and fruit set in three
varieties of groundnut. Neth. J. Agrie. Sci. 7 317-26.
Cahaner, A., and A. Ashri. 1974. Vegetative and reproductive devel
opment of Virginia-type peanut varieties in different stand
densities. Crop Sci. 14: 412-6.
Cox, F.R. 1978. Effect of quantity of light on the early growth and
development of the peanut. Peanut Sci. 5: 2730.
Cox, F.R. 1979. Effect of temperature treatment on peanut vegeta
tive and fruit growth. Peanut Sci. 6: 14-7.
Duncan, W.G. 1974. PENUTZ, a simulation model for predicting growth,
development, and yield of a peanut plant. Amer. Peanut Res. Ed.
Assoc. Proc. 6: 72.
Duncan, W.G., D.E. McCloud, R.L. McGraw, and K.J. Boote. 1978.
Physiological aspects of peanut yield improvement. Crop Sci.
18: 1015-20.
Enyi, B.A.C. 1975. Effects of defoliation on growth and yield in
groundnut (Arachis hypogaea), cowpeas (Vigna unguiculata) soyabean
(Glycine max) and green gram (Vigna aurens). Ann. Appl. Biol. 79
55^
Fehr, W.R., C.E. Caviness, and J.J. Vorst. 1977. Response of in
determinate and determinate soybean cultivars to defoliation and
half-plant cut-off. Crop Sci. 17: 913-7.
206


DATA
1
DATA
DATA
1
DA TA
1
2
DATA
DATA
DATA
DAT A
DATA
DA TA
DATA
DA TA
DATA
DATA
1
i
DATA
DA rA
DATA
DATA
DA TA
DATA
DA TA
.DAT A
DATA
DATA
DAI A
DATA
DA TA
DAT A
DA TA
DATA
DATA
DA TA
DATA
DA TA
END
NDEX1 N TEX 2, NDCX J. NDE. X5 T S YN P T SR U T A SPj ST. DA Y I NC /
0,0,1 ,0,14*0.0,7*25.8,0.3/
UPTIME, T I ME LP / 5.4 1 0 ?. /
1ST FZM, NODE, XLE AFN. S [ l EL E. W TLP AP WT I NOD W T PL T ANEALE ,
WGMTLF WT5TEM XNLF.AP wTFiOUT 1 COilNI P DAY AGNPTS/ 2450*0,
2450*0,7*0.0,1400*0,0.200*0.0,1400*0.0.21*0.0,1407*0.0
2450*0.207*0.0/
STM 12 WTLF M2, GRPTSM ,X NOLF M.TOTM!, PITNUTM P MU I TM EtSTPDM ,
MS T PM M, DEOS M2. OUT DM2. DM MI DM DLIUIMM XL A 1 IDA Y/26 01 O. 0 .
200+0/
DAYADD/J.0/
I MERGE/7*100/
pl:nu r / *-mui r, ms t pod, ms tfm i pegs m pnm I PE. Pc T WT/56*0.0/
XM A Tl JIT / 140./
PI TLA I. i3/2*0.0/
PN/20 0* O.0/
STLPMT/0.0/
ASPGEM PMZDAY/2 0 7+0.0/
WANTLP,NUMDN, XI NODE/7*0. C, 7* 0, 1 400*0.0/
PDDW OT MMM.l. DLOOMZ. KPEGS T PEGMD POD5T POOL AD AGE MA X GMA Tr.K
KPODST,PODODS.DONUTS.POOAGE/14 00*0 .0,0.1400*0 .0.0. 1400*0.0
7*0.0, 2 SO 0*0.0, 22.0,0, 14*0.0,20 0*0.0/
ST MM IN,ST ML 05/7 0.0,7 *0.0/
XNONilD NCUUNT SUME AC/7 *0.0,200*0,1400*0.0/
WGTUMZ.PTSS/1401*0.0/
LCGUNT/2450 *0/
MOO TM2/20 0*0. 0/
NEWVEG/1400*0/
XL IMT/7+0.0/
ROMTF, SMA INF/0.6H. 0.40/
MERGE/1/
I'DRT/l.O.ft+O. 0/
PDDLM/0 .0/
XLMMAZ/0.0/
FFELA1/200*0.0/
AMTLT/20 0*0 .0/
NDE X6/0/
NDEXD/O/
STORE/200*0.0/
NTYPF/2/
CONDEP/l.O/
CONGMU/O.0/


38
area and all leaves falling outside of the wires were removed; those
inside were left alone.
Leaves and stems were marked in a manner Similar to that of pre
vious experiments except only the last 2 leaves on each branch were
marked. Pegs that had entered the ground also were marked with wound
clips. In this experiment any newly emerging leaf also was removed if
the petiole was extended sufficiently for a wound clip to be placed
around it.
When the plants were harvested, plant parts were separated, weighed,
counted, and measured as in the other experiments and 1 plant from each
treatment plot was mapped. This time pods were divided into marked
versus unmarked and then into size categories P3~P5 After drying and
weighing, nuts in the P5 category (fully expanded shell which did not
shrink upon drying) were shelled and weighed.
Canopy light interception measurements were made in the treatment
plots the day after defoliation and just before the 2-week harvest.
Third Defoliation
The third defoliation was performed when the plants were 12 weeks
old. This experiment was identical to the second defoliation except
that pegs were not marked and plants were harvested 2 and b weeks after
treatment.
Fourth Defoliation
The last series of defoliations took place when the plants were 16
weeks of age. As it was late in the season, the treatments were 50%
uniform and 100% defoliation. All plants were harvested 2 weeks later.


58
stem reserves are apparently used for seed growth, as very little new
leaf material is added.
The morphogenetic approach to crop modeling is based on the assump
tion that individual plant organs have maximum potential growth rates
or sink strengths which may vary with temperature and may not be
achieved on any given day if substrate is limiting. In order to con
struct a morphogenetic model, it is necessary to estimate the maximum
potential growth rates for the various plant organs, such as leaves and
pods, and to provide rules for the division or partitioning of the avail
able carbohydrate and nitrogen on any day when there are insufficient
amounts to fill all demands.
From the results of the experiments dealing with normal plant
growth, an estimate of maximum average leaf size could be obtained. Di
viding this by the number of days required for growth of the leaf pro
vided an estimate of the maximum potential growth rate for leaves.
PENUTZ contained estimates of the maximum growth rates for seeds and
shells. An estimate of maximum growth rate for individual stem inter
nodes was somewhat more difficult to obtain. In order to do so, I as
sumed that the ratio of leaf weight to stem weight of 2.15, which held
for the first 7 weeks of plant growth, was equal to the ratio of maximum
growth rate for an individual leaf to that for an individual stem inter-
node. Estimates were therefore available for maximum growth rates of
individual leaves, shells, seeds, and stem internodes.
Many small roots are lost when plants are harvested, and root
nodules require carbohydrate for nitrogen fixation. This makes calcu
lation of root demands difficult. A decision was made to exclude roots
from the daily balancing of potential growth versus available substrate


33
defoliation just prior to pod appearance unless they allowed the plant
to "compensate" for leaf loss by using photosynthate destined for
temporary storage in the stems to produce extra leaves instead.
The experiments discussed in this chapter were designed to deter
mine the effects of mechanical defoliation on certain aspects of plant
growth. Severe uniform defoliation (50% or more) appears to have the
effect of increasing growth of leaves (Nickle 1977, Williams et al.
1976) and decreasing stem growth (Enyi 1975, Williams et al. 1976), at
least until fairly late in the season. This could happen if leaves
left on the plant gain in weight (as suggested by Williams and his co
workers) and stems stop or slow down growth (as suggested by Enyi).
Alternatively, the plants might grow leaves at an increased rate at
current growing points and/or initiate new growing points at previously
inactive vegetative nodes. New growing points might be initiated only
in places where light penetrates due to the defoliation. This in
creased growth of leaves when photosynthetic supply has been decreased
could be accomplished by depletion of storage reserves (probably in the
stems) or by a change in the partitioning of available photosynthate
to the various plant organs.
It appeared likely that defoliation at different times in the
season would have different effects on plant growth. Early in the
season with the plants growing at a maximum rate, defoliation was ex
pected to have the effect of slowing down vegetative growth of the plant
and thus delaying the time of full ground cover, and podsetting during
pegging and podsetting. It was hypothesized that defoliation would de
crease the number of fruit set, due to a decrease in available photo
synthate and a shift in photosynthate partitioning to new leaves at a


CHAPTER V
SUMMARY AND CONCLUSIONS
The growth of Florunner peanuts was followed on a weekly basis
during the summer of 1978. For these plants leaf growth slowed down
after week 12 and ceased after week 17- Stem growth, as indicated
by the ratio of stem weight to length, continued until week ]k, and
there was a high correlation between stem weight to length ratio and
plant age. The pod load was set by week 12, in that very few pegs
that entered the ground after week 12 had expanded into pods by week
16.
A series of defoliation experiments was also performed. For the
plants defoliated at H weeks, all plant parts appeared to be equally
affected by defoliation; i.e., if stem weight was reduced, so were
root weight and leaf number and weight. In the later experiments, stem
growth was affected more than leaf growth. Leaf weight for the defoli
ated plants increased as much as or more than did that for the check
plants in the 2 weeks immediately following treatment. Removal of
leaves from the outer portion of the canopy resulted in a greater num
ber of new vegetative branches and in more new leaves 2 weeks following
treatment. This high level of leaf growth following defoliation was at
the expense of stem and pod growth. In all cases the ratio of stem
weight to length for defoliated plants was lower than for the control
plants. Even at week 16, when stem elongation had ceased, this ratio
was negatively affected by defoliation, indicating that the plants
115


sunnnuTfne attac
D I ME NS I ON A .CLAK ( 7 )
DIMENSION S JML A R I 7 )
COMMON / GC0 41/ AT R I 1 (25 ) J EVN T MFA MET. ( 10 .)), MEE ( 100) M STOP .NCRDR N
1 NA PD, 1-IN A(> T .fJNATH NNF IL NNO ( 1 00 ) NNT RY NPRI1T PP AKM( 50 4 ) T NO*! T TilEG
?. rTCLR.T rrM,TTf)r..)( 25), ttset
COMMON /SCO a;?/ Of) ( 1 0 0 ) DDL t 1 00 ) OT | |JL DTNOW I SEE5. LEL AG ( 50 ) NK L AC. ,
1NNEOD MNEO S, NNEQ r SS( 100) SSI ( 1 00) T OCX
COMMON /UCOM 1/NOEX 1, NDEX2.NUE X 3 NOE X 5 NO *1 P T SYN { 7 ) .PTSKUTI /) .
1 A Si") ST (7 ) DAY I NC, J, MERGE MORROW
COMMON /UCO 4 5/1 ST 2 4 ( 7.150) NO )E ( 7,35 0) XLF AF N( 7 ) 5 I Zl'LF C 7.2 0 0 ) ,
1 OH. 0 AF ( 7,2 00 ). W T I NODI 7 2 0 0 ) WTPLT ( 7, CO 0 ) ARLALE ( 7 ) ,
2 WGM TLT ( 7 ) W T STL M( 7 ) X Nl.E AF < 7 20 0 ) W T ROOT { 7 ) I CHUN 1 ( 7 150 ) ,
3 P DA Y ( ? 0 0 ) A GRP T S ( 7)
COMMON /UCO A J/PROPOR ( 7 ) DAY ADD
CO -1MOM/UCD11 2/PL T LA l PT S
COMMON / UCO-124/XNONOD ( 7 ) NC HUNT I 200). SURE AC I 7,200) VEGGRO ,
2 VuC.NI T VEGNCR ASV.FGE, V2GCNR, POP.L F, POR PI PRN. 31. W
COMMON /UCO A JO/COl IDLE,DEE I 1M,NTYPE
COMMON /UCO4O/TOTEAT
DATA AGE LAE/7* 0. 0/
DATA SUMLAR/20. 0, b*0,0/
DATA A/0.011/
DATA 0/2.093/
DATA CUNSUM/0.0/
EATEN = 0.0
DO 10 J = 1,MERGE
AGELARIJ) AGFLAP(J ) + 1.0
IE ( AGE LARI J) .GE.27.0) GO TO 10
E A TEN = CATEN *- A SUMLAR(J) AGELAI (.))**!) PKOPORIJ)
10 CONTINUE
CONGUM = EATEN TOT FAT
IE ( CONSUM .L 2 0.0 ) COM SUM = 0.0
TOTEAT = TOT EAT T CONSUM
IF I SSI 3) .11.0.0) GO TO 15
CON DEE = 1.0- (CONSUM / (SSI 1) 10 000.))
GO TO 16
15 CONTINUE
CONDEE O.J
16 CONTINUE
IE (CUMOEi'.LT. 0.0) CONDF.F = 0.0
KK = 0
)0 20 J = 1,MERGE
IE I SUMLAI! (J).EO.O.O) GO TO 20
IE { AGCL AN I J ) GE .2 7.0 ) GO TO 20
KK = KK 1
20 CONTINUE
IE (KK) 40,40,30
03
to


WATERX
LEAVES
N>
UO
MAIN
GASP
INTLC
EVNTS
ATTAC
INSECT
BEGIN
PNTLAI
FRUFIL
PNTLAI
Systems flow diagram showing the relationships between GASP IV (Pritsker 197*0 and PMINUS subroutines.
(See Table 23 for a functional description of these subroutines.)


102
There is a great deal of variability between plants in this respect.
Also, the problem is perhaps partially due to the cut and dried method
of allocating available photosynthate to oldest pods first. As pod
dry weight/m2 is usually well within the confidence limits for the
experimental means, the difference in pod number between field re
sults and model simulation is a difference mainly in number of small
pods.
O
The model estimate of weight of new leaves/m for the control
plants is higher than the field average for plants marked at 9 weeks
and harvested at 11 weeks (Table 27) and for plants marked at 12 weeks
and harvested at 14 weeks (Table 29). This is due to a difference in
the marking system for plants used as controls in the defoliation ex
periments as opposed to that for plants marked weekly for determination
of weekly growth of leaves, as used in model development. In the de-
foliation experiments a leaf was marked if the petiole was sufficiently
extended for a surgical wound clip to fit around it, whereas in the
weekly plant markings a leaf was marked if the leaf above it was
starting to unfold. When the plants were harvested, in both cases a
leaf was included in the count of new leaves only if the leaf above it
was starting to unfold. This had the effect of decreasing the number
of new leaves per branch by one in the 2 weeks following marking in the
defoliation experiments, as compared to the weekly plant samples. The
difference in leaf weight between model and field control diminished
in the following 2 or 3 weeks (Tables 28 and 30) due to the fact that
the specific leaf weight and weight/leaf of leaves initiated after the
field plants were marked increased as the leaves aged, whereas these
remained constant in the model.


13^


2
performing experiments to directly determine the effects of interactions
between the various factors, modeling and computer simulation can be
effectively used in pest management programs for studying crop manage
ment decisions on the basis of overall costs and gains. In addition,
the modeling approach can be used to evaluate various hypotheses of how
particular processes in pest management systems are controlled and func
tion. For example, there is much about plant growth that is still not
fully understood, and any model of plant growth contains many explicit
or implicit assumptions about the operation of the various processes.
Although simulation cannot be used to prove that a particular process
operates in a certain manner, it can be used to separate hypotheses that
warrant further experimentation from those that are inoperable.
The purpose of my research was to develop a computer simulation
model of peanut plant growth containing the necessary mechanisms for
coupling it to an insect development model. As this research was part
of an interdisciplinary pest management project concerned with the
effects of diseases as well as insects, a model structure of sufficient
complexity to allow for the incorporation of both was needed.
There has been at least one research effort aimed at modeling the
effect of foliage-consuming insects on peanut yield (Smith and Kostka
1975). These investigators fitted a response surface of yield to plant
defoliation and plant phenology. This method of modeling has the
disadvantage that it does not allow for interactions of the various
components of the crop system which account for the final yield, and
was therefore unsuitable for the purposes of this study. There were 2
peanut plant growth models available for consideration: that developed
by Young et al. (1979) and that developed by Duncan (197^). There were


32
Stem growth rate was correspondingly slowed by defoliation. In plants
that were both depodded and defoliated, stem growth rate was not as
severely decreased as in plants with only defoliation. The results
also indicated that few if any pods were initiated when the plants
were depodded at 21 weeks--in fact the plants appeared to abort pods
at this stage if they were defoliated but not depodded. Williams et al.
(1976) hypothesized that the increased leaf growth with defoliation and
corresponding decrease in stem growth could be accounted for by in
creased mass per unit area of leaf, due possibly to greater accumulation
of assimilated material in leaves no more completely illuminated.
Differences in branching patterns between varieties of peanuts
may affect the response to leaf removal. Smith and Jackson (197^) found
that defoliation of Florunner decreased final yeild less than did an
equal percentage of defoliation of Starr peanuts (a Spanish variety).
This difference might be explained by the determinate branching system
of Spanish peanuts (Gregory et al. 1951) as opposed to an indeterminate
branching pattern in Florunner and the consequent ability of Florunner
to put on more new leaves when defoliated. Fehr et al. (1977) found
that defoliated determinate cultivars of soybeans had significantly
greater yield reduction than did indeterminate cultivars similarly
defoliated. They also found that the indeterminate cultivars put on
more new leaves following defoliation than did the determinate ones.
In addition, the number of new leaves produced after defoliation sig
nificantly exceeded the number for the untreated check at some growth
stages. Rudd et al. (1980), in modelling soybean growth, found that
their model overestimated the damage done to final yield by 1 mechanical


69
Table 2k. Root growth during the 1978 growing season, as indicated by
weekly plant samples.
Week from
Planting
Root Weight,
g/m2
Root Growth as % of
Total Plant Growth
1.3
25.3
3.3
28.1
k.2
7.0
5.3
2.2
12.2
9.2
17.7
11. k
11.5
--
13.1

10


17
these were early pods close to the base of the plant with little or no
peg visible above ground. Very few pods were added after week 12.
Weather data for the growing season are summarized in Appendix 1.
Second Experiment
Leaf, stem, and pod growth are summarized in Tables 3, and 5,
respectively. Based on the number of new leaves and the ratio of stem
weight to length, both leaf and stem growth seemed essentially to cease
after week 14. As can be seen in Table 3, specific leaf weight and
weight per leaf of new leaves changed rather abruptly twice during the
seasonbetween weeks 5 and 6 and again between weeks 10 and 11. Num
ber of new leaves per active vegetative meristem also decreased between
weeks 10 and 11 (Table 6). The number of active vegetative growing
points was derived from a study of the plant maps made of the 3 marked
plants harvested weekly. From week 9 on, some growing points were
being inactivated even as new ones were being initiated closer to the
exterior of the canopy. Presumably this was due to a lack of light
penetration to the interior of the canopy.
No consistent pattern of leaf loss could be determined from the
available data (Table 7). Even though an attempt was made to minimize
size differences between plants of the same age by hand planting the
seeds and by selecting only plants which met certain criteria at week
3, large differences still existed in plant size each week, and thus
larger samples would have been necessary to separate leaf loss from
sample variability. It appears in Table 7 that some stress between
weeks 7 and 8 caused the plants to lose about 20 leaves and then more
leaves were not lost until week 13.


no
inactivating vegetative growing points than non-defoliated plants,
with the result that final photosynthetic rates for defoliated and non-
defol iated plants were almost equal. This was due to the mechanism used
to determine growing point inactivation in the model. Further experi
ments need to be performed to determine the true mechanism for growing
point inactivation.
The model predicted no difference in yield between plants defoli
ated only at 11 weeks and those defoliated at 11 weeks and again at 15
weeks, and this was in agreement with the field results (Table 3^).
The predicted level of yield reduction was also close to the actual
amount.
Simulation of Insect Cohort Entering the Field
The simulations of an insect cohort entering the field at 3 dif
ferent points in the growing season and at 2 different population lev
els indicate that the plants can tolerate larger infestations at some
times than at others and that the location of feeding damage does make
a difference. When 10 larvae/plant were introduced at 21 days after
planting, the plants were destroyed. When the same number was intro
duced at 35 days post planting, no damage to final pod weight was sus
tained by plants on which feeding occurred randomly, whereas final
pod weight was reduced by 6% when feeding was on the youngest leaves
(Figure 15). Although LAI was essentially the same for the 2 types of
feeding, effective LAI and consequently photosynthetic rate were higher
for the plants defoliated randomly. When 10 larvae/plant entered the
system at day 56 (feeding until day 82), the results were essentially
the same as those for entry at day 35--less than \% reduction in final


209
Schenk, R.U. 1961. Development of the peanut fruit. Georgia Agrie.
Exp. Stn. Tech. Bull. N. S. 22.
Smith, B.W. 1954. Arachis hypogaea reproductive efficiency. Amer.
J. Bot. 41: 60
Smith, J.W., Jr., and P.W. Jackson. 1974. Research on the economic
thresholds of peanut insects. Ann. Prog. Report, Texas ASM Univ.,
unpub 1ished.
Smith, J.W., Jr., and D.G. Kostka. 1975. Modeling foliage consuming
lepidoptera on peanuts. Proc. Amer. Peanut Res. Ed. Assoc. 7: 66.
Stapleton, H.N., and R.P. Meyers. 1971. Modeling subsystems for cot-
ton--the cotton plant simulation. Trans. ASAE 14: 950-3.
Trachtenberg, C.H. 1976. Net photosynthesis of peanut leaves at vary
ing light intensities and leaf ages. M.S. thesis, Univ. Fla. 36 pp.
Williams, J.H., J.H.H. Wilson, and G.C. Bate. 1975. The growth and
development of four groundnut (Arachis hypogaea L.) cultivars in
Rhodesia. Rhod. J. Agrie. Res. 13:131-44.
Williams, J.H., J.H.H. Wilson and G.C. Bate. 1976. The influence
of defoliation and pod removal on growth and dry matter distribution
in groundnuts (Arachis hypogaea L. cv. Makulu Red). Rhod. J.
Agric. Res. 14: 111-7.
Wynne, J.C. 1975. Inheritance of branching pattern in Arachis hypogaea
L. Peanut Sci. 2: 1-5.
Young, J.H., F.R. Cox, and C.K. Martin. 1979. A peanut growth and
development model. Peanut Sci. 6: 27-36.


139


10
Yield was most reduced by shading during the pod filling period (83 to
10* days after planting).
The experiments discussed in this chapter were designed to provide
basic information on normal peanut plant growth, necessary for modifi
cation of PENUTZ. In the first experiment the growth of several plants
was followed throughout the course of the season to give a unified view
of addition and loss of leaves, addition of vegetative branches, and
development of pods of a known age. The second experiment was planned
to furnish weekly estimates of LAI, the number of new 1eaves/branch,
the weight, specific leaf weight, and area of new leaves, the size of
stem internodes, and changes in weight of other plant parts. Plant
maps were made so that the time and order of initiation of vegetative
and reproductive branches could be determined. Light interception was
measured periodically throughout the season and was correlated to LAI.
The calculation of photosynthesis each day in the model could then be
based upon LAI, rather than canopy geometry, as it was in PENUTZ.
Methods and Materials
Crop Management
Florunner peanuts were hand planted 2 per hill on 2* May 1978 at
the University of Florida agronomy farm, Alachua County, Florida. The
plants were thinned to 1 per hill after emergence. Rows were 76.2 cm
apart and there were 13.8 cm between plants, giving a plant population
of 9.5 plants per m^. This is within the plant density range for maxi
mum yield (Malagamba 1976).


APPENDIX 3
COMPUTER PRINTOUT OF PMINUS


sum OUT I Nr: DIVIDE
COMMON /UCDM 1 /N DC XI* NOE X.'?* NDEX .3 NDE X 6, NOW PT SYN( 7 > P TSRUT ( 7)
1 ASP OS T (7)iOAYl NC J MliRS.: MOUND W
COMMON /UCOM2/UF TI Mu r I MELF
COMMON /UCOM 5/ 13TEM( 7, 3150) NJOE ( 7. 360) XLLAFNt 7 ) S I 2l£LF C 7.2 0 0) .
1 WTLF AF (7 ,200 ) w T INOD(7,200 ) WTPfT (7, 200 ) ,AREAL F( 7 ) ,
2 WGHTLF ( 7 > WT 5TEM( 7 ) XNLE AF < 7 ,2 0 0) WTROUT ( 7 ) I COUNT (7 3 60 ) ,
3 PC) AY ( 20 0 ), AGRPTS ( 7 )
COMMON / U C M 2 0/WANTLF(7) NUM'iK ( 7 ) X I NODE (7,200 )
COMMON /UCflM 2 1 /Pi) D'wGT ( 7, 100) 30RK ,ULflf)MZ( 7,200) KPEGST ,
1 P E < J N I ( 7,200 ), PO 1) jT ( 7 ) .60 DC AIM 7, 200 ) ACEMA X( 7, 200) SIM TEK ,
2 KPIIDOI ,GRRA TE .POPOOS ( 7 ) PONUT S ( 7 ) PODASE ( 200 )
COMMON /UCOM22/NEWVCG(7,200),ADDLE
COM MON /UCOM2 I/STMMlN(7).STMLOS<7)
COMMON / OCO M24/XNONUO( 7) ,NC 0 ) N T(200) ,SUUFAC(7 ,200 ) ,VESGKO,
2 VESNir .VEGNCR. ASVEGF. VE GCNR PORLF .PORPT PORNlJO, SL W
/UC O'M 2 6/ AS PRC 0
/UCOM26/WG r:)N2 ( 7,200) PEANUT ,RA 1 I i), PT S3
/UCOM2 7/PCT C, ;>ODC, PCTM, PODN, A SPPRO, O ILF AC
/UCDM 31/R0!) 7F ,SMAINF
/UCOM43/WN TNUT(7).WNTPOD(7) ,WNTSTO 7) ,WNT STM(7) .AVLC0N 7)
J = 1.MERGE
= 0.0
C DMMON
COMMON
COMMON
COMMON
COMMON
DO 2 CO
FR UC HO
FRUN IT
PNTCHO
PODCHO
IF
IF
1 0
1 5
1 6
IF
I F
PT
0,0
PON ITS (J) PC T C / OIL F A C
PQPODS(J) POOC
( WNT NOT ( J ) *- WNTPO.)( J ) .LE.O .001 )
( WNTNUT(J).LE. 0.0001 ) GO TO 100
(PTSYN(J) WNTNUri))) 10,20,20
( STM M IN ( J ) -WNTNUT (J ) FTSYMt J ) ) 1
YN ( J ) P T S Y ,N( J ) M ST MM I N ( J )
GO TO 200
16, 1 o
VTSTrM( J )
0.0
WTSTEM ( .1 )
S T M M I N ( J )
GO TO 0
ST MM IN( J) = STMMIN(J) -
wTSTEM(J) = WTSTEM(J) -
JTSYN( J ) = WNTNUT ( J )
IF (PTSYNIJ) .LE.O. 000 1 )
FRUCHO = AMIN1(PTSYN(J)
- GTMMIN(J) / 1000.
WNTNUT(J)
(WNTNJT(J)
GO TO 200
WNTNUT(J))
- PTSYN(J)
- PTSYN(J ) )/ 1 000
1 0 J
FRUNIT = (TRUCHO + OIL FAC /
FRUCHO = FKOCHO AVLCON(J)
IF (TRUCHO.LE.0.0001) GO TO
PC TC ) PC T N
* WNT POD(J)
20 0
+ WNTPUD(J)
FRUN IT = FRJNIT AVLCON(J)
F RUNG R = FRUNIT / FRUCHO
FR UCNR = FRUCHO / FRUNI T
ASPREQ = FRUN IT ASPPRO
IF {ASPGST(J).GT.ASPREQ) GO TO 110
FRUCHO = (ASPCGT(J) / ASPPR> + F R UC NR
* PODN
N)


gn n
Nan 13?i
coc / jocuk.c! + (r)j(ioiiw = (Dochih o i
NX-13 J:J CIlINGc ( r JN3'. d5V
JLOlNKic! ( C } 11.U Id GCNOc!
ucnnj 3DI3WM = r 01 r.)CI
/O l/NX 33 31 vivo
ziNi vws* urna/ if worn/ nonwoi
( JNIDdSV/OI KI.O1/ NONN03
(OGF/)J NON 3 I ( )
< Z)31V3dV*
(CO? > 31171 S*
( L ) 10)1 G1 c) ( l
(l ISidaOV* (00? )AV(lrJ
10UH1M ( 00? 4 L ) JV11NX ( L )W-11S1I<' ( l ) rJUHVIi
( 0 02* / ) J IctlM ( 00 2 4 L JOHN I 1M (00 Z *1 ) 3V DU M
( / )M3V11X ( OSK )ICON (0SC*)W3JLS 1/00030/ NONNO 3
flOilHOKTlIOH'r 3 N I AVG ( ) JSOcJSV
)NA ciONina iNiinoanni;
i
i
CM


40
Table 11. Summary of the defoliation experiments performed during the
1978 growing season on Florunner peanut plants.
Week from Treatment Week
Plant ing Number Treatment Type Harvested
9
12
16
1
2
3
4
5
6
7
Check
25% un i form
50% uniform
100%
50% uniform + veg. growing pts.
100% uniform + veg. growing pts.
0% + vegetative growing points
7
7
7
7
7
7
7
1 Check
2 50% uniform
3 Outer 50% of the canopy
4 Check
5 50% uniform
6 Outer 50% of the canopy
1 Check
2 50% uniform
3 Outer 50% of the canopy
4 Check
5 50% uniform
6 Outer 50% of the canopy
1 Check
2 50% uniform
3 100%
1 1
1 1
1 1
15
15
15
14
14
14
16
16
16
18
18
18


10
Figure
O
O
c\)
to
~o
o
CI
TO
O)
"O
c
o
CL
X
UJ
O)
-Q
E
D
9
8
7
6
5
4
3
2
1 k
0
0 1
simulation
mean + 2 SE for
field samples
f

L
7 89 10 11 12 13
Weeks from Planting
18 19 20
8. Simulated and experimental change in number of fully expanded pods for Florunner peanuts planted
on 2k May 1978.
oo
o>


SUO-DUTINE LEAVES
O I MENS I ON A DO OLD ( 7 ) ADD 2( 7)
DIMENSION AD OU AT (7)
COMMON /GC0M2/ ODdOOl.MLUOJi, DFUL NT NOW IS EES L FLAG ( SO ). NIL AG.
1 NNE'IO NNIiOSi NNEOT SS ( l 0 0 > 5SL 1 0 0 > T TME X
COMMON /UCDM1/NDLX1.NDEX2,NOEX3,NDLX5,NOW,PTSYN( 7).PTSRUT( 7) ,
1 A Sr* G ST ( 7) ,DA Y I NC J MERGE MOD ROW
COMMON /UCC1M2/HFT IMC.T l MELF
COMMON /UCOM5/I STEM! 7) NO Ju ( 7, 3SJ ) XL C A F N ( 7 ) S I Z EL F ( 7,2 O'JI,
1 >V T L F A F ( 7,300) WTI NIDI 7 ,200) WTPF.1 ( 7,20 0 ) ARE ALT ( 7 ) ,
2 WGIITLI- ( 7 ) wTSTEMl 7 ) XNLi'.AF ( 7, 200) WTROOTI 7) ICflUNT ( 7 350) .
3
PD AY(2 0 0) ,A G R P T S(7)
COMMON /UCOM3/PROPUR(7),GAYADO
COMMON /OCOM v/PENU T Z (7 ) FRO I T ( 7 ) (1ST POL) ( 7 ) 11 5 TFR T ( 7 ) PE G S ( 7) ,
1 R( 7) .PNRIPE C 7 ) PE Tw 1 { 7)
COMMON /OCOM 1 4 / IM ER GE ( 7 )
COMMON /l) CO M2 0/WANTL E ( 7 ) NO MOM ( 7 ) X I NU DE ( 7 200 )
COMMON /UCOM2J/GTMMINC7),STMLJS(7)
COMMON / JC 0M2 4/XNONOD ( 7 ) MCOII T { 200 ) SORT AC ( 7.200) VEGGRO ,
VFGNI T VEGNCR ASVEGF V2GCNR, POILF, PORPT .PORNOD, SLW
COMMON /UCOM 25/A SI* RED
COM ION /UCOM 4 J/,.NT NUT ( 7 ) WNTPJl) ( 7 ) WNTSTl) ( 7 ) ,*'NTSTM( 7 ) A VL CON ( 7)
COMMON /UCOM4J/WANTDGI7)
DO 450 J 1,MERGE
ADD2(J) = 0.0
IF ( WAN It F( J ) .Lfc* 0.0 ) Gf) TO 4 4 5
IF CNDEX1.GE.4) AVLLF = AVLCON(J) WAIMTLKI J)
IF (NDEX1.GE.4) GO TO 410
AVLLF = AM IN 1( WAN TLF C J ) ,PTSYN( J) )
413 CUNTINUF
IF ( AVLLF.LT. 0. 00 01 ) GU TO 44j
VEGGRO = AVLLF
430 VEGNIT = VEGGRO VEGNCR
ASPKFQ = VEGNI T ASVEGF
IF (ASPGST(J ) .GF .ASPUFQ ) GO TU 4m0
VEGNIT = AS
PGS
T ( J ) /
ASVEGF
VEGGRO = VK
GN I
T VE G
C NR
PTSYNJ) =
PT5
YN(J) -
V F.GGRO
A SPSST( J) =
0.
0
PTSRUT(J)
p r
SHUT ( J )
* PT5YN
PT SY N ( J ) =
GU TO 445
0 .0
440
PTSYN(J) =
P T S
YN( J ) -
VEGGRi 1
ASPGST(J) =
AG
PGS I ( J )
- ASPRI'.O
44 5
AGORA 1 (J) =
GO TO 447
VC
CGRO /
WANTLF ( J)
4 4 4
ADDP AT( J ) =
.) .
0
44 7
CONTINUE
O'
VX>


71
partially on canopy LAI, as an indicator of light interception. Devel
oping seeds have priority over all other plant parts, and after podset,
they may draw from stem storage, if necessary, to fill their demands.
This is based on my own field results and the observations of Hang An
(1978) who performed plant shading experiments. There is a limit to the
amount of photosynthate which seeds assimilate on any day. In PMINUS,
this limit is 65% of the day's net photosynthate or, after podset, 65%
of the maximum 5day-average net photosynthate. Thus, once the pod load
is set, pods may get more than 65% of the day's net photosynthate if it
is less than the maximum 5day-average. In PENUTZ, a maximum was set
in a similar manner on amount of photosynthate allocated to all pods,
rather than to seeds. On any day when there is insufficient carbohy
drate available for seeds to satisfy total seed demand, priority is
g i ven to older pods.
If the effective LAI (E LA I) is less than 2.5, then developing
leaves and their attached petioles and internodes have priority over
all plant parts except seeds. If ELAI is less than 2.0, the leaves
which are more than half-grown may draw from stem storage, if necessary,
to meet their demands. If there is excess carbohydrate after leaf
demand is met (ELAI < 2.5), then the initiation of new vegetative
branches has next priority.
Early in the season (before LAI reaches 0.16 for the first time)
vegetative growing points become active automatically without carbohy
drate and nitrogen availability being taken into account. Once LAI
reaches 0.16 for the first time, growing points are initiated only if
there is excess carbohydrate left after root, seed, and leaf demands


7^
development time. Lack of sufficient carbohydrate to meet total demands
from pods, stems, and leaves on any given day may result in leaves that
are smaller than the maximum size. After day 82, the weight/leaf of
all leaves completing development on day K is checked against SIZMIN
(70.0 mg). If WTLEAF(J,l), the weight of a single leaf initiated on
day I on plant J, is greater than SIZMIN, then no growing points are
inactivated. If WTLEAF(J,l) is less than SIZMIN, growing points are
shut down in the proportion of WTLEAF(J,I)/SIZMIN; i.e., the smaller
the leaves that are just completing development, the greater the number
of growing points which are shut down.
Cessation of Peg and Pod Initiation
Reproductive nodes continue to be activated and pegs continue to
grow until the time the pod load is set. This point is reached when
seeds have demanded more photosynthate than is available to them for 5
days. When this occurs, flowering ceases and all pegs which have not
developed to the point that they can expand as pods (i.e., they are
less than 27.0 physiological days old) are removed from the system. On
any day from the time the first pod starts to swell until podset, no
new reproductive nodes are activated if there is no photosynthate avail
able on that day for stem growth and pod expansion. This was based on
the observation by Hang An (1978) that 75% shade (and the resulting
shortage of photosynthate) reduced flowering and reduced peg formation
after 7 days.
If a peg has not started swelling (i.e., its weight is still zero)
after 32 physiological days as a potential pod, then it is deleted from


3 0 FORMAT ( 20 X I .7X.F4.2. 1 1X.F4.-2. 16X.F6.2)
K. = K 1
150 CONTINUE
FACTOR = (1.0 CONI1EF) 100.
CONG RO = CO N>T RO 10 0.
WRITE (6,050) FAC TOR OFF TI M ,M TYRE
250 FORMAT (1 X////20X 'PERCENT OFF C)L l AT I ON = F 1 0 1 / 20 X,
1 DAYS FROM PLANTING T1 START OF OFF OLl AT 1 ON =',F6.0/
2 .? OX, TYP E OF DEFOLIATION =',I2///I
WRITE (6,255) C.ONGRO
FORMAT ( 2 0 X 'PERCENT OF GROWING TIPS REMOVED =',F10.1///>
WR I TE (,260 )
260 F ORMAT ( 2 0 X TY IF 1 OEFNI IATKiN MEANS UNIFORM THROUGHOUT T I IF CANOPY
1 / 2 0 X, TYPE 2 ME AN 3 OUTER PORTION OF CANOPY ONLY'/
2 POX.'TYPL 3 MEANS UNIFORM DEFOLIATION OF FULLY DEVELOPED
ILF A VES AND DEVELOPING LEAVES AND GROWING POINTS')
WR IT E (6,270) TOTEAT
270 FORMAT(20X,'TOTAL FOLIAGE CONiUMED HY LARVAE. CM2 =',F12.2)
RE TURN
CNC


89
Table 25. Comparison of
leaf growth
in the field
with model
predictions.
Period of Time,
No. of New Leaves/m^
Wt. of New
Leaves,g/m^
Weeks from Planting
Field
Mode 1
Field
Mode 1
0 3
102.6
104.5
2. 1
1.9
3 4
70.3
47.5
2.0
2.0
4 5
112.1
142.6
5.6
9.0
5 6
228.0
142.5
18.5
13.1
6 7
346.8
370.6
34.4
30.3
7 8
397.1
323.1
31.9
26.7
8 9
482.6
627.2
47.3
53.5
9 -10*
291.6
370.6
24.5
28.9
10 -11
337.2
332.6
24.3
20.6
11 -12
475.0
465.7
32.9
28.5
12.-13
196.6
199.5
14.0
8.4
13 -14
196.6
114.1
15.0
6.8
14 -15
28.5
38.0
1.4
2.8
15 -16
31.4
19.0
1.9
1.0
16 -17
2.8
0.0


Leaves were marked 2 days late this week, so this is the number and
weight of leaves grown in a 5~day period.


Stem Weight, g/m
Figure 5.
Simulated and experimental stem growth for Florunner peanuts planted on 2k May 1978.


Table 33.
Comparison of
2 weeks immed
simulated and experimental
iately following defoliation
(Mangold, 1979)
at 8 weeks.
growth of Florunner
peanuts
in the
Wt. of New
Leaves, g/m^
Wt. of Stems,* g/m2
Wt. of
Pods, g/m2
Treatment
Field
Mode 1
Field
Mode 1
Field
Mode 1
Check
52.1
56.6
21*8.5
222.0
1*1*.1
1*1 .1*
75% uniform
76.3
58.1
181.7
152.5
26. 1
19.8
75% uniform
+ buds**
33.^
37.0
182.6
126.9
23.4
5.5
'"Includes weight of leaf petioles.
'""Buds removed for 7 days.


Number of Leaves/m
gure 3. Simulated and experimental change in leaf numbers for Florunner peanuts planted on 2k May 1978.


90
(Figure 6). The difference at week 17 can probably be explained by the
small sample size (3 plants). I cannot explain the difference at week
16. There were 15 plants in the sample, but for some reason they were
smaller than average, as indicated by pod number, leaf number, and leaf
and stem weight. The difference at week 12 is probably due to the way
photosynthate is distributed in the model. The stepwise increase in
pod numbers after week 11 is due to the fact that in the model available
carbohydrate is distributed to expanding pods on an oldest-first basis.
Only on a day when radiation and photosynthesis are extremely high is
there sufficient carbohydrate left over, after the demand of existing
pods is met, to initiate new pods. Distribution of photosynthate may
not be quite so cut and dried in reality. Giving 100% priority to the
oldest fruits does result in a good correspondence between field and
model of number and weight of fully expanded pods (Figures 8 and 9)
Comparison of Model Predictions with Results of the Field Defoliations
Table 26 is a summary of plant growth in the 2\ weeks following
defoliation at week k?, as indicated by model simulation and by the
field experiment. There was a large amount of variation between treat
ments in the average LAI just prior to defoliation. This variation
seemed to affect the model's ability to simulate the effect of defolia
tion on leaf growth. The closer the initial LAI of the field plots
was to the initial model LAI of 0.1**, the closer was the correspond
ence between field and simulated LAI and leaf weight at harvest. The
model underestimated the stem weight at harvest for the control plants
and for the plants which were defoliated 50% and 100%. Otherwise,
model and field stem weights matched well except for the plants from


11*6


141
Return


Parameter
Description
Source
Numerical Value(s)
PR 1 FAC
Priority factor for assignment of available
photosynthate to expanding pods (0.0 = complete
priority to older pods, 1.0 = each pod receives
equal percentage of its demands)
0.0
Duncan (197^
£ pers. comm.
PSLOPE
Slope of the photosynthetic equation, g/langley
0.0836
Duncan (197^
& pers. comm.)
PTSFAC
Factor related to photosynthetic efficiency of
different cultivars
1.10
Duncan (197^
& pers. comm.)
REPTIM
Number of physiological days between nodes on
a reproductive branch
6.0
field results
RESPFC
Growth respiration factor
0.30
Duncan (197^
& pers. comm.)
ROOTF
Proportion of photosynthate allocated to roots
which is used for root growth and maintenance
respiration
0.68
0.43
0.01
p.t. £ 3^
3** < p. t. <.60
p. t. > 60
calibration,
field results
SETMIN
Temperature below which development does not
occur, UF
50.0
Duncan (197^
6 pers. comm.)
S1ZM1N
If leaf completing development after day 82
weighs less than this amount, growing points
70.0
calibration,
field results
are inactivated, mg


61
Table 23. A brief description of the user-written subroutines included
in PMINUS.
Subroutine
Description
INTLC
Initializes some model variables
EVNTS
Computes changes in system status which occur whenever an
event occurs
SCOND
Checks state variables at the end of each time step to
determine if any of them crossed a specified threshold,
thereby triggering a state event
BEGIN
Called at time of plant emergence to initialize plant
variables
STATE
Each day calls the subroutines which calculate environ
mental changes and plant growth
WATERX
Calculates water stress factoiat present a dummy sub
rout i ne
PTOTAL
Calculates carbohydrate and nitrogen available to each
plant each day
PLTGRO
Calculates sink demand for various plant organs, initiates
new leaves, branches, and pegs and calls the subroutines
which divide the available carbohydrate and nitrogen
LEAVES
Calculates daily growth of leaves
DIVIDE
Calculates amount of carbohydrate and nitrogen available
for pod growth and calls FRUFIL
FRUFIL
Calculates daily growth of pods
GRPTS
Initiates new vegetative growing points
STEMS
Calculates daily growth of stems
PNTLAI
Calculates percent light interception for use in photosyn
thetic equations
PHZDAZ
Calculates number of physiological days in each calendar
day
RUTNOD
Calculates daily growth of roots and nitrogen manufacture
ATTAC
Describes time and type of insect invasion or mechanical
defoliation and calls INSECT
INSECT
Calculates effect of defoliation each day on leaf area,
leaf weight, and canopy light interception and initiates
special growing points if damage is severe enough


136


52
Treatment 6, but in Treatments 2 and 3 essentially identical amounts of
leaf material were removed. Of the plants harvested at 1 ** weeks, plants
which were defoliated non-uniformly had an increase in number of grow
ing points and in number of small pods (P3)- By 16 weeks, defoliated
plants had significantly more aerial pegs, but the number and weight
of mature pods (P5) were lower, although the difference between check
and 50% uniform defoliation plants was not significant.
For the plants harvested at lA weeks, block (row) had a signifi
cant effect only on weight of PVs (fully expanded pods which shrivel).
For those removed at 16 weeks, there was a significant difference be
tween rows for number of new growing points and leaf weight prior to
treatment.
Light interception data are summarized in Table 20. Average light
interception immediately following defoliation by plants defoliated
uniformly was 86% of that by the check plants; average light inter
ception by plants defoliated non-uniformly was 81% of that of the check
plants at the same time. Again, there was no appreciable difference in
light interception between check and defoliated plots 2 weeks post
treatment, although LAI was much less in the defoliated plots than in
the check plots.
Fourth Defoliation
There was a significant difference between treatments for only 3
of the variables considered in this late season experiment. As can be
seen in Table 21, the only discernible differences were in number and
weight of new leaves and ratio of stem weight to length. The order of
response was the same as in the previous experiments--the more serious


62
Table 23
OTPUT
Cont¡nued
Prints results of the simulation
BLK DATA
Provides initial values for many model variables


POD DRY WEIGHT, g/m2 LEAF AREA INDEX
97
Figure 11. The simulated and experimental effect of removal of all leaves
from the outer 50% of the canopy at 9 weeks after planting on
LAI (a) and pod dry weight (b).


208
Linker, H.M. 1980. An analysis of seasonal abundance and sampling
procedures for the major defoliating Lepidoptera in peanuts and
soybeans in north Florida. Ph.D. Dissertation, Univ. Fla. 183 pp.
Malagamba, J.P. 1978. Plant density relationships in peanuts (Arachis
hypogaea L.) Ph.D. Dissertation, Univ. Fla. IOA pp.
Mangold, J. 1979. Seasonal abundance of defoliating 1epidopterous
larvae and predaceous arthropods and simulated defoliator damage to
peanuts. Ph.D. Dissertation, Univ. Fla. 109 pp.
McCloud, D.E. 197*1. Growth analysis of high yielding peanuts. Soil
Crop Sci. Soc. Fla. Proc. 33: 24-6.
McGill, J.F. 1973. Economic importance of peanuts, pp. 3~15. _[_n_
PeanutsCulture and Uses. Amer. Peanut Res. Ed. Assoc. Oklahoma
State Univ., Stillwater, Oklahoma.
McGraw, R.L. 1977. Yield dynamics of Florunner peanuts (Arachis hypo
gaea L.) M.S. thesis, Univ. Fla. 37 pp.
McKinion, J.M., D.N. Baker, J.D. Hesketh, and J.W. Jones. 1975.
SIMC0T II: A simulation of cotton growth and yield, p.
J_n_ Computer Simulation of a Cotton Production SystemUser's
Manual. ARS-S-52, New Orleans, La.
Morgan, L.W. 1979. Economic thresholds of He 1iothis species in peanuts,
p. 71-4. J_r^ Economic Thresholds and Sampling of Hel ioth i s Species
on Cotton, Corn, and Other Host Plants. Southern Cooperative Se
ries Bull. No. 231. 159 pp.
Nickle, D.A. 1977. The peanut agroecosystem in central Florida:
Economic thresholds for defoliating noctuids (Lepidoptera, Noctu-
idae); associated parasites; hyperparasitism of the Apanteles com
plex (Hymenoptera, Braconidae). Ph.D. Dissertation, Univ. Fla.
131 pp.
Pallas, J.E., Jr., and Y.B. Samish. 1974. Photosynthetic response of
peanut. Crop Sci. 1A: 478-81.
Pritsker, A.A. 197**. The GASP IV Simulation Language. John Wiley &
Sons, New York. 451 pp.
Ritchie, J.T. 1972. Model for predicting evaporation from a row crop
with incomplete cover. Water Resources Res. 8: 12041213.
Rudd, W.G., W.G. Ruesink, L.D. Newson, D.C. Herzog, R.L. Jensen, and
N.F. Marsolan. 1980. The systems approach to research and
decision-making for soybean pest control. J_n New Technology of
Pest Control (C.B. Huffaker, Ed.). John Wiley £ Sons, Inc., New
York (in press).


1 -44
1 40
1 45
1 4 6
143
10
1 1 5
1 1 5
1 1
1 1 7
120
1 4 1
1 5 0
XNLEAF ( J.NOW ) = XNLEAF! J.N.IN) + 1.
XI NODE ( J .NOW) = XI nodi: l J .NOW ) 1.
30 TO 143
NF WRCP J, NOW) = NEWREP ( J. NOW ) 1
if c Morx.i.n.2) r,o to i 48
NUM01HJ ) = NUMORtJ) + 1
I S Til M ( J NO MOR ( J ) ) =5
NODE ( J NO O 1!1 ( J ) ) = 1
I COUNT ( J, NU MOR 1J ) ) -= NOW
ni: w'?e p j now) = newrep ( j. now ) i
riLOOMZ ( J NOW ) = 5LUOMZ ( J.IIJW) t 1.
IF (KPEGST.EO.O ) KPEGST = NOW
50 TO 1 4 3
IF (L-6) 148,146,148
l F { 1.-4 ) 145,144,143
IF tt!L/2)/2)+2 CL/2)) 143,144,143
CUNT IN'JF.
= I COUNT( J,K)
(NDEX6.LT. 1) GO TO 116
( V/TLEAF J, I ) ,LT .3 I Z.M IN )
TO 116
)
GO TO 11
K )-
I )
1
>
i
3
. 1
15,1
20
X) .
NE
. 0
)
GO
I 0
120
1 )
GO
T
O
1 1
6
I ) .
LT
1)
I z
MI
N/3 .
0) GO TO 117
I C
OUST
(
J
, K
)
LX
IF
IF
GO
IF (ICOUNT(
CONTI HUE
IF (LCOUN T(
IF (NDEXO.L
LX = I
IF ( WTLEAFC
CUNT INUf
LCOUNT(J,K)
I COUNT! J,K)
XNLEAFt J,MORROW ) =
XI MODI'< J .MORRO W) -
GO TO 1 2 D
I F (XDUOP.LE. J. 31 ) G O
XDROP = XDRDP 1.0
I S T EM ( J K ) = 6
LCCUNT(J.K) = ICDJNTCJ,K)
A50iT5(J) = AGRPTG(J) 1.
If- ( WTL EAF( J ,LX ) GE .20.0 )
aTPJTC J.I.X) = W TPl-IT { J ,LX )
XNLF.Af ( J ,L X ) = XNL HA F ( J 1. X )
WT PET ( J LX ) = wTPE T ( ) ,L X ) <
SI 7EI.FC J ,LX) = SIZE LF ( J LX )
X I NONE(J,LX) = X I NODE(J,LX)
CON TI NOE
CONTI HUE
DO 160 J = 1,MERGE
IF {POAY(I ).5u.HFrI ME) WANTJGIJ) =
= MORROW
XNLEAF(J,MORROW ) -
X I NODE( J,MORROW) l
TO 116
GO TO 120
/ XNLL AF( J,LX )
- 1.0
XNLEAF( I ,L X )
- wTLEAF! J.LX )
- 1.0
O'
W ANT !li. ( J ) X NLLAFC J I ) AODL F


37
Second Defoliation
Plants for this experiment were in the same field as those in
Chapter II, and all crop management practices were identical. The
plants were defoliated 9 weeks after planting, and half were harvested
2 weeks after treatment; the other half 6 weeks post treatment. The
experiment consisted of 6 treatments applied to 4 blocks. Plants were
again blocked by row, there being a buffer row between treatment rows
and at least 2 plants between treatment plots in a row. Again there
were 5 plants per treatment plot, but only the interior 3 were in
cluded in the sample. Plants were dug up by shovel to save as many
pods and roots as possible.
The 6 treatments were:
1. Check--harvested at 11 weeks
2. 50% uniform defoliation--harvested at 11 weeks
3. Removal of all leaves from the outer 50% of the canopy-
harvested at 11 weeks
4. Check--harvested at 15 weeks
5. 50% uniform defoliation--harvested at 15 weeks
6. Removal of all the leaves from the outer 50% of the canopy-
harvested at 15 weeks.
For treatments 3 and 6 the outer 50% of the canopy was determined on a
volume basis. Several measurements were made to determine the average
height and width of the canopy and the cross-sectional area was calcu
lated using the formula for an ellipse. The proper height and width
were then calculated to obtain a canopy with only ? the original cross-
sectional area. Wires were bent across the canopy delineating this


PLTC5R0
yes
yes


I Mi


66
Calculation of the Day's Net Photosynthate
The photosynthetic equations used in PMINUS are essentially the
same as those used in PENUTZ. First, gross photosynthate is calculated
by the following equation:
PTS = PLTLAI CL I MAT(NOW,1) PS LOPE PTSFAC (l)
where PLTLAI is a measure of canopy light interception, CLIMAT(N0W,1)
is total radiation in langleys, PSLOPE is the slope of the photosyn
thetic equation (0.0836g/1ang1ey), and PTSFAC is a factor which changes
with cultivar, as some cultivars have higher photosynthetic rates than
others. Photosynthate is then reduced as follows:
PTS = PTS STRESF DECFCT (2)
where STRESF denotes reduction in photosynthesis due to water stress
and DECFCT represents lost photosynthetic efficiency of an aging can-
opy. Net photosynthate/m is then calculated by the equation
PTS = PTS PTS RESPFC BMETFC STLFRT (3)
where RESPFC is a growth respiration factor (0.30), BMETFC is the main
tenance respiration coefficient (0.01), and STLFRT is the dry weight
of stems, leaves, and petioles. This calculation of net photosynthate
differs from Duncan's in that it is calculated on a square meter rather
than per plant basis. PLTLAI is also calculated in a different manner.
In PENUTZ, PLTLAI is the ground area covered by 1 plant. In PMINUS,
PLTLAI is a measure of percent light interception and it is determined
from the LAI versus percent light interception equation developed in
Chapter I I:
PLTLAI = (11.767 + 27.167 SS(1) 2.192 SS(1) SS(1))/100 (k)
where S S (1) is the state variable representing "effective" leaf area


77
canopy, the canopy is effectively returned to the size of a normal
canopy with the lower LAI, as photosynthesis by bare stems is negli
gible (Jones et al. 1980).
If the level of defoliation is severe enough that percent light
interception is reduced by more than 40% from its level when INSECT is
first called, new vegetative growing points may be initiated, if there
are any potentially active ones present. These growing points are of
a special type in that they may only grow 1 leaf before shutting down.
I assume that the normal maximum number of active growing points is
2
333/m and that only when stems are exposed to light may this number
be temporarily exceeded until the canopy closes over again. The selec
tion of 40% as the trigger point for this reaction was based on the
fact that the 50% uniform defoliations (which reduced light intercep
tion by 25%) caused no increase in vegetative growing points, whereas
the literature indicates (Mangold 1979, Williams et al. 1976) that
75% defoliation (50% decrease in light interception) resulted in in
creased leaf growth, which was probably due to an increase in the
number of growing points.
If growing points are destroyed, then the last 2 nodes on the
affected branch are checked to determine if they are vegetative or
reproductive. If either of them is vegetative, then a new branch is
initiated to replace the one destroyed.
Subroutine ATTAC
This is the subroutine which simulates insect entry into the sys
tem. It may do nothing more than call the subroutine INSECT on a
given day to remove a certain portion of the leaves on that day, or it
may be considerably more complicated.


FRUFIL )
Return


200
2
BL00MM(I) number of flowers per m on day I
BL00MZ(J,l) number of flowers on plant J on day I
2 2
CONSUM leaf area consumed by larvae on a given day, cm /m
DAYADD change in LAI from one day to the next
DAYINC number of physiological days in one calenday day (computed each
day)
DECFCT ratio of photosynthetic efficiency of aging canopy to maximum
efficiency
EFFLAl(l) effective leaf area index on day I
FRUCHO amount of carbohydrate used in seed and shell growth on a given
day, mg
FRUIT(J) weight of peanuts on plant J, g
2
FRUITM(l) weight of peanuts in g/m on day I
FRUNIT amount of nitrogen allocated to seeds and shells on a given
day, mg
2
GRPTSM(I) number of active vegetative growing points/m on day I
GRRATE amount added to each growing peanut in rag on a calendar day
o
HSTFRM(l) weight of fruit that are filling seeds on day I, g/m
HSTFRT(J) weight of fruit that are filling seeds on plant J on a
given day, g
HSTPDM(I) number of fruit that are filling seeds per rn on day I
HSTPOD(J) number of fruit that are filling seeds on plant J on a
given day
I COUNT(J,K) day of initiat ion of the most recent leaf on plant J,
stem K, starting from beginning of simulation
I DAY(I) day from planting on day I


ACKNOWLEDGEMENTS
I wish to express my sincere appreciation to Dr. S. L. Poe for
serving as chairman of my supervisory committee during the major portion
of my graduate program, and for providing aid and advice when needed.
I also thank Dr. S. H. Kerr for assuming the role of supervisory chairman
upon Dr. Poe's departure from the University of Florida, and for providing
editorial assistance In the preparation of this manuscript.
To Dr. J. W. Jones I extend my sincere thanks for his Invaluable
assistance in all phases of this research. I would also like to thank
Dr. K. J. Boote for his help In designing the field experiments, and
Drs. T. R. Ashley and R. C. LIttell for their advice, encouragement, and
manuscript review. My appreciation also Is extended to Dr. C. S. Barfield
for reviewing the manuscript.
I especially want to thank Dr. W. G. Duncan for so kindly allowing
me to use his PENUTZ model and for discussing It with me.
To John Mangold, Carol LIppincott, Randy Stout, and Gall Childs I
express my heartfelt thanks for their help with the field work, for with
out their assistance this research would not have been possible.
I wish to thank Mary Jermann for her help in typing the final
copy of this dissertation, and I especially want to thank Barbara Lemont
for her excellent work on the graphs contained in this dissertation.
Above all, I thank my son, Trevor, for putting up with a grouchy
mom on many occasions.


POD DRY WEIGHT, g/m2 LEAF AREA INDEX
100
Figure 12. The simulated and experimental effect of 50% uniform defolia
tion at 12 weeks of age on LAI (a) and pod dry weight (b).


138


137


5
There were some indications in the literature that defoliation
might have a more complex effect on peanut plant growth than simply
reducing leaf area, light interception, and therefore photosynthesis.
Experiments were designed to investigate the effect of different kinds
and levels of mechanical defoliation upon plant growth--in particular
upon the plant branching pattern and the partitioning of available
photosynthate into the various plant organs. These experiments are
discussed in Chapter III.
A computer simulation model was developed, using the results of the
experiments discussed in Chapters II and III, information contained in
the literature, and portions of PENUTZ. As there were many elements of
peanut plant growth for which there was no information available for
determination of model structure and parameters, various hypotheses were
tested until a model structure and parameters were developed which suc
cessfully described growth of both defoliated and non-defo1iated plants.
Defoliation experiments performed by Mangold (1979) were then simulated
to partially validate the model. A theoretical insect population was
introduced at various points in the growing season, at 2 population
levels, to demonstrate the usefulness of the model and to investigate
the importance of time and location of damage to final yield. Chapter
IV deals with this simulation model.


Figure
O
O
C\J
a)
CL
tn
"O
O
CL
o
-O
E
r>
16 r
14
12
10
8
6
4
2
0
0
simulation
mean +_ 2 SE for
field samples
J L
J I L
Simulated and experimental changes in pod numbers for Florunner peanuts planted on 24 May 1978.
oo


7
index') reaches ca. 3.0; leaf area continues to climb until week 11 or
12; and stems increase in weight until week 13. Flowering starts at
day 30 to 35, reaches a peak at 8 to 9 weeks, then declines to zero by
2
week 13. Pegs appear 1-2 weeks after the first flowers, reach a maxi
mum about 6 weeks later, then decrease in number. Pegs start to swell
about a week after they first appear; the number of pods increases until
about week 12, when it plateaus; and seeds begin to fill around day 70.
Harvest occurs between 19 and 20 weeks after planting (McGraw 1977,
McCloud 197*1, Duncan et al. 1978).
The time required to reach 100% ground cover varies with planting
density, as do the maximum LAI achieved and the number of pegs and pods
per plant (Malagamba 1975). Final yield per unit ground area is much
less affected by density, however, Cahaner and Ashri (197*0, working
with 4 Virginia-type varieties, found equal yields of mature pods for
the 3 planting densities investigated. Malagamba (1976) found a fast
increase in yield was obtained, then a slow decline phase starting at 20
2
to 22.5 plants/m .
Many flowers bloom and fail to produce pegs and many pegs fail to
develop into mature pods. Smith (1954), investigating reproductive
efficiency in a Virginia Runner variety, found 93.3% of the egg cells in
all ovules were fertilized but only 63.5% actually elongated as pegs.
Of the pegs which did elongate, only one-third reached the stage of pod
enlargement, and a third of these pods failed to reach maturity. Only
Leaf area index is the ratio of leaf area to ground area.
2
The ovary elongates as a peg and enters the ground before enlargement
of the pod commences.


CHAPTER I I
GROWTH OF NON-DEFOLIATED PEANUT PLANTS
Introduction
The Florunner cultivar of peanuts used in this study is a prostrate
member of the Virginia varietal group (Arachis hypogaea L. var. hypogaea),
according to the classification system given by Gregory et al. (1951).
As such, it is characterized by indeterminate growth and a branching sys
tem which consists of a central stem axis and variable numbers of later
al axes, including 2 prominent cotyledonary laterals. All branches
directly off the mainstem are vegetative, and all lateral branches are
vegetative in the first node and predominantly vegetative in the second
node. Nodes on vegetative branches of all orders generally occur in
alternating vegetative and reproductive pairs. Malagamba (1976) found
that the number of primary, secondary, and tertiary branches produced
by Florunner is related to planting density. In his experiments, the
2
number of primary branches/m increased linearly with increasing plant
density, while number of secondary branches reached a peak at approxi-
2
mately 30 plants/m and then declined. The number of tertiary branches
decreased with increasing plant density--there being no tertiary branches
at the higher densities.
In Florida, growth of Florunner typically proceeds in the following
manner: plants begin to emerge ca. 5 days after planting; 100% ground
cover is reached 8 to 9 weeks after planting when the LAI (leaf area
6


5 LOR OUT IMIE tNTLA 1
COMMON /GCOM2/ IX)( 10 0), DDL ( 1 00 ) DTI UL I) IN.) W I St US, LF LA G( 50) Nr' LAG,
1NNLOD .NNLOS,NNLOT, SS(1 OO) ,SSL( 100) ,T XNLX
COMMON /UCOM 1/NDUX l ,NOLX2.NDLX3,N >LX5,NOW,PT6YN( 7) .PTSUUK7) .
1 A SOOS T {7 ),DAY INC, J,MLR Gil,MORROW
COMMON /UCO.M1 2/PLTLAI PTS
COMMON /UCDM32/AMTLT(200)
IF ( NOFX 1 LT .2 ) GO TO 10
L TLA 1 = (11.767 2 7.167 V SKI) 2.1^2 4 SS(1) S3(l))/100.
GO TO 20
1 0 PL IL A I = SS( 1 )
20 AMTLT(NOW) PL TLA I 100. 4 1.05
RCTURN
END


CHAPTER
PAGE
Calculation of Increases in Total Dry Weight per
Unit of Carbohydrate 72
Inactivation of Vegetative Growing Points 73
Cessation of Peg and Pod Initiation lb
INSECT Subroutine 75
Subroutine ATTAC 77
Results and Discussion 79
Comparison of Model Predictions with Growth of Non-
defol iated Plants in the Field 79
Comparison of Model Predictions with Results of
the Field Defoliations 90
Simulation of Insect Cohort Entering the Field 110
V SUMMARY AND CONCLUSIONS 115
APPENDICES
1 WEATHER DATA FOR THE 1978 GROWING SEASON 118
2 FLOW CHARTS OF THE MAJOR SUBROUTINES IN PMINUS 123
3 COMPUTER PRINTOUT OF PMINUS 151
b DESCRIPTION OF MODEL PARAMETERS 193
5 INPUT PARAMETERS AND VARIABLES DESCRIBING DYNAMICS
OF PEANUT PLANT GROWTH. 198
REFERENCES CITED 206
BIOGRAPHICAL SKETCH 210


IF (NDEX1 GE .3 ) GO TO 45J
IF ( 3TMMIN ( J) .LE. 0.0001 ) GO TO 450
AI)!)1LD( J ) = 1.0 AO OH A T ( J )
W A N T L F ( J ) ADOOLO(J) WANTiT (J }
IF ( WANTLFI J) .LT. 0.000 1 ) GO I) 450
AG REQ WANTl.F(J) VEGNCR A ASVEGF
IF (A SPRE O. GT. A3P3ST ( J> ) GO TO 450
IF (STMMIN(J) WANTLF(J)) 500,550,550
500 VEGGRO = GIMMIN(J)
GO TO 600
55 0 VEGGRO = WAMIL Ft J )
60 0 CO NT I NO li
WT GTL. M ( J )
ST'MINt J)
A5PGGT(J)
AD02(J) =
= WTSTEM(J) VEGGOO/1000.
- STMMIM(J) VEGGR )
= A5PGSTJ) VEGGRO A VEGNCR A
VEGGRO / WAN TLF ( J) ADOIILOt J)
ASVEGF
450 CONTINUE
10 4 3 0 I
=
1 .NOW
IF (PDAYI
l
)
.LE.0.0 ) G n
TO
4 0 0
DO 460 J
1 lERGE
Ir (I MERGE
I
J ) L E 0 ) G U
TO
4 60
jCTLEAFI J,
I
)
= WTLEAF(J
. I )
A PORL.F
<' ADDEAT t J)
A DAY INC
GlZELF( J ,
I
)
= 5 IZELF ( J
. I )
+- P )I!LF
4 AODR AT (J )
A DA Y INC A
1
X nle AF( J
, I )
WT PET(J, I
)
= WTPET I J I
) A
P0I6* T *
ADDI'A T( 0)
A
XNLE AF ( J I )
w T I N 010 ( J ,
I
)
= WT IN00 ( J
. I )
A PORNO!)
* AODR AT
( J
) A DAY INC
460 CONTINUE
IF {POAYI
I )
.L T .MF r I ME )
GO
TO 4 3 0
DO 455 J
=
1 .ME ROE
wTL E AF( J .
I
J
= W TLE AF( J
. I )
A PJOLF
* A 1)02 ( J )
A
DAY I NC
5 I ZELF ( J ,
I
)
= SIZELF(J
. 1 )
A >0 OL F
AOD2J)
**
DAY INC A
1
XNLEAF( J ,
I )
W TOUT(J I
)
= :J T P E T ( J 1
) A
POUPT A
AO 02 ( J) A
XNLEAEJ.I) *
WT INOD< J,
I
)
- wriNOOIJ
1 >
A ri 1 0 NOD
A A 00 2(J
)
A D A Y I N C
455 CONTINUE
IF (POAYI
I
)
.LT .T I MELE )
G')
TO 4 30
POAY(I) =
0
. 0
NCfJUNT ( I )
=
NO w
DO 470 J
=
1 I LT: Gt
IF ( IMERG
1.7
(J).LE.O) GO
TO
40 )
5 I ZELF( J ,
I
)
= 51 ZELF ( J
. I )
/ 0. 0 7
XLEAFNJ)
-
XLEAFN(J)
A XNL E AF ( J .
l
)
XNONIHX J)
XNONU ) { J )
A X I NODE ( J ,
I
)
SURF AC ( J ,
1
)
= GIZELF( J
. I )
/ SL a
0AY ALO =
NAY A ) 0 (SURFACIJ, I) A
1
GO OR IJ ) )
/
1 J ) 0 0 .
>>(. I WT I J )
-
PET W T( .) f
W T PE
T ( J. I )
/
(1000. A
0
. f )
ARF.ALFl J )
=
Ail;al r ( j )
A GUiiF AC ( J,
I
)
wGOTLF(J)
WGMf LF< J )
A SI
ZELF ( J ,
1
) / 1000.
A DAY INC
DAYINC
o


Abstract of Dissertation Presented to the Graduate Council of
the University of Florida in Partial Fulfillment of the Requirements
for the Degree of Doctor of Philosophy
SIMULATION OF PEANUT PLANT GROWTH AND THE EFFECT
OF DEFOLIATION ON GROWTH AND YIELD
By
Gail G. Wilkerson
June 1980
Cha i rman : S H. Ke r r
Major Department: Entomology
Field experiments were performed to produce information nec
essary for modification and expansion of an existing peanut plant
growth model so that the effects of insect defoliation could be simu
lated. In order to provide a baseline for normal growth, several
plants were selected at the beginning of the season and their growth
followed until the end of the season. In addition, plants were har
vested weekly. Plants were defoliated mechanically at Ai, 9, 12, and
16 weeks after planting and were harvested 2, A, or 6 weeks following
treatment.
Early season defoliations (at Aj weeks) resulted in reductions
in weights of all plant parts; whereas later defoliations resulted in
significantly lower stem weight to length ratios, lower pod numbers
and weights, and equal or higher leaf numbers and weights. Apparently
x


105
Table 32 and Figure 14 are comparisons of model and field results
for plants defoliated at 16 weeks and harvested 2 weeks later. Experi
mental and simulated results match well except for the weight of new
leaves/m^. The model plants have already shut down all vegetative
growing points by week 16, whereas a few are still active on the field
plants at 16 weeks.
The simulations of 4 of the defoliations performed by Mangold
(1979) fit field results well in some respects and not so well in
others (Tables 33 and 34). The model underestimated the weight of new
leaves 2 weeks after treatment for the plants defoliated 75% (Table 33)*
According to the model there was little carbohydrate in stem storage at
8 weeks which could be drawn upon to grow leaves, but apparently in
the field the plants were able to draw upon reserves to grow leaves.
A more rapid increase in LAI during the first week following defolia
tion would yield a higher level of photosynthesis during the following
week which could produce the higher stem and pod weights observed in the
field at 10 weeks.
The model did a good job of fitting weight of new leaves for
plants defoliated 75% at 8 weeks with 75% of new leaves removed for 7
days subsequently (Table 33). Simulated stem and pod dry weights at
10 weeks are low. The plants may have been larger than the simulated
plants prior to defoliation, but I don't have the information necessary
to determine whether this was the case.
The model underestimated the amount of damage to final yield done
by the 75% defoliation at 8 weeks and the 75% defoliation plus new
leaves for 7 days at 8 weeks (Table 34). This is probably due to the
fact that in the simulations the defoliated plants were slower in


148


117
insect cohort entering the system support the view that time in the
season and distribution of feeding damage do influence the plants'
ability to tolerate an insect attack.
The model structure is such that the influence of other compon
ents of the crop system which affect plant growth and final yield,
such as disease and water stress, can be incorporated fairly easily.
There is already a water stress subroutine developed by Ritchie (1972)
included in PENUTZ. With minor changes it could be incorporated into
PMINUS. GASP IV, the simulation language used in construction of this
model, allows for the easy programming of events. This makes it pos
sible to simulate insect or disease attacks of some complexity with
relative ease.
More research is needed to refine the model for use in a pest
management program. At present, it can be a useful research tool in
the study of plant response to pest damage. With further comparisons
between results of field experiments and model predictions, it should
become clearer which of the various hypotheses incorporated in the
model are in need of modification.


129


(LI-COR 2005) was pulled by its cord manually along the track at a con
stant rate for 1 minute. The pyranometer was connected to a quantum-
radiometer-photometer5 (LI COR 185) and printing integrator^ (LI -COR
550). PAR measurements were made on days of clear skies between 900-
1500 hours EST and an ambient full-sun reading above the canopy was
recorded within 1-2 minutes of the canopy reading.
Results
First Experiment
One of the 5 plants which were harvested 16 weeks after planting
had been attacked by white mold and thus had to be discarded. Data ob
tained on leaf growth are summarized in Table 1; that for pod growth i
Table 2. The number of new leaves per plant per week was at a maximum
during weeks 9, 10, and 11, and fell sharply after week 12. By week
16, approximately 80% of the leaves grown during the first 3 weeks
following planting had been lost, but only 3b% of the leaves grown be
tween weeks 3 and k had been lost. Most of the leaves grown after
week 5 were still present at 16 weeks. There was a sharp drop in
specific leaf weight after week 5- No new vegetative branches were
initiated after week 13.
Pegs first entered the ground between weeks 6 and 7, as can be
seen in Table 2. Some of these earliest pods failed to mature by week
16. The greatest number of pods appeared to be added between weeks 9
and 10, although about 27% of all pods escaped marking and many of
'Lambda Instruments Corporation, Lincoln, NE.


Pod Dry Weight, g/m
CM
1000
900
800
700
600
500
400
300
200
100^
0
0 1
simulation
mean +_ 2 SE for
field samples
Simulated and experimental pod growth for Florunner peanuts planted on 2h May 1978.
oo
vn
Figure 7.


119
Day
Solar
Rad 1 at¡on,
1ang1eys
Temperature
Max.
(c)
Min.
Rainfa
1 rrigat
1 July
62A
33.9
23.3
2 July
636
3 A. A
23.3
3 July
638
33.9
25.0
A July
29A
28.3
23.9
3.3
5 July
A30
31.1
23.9
6. A
6 July
258
27.8
21.1
5.3
7 July
335
22.8
20.0
8.A
8 July
A78
31.1
22.2
1.2
9 July
609
31.1
22.2
3.8
10 July
590
33.3
23.3
11 July
kk3
33.3
23.3
12 July
270
30.6
22.2
9.9
13 July
370
27.8
22.3
. 8
1A July
A25
30.0
22.8
15 July
A80
31.1
23.3
16 July
103
31.1
23.3
37.6
17 July
392
30.6
22.8
8.A
18 July
A85
30.0
23.3
10.1
19 July
397
30.6
21.7
A.3
20 July
k] 1
28.9
22.2
.3
21 July
519
32.2
22.2
. 8
22 July
533
32.2
23.3
6.6
23 July
62A
32.2
23.3
2 A July
628
32.2
22.2
.3
25 July
583
33.9
22.8
2.0
26 July
337
30.6
21.7
1.3
27 July
A5A
31.1
22.8
77.5
28 July
220
27.8
23.3
7.1
29 July
330
29.A
22.8
9.1
30 July
All
31.1
23.9
6.6
31 July
2A9
30.6
21 1
1 August
A32
30.6
21.1
82.8
2 August
502
31.7
22.2
11.9
3 August
61A
31.7
21.1
k August
51A
31.1
22.2
5 August
A78
30.6
22.8
2.3
6 August
313
31.7
22.2
7 August
571
33.3
21.7
8 August
311
30.0
23.9
.3
9 August
633
31.7
21.7
A.6
10 August
387
30.6
22.2
. 8
11 August
280
30.0
22.8
12.2
12 August
3A2
31.7
23.3
2.8
13 August
2A9
28.9
22.8
i .0
lA August
380
30.0
22.2
15 August
A 85
33.3
22.8
50.1


5 l 2 EL F ( J I )
s i zi:l f i j
. I >
*
CUNDE!
W IL L A F ( J I )
-
WTLL AF l J
. I )
4-
CONOEF
SURFAC(J I )
=
SURF AC I J
. I )
*
CONDEF
2 0
CONT INUE
SSI 3) = SSI i)
* COND.EF
50
IF IN TYPE -
2)
140,55,
1 0 0
55
ALEFT = 0.0
no 95 J = 1 ,
mi:
RGE
AMTOCF = AREALF(J) CUN!)t£F
on no r i,now
jk = now i <-1
IF ( NCOUU r ( JK ) .EG 0 ) GO TO 90
Cl = SURF AC( J,JK)
C2 = AR CALFl J > Cl
IF (C2.LT
. AM f L)EF ) GO TO
GO
WTLEAFIJ,
JK )
= 0.0
WGMTLFIJ)
-
WGIITLF I J ) -
31ZELF I J ,
JK )
/
1000.
S I 2El.F I J.
JK )
= 0.0
AREiALFIJ)

ARuALF I J ) -
SURF AC IJ .
JK )
SURF AC I J,
GO TO 90
JK )
= 0.0
C2 = ARE ALT(
J) AMTLOEF
C3 = 1.0
c
2/SURFACIJ,
JK )
SURF AC I J ,
JK )
= SURF AC IJ
, JK) C2
wgutlrI J )
r:
WGIITLF I J ) -
51 ZE LE ( J ,
IK)
/
10 0 0.
SI2ELFIJ,
JK )
= S I Z EL F I J
. JK ) C3
IfcTLEAF( J ,
JK)
= W TLC AF(J
, JK) A C 3
iVGHTLF I J )
=
WGHTLFIJ) +
SIZELF I J ,
JK )
/
1 0 0 0.
AREALFI J )
AMTDLF
GO TO 91
90 CONTINUF
91 CONTINUO
AL£F T = ALFF r + (AREAL! (J) 1 RUPi !R( J ) ) / 1 0 0 0 0 .
9-3 CONTINUE
3SI3) = ALEF T
GO TO 140
100 CONT INUE
OO 130 J = 1.MERGE
N NUMHR(J)
no 125 I = l, NOW
IF (NCOUNI(I).NL.3) GO TO 125
IF {XNLIAF(J,I).LE.0.01) GO TO 125
UO 120 K = 1,N.M
IF ( I STEM! J,K).GE.5) GO TO 120
IF (ICOUNT!J, K).NE.I) GO TO 120
SIZELFIJ,I) = 5 I ZELF (J. I > WTLEAF(J.I)
UTP.CTIJ.IJ = WT iT ( J I ) / XNLtAFI Jil )
XNLEAFIJ.I) XNLEAFIJ.I) 1.0


POD DRY WEIGHT, g/rn2 LEAF AREA INDEX
Figure 14. The simulated and experimental effect of 50% uniform and
100% defoliation at 16 weeks after planting on LAI (a) and
pod dry weight (b).


POD DRY WEIGHT, g/m2 LEAF AREA INDEX
111
Figure 15- The simulated effect of 10 larvae/plant entering the field
on day 35 after planting and feeding for 26 days at an
increasing rate.


The soil type at the site was Arredondo fine sand. The field was
wel1 -irrigated prior to planting and irrigated again briefly the day
after planting. A tensiometer was installed in the field to measure
soil water tension at different depths and the plot was irrigated as
needed to prevent significant water stress. Rainfall and maximum and
minimum temperatures were recorded daily.
Rhiboziurn innoculum was added to the furrows at planting, and gyp
sum was applied by hand at the rate of 1700 kg/ha on 26 June. Weeds
were controlled with preplant and cracking time herbicides. Ethylene
dibromide was injected into the soil 5 days before planting for nema
tode control. The fungicide chlorothaIon i 1 was applied from 22 June
until 22 September at 7"10 day intervals. Insecticides were applied
as needed to minimize damage by foliage-feeding 1epidopterous larvae.
On 2*4 August, fensulfothion RCNB granules were hand-broadcast to slow
the spread of white mold, Sclerotiurn rolfsii. Further details of the
pesticide applications can be found in Mangold (1979).
First Experiment
For the first experiment, in which the growth of several plants
was to be followed throughout the season, 7 plants were selected on
1*4 June, 3 weeks after planting. These plants were marked once a week
until 9 August, when 2 plants were harvested. The remaining 5 were
harvested on 13 September, 16 weeks after planting. The experimental
plants were all surrounded by healthy plants which were left undisturbed
throughout the season.
Once a week each new, fully expanded leaf on the selected plants
was marked by placing a colored surgical wound clip around the petiole.


FIGURE
PAGE
13 The simulated and experimental effect of removal of
all leaves from the outer 50% of the canopy at 12
weeks after planting on LAI (a) and pod dry weight
(b) .101
14 The simulated and experimental effect of 50% uni
form and 100% defoliation at 16 weeks after planting
on LAI (a) and pod dry weight (b) 107
15 The simulated effect of 10 larvae/plant entering the
field on day 35 after planting and feeding for 26 days
at an increasing rate .Ill
16 The simulated effect on LAI (a) and pod dry weight
(b) of 10 larvae/plant entering the field on day 56
and feeding for 26 days at an increasing rate 113
17 The simulated effect on LAI (a) and pod dry weight
(b) of 20 larvae/plant entering the field on day 35
and feeding for 26 days at an increasing rate 114


145


Initiation of New Leaves and Branches
Plants emerge 11 physiological days after planting with a fully
expanded leaf on the mainstem, 3 partially developed leaves on the
mainstem, and 2 partially developed leaves on each cotyledonary lateral.
In the field experiments, plant emergence began on the fifth day follow
ing planting, and plants continued to emerge for more than 2 weeks, al
though the plants used in the experiments were those that emerged during
the first 9 days of the emergence period. The earliest leaves expanded
more quickly than later leaves. It was easier to simulate this by
having the plants emerge later than they did in actuality with some
leaves already forming, than by having the earliest leaves grow more
rapidly than later ones and draw upon seed reserves.
The program keeps track of the number of branches, both vegetative
and reproductive, on each plant, and the date of initiation of the last
2 leaves on each vegetative stem. When the first leaf on a branch is
half-grown, a new leaf is initiated on that stem. When a leaf com
pletes development then a new leaf is initiated, and a new branch,
either vegetative or reproductive, may be initiated 2 nodes back on
the stem. Whether the new branch is vegetative or reproductive de
pends on the fixed branching pattern of the plant. Suppose, for ex
ample, that the stem in question is the first lateral off the mainstem
and that it has 1 node with no attached leaf, ^ fully developed leaves
at nodes 2-5, a leaf completing development at node 6, and a half-
grown leaf at node 7 on day K. There should already be a vegetative
branch at node 1, a reproductive branch at node 2, and another vegeta
tive branch at node 3. On day K the leaf at node 6 completes develop
ment, and a branch can be initiated at node k. This branch will be


202
NEWREP(J,I) number of potentially active reproductive nodes on plant J
which were added to plant on day I not used at present
NEWVEG(J,l) number of potentially active vegetative nodes on plant J
which were added to plant on day I
N0DE(J,K) number of nodes on stem K of plant J
NOW integer equivalent of TNOW
NUMBR(J) number of vegetative and reproductive branches on plant J
PDAY(l) physiological days from day I ( only non-zero when there are
growing leaves initiated on day l)
PEANUT amount of carbohydrate available for fruit growth on a given
day
PEGDED(J) number of days there has been no photosynthate available to
fill demand from expanding pods on plant J
PEGN0(J,1) number of peanuts on plant J initiated on day I
PEGS(J) total number of pegs on plant J on a given day
2
PEGSM2(l) number of pegs per m on day I
2
PENUTM(l) number of peanuts per m on day I
PENUTZ(J) number of peanuts on plant J on a given day
PETWT(J) weight of petioles on plant J on a given day
PHZDAY(l) physiological days since day I (used for turning flowers
into peanuts)
PN(I) net photosynthesis on day 1, g/m
PNRIPE(J) weight of ripe peanuts on plant J on a given day
PNRIPM(l) maximum weight of ripe peanuts per m up until day I
PNTCHO amount of carbohydrate used in seed growth on a given day, mg
P0DCH0 total amount of carbohydrate required by shells for maximum
growth on a given day, mg


XI NODE(J, I) XI NODE(J. I ) 1.0
WTPET(J.I) = WTPifTt J, I) XNL.IAFiJ.l)
AGn1S(J> = AGRPTSCJ) 1.0
L L CO UN T(
J
. K )
IF ( L.r0.0 )
GO TO
1 1
5
5 I zr. LF ( J L )
= 51 Z
1.
LF
(
J
*
L
)
-
TLE
AT ( J,L )
WTP.ZT ( J ,L )
=
W I PII
r ( j

L
)
/
XNL
I AF
( J L )
X NLi: AF { J L )
= XNL
AF
(
J

L
)
i
. 0
XI NODE ( J L )
= XI N
1 )
of:
(
J
*
l
)

i
. 0
WTPET(J,L)

wtp r.
r
i j
t
L
)
*
XNL
2 AF
( J L )
1
1
5
MN I5TEM
J
,K )
I GTEM (J.K)
=
6
L = NODE(J,
K
)
1
1
4
GO TO (116,
1
17,11
3
. i
1
0
)
*
M
N
1
1
f,
NUMTR(J) =
N
UMDK (
J
>
4-
1
AGRPT5(J) =
AGRPT
j
( j
)

1
.0
I STEK{ J NUM )R ( J) ) =4
IF (L .Lt:.4 .AND.M.N.EO 1 ) (STr'K J.NOM'ikl JJ 1 J
NOr>£ ( J NUMTIR ( J ) ) 1
(COUNT(J.NUM3R(J)) MORROW
XNLEAF ( J MORROW ) = XNLL AF ( J M J f?RO W ) 4 1.
XI NllO: ( J, MORROW) = X 1 Nil OIK J MORROW ) ^ 1.
GO TO 121
117 IF (L.LE..ANI).L .NC.2) GO TO li
IF ( ( ( ( L 4 1 ) /'? ) /2 ) 2 ( ( L H ) /2 ) ) 12 1,116,121
113 IF (L.LT.6.ANO .L .Nfi,2) GO TO 116
110 IF { ( (L/2 )/2 )*2-(L/2 ) ) 12 1,110,121
121 IF (L.NF:.000F( J.K)) GO TO 120
1. = NOTE ( J < ) 1
IF (L.NE.O) GO TO 114
120 CONTINUE
125 CONTINUE
130 CUNT I NOE
140 CONTINUE
IF (NTYPC 2) 200,150.200
150 CONTINUE
GS { 1 ) = ~j 5 ( J )
GO I O 3 00
200 Y = 00. 45 0. 071 5 DEEPER 0. OOO1 6 OCF PER* OI.FPCR
Y = ->L TLA I Y
IF (Y.IE.16.1) GO TO 250
Y = Y 11.767
55(1 ) = (27.167 S3RT( 27. 167* *2 4.0 2. 1 02* Y ) ) / ( 2 *2.1 W: )
GO TO 3 0 0
2 5 0 5 5(1) = Y / 100.
.300 CALL PMTL A I
IF ( PLT1.AI LC.PLTMAX ) I DAM = 1
IF (K)AM) 400,400, 350
oo


20
Table 5. Average numbers and weights of pods present on the Florunner
peanut plants harvested each week during the 1978 growing
season.
o"! No. No. o"! F4 No. P5 Kerne 1
Week PI P2 P3 P4 Wt. g P5 Wt. g Wt. g
7
2.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
8
3.3
6.3
1.6
0.0
0.0
0.0
0.0
0.0
9
12.8
13.9
11.1
2.3
0.6
0.8
0.3
0.4
10
18.6
13.2
16.4
8.8
1.9
1.0
0.4
0.4
11
20.3
27.9
34.4
10.4
1.9
18.9
9.3
5.6
12
17.8
44.0
46.7
17.2
2.3
23.0
14.1
9.7
13
16.0
24.3
47.6
20. 1
4.6
31.2
24.9
18.3
14
15.9
23.5
30.7
21.9
6.6
30.3
27.4
20.9
15
7.6
20.4
34.4
17.5
5.4
43.0
40.3
31.3
16
6.A
19.3
17.5
14.5
5.9
42.3
48.0
37.3
17*
16.3
22.3
43.7
30.3
11.0
58.3
61.5
49.1
18
9.6
17.5
26.3
22.4
6.5
57.1
63.7
51.4
20
7.7
14.3
14.3
17.6
6.0
55.4
63.6
49.8
:':0nly 3 plants harvested this week.


65
vegetative according to the plant's branching pattern. A new leaf is
also set to start development the next day at node 8.
Each leaf grows for a set number of physiological days. This
number depends on the stage of development of the plant. Up until 82
physiological days (about 68 calendar days) after planting, a leaf
takes 10.8 physiological days (about 9 calendar days) to develop. This
rate of growth yields about 1.4 leaves/branch/week, in keeping with the
field results for weeks 4-10 presented in Table 6. Late in the season
(after day 82), leaves take 14.4 physiological days to complete devel
opment. This yields approximately 1.1 leaves/branch/week, again in
accordance with the results in Table 6. The underlying cause for this
apparent decrease in growth rate could not be determined, and it may
have been due to non-linearity in the leaf growth versus temperature
response curve.
In the model a maximum of 333 vegetative growing points/m^ are
allowed. In the field there may be many more than this present, but in
my plot this was the maximum number of active ones present at any one
time (35/plant, on the average). It was simpler to stop the initiation
of growing points when the maximum/m^ was reached, rather than to pro
gram the simultaneous initiation and shutdown of branches.
The length of time between nodes on a reproductive branch is set
at 6.0 physiological days in the model. A maximum of 4 nodes is allowed
per reproductive branch. In the field there are occasionally more than
4 nodes per branch. The model does not keep track of flowers and pegs
separately; rather, once a reproductive node has been activated, a pod
may start to swell at that node 27.0 physiological days later.


VTSTEM(J) = ITSTEM ( J ) + { rf T I! IJi) ( J 1 ) + XML'.AT (J.I )>/( 1 00 0. 07 )
470 CONTINUE
400 CONTINUE
WITUPN
EN')


70
grow and demand carbohydrate until 32.4 physiological days (27 calendar
days) after initiation.
Shell demand is calculated according to the formula
WANT = (10.0 + 0.25 PODWGT(J,K)) DAY INC (6)
where P0DWGT(J,K) is the weight of an individual pod initiated on day
K on plant J and DAYINC is the number of physiological days in the
given calendar day. About 85% of this demand is for carbohydrate
(McGraw 1977) When the pod reaches 17% of its capacity it is consid
ered to be fully expanded and shell growth stops and seed growth begins
If there is no shortage of carbohydrate it takes approximately 8 cal
endar days for the first pods to become fully expanded.
In this model, as in PENUTZ, pods that are filling seeds may grow
at a maximum rate of 22 mg/physiological day. Since more energy is
expended in making kernels than in making other plant parts, 35-9 mg of
carbohydrate are required to produce this 22 mg of kernel dry weight.
This is a result of the higher oil and protein concentration in seeds
than in other plant parts (McGraw 1977). Each developing pod that is
filling seeds thus demands 35-9 mg/day until it reaches 80% of its
capacity. It then continues to grow at half this rate until fully
grown. Schenk (1961) noted that pod growth rate declines in the later
stages of seed enlargement. In both PMINUS and PENUTZ, the later in
the season a pod is initiated, the smaller is its capacity.
If there is a surplus of carbohydrate after all growth demands are
filled on any day, then the excess is sent to stems for storage. If
there is a shortage, then allocation of the available photosynthate is
determined on a priority basis. The system of priorities is based


205
WTLEAF(J,I) weight in mg of an individual leaf initiated on day 1 on
plant J
2
WTLFM2(l) weight of leaves in g/m on day I
WTPET(J,l) total weight in mg of all petioles initiated on day I on
plant J
WTROOT(J) weight of roots on plant J, g
WTSTEM(J) weight of stems on plant J, g
XI NODE(J,I) number of internodes on plant J initiated on day I
XLAl(l) leaf area index on day I
XLEAFN(J) number of leaves on plant J on a given day
XLIMT(J) proportion of day's photosynthate which may be used by
plant J for seed development
XLMMAZ maximum average of 5 days' photosynthate
XNLEAF(J,I) number of leaves on plant J which were initiated on day I
2
XNOLFM(l) number of leaves per m on day I
XNONOD(J) number of internodes on plant J on a given day


24
Table 8. Comparison of specific leaf weights for leaves initiated at
the same time but harvested within a week or at week 16.
Interval of
Leaf Initiation,
Weeks
Spec ific Leaf
Weight, mg/cmz
Leaves Harvested at
End of Week
Leaves Marked at End
of Week but Harvested
at Week 16
0-3
4.66
5.48
3-4
4.92
5.96
4-5
5.05
5.42
5-6
3.66
4.11
6-7
4.00
3.82
CO
1
3.68
3.74
8-9
3.73
3.98
9-10
3.78
4.04
10-11
3.27
4.10
11-12
3.09
4.23
12-13
3.39
4.27
13-14
4.02
4.24
14-15
3.17
4.12


55
the level of defoliation, the more new leaves were grown and the more
the stem weight to length ratio was reduced. Plants defoliated 50%
intercepted 80% as much light immediately following defoliation as did
the check plants (Table 22). Plants from which all leaves had been
removed still intercepted 46% as much light as the check plants.
Plants did not put on sufficient new leaf matter following defoliation
for canopy light interception to recover.


31
process. Yields from single defoliations of 50% or more at 9, 12, and
15 weeks had a higher percentage of split and damaged nuts than the
controls, but the percentage of sound, whole nuts from multiple defoli
ation treatments was significantly higher than that from the control.
A comparison of leaf biomass removed in single defoliations with
that removed in multiple defoliations indicates that defoliated plants
probably put on greater new leaf mass between treatments. For example,
35-6 g/plant total leaf weight was removed from plants defoliated at
9 and 12 weeks, whereas only 30.1 g was removed from plants defoliated
at 12 weeks.
Williams et al. (1976) studied the influence of defoliation and
pod removal on growth and dry matter distribution of the Makulu Red
variety of peanuts in Rhodesia. Normal growth of this variety in
Rhodesia, as reported by Williams et al. (1975), proceeds as follows:
flowering begins 55 days after planting, continuing until 100 days.
Stems increase in weight until 18 weeks after sowing, as does the plant
as a whole. Leaf area reaches a maximum at 16 weeks, kernels start to
form at 12 weeks, and pegs reach a maximum number at 20 weeks, as do
the pods. Kernel number is set at 22 weeks. In their defoliation and
depodding experiments, Williams et al. (1976) defoliated 0, 50, or 75%
and depodded either 0 or 50% at 3 stages of growth (17, 19, and 21
weeks). They defoliated by removing leaflets from each leaf and de
podded by severing at ground level all pegs on one half of the plant.
The plants were harvested and measured 2 weeks after the treatment.
Defoliation at all periods greatly increased leaf growth rate over the
control. At 17 and 19 weeks, defoliation of 75% increased leaf growth
rate more than 50% defoliation did. The reverse occurred at 21 weeks.


Table 31* Specific leaf weights and average size of new leaves grown
in the 2 weeks following defoliation.
Defoliation
Date, Week
T reatment
Type
SLW-of
New Leaves,
mg/cm^
Average Wt.
per Leaf, mg
Average Area
per Leaf, cm'
9
Check
5.kb
83.0
24. 1
50% uniform
3.5k
93-5
28.0
50% outer
3.46
80.2
23.2
12
Check
3.88
88.3
22.8
50% uniform
*4.25
84.2
19-8
50% outer
3.66
64.7
17.7
16
Check
2.60
14.8
5.7
50% uniform
4.09
20.8
5.1
100%
3.45
17.6
5.1
^Specific leaf weight


12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
PAGE
41
43
45
46
47
49
50
51
53
54
56
61
69
89
91
94
The effect of various levels of defoliation at
4 weeks upon plant size at 7 weeks
Estimated leaf and stem gains in the 2 weeks
following defoliation at 4? weeks
Summary of light interception by plants 7 weeks
of age which had been defoliated at 4j weeks.
The effect of 50% defoliation at week 9 upon
plant size at week 11
The effect of 50% defoliation at week 9 upon
plant size at week 15
Summary of light interception by plants
defoliated at 9 weeks of age
The effect of 50% defoliation at week 12 upon
plant size at 14 weeks .
The effect of 50% defoliation at week 12 upon
plant size at week 16
Summary of light interception by plants
defoliated at week 12
The effect of defoliation at 16 weeks upon
plant size at 18 weeks
Summary of light interception by plants
defoliated at 16 weeks
A brief description of the user-written sub
routines included in PMINUS
Root growth during the 1978 growing season, as
indicated by weekly plant samples
Comparison of leaf growth in the field with
model predictions .
Comparison of model predictions with field
results for plants defoliated at 4i weeks and
harvested at 7 weeks .
Comparison of model predictions with field
results for plants defoliated at 9 weeks and
harvested at 11 weeks
vi


36
Uniform defoliation refers to removing the same number of leaflets
from each ^-leaflet leaf on the plant. Only leaves which had another
leaf starting to open above them on the branch were defoliated or
marked. Growing points were removed by snapping off newly forming
leaves as far down within the stem as possible.
Plants in treatments 1 and 7 were marked with surgical wound clips
and acrylic paint as discussed in Chapter II. A surgical wound clip
was placed around the petiole of each fully expanded leaf, and all
stems were marked with a spot of paint. The stems of treatments 2-6
plants were also marked with paint and the defoliation process itself
adequately marked the leaves. Removed leaflets from each treatment
were measured and then dried and weighed.
The plants were harvested 7 weeks after planting--25 weeks follow
ing treatment. One plant from each treatment plot was selected for
mapping. This plant was the "average" plant in that it was intermedi
ate in size between the other 2 sample plants contained in the plot.
The positions of new and old leaves and branches were noted and each
stem was given a code number and measured. Each harvested plant was
broken down into the following parts: old leaves, new leaves, petioles,
stems, vegetative growing points, pegs and reproductive branches, and
pods. Leaves were counted and a subsample was measured for leaf area.
The numbers of new and old stems and number of pegs were obtained. All
stems were measured. The various plant parts were then dried and
weighed.
Canopy light interception was measured for each treatment plot
in 2 rows just before the plants were harvested, in the manner dis
cussed in Chapter I I.


FRUNIT = ASPGST(J) / ASPPH
A jPGSn J ) = 0.0
PTSRUT(J) = PTMRUT(J) PTSYM(J) FRUCHU
PTSYN(J) =0.0
GOTO 115
110 CONTINUE
PTSYN(J) = PTSYtH J) EPUCHO
AS PGM r ( J ) = AriPGSr(J) A SPHl: 0
115 CONTINUE
PEANUT = FRUCUO
IF ( PCDCll l ) 1 20, 120. 1 1 U
110 IF (FOUCH1 PflTCHO) 120.120,125
12 0 P A fIO = 1.0
GO TO 1J0
125 NATIO = (EPUCHQ PNTCHO) / POOCMU
150 CONTINUE
IT (PATIO.GT.1.0) RATIO = 1.0
IF (RAI lfl.LZ.0.0) RATIO = 0. 0001
CALL FRUF 1L
PTSYN(J) = P T > Y N( J) f P T MS
AM PGM T (J 1 = A3PGSMJ) PTSS FRUMCR
'T SM = 0.0
200 CONTINUE
RETURN
END


1
2
3
k
5
6
7
8
9
10
11
LIST OF TABLES
PAGE
Average leaf growth for A Florunner peanut plants
marked weekly and harvested at 16 weeks 15
Average numbers and weights of pods of various
size categories from A Florunner peanut plants
marked on a weekly basis during 1978 and har
vested at 16 weeks of age 16
Average leaf growth for Florunner peanut plants
during the 1978 growing season, as indicated by
weekly plant samples 18
Average stem growth for Florunner peanut plants
during the 1978 growing season, as indicated by
weekly plant samples 19
Average numbers and weights of pods present on
the Florunner peanut plants harvested each week
during the 1978 growing season 20
Number of new leaves per branch during the 1978
growing season, as indicated by weekly plant
samples 21
Estimation of leaf loss by Florunner peanut plants
during the 1978 season, as indicated by weekly
plant samples 22
Comparison of specific leaf weights for leaves
initiated at the same time but harvested within
a week or at week 16 2*4
Results of linear correlations of stem size to
plant age and plant size for Florunner peanuts. ... 26
Average size of stem internodes during the 1978
season, as indicated by weekly plant samples 27
Summary of the defoliation experiments performed
during the 1978 growing season on Florunner pea
nut plants 40
v


201
I MERGE(J) date of emergence of plant J
INIT day plants start emerging
I STEM(J,K) type of stem K on plant J (1 = mainstem, 2 = cotyledonary
lateral, 3 = one of first 4 laterals off the mainstem, 4 = other
vegetative branch, 5 = reproductive branch, 6 = branch that has
stopped growing)
J index for plants that emerged on same day (from 1 7)
KPEGST date flowering starts
KPODST date pods start to form
LC0UNT(J,K) date of initiation of the next-to-the-last leaf on plant J,
stem K
MERGE number of days on which plants emerge
MORE not used at this time
MORROW current simulation day + 1, counting from start of the simulation
NCOUNT(l) date leaves initiated on day I completed development
NDEX1 an indicator of ELAI ( 0 = less than 0.161, 2 = less than 2.0,
3 = less than 2.5, 4 = greater than 2.5)
NDEX2 an indicator that enough physiological days have passed that
plants can start emerging
NDEX3 an indicator that the pod load has been set
NDEX5 ~ an indicator that a given ELAI has been surpassed at least one
time
NDEX6 an indicator of whether GRPTS should be called to initiate new
vegetative branches on a given day
NDEX9 an indicator of whether vegetative growing points may be inacti
vated


Table 29. Comparison of model
vested at 14 weeks.
predictions with
field
results for plants
defoliated
at 1 2 weeks and
ha r-
Plant Variable
T reatment
Control
50% Uniform
Outer
50% of
Canopy
Field*
Mode 1
Field*
Model
Field*
Mode 1
Original LAI
5.6
(0.9)
5.9
6.1 (0.9)
5.9
6.7
(0.6)
5.9
LAI after defoliation
5.6
5.9
2.7
3.0
2.6
2.7
LAI at harvest
5.8
(0.9)
6.4
3.0 (0.5)
3.4
3.1
(0.3)
3.0
2
Leaf weight at harvest, g/m
216.6
(34.*4)
233.5
122.3 (18.3)
121.8
116.3
(12.1)
114.5
2
Weight of new leaves, g/m
8.5
(1.2)
15.2
12.1 (2.4)
11.2
19.6
(3.0)
10.3
2
Stem weight, g/m
26*4.6
(41.3)
291.4
251.9 (38.2)
283.5
280.5
(34.4)
276.3
2
Gain in stem weight, g/m
*49.8
49.6
25.2
42.7
8.5
35.5
2
Number of pods/m
708.5(135.8)
855.3
711.7(120.7)
598.7
897.0(101.2)
598.7
2
Weight of pods, g/m
3^0.3
(61.0)
343.3
335.6 (55.5)
293.2
349.7
(39.8)
287.9
2
Number of P4-P5/m
*452.8
(74.3)
503.6
427.5 (68.4)
418.1
428.3
(55.0)
418.1
Weight of P4-P5, g/m^
313.1
(58.2)
329.6
327.4 (54.3)
286.0
338.8
(38.7)
281.9
"Number in parentheses is standard error of the mean.


20
STMMIN(J) amount of carbohydrate in stem storage for plant J, mg
2
STMM2(I) weight of stems on day 1, g/m
STRESF water stress factor
SUMLAR(J) number of larvae feeding on plant J
SURFAC(J I) leaf area of fully developed leaves on plant J initiated
on day I
TNOW current simulation day, counting from start of simulation
TOTEAT total amount of foliage consumed by insects attacking the crop,
2, 2
cm /m
2
T0TM2(l) total plant weight in g/m on day I
WANTBG(J) amount of carbohydrate needed for maximum growth by leaves
developing on plant J which are more than half-grown on a given
day, mg
WANTLF(j) amount of carbohydrate necessary for maximum growth of leaves
developing on plant J on a given day, mg
WGHTLF(J) weight of leaves on plant J, g
WGTBNZ(J,l) weight of peanuts on plant J initiated on day I, mg
WNTNUT(J) amount of carbohydrate needed by seeds on plant J for
maximum growth on a given day, mg
WNTPOD(J) amount of carbohydrate needed by expanding pods on plant J
for maximum growth on a given day, mg
WNTSTM(J) amount of carbohydrate needed by developing stem internodes
on plant J for maximum growth on a given day, mg
WNTSTO(J) amount of carbohydrate "wanted" by stems for storage on
plant J on a given day--always zero at present
WTIN0D(J,l) weight in mg of an individual internode initiated on day I
on plant J


BIOGRAPHICAL SKETCH
Gail Ellen Geier Wilkerson was born on 12 November 1946 in Nashville,
Tennessee. She attended public schools in Nashville until graduation from
John Overton High School in 1964. She then entered Duke University in
Durham, North Carolina, and received a B. S. degree in mathematics in 1968
In 1967 she and Richard Wilkerson were married. She received a Na
tional Science Foundation Traineeship and began graduate studies in math
ematics at the University of Florida in the fall of 1968. Upon the in
duction of her husband into the U. S. Army in the summer of 1969, she
moved to San Antonio, Texas, where she worked as a technical secretary
and teacher until 1972. She then returned to Gainesville to pursue gra
duate studies in entomology, and she received her Master of Science degree
in 1974.
She then moved to Cali, Colombia, and worked as a computer programmer
for the International Center for Medical Research until the summer of 1976
when she again returned to Gainesville to begin work toward the degree of
Doctor of Philosophy in the Department of Entomology and Nematology, Uni
versity of Florida, under the auspices of a CSRS pest management grant.
She had a son, Trevor Alan, in November 1976. Her marriage ended in di
vorce in 1978.
Gail Wilkerson is a member of the Phi Kappa Phi Honor Society.
210


3URFAC ( K J)
= AREANM
ARCALF(K > =
ARFANW
WGMTLF(K) =
WT NEW /
(1000. *
0 .07)
WT3TEM(K) =
STEMNW /
(1000. *
0.57)
PETWT(K) =
: ETNE/r /
(1000. 0
0.97)
WTROGT(K) =
ROOT NW /
1000 .
XNLFAF K J )
= l 0
X I nodi: ( K J )
= l 0
XX = { T I
F 2.0)
/ TIMELF
s i 2!.:lh k m )
= W T NT. 1*
* XX
WTLTAP ( K > -1 )
= WT NEW
* XX
W T I NOO ( K I)
= 3 T F M N W
* XX
WTPF.T (K -U
- P f TN E Vi
* XX
XNLFAF{K,M)
- 1.0
XI NODE( K ,M)
= 1.0
IF (;>OAY(M)
L T .TI MEL
F 3.0)
POAY(M) =
T I
XNLi: AF ( K ,L )
- 3.0
X INODtK K ,L )
= 3.0
SIZELF(K,L )
= (WTNEW
/ 2. ) *
XNLFAF(X.L
)
WTLFAf ( K ,L )
= W T NE A
/ 2 .
WT INI) 0( K L. )
= STEMNW
/ 2.
WTPT.TI K ,L )
= (PFTNEW
/ 2. ) *
X NL FA F ( K L
)
IF ( lDAYU. ) .LT.HFT I ME > POAY(L) UPTIME
XX = (UPTIME -2.0) / TIMELF
XNLFAF(K.N) = 3.0
X I NO Or. ( K i N ) = 3.0
WTPET (KH) = PET NEW XX
SIZL'LF(K.N) = 3.0 wTNEW 3 XX
WTLCAr(KiM) = W TN E W XX
WTINDD(K.N> = 5TEMNW T XX
IF ( DA Y( M) L T. I IF T l Mia-2.0 ) P)AY(N) = UPTIME 2.0
I COUNT (K,
1 ) =
N
ICUUNT( K .
2 ) -
N
ICO UN T( K .
1 ) =
N
NCOUNT(J )
- NOW
AGRPT 9( K)
- 3.
S>( 1 ) 3
5(1)

( AREALT(K )
PROPOR(K))
/
1 0 00 0 .
33(3) S
5(3)
( AREAL T (K )
* 3 ROPOR { K ) )
/
10000.
CALL PUT LA I
5 00 RETURN
I; NO
i


Table 30. Comparison of model
vested at 16 weeks.
predictions with
i field
results for pi ants
defoliated
at 12
weeks and har-
Plant Variable
T reatment
Control
50? Uniform
Outer
50? of
Canopy
Field*
Mode 1
Field*
Model
Field*
Model
Original LAI
5.6
(0.4)
5.9
5.8
5.9
5.0
5.9
LAI after defoliation
5.6
(0.4)
5.9
3.0 (0.3)
3.0
1.8
(0.3)
2.0
LAI at harvest
6.0
(0.5)
6.5
3.5 (0.3)
3.5
2.6
(0.3)
2.5
2
Leaf weight at harvest, g/m
213.1
(19.9)
237.3
123.2 (9.6)
125.7
101.9
(12.5)
93.6
. 2
Weight of new leaves, g/m
15.3
(2.6)
19.0
19.8 (2.7)
15.1
36.4
(3.7)
17.2
2
Stem weight, g/m
269.9
(25.9)
295.2
246.0 (24.1)
286.8
196.3
(23.2)
265.6
2
Gain in stem weight, g/m
79.5
53.4
33.4
46.1
0.5
24.8
2
Number of pods/m
729.1
(67.0)
959.8
795.2(121.9)
826.7
654.6(108.6)
598.7
2
Weight of pods, g/m
552.0
(45.5)
520.8
511.9 (53.1)
443.1
417.7
(57.0)
385.8
2
Number of P4-P5/m
558.1
(43.6)
674.7
549.3 (62.9)
598.7
411.1
(58.7)
503.6
2
Weight of P^-P5, g/m
546.0
(44.6)
511.2
505.9 (52.1)
439.6
362.9
(55.3)
383.6
* Number in parentheses is standard error of the mean.


5**
Tab 1e 21.
The effect of defoliation at 16 weeks
18 weeks.
upon plant size at
Treatment
Number of New
Leaves
Weight of
New Leaves,q
Ratio of Stem Weight
to Length, mg/cm
Check
6.1b
0.1b
22.5a
50% uniform
13.9b
0.3ab
21.2ab
100%
33.0a
0.6a
19.2b
Note: Means in a column followed by the same letter are not signifi
cantly different according to a t-Test (a = 0.05).


Table 26. Comparison of model predictions with field results for plants defoliated at 4i weeks and har
vested at 7 weeks.
Initial
LAI
LAI ;
after Defoliat ion
LAI
at Harvest
Leaf Weight at
Harvest, g/m2
T reatment
Field
*
Mode 1
Field*
Mode 1
Field*
Mode 1
Field*
Mode 1
Check
0.14
(0.02)
0. 14
0. 14
(0.02)
0.14
1.42
(0.17)
1.42
56.7
(7.1)
56.2
25% uni form
0.10
(0.02)
0.14
0.08
(0.01)
0.10
1.07
(0.15)
1.36
42.0
(5.8)
55.2
501 uniform
0.16
(0.02)
0.14
OO
O
O
(0.01)
0.07
1.32
(0.17)
1.27
51.7
(6.5)
51.3
1001
0.15
(0.02)
0.14
0.00
(0.00)
0.00
0.90
(0.15)
0.93
32.7
(5.0)
35.9
0% + veg.
0.22
(0.03)
0.14
0.22
(0.03)
0.14
0.97
(0.14)
0.79
36.4
(4.8)
31.6
growing points
50% + veg.
0.14
(0.02)
0.14
0.07
(0.01)
0.07
0.59
(0.08)
0.63
23.6
(3.1)
24.7
growing points
100% + veg.
0.20
(0.03)
0.14
0.00
(0.00)
0.00
0.25
(0.04)
0.10
9.3
(1.4)
3.8
growing points
''Number in parentheses is standard error of the mean.


30
defoliation at 8 and 12 weeks significantly reduced the weight of 1000
kernels, while half defoliation at any time between ^ and 1^ weeks
(the extent of the experiment) significantly reduced pod number per
plant and dry weight of stems. In fact, in correlating pod number (N)
to stem dry weight (S) he found that a variation in S accounted for
about 80% of the variation in N between treatments (R=0.896). A simi
lar correlation existed between pod dry weight and stem dry weight
(R=0.913) Defoliation always significantly increased shelling per
centage. Enyi hypothesized that defoliation reduced pod number by
depressing growth of stems and consequently reducing the number of
flowering nodes, the number of pegs formed, and hence the number of
pods per plant.
Nickle (1977), working in Gainesville, Florida, defoliated the
Florunner variety of peanut from 25 to 100% by removing from 1 to k
leaflets from each leaf. He defoliated plants at 3, 6 (beginning of
flowering), 9 (pegging), 12 (beginning of pod filling), and 15 weeks
of age. Some plots were defoliated 50% 2 or more times. For example,
50% of the leaves were removed at 3 weeks and 50% of the new foliage
was removed 3 weeks later. He obtained dry weights for the leaves re
moved at each treatment period, and dry weight and quality of nuts per
treatment plot at harvest. For all single defoliation levels he found
greatest yield reduction at 9 weeks, followed by 12 weeks. A single
defoliation at 3 or 6 weeks resulted in a delay of flower production by
as much as 2 weeks. Defoliation at 9~12 weeks inhibited floral pro
duction or, if severe, caused flower drop and cessation of flower
production. It also resulted in a delay or cessation of the pegging


25
nodes vegetative, and this perhaps contributes to the high-yielding
capability of Florunner.
Although there was a large amount of variation between plants of
the same age in stem length and weight, the ratio of stem weight to
length was closely correlated to plant age; in fact, there was a much
higher correlation between this ratio and plant age than between it and
plant size, when total length of all stems was used as the measure of
plant size (Table 9)- Internode length and weight also depended more
on plant age than on plant size (Table 9)- Table 10 is a summary of
week versus internode length and internode weight. Both length and
weight per internode remained constant for the first 5 weeks after
planting, then began to increase. Weight increased steadily until
week 16, but average length was somewhat more variable from week to
week.
Figure 1 is a graph of the measured canopy light interception
versus LAI. The fitted equation has an value of 0.98.
The results of these experiments as they relate to the develop
ment of the plant growth model will be discussed in greater detail in
Chapter IV.


131


130


CO TO 12
'3 0 CONTINUE
WANT 1 = PUD 31 2 PODWGTtJ.K)
ANT 2 = ( 10.) F 0.25 F POD WG T{ J K 1 ) DAY INC
WANT = A MINI (XANT1.WANT2)
GUO Til = WANT GOO w
"NT C HO = GUO T U PEGNJ(J.K) F PODC
55 CONTINUE
A VI.G 10 = A VL jlii) PN ICON
IF C AVL GUO Gil .0.0) GO TO 60
0 (PNTCMO F AVLGRO) / PNTCH) GUO T11
GO TO 5 0
60 CONTINUE
PODWGT(J.K) PODwGT(J.K) GUETH
WGT 1NZ( J. K 1 = WGTUNZ(J.K) f GUO Til *
GO TO 12
20 PNHfPX(J) = PNRIPX(J) F wGTONZ(J.K)
PE GOUT ( J K ) = PE GUO T ( J K ) F 1.
IF (PCGRUT(J ,K ) ,LT .PEGL3T ) GO TO 12
R(J> = R ( J ) F WGTUNZ(J.K) / 1000 .
51 SHPCT(J.K) 0.0
WG TO NZ ( J K ) 0.0
"ODWGT(J,K) = 0.0
PEGNO(J.K) = 0.0
12 CONTINUE
IF (POOWGT{J.K) .LE. 0.0001 ) GO TO 11
FRUIT (J) = FUUIT(J) F WGTONZ(J.K) /
PENUTZ(J) = PLMUTZ(J) F PEGNO(J.K)
IF ( PODVi j T ( J K ) .LT .POD-3 I Z ) GO TO 11
UGTPOD(J) = HGTPOO(J) F PEC.NO(J.K)
ilJTFI T( J) USTFKT(J) F WGTUNZ(J.K)
1 1 CO NT I NU E
IF (PNUIPC(J). GE.PNU IPX(J) ) GO TO 65
p.n u i p r: t j ) = pnripx(j)
65 CONTINUE
PT S 3 = AVLGRO
AVLGRO = 0.0
RETURN
END
PE G Nil ( J iK)
/ 1000.
10 0 0.
/ 1000.
--j


Cvl
LA
QN7J
Njnia.'
ddfiiiti (rjiiiUcJ = (r)yodiJijd ci
u- i = r o oc
(OlKM'd l)dOKO) / t'DC I = ¡Odl'V
UIDNf.'DA 4 0*1) / ( ( Ole: INd I
- TlfJlNcI 0*9,6) 4 <9W*' llfilNd) ) / (OHcliN.J 0*96) = DVJ1IO
9 t 9 / t I Z t = LnrJS V
0#o /f I / 1? = d*D3A9V
( flM'J'J HA 4 0*1 ) / ZO*C = NOCJcl
( MNDlNi 4 0*1) / 0>A*C = Ni Dd
OridlNd / (IWcMNd C 90 ) = ¡(NJlMd
( DN 9 3A 4 0*1) / Z 6 O = DCIM
ODMiNd 4 0*1) / f.-O DADO
(ilcINd 0*96) / fiHt.'INd = DNifJd
O> t = 'AIS
Z6*0 C t = CIO NHL1 t
6*0 00* o -- 1 clfiCid
6*0 + I t* = dlUDd
(IDNO.-IA 4 0*1) / (0*0 60* ti) = dlCiCiV
(Jc!'D3A / ( fj dd 9 3A C*/6) = 1003A
(()d4J3A 0*ZC) / 0d93A = HDN93A
/ O 9 Z. 4 I 9 l /O I WA'fJM JdSWOd Vi vo
/(.' 09* O O O C I /TI UlNcUdJ fid* J10£A VJ VO
c oo i id/91 hton/ nnt hcid
DV-nui4 oMdc'j v NtiUr' 4m i do o o o o ji Dd/z;: v- ron/ nv.i- o o
Mis OONdCUJ 4 iillUtl *3 lMUi MND 0 A rlOHASV 4 tOM'J'IA4 i IN93A V.
4 ouoda 4 (cor.4 ):v -id 4 ( oor) into dm 4 < ) cCKiDnx/tdMiDn / r -¡Odwro
rnoov* ( 00c4 L )93A WSN/.'dk UDO/ NCHd'OD
( Z ) AMIJd/9 ll- (ion/ NOHWCO
CCVAVt 4 (Z ) t:t'dCic'/M.On/ KOhVfOD
W19C!(.IV/t^ l'"jn/ NGITiWL'J
WtllldflK 4 303W 4r 4 jNI A VO 4 ( Z) ASOdCV l
4 ( ) indSi.i 4 ( Z ) N A9 J < I 4 MI1N 4 9X30N 4 £ X J ON 4 o X 3 CM 4 l X DON/ I V- 1.00/ NOK'KTO
13 O 114 ( 9 Z ) 11 I >J i 1 4 N I 31 1 4 en DI 1 4 S
O^Cii i 4 ."O KM 4 (t'OG)l': lVdd* 1 N>ldN 4 A di NN 4 ( 0 0 I ) NN 4 II 3NN 4 IVKN 4 IdV KN 4 Qc.VN I
M 4 KDO K 4i (JiSW 4 ( OC I ) 1 1K (COI) 3 3K 4 V3d 4 II- A 30 4 (GZHil DHJKM 3KJ AnOt.O'o


>U incur INK GCflNO
COMMON /GO) 42/ r>.> C 1 JO) ,IJOL( 1 OJ ) ,!)TFUl. .DTNMW
1 NNFGD, NNflOG, NNEOT SG { 1 0 0 ) GSL ( 100), T THE X
DATA EMERGE/ 11.0/
LFLAG( 1 )
-
KKOSfit 1

0
9
0

0
9
0 161
9
1

0.2
)
EFLAG { 2 )
< miSG ( 2
9
0
9
0

0
9
¡J2.0,
1
9
O
. 0 )
LF LAG ( 1)
-
Kll OGG ( 1
9
0
9
0

0
9
2 .0.1
9
p
m
0 )
LKLAGI A )
-
KROGGt1
9
0
9
0

0
9
2.0,-
1
9
O
. 0)
LFLAG15)
=
KHOGS (2

0
9
0

0
9
6 J 3 ,
1
9
O
.0 )
LFL AG ( f.)
KRO GS( ?.
9
0
9
0

0
9
i' mi: pg
E
9
1
o
9
0 )
LFL AG ( 7 )
-
KRl) GG< 2

0
9
0

0
9
1 4.0,
1
9
2
. 0)
LFLAG(M )
-
KRD'iS ( 1
9
0
9
3

0
9
2.0,1
9
P

0 )
LFL AG( c, )
r
KRtlG.GC 1
9
0
9
0

0
9
2.0,-
1
9
l.
. 0)
LFLAG(10
)
= KROSS (
O
,
0
9
0

0
,40.0
9
1
*
2 J )
l-vl TURN
i"N D
, IGEES, LFLA G(GO ). MFLA,
\r\


Pa rameter
Description
Numerica1
JL
Value (s)
Source
DAYDEG
Number of F in a physiological day
25.0
Duncan (197**
S pers. comm.)
DECRTE
Coefficient for linear decline in canopy
photosynthesis after day 119
0.33
Jones et a 1.
(1980)
GRATEK
Maximum potential growth rate for kernels in
1 pod, mg/physiological day
22.0
Duncan (197**
& pers. comm.)
HFTIME
Number of physiological days for a leaf to
be ha If-grown
5.** P-t
7.2 p.t
. < 82
> 82
Table 6
HSTCPY
Ratio of photosynthetic efficiency of canopy
at maximum to efficiency at harvest
0.30
Jones et a 1.
(1980)
01LFAC
Ratio of weight of oil + carbohydrate in seed
to weight of carbohydrate necessary to produce it
0.A3
Duncan (197**
& pers. comm.)
PARFAC
Proportion of maximum 5-day-average of photosyn-
thate which may go to seeds
0.65
calibra tion,
field results
PCTC
Proportion of seed weight which is oil or
carbohydrate
0.70
Duncan (197**
& pers. comm.)
PCTN
Proportion of seed weight which is nitrogen
0.25
Duncan (197^
& pers. comm.)
PNTCNR
Ratio of carbohydrate + oil to nitrogen in seeds
0.36
Duncan (197**
& pers. comm.)


Weight of Leaves, g/m
C\J
Simulated and experimenta1 leaf growth for Florunner peanuts planted on 24 May 1978.
Figure 4.
CD
1-0


APPENDIX 2
FLOW CHARTS OF THE MAJOR SUBROUTINES IN PMINUS


1*3


this peanut cultivar (Florunner) accumulates reserves in the stem
during the course of the season which can be utilized to grow new
leaves or to fill pods in the event of defoliation.
PMINUS is the simulation model developed on the basis of these
experiments. Plant growth depends upon physiological time and inter
cepted radiation. The model keeps track of the number and weight of
leaves, internodes, and pods initiated each day. New vegetative and
reproductive branches are initiated according to the branching pattern
of the plant. Light interception (calculated on the basis of leaf
area index) is used to determine amount of photosynthesis each day.
Carbohydrate supply and demand are balanced each day based on a sys
tem of priorities which changes during the course of the season. The
model successfully describes the growth of both defoliated and non-
defoliated plants. PMINUS is designed so that it can be easily coupled
to either a plant disease or an insect development model, as is demon
strated by the introduction of a theoretical insect population.


POD DRY WEIGHT, g/m2 LEAF AREA INDEX
101
Figure 13.
The simulated and experimental effect of removal of all leaves
from the outer 50% of the canopy at 12 weeks of age on LAI (a)
and pod dry weight (b).


132


1 DAY INC
16) WANTLF(J) = *ANTLf ( J ) F XNLEAF(J.I) A DDL E DAY INC
20 0 CONTINUE-'
PH 20AY (NOW) = DAY INC
DO 210 J = 1,MERGE
IF (XNLEAFIJ.NOW) .LT .0.01 ) GO TO 210
Pi) AY (NOW) = DAY INC
WANTLF(J) = WANTLF(J) F XNLF. AF (J NOW ) ADOLF DAY INC
2 10 CUNT INUF
IF INDEX 3 2 ) 3 00 ,5 00,3 00
300 DO 3 DO J = 1 .MERGE
N = NUM HR ( J )
IF ( N ) 3 5 0,3 5 0.3 1 0
310 DO 150 K -- 1 N
IF { 1ST CM ( J K ) ,NF. 5) G(J TO ISO
IF { NODE ( J K ) <312 4 ) GO TO 3f>0
LI. I COON T ( .), <)
IF (FHZDAY (LL ) .LT .lU'iH IM ) GO TO 350
ND>E(J,K) NODL(J.K) F 1
IC O UN T ( J K ) = MOR R O W
OLCOMZ(J,MORROW) = HLOOM2(J,MORROW) F 1.
3D J CONTINUE
500 CONTINUE
IF ( KPET.SI .cl.O > GO TO 60 0
DO 50 1 J = 1, MERGE
50 1 13 E G 5 ( J ) = 0.0
DO 310 K = KPEGGT, NOW
DO 510 J = 1, MERGE
IF (OLOOMZ(J,K) 0.01) 510,510.303
5 03 1F ( PH2D AY(K ) CONS 1 ) 509,506,3 06
503 PEGNO(J,MORROW) = PE'GNO ( J MOR; O W ) f ULOOMZ(J.K)
OLniMZ(J.K) = 0.0
IF (POO ST( J) .LL.0.0) PODST(J) = MORROW
RED = MORROW
RED = WED PO)ST(J)
IF (KPODST.EO.0) KPODST NOW
1JODCAP( J MORROW ) POVMAX SI.'RED -> RED I'lJOMAX
ASEMAX(J,MORROW) = 35.0 1.2
50) PEGS(J) = P E G 3 ( J ) f fH.nOIZ(J.K)
510 CONTINUE
IE (KPODST.50.0) GO TO 600
GRRATE = GR ATE K DAY INC
DO 512 J 1,MERGE
POPOOS ( J) = 0. 0
512 PDNOTS(J) 0.0
DO 530 K = KPODST, NOW
PODAGE(K) PODAGEIK) F DAY INC
>0 530 J 1, MERGE


SIMULATION OF PEANUT PLANT GROWTH AND THE EFFECT
OF DEFOLIATION ON GROWTH AND YIELD
By
Gail G. Wilkerson
A DISSERTATION PRESENTED TO THE GRADUATE COUNCIL OF
THE UNIVERSITY OF FLORIDA
IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE
DEGREE OF DOCTOR OF PHILOSOPHY
UNIVERSITY OF FLORIDA
1980

ACKNOWLEDGEMENTS
I wish to express my sincere appreciation to Dr. S. L. Poe for
serving as chairman of my supervisory committee during the major portion
of my graduate program, and for providing aid and advice when needed.
I also thank Dr. S. H. Kerr for assuming the role of supervisory chairman
upon Dr. Poe's departure from the University of Florida, and for providing
editorial assistance In the preparation of this manuscript.
To Dr. J. W. Jones I extend my sincere thanks for his Invaluable
assistance in all phases of this research. I would also like to thank
Dr. K. J. Boote for his help In designing the field experiments, and
Drs. T. R. Ashley and R. C. LIttell for their advice, encouragement, and
manuscript review. My appreciation also Is extended to Dr. C. S. Barfield
for reviewing the manuscript.
I especially want to thank Dr. W. G. Duncan for so kindly allowing
me to use his PENUTZ model and for discussing It with me.
To John Mangold, Carol LIppincott, Randy Stout, and Gall Childs I
express my heartfelt thanks for their help with the field work, for with
out their assistance this research would not have been possible.
I wish to thank Mary Jermann for her help in typing the final
copy of this dissertation, and I especially want to thank Barbara Lemont
for her excellent work on the graphs contained in this dissertation.
Above all, I thank my son, Trevor, for putting up with a grouchy
mom on many occasions.

TABLE OF CONTENTS
CHAPTER PAGE
ACKNOWLEDGEMENTS '
LIST OF TABLES v
LIST OF FIGURES vil ¡
ABSTRACT.
x
I INTRODUCTION 1
II GROWTH OF NON-DEFOLIATED PEANUT PLANTS. 6
Introduction
Effect of Temperature on Plant Growth
Photosynthesis
Methods and Materials
Crop Management
First Experiment
Second Experiment
Results
First Experiment
Second Experiment
6
8
8
10
10
1 1
13
1 4
14
17
THE EFFECTS OF DEFOLIATION ON PEANUT PLANT GROWTH .... 29
Introduction 29
Methods and Materials 35
First Defol iation 35
Second Defoliation 37
Third Defoliation 38
Fourth Defoliation 38
Results 39
First Defoliation 39
Second Defoliation 44
Third Defoliation 48
Fourth Defoliation 52
IV THE SIMULATION MODEL 57
Introduction 57
Description of the Model 60
Initiation of New Leaves and Branches 64
Calculation of the Day's Net Photosynthate 66
i i i

CHAPTER
PAGE
Calculation of Increases in Total Dry Weight per
Unit of Carbohydrate 72
Inactivation of Vegetative Growing Points 73
Cessation of Peg and Pod Initiation lb
INSECT Subroutine 75
Subroutine ATTAC 77
Results and Discussion 79
Comparison of Model Predictions with Growth of Non-
defol iated Plants in the Field 79
Comparison of Model Predictions with Results of
the Field Defoliations 90
Simulation of Insect Cohort Entering the Field 110
V SUMMARY AND CONCLUSIONS 115
APPENDICES
1 WEATHER DATA FOR THE 1978 GROWING SEASON 118
2 FLOW CHARTS OF THE MAJOR SUBROUTINES IN PMINUS 123
3 COMPUTER PRINTOUT OF PMINUS 151
b DESCRIPTION OF MODEL PARAMETERS 193
5 INPUT PARAMETERS AND VARIABLES DESCRIBING DYNAMICS
OF PEANUT PLANT GROWTH. 198
REFERENCES CITED 206
BIOGRAPHICAL SKETCH 210

1
2
3
k
5
6
7
8
9
10
11
LIST OF TABLES
PAGE
Average leaf growth for A Florunner peanut plants
marked weekly and harvested at 16 weeks 15
Average numbers and weights of pods of various
size categories from A Florunner peanut plants
marked on a weekly basis during 1978 and har
vested at 16 weeks of age 16
Average leaf growth for Florunner peanut plants
during the 1978 growing season, as indicated by
weekly plant samples 18
Average stem growth for Florunner peanut plants
during the 1978 growing season, as indicated by
weekly plant samples 19
Average numbers and weights of pods present on
the Florunner peanut plants harvested each week
during the 1978 growing season 20
Number of new leaves per branch during the 1978
growing season, as indicated by weekly plant
samples 21
Estimation of leaf loss by Florunner peanut plants
during the 1978 season, as indicated by weekly
plant samples 22
Comparison of specific leaf weights for leaves
initiated at the same time but harvested within
a week or at week 16 2*4
Results of linear correlations of stem size to
plant age and plant size for Florunner peanuts. ... 26
Average size of stem internodes during the 1978
season, as indicated by weekly plant samples 27
Summary of the defoliation experiments performed
during the 1978 growing season on Florunner pea
nut plants 40
v

12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
PAGE
41
43
45
46
47
49
50
51
53
54
56
61
69
89
91
94
The effect of various levels of defoliation at
4 weeks upon plant size at 7 weeks
Estimated leaf and stem gains in the 2 weeks
following defoliation at 4? weeks
Summary of light interception by plants 7 weeks
of age which had been defoliated at 4j weeks.
The effect of 50% defoliation at week 9 upon
plant size at week 11
The effect of 50% defoliation at week 9 upon
plant size at week 15
Summary of light interception by plants
defoliated at 9 weeks of age
The effect of 50% defoliation at week 12 upon
plant size at 14 weeks .
The effect of 50% defoliation at week 12 upon
plant size at week 16
Summary of light interception by plants
defoliated at week 12
The effect of defoliation at 16 weeks upon
plant size at 18 weeks
Summary of light interception by plants
defoliated at 16 weeks
A brief description of the user-written sub
routines included in PMINUS
Root growth during the 1978 growing season, as
indicated by weekly plant samples
Comparison of leaf growth in the field with
model predictions .
Comparison of model predictions with field
results for plants defoliated at 4i weeks and
harvested at 7 weeks .
Comparison of model predictions with field
results for plants defoliated at 9 weeks and
harvested at 11 weeks
vi

TABLE PAGE
28 Comparison of model predictions with field
results for plants defoliated at 9 weeks and
harvested at 15 weeks 95
29 Comparison of model predictions with field
results for plants defoliated at 9 weeks and
harvested at 14 weeks 98
30 Comparison of model predictions with field
results for plants defoliated at 12 weeks and
harvested at 16 weeks 99
31 Specific leaf weights and average size of new
leaves grown in the 2 weeks following defoliation. .104
32 Comparison of model predictions with field
results for plants defoliated at 16 weeks and
harvested at 18 weeks 106
33 Comparison of simulated and experimental (Mangold,
1979) growth of Florunner peanuts in the 2 weeks
immediately following defoliation at 8 weeks 108
34 Comparison of simulated and experimental (Mangold,
1979) yields for Florunner peanuts defoliated at
various points in the season 109
v 1 1

LIST OF FIGURES
FIGURE PAGE
1 Relationship between leaf area index and percent
light interception for Florunner peanuts planted
on 2k May 1978 28
2 Simulated and experimental leaf area index for
Florunner peanuts planted on 2k May 1978 80
3 Simulated and experimental change in leaf numbers
for Florunner peanuts planted on 2k May 1978 8l
k Simulated and experimental leaf growth for
Florunner peanuts planted on 2k May 1978 82
5 Simulated and experimental stem growth for
Florunner peanuts planted on 2k May 1978 83
6 Simulated and experimental changes in pod numbers
for Florunner peanuts planted on 2k May 1978 8k
7 Simulated and experimental pod growth for Florunner
peanuts planted on 2k May 1978 85
8 Simulated and experimental change in number of
fully expanded pods for Florunner peanuts planted
on 2k May 1978 86
9 Simulated and experimental growth of fruit filling
seeds for Florunner peanuts planted on 24 May 1978. 87
10 The simulated and experimental effect of 50% uni
form defoliation at 9 weeks after planting on LAI
(a) and pod dry weight (b) 96
11 The simulated and experimental effect of removal
of all leaves from the outer 50% of the canopy at
9 weeks after planting on LAI (a) and pod dry
weight(b) 97
12 The simulated and experimental effect of 50% uni
form defoliation at 12 weeks after planting on
LAI (a) and pod dry weight (b) 100
VI i i

FIGURE
PAGE
13 The simulated and experimental effect of removal of
all leaves from the outer 50% of the canopy at 12
weeks after planting on LAI (a) and pod dry weight
(b) .101
14 The simulated and experimental effect of 50% uni
form and 100% defoliation at 16 weeks after planting
on LAI (a) and pod dry weight (b) 107
15 The simulated effect of 10 larvae/plant entering the
field on day 35 after planting and feeding for 26 days
at an increasing rate .Ill
16 The simulated effect on LAI (a) and pod dry weight
(b) of 10 larvae/plant entering the field on day 56
and feeding for 26 days at an increasing rate 113
17 The simulated effect on LAI (a) and pod dry weight
(b) of 20 larvae/plant entering the field on day 35
and feeding for 26 days at an increasing rate 114

Abstract of Dissertation Presented to the Graduate Council of
the University of Florida in Partial Fulfillment of the Requirements
for the Degree of Doctor of Philosophy
SIMULATION OF PEANUT PLANT GROWTH AND THE EFFECT
OF DEFOLIATION ON GROWTH AND YIELD
By
Gail G. Wilkerson
June 1980
Cha i rman : S H. Ke r r
Major Department: Entomology
Field experiments were performed to produce information nec
essary for modification and expansion of an existing peanut plant
growth model so that the effects of insect defoliation could be simu
lated. In order to provide a baseline for normal growth, several
plants were selected at the beginning of the season and their growth
followed until the end of the season. In addition, plants were har
vested weekly. Plants were defoliated mechanically at Ai, 9, 12, and
16 weeks after planting and were harvested 2, A, or 6 weeks following
treatment.
Early season defoliations (at Aj weeks) resulted in reductions
in weights of all plant parts; whereas later defoliations resulted in
significantly lower stem weight to length ratios, lower pod numbers
and weights, and equal or higher leaf numbers and weights. Apparently
x

this peanut cultivar (Florunner) accumulates reserves in the stem
during the course of the season which can be utilized to grow new
leaves or to fill pods in the event of defoliation.
PMINUS is the simulation model developed on the basis of these
experiments. Plant growth depends upon physiological time and inter
cepted radiation. The model keeps track of the number and weight of
leaves, internodes, and pods initiated each day. New vegetative and
reproductive branches are initiated according to the branching pattern
of the plant. Light interception (calculated on the basis of leaf
area index) is used to determine amount of photosynthesis each day.
Carbohydrate supply and demand are balanced each day based on a sys
tem of priorities which changes during the course of the season. The
model successfully describes the growth of both defoliated and non-
defoliated plants. PMINUS is designed so that it can be easily coupled
to either a plant disease or an insect development model, as is demon
strated by the introduction of a theoretical insect population.

CHAPTER I
INTRODUCTION
Peanuts are an important food and oil crop. During the period
1967_1969, an average of nearly 45 million acres of peanuts was grown
annually throughout the world and over 1.4 million acres were grown in
the United States (McGill, 1973). The peanut agroecosystem is complex,
in that there are numerous arthropods, weeds, and diseases which attack
peanut plants and affect crop growth and yield. In addition, growth and
yield are influenced by soil and weather conditions, and by crop manage
ment practices. The effects of many of these factors are dynamic--for
example, final yield may be less affected by a given level of moisture
stress or defoliation at one time in the season than at another. Fur
thermore, there is interaction between factors; a plant that has been
weakened by disease may be less able to withstand insect defoliation.
Linker (1980), working in north Florida, noted an interaction between a
crop management practice (date of planting) and numbers of fall army-
worm, Spodoptera frugiperda (J.E. Smith), and corn earworm, Heliothis
zea Boddie, larvae obtained in his field samples. As a result of this
interaction, in 1975 and 1976 the later in the season the crop was
planted, the more insecticide treatments were required for crop pro
tection.
Given the dynamic nature of the different factors involved in de
termination of final yield, and the difficulty of designing and
1

2
performing experiments to directly determine the effects of interactions
between the various factors, modeling and computer simulation can be
effectively used in pest management programs for studying crop manage
ment decisions on the basis of overall costs and gains. In addition,
the modeling approach can be used to evaluate various hypotheses of how
particular processes in pest management systems are controlled and func
tion. For example, there is much about plant growth that is still not
fully understood, and any model of plant growth contains many explicit
or implicit assumptions about the operation of the various processes.
Although simulation cannot be used to prove that a particular process
operates in a certain manner, it can be used to separate hypotheses that
warrant further experimentation from those that are inoperable.
The purpose of my research was to develop a computer simulation
model of peanut plant growth containing the necessary mechanisms for
coupling it to an insect development model. As this research was part
of an interdisciplinary pest management project concerned with the
effects of diseases as well as insects, a model structure of sufficient
complexity to allow for the incorporation of both was needed.
There has been at least one research effort aimed at modeling the
effect of foliage-consuming insects on peanut yield (Smith and Kostka
1975). These investigators fitted a response surface of yield to plant
defoliation and plant phenology. This method of modeling has the
disadvantage that it does not allow for interactions of the various
components of the crop system which account for the final yield, and
was therefore unsuitable for the purposes of this study. There were 2
peanut plant growth models available for consideration: that developed
by Young et al. (1979) and that developed by Duncan (197^). There were

3
problems involved with using either of these models for simulation of
Insect and disease damage. PENUTZ, the model developed by Duncan (197^0,
does not Include leaf and stem components explicitly, only as vegetative
top weight. Photosynthesis each day Is based on percent ground cover
which Is calculated by considering the plant canopy as expanding circles
which eventually overlap and achieve 100% ground cover. The rate of
expansion Is determined by temperature (Duncan et al. 1978). Insects
eat leaves and the translation of feeding Into changes In canopy geom
etry would be difficult, If not impossible. Duncan's model therefore
could not be used without modification.
The model developed by Young et al. (1979) does separate leaf from
stem mass and it does store the amount of leaf mass added each day so
that leaf material of a given age can be removed from the system. This
ability to separate plant material by age is important for simulation
of either insect or disease damage. For this reason, the model of Young
and his co-workers would have been used if it had not had one serious
disadvantage. The model requires values for a large number of empirical
parameters. In order to find values for these parameters, Young et al.
fitted data for 9 planting dates each year. In many cases a parameter
value changed radically from one year to the next. There were insuffi
cient data available for determination of realistic values of these
parameters for Florida growing conditions in 1978. Duncan's model was
developed largely from data obtained in Gainesville, Florida, and I
therefore anticipated fewer problems in fitting growth of my non-defoli-
ated plants to his model. Thus a decision was made to modify his model
for this study.

i*
Of the 3 general approaches for partitioning growth into crop
components discussed by Jones and Smerage (1978), the morphogenetic
approach seemed the most applicable for the purposes of this study. In
this view of growth, individual plant organs (such as leaves and pods)
are initiated and grow for a finite time. Potential growth rates of
individual organs are calculated, sink demand is calculated for each
crop component, and growth is limited by substrate availability. A
tobacco model (Hackett 1972) and several cotton models (Stapleton and
Meyers 1971, McKinion et al. 1975, and Jones et al. 1980) have used the
morphogenetic approach to partitioning.
Duncan's PENUTZ model is based on the philosophy that the peanut
plant partitions a certain amount of the available photosynthate to the
reproductive portion of the plant and that this amount varies with cul
tivar. Since it calculates pod demand each day, it was only necessary
to add the initiation of vegetative organs and the calculation of vege
tative demands each day to develop the morphogenetic model, PMINUS, from
PENUTZ. As there were insufficient data available in the literature to
do this, experiments were designed to provide information on initiation
and rate of growth of leaves and branches and the weight and area of
individual leaves throughout the season on plants without insect damage.
The development of stems, roots, and pods was also followed in these ex
periments so that model predictions of plant growth could be verified.
Since Florunner is the most commonly grown cultivar in the United States
(Duncan et al. 1978), it was used in all experiments. These experiments
dealing with the normal growth of non-defoliated plants are discussed in
Chapter I I.

5
There were some indications in the literature that defoliation
might have a more complex effect on peanut plant growth than simply
reducing leaf area, light interception, and therefore photosynthesis.
Experiments were designed to investigate the effect of different kinds
and levels of mechanical defoliation upon plant growth--in particular
upon the plant branching pattern and the partitioning of available
photosynthate into the various plant organs. These experiments are
discussed in Chapter III.
A computer simulation model was developed, using the results of the
experiments discussed in Chapters II and III, information contained in
the literature, and portions of PENUTZ. As there were many elements of
peanut plant growth for which there was no information available for
determination of model structure and parameters, various hypotheses were
tested until a model structure and parameters were developed which suc
cessfully described growth of both defoliated and non-defo1iated plants.
Defoliation experiments performed by Mangold (1979) were then simulated
to partially validate the model. A theoretical insect population was
introduced at various points in the growing season, at 2 population
levels, to demonstrate the usefulness of the model and to investigate
the importance of time and location of damage to final yield. Chapter
IV deals with this simulation model.

CHAPTER I I
GROWTH OF NON-DEFOLIATED PEANUT PLANTS
Introduction
The Florunner cultivar of peanuts used in this study is a prostrate
member of the Virginia varietal group (Arachis hypogaea L. var. hypogaea),
according to the classification system given by Gregory et al. (1951).
As such, it is characterized by indeterminate growth and a branching sys
tem which consists of a central stem axis and variable numbers of later
al axes, including 2 prominent cotyledonary laterals. All branches
directly off the mainstem are vegetative, and all lateral branches are
vegetative in the first node and predominantly vegetative in the second
node. Nodes on vegetative branches of all orders generally occur in
alternating vegetative and reproductive pairs. Malagamba (1976) found
that the number of primary, secondary, and tertiary branches produced
by Florunner is related to planting density. In his experiments, the
2
number of primary branches/m increased linearly with increasing plant
density, while number of secondary branches reached a peak at approxi-
2
mately 30 plants/m and then declined. The number of tertiary branches
decreased with increasing plant density--there being no tertiary branches
at the higher densities.
In Florida, growth of Florunner typically proceeds in the following
manner: plants begin to emerge ca. 5 days after planting; 100% ground
cover is reached 8 to 9 weeks after planting when the LAI (leaf area
6

7
index') reaches ca. 3.0; leaf area continues to climb until week 11 or
12; and stems increase in weight until week 13. Flowering starts at
day 30 to 35, reaches a peak at 8 to 9 weeks, then declines to zero by
2
week 13. Pegs appear 1-2 weeks after the first flowers, reach a maxi
mum about 6 weeks later, then decrease in number. Pegs start to swell
about a week after they first appear; the number of pods increases until
about week 12, when it plateaus; and seeds begin to fill around day 70.
Harvest occurs between 19 and 20 weeks after planting (McGraw 1977,
McCloud 197*1, Duncan et al. 1978).
The time required to reach 100% ground cover varies with planting
density, as do the maximum LAI achieved and the number of pegs and pods
per plant (Malagamba 1975). Final yield per unit ground area is much
less affected by density, however, Cahaner and Ashri (197*0, working
with 4 Virginia-type varieties, found equal yields of mature pods for
the 3 planting densities investigated. Malagamba (1976) found a fast
increase in yield was obtained, then a slow decline phase starting at 20
2
to 22.5 plants/m .
Many flowers bloom and fail to produce pegs and many pegs fail to
develop into mature pods. Smith (1954), investigating reproductive
efficiency in a Virginia Runner variety, found 93.3% of the egg cells in
all ovules were fertilized but only 63.5% actually elongated as pegs.
Of the pegs which did elongate, only one-third reached the stage of pod
enlargement, and a third of these pods failed to reach maturity. Only
Leaf area index is the ratio of leaf area to ground area.
2
The ovary elongates as a peg and enters the ground before enlargement
of the pod commences.

8
11.4$ of the ovules present at anthesis became seeds. Smith noted that
the ovaries of pollinated peanut flowers can remain dormant for several
weeks without losing their ability to resume active fruit development
and that flowering resumes when fruits are removed. Bolhuis (1958)
found that continuous removal of flowers (thus preventing fruit devel
opment) resulted in not only a prolonged flowering period but also a
greater than normal number of flowers per plant per day. Gupton et al.
(1988) found that the order of pegging is related to the branching pat
tern of Virginia type peanuts and that the order of peg development is
essentially the same as the order of peg placement.
Effect of Temperature on Plant Growth
Temperature has an important effect on peanut plant development.
Bolhuis and DeGroot (1959) found that a temperature of 33C was too high
for normal development and a temperature of 21C was too low. In their
study of 3 varieties they noted that tolerance to different temperatures
increased as the latitude from which the varieties originated increased.
Jacobs (1951) found that vegetative and gynophore (peg) growth reacted
differently to various temperature combinations. In a study of Flori-
giant peanut plants, Cox (1979) determined that early growth was optimum
at a weighted mean temperature of 27.5C and no growth occurred at 15.5
C. Treatments 4C above or below the optimum 30/26C temperature re
sulted in less dry weight. The optimum temperature for fruit growth
(24C) was lower than that for top growth.
Photosynthesis
In a study of 5 genotypes, including 2 cultivars of Arachis hypogaea
L. and 3 wild species of Arachis, Florunner was found to have the highest

9
rate of photosynthesis by Bhagsari and Brown (1973) In an expanded
study of 31 peanut genotypes, Bhagsari and Brown (1976) again found
Florunner to have the highest photosynthetic rates. Pallas and Samish
(197*0 also found Florunner to have one of the highest rates of photo
synthesis of the extensively cultivated varieties. Even though their
plants were grown at low light intensity, they did not photosaturate at
the highest light intensity tested, which was slightly less than full
sunlight.
Pallas and Samish (197*+) noted that the photosynthetic rate of an
individual peanut leaf dropped after it was 3 or *+ weeks of age. Henning
et al. (1979) obtained similar results, with younger leaves exhibiting
higher apparent photosynthetic (AP) rates. In addition, they noted that
the mean AP rate decreased in a nearly linear fashion with increasing
plant age from 80 to l*+0 days. Trachtenberg (1976) found that leaf net
photosynthetic rates increase with leaf age until peanut leaves are
less than 2 weeks old, then decline with leaf age. The P (theoreti-
max
cal maximum photosynthesis) for individual peanut leaves in his experi-
2.
ment was calculated at 77 mg CO2 dm hr' and the Pmax for leaves
over 6 weeks old was *+3.5 mg CO2 dm"2 hr-'.
Gautreau (1973) found that differences in climatic factors greatly
affected the growth of all plant parts. He felt that differences in
light intensity were particularly responsible for differences in length
of stem internodes and of the mainstem and other branches. Cox (1978)
determined that mainstems were quite elongated under low light treat
ments and the number of flowers was markedly reduced. Hang An (1S78)
found that shading affected flowering, pegging, and size of fruit load.

10
Yield was most reduced by shading during the pod filling period (83 to
10* days after planting).
The experiments discussed in this chapter were designed to provide
basic information on normal peanut plant growth, necessary for modifi
cation of PENUTZ. In the first experiment the growth of several plants
was followed throughout the course of the season to give a unified view
of addition and loss of leaves, addition of vegetative branches, and
development of pods of a known age. The second experiment was planned
to furnish weekly estimates of LAI, the number of new 1eaves/branch,
the weight, specific leaf weight, and area of new leaves, the size of
stem internodes, and changes in weight of other plant parts. Plant
maps were made so that the time and order of initiation of vegetative
and reproductive branches could be determined. Light interception was
measured periodically throughout the season and was correlated to LAI.
The calculation of photosynthesis each day in the model could then be
based upon LAI, rather than canopy geometry, as it was in PENUTZ.
Methods and Materials
Crop Management
Florunner peanuts were hand planted 2 per hill on 2* May 1978 at
the University of Florida agronomy farm, Alachua County, Florida. The
plants were thinned to 1 per hill after emergence. Rows were 76.2 cm
apart and there were 13.8 cm between plants, giving a plant population
of 9.5 plants per m^. This is within the plant density range for maxi
mum yield (Malagamba 1976).

The soil type at the site was Arredondo fine sand. The field was
wel1 -irrigated prior to planting and irrigated again briefly the day
after planting. A tensiometer was installed in the field to measure
soil water tension at different depths and the plot was irrigated as
needed to prevent significant water stress. Rainfall and maximum and
minimum temperatures were recorded daily.
Rhiboziurn innoculum was added to the furrows at planting, and gyp
sum was applied by hand at the rate of 1700 kg/ha on 26 June. Weeds
were controlled with preplant and cracking time herbicides. Ethylene
dibromide was injected into the soil 5 days before planting for nema
tode control. The fungicide chlorothaIon i 1 was applied from 22 June
until 22 September at 7"10 day intervals. Insecticides were applied
as needed to minimize damage by foliage-feeding 1epidopterous larvae.
On 2*4 August, fensulfothion RCNB granules were hand-broadcast to slow
the spread of white mold, Sclerotiurn rolfsii. Further details of the
pesticide applications can be found in Mangold (1979).
First Experiment
For the first experiment, in which the growth of several plants
was to be followed throughout the season, 7 plants were selected on
1*4 June, 3 weeks after planting. These plants were marked once a week
until 9 August, when 2 plants were harvested. The remaining 5 were
harvested on 13 September, 16 weeks after planting. The experimental
plants were all surrounded by healthy plants which were left undisturbed
throughout the season.
Once a week each new, fully expanded leaf on the selected plants
was marked by placing a colored surgical wound clip around the petiole.

12
A leaf was considered fully expanded if the next leaf on the branch was
starting to unfold. New vegetative branches were marked by placing a
spot of acrylic paint on the axil of the leaf at the node from which
the branch was emerging. Pegs that had entered the ground during the
preceding week also were marked with colored surgical wound clips.
The color of paint and clips was different each week so that at the end
of the experiment the age of each leaf, stem, and pod could be deter
mined. The numbers of marked pegs, leaves, and stems were recorded
each week.
When the plants were brought in from the field, the location and
age of leaves, stems, and pods were mapped. The leaves were separated
by age and counted; leaf area was determined by use of a Lambda^ leaf
area meter; and after drying the leaves were weighed. Marked pods also
were separated by age and further divided into categories of P3, P4,
and P5. A P3 pod is defined as one that is slightly swollen; a P4 as
one that is fully expanded but which shrinks when dried; and a P5 is
one that is fully expanded which does not shrink when dried (Hang An
1976). The pods in the various categories were counted, then dried and
we ighed.
All plant parts in all experiments were dried at 60C for at least
48 hr prior to weighing. Data were analyzed using the Statistical
Analysis System on an Amdahl 470 V/6-11 with OS/MVS Release 3.8 and
JES2/NJE Release 3- Computing was done using the facilities of the
Northeast Regional Data Center of the State University System of Flori
da, located on the campus of the University of Florida in Gainesville.
^Lambda Instruments Corporation, Lincoln, NE.

13
Second Experiment
In this experiment 11 rows of plants were used. Sample plants
were selected from rows 2, 4, 6, 8, and 10. The other rows were left
undisturbed. Three weeks after planting, healthy plants which had a
healthy plant on each side were selected, numbered, and marked with a
flag. There were always at least 2 plants between sample plants. A
random number table was used to select the plants to be harvested each
week. Nine or 10 plants were harvested 3, 5, 6, 7, 8, 9, 10, 12, 13,
and 20 weeks after planting. On weeks 11, 14, 15, 16, and 18 the con
trol plants from the defoliation experiments performed in the same
field were used in determination of plant growth for those weeks. Each
week 3 plants were marked in a manner similar to that described in the
first experiment, and the plants were harvested the following week so
that number of new leaves, stems, and pods could be determined on a
weekly basis. These 3 plants were mapped as to location of branches,
both reproductive and vegetative, old and new leaves, and pegs and
pods. Old and new leaves were counted and weighed. A 50 or 100 leaf
let sample was measured for determination of specific leaf weight.
All the plants harvested each week were taken apart and leaves,
P1-P5, and growing points were counted. All stems were measured and
dry weights were obtained for leaves, stems, roots, vegetative growing
points, reproductive branches and pegs, petioles, P3-P5, and kernels.
Beginning when the plants were 6 weeks old, canopy interception of
photosynthetica11y active radiation (PAR) was measured periodically in
the following manner: a metal track 3 cm wide with 3 cm sides was in
serted perpendicular to the row between plants and a pyranometer^
k
Lambda Instruments Corporation, Lincoln, NE.

(LI-COR 2005) was pulled by its cord manually along the track at a con
stant rate for 1 minute. The pyranometer was connected to a quantum-
radiometer-photometer5 (LI COR 185) and printing integrator^ (LI -COR
550). PAR measurements were made on days of clear skies between 900-
1500 hours EST and an ambient full-sun reading above the canopy was
recorded within 1-2 minutes of the canopy reading.
Results
First Experiment
One of the 5 plants which were harvested 16 weeks after planting
had been attacked by white mold and thus had to be discarded. Data ob
tained on leaf growth are summarized in Table 1; that for pod growth i
Table 2. The number of new leaves per plant per week was at a maximum
during weeks 9, 10, and 11, and fell sharply after week 12. By week
16, approximately 80% of the leaves grown during the first 3 weeks
following planting had been lost, but only 3b% of the leaves grown be
tween weeks 3 and k had been lost. Most of the leaves grown after
week 5 were still present at 16 weeks. There was a sharp drop in
specific leaf weight after week 5- No new vegetative branches were
initiated after week 13.
Pegs first entered the ground between weeks 6 and 7, as can be
seen in Table 2. Some of these earliest pods failed to mature by week
16. The greatest number of pods appeared to be added between weeks 9
and 10, although about 27% of all pods escaped marking and many of
'Lambda Instruments Corporation, Lincoln, NE.

Table
1. Average leaf
growth for 4 Florunner
peanut plants
marked weekly and
harvested at
l6 weeks.
Week
No. Leaves
Marked
No. Leaves Still
Present at 16 Weeks
Leaf
Area, cm^
Specific Leaf
Wt., mg/cm^
Weight per
Leaf, mg
No. New Veg.
Growing Pts.
3
8.5
1.8
24.3
5.48
73.9
4.6
4
11.0
7.3
50.8
5.96
41.5
3.2
5
21.0
15.5
129.7
5.42
45.4
8.6
6
34.2
31.2
484.9
4. 1 1
63.9
10.4
7
34.8
33.0
777.5
3.82
90.0
5.8
8
34.2
33.0
941.4
3.74
106.7
6.0
9
44.8
39.8
1220.8
3.98
122.1
5.4
10
42.8
40.8
1097.3
4.04
108.7
1.8
11
39.5
39.0
995.3
4.10
104.6
5.0
12
34.8
34.8
833.6
4.23
101.3
1.4
13
25.2
25.0
492.3
4.27
84.1
1.2
14
18.2
16.5
280.7
4.24
72.1
0.0
15
10.5
10.5
164.6
4.12
64.6
0.0
16
10.2
10.2
167.4
4.17
68.5
0.0

Table 2.
Average numbers and
marked on a weekly
weights of pods of various size
basis during 1978 and harvested
categories
at 16 weeks
from 4
of age.
Florunner peanut plants
Week Peg
Entered
P3 at
Harvest
P4 at
Harvest
P5 at
Harvest
Total
at
Pods Present
Harvest
Kernel Weight
Ground
Numbe r
Weight, g
Number
Weight, g
Numbe r
Weight, g
Number
Weight, g
at Harvest, g
6-7
0.0

0.6
0. 1
2.4
3.0
3.0
3.0
2.5
CO
0.2
0.0
1 .2
0.7
5.0
6.7
6.4
7.4
LA
LA
8-9
o
OO
0.0
1.2
0.4
6.0
6.5
8.0
6.9
5.4
9-10
2.0
0. 1
3.6
1.7
1 1.4
11.7
17.0
13.4
9.6
10-11
1.8
0. 1
OO
1.8
6.8
5.5
12.4
7.4
4.3
11-12
1.2
0.0
2.0
0.7
2.0
1.6
5.2
2.4
1.2
12-13
0.0

0.6
0.1
0.4
0.3
1.0
0.4
0.3
13-14
0.2
0.0
0.2
0.0
0.0

0.4
0.1
0.0
14-15
0.0

0.0

0.0

0.0


15-16*
6.8
0.2
2.2
0.5
11.4
12.5
20.4
13.2
10.2
Actually pods that were not marked.

17
these were early pods close to the base of the plant with little or no
peg visible above ground. Very few pods were added after week 12.
Weather data for the growing season are summarized in Appendix 1.
Second Experiment
Leaf, stem, and pod growth are summarized in Tables 3, and 5,
respectively. Based on the number of new leaves and the ratio of stem
weight to length, both leaf and stem growth seemed essentially to cease
after week 14. As can be seen in Table 3, specific leaf weight and
weight per leaf of new leaves changed rather abruptly twice during the
seasonbetween weeks 5 and 6 and again between weeks 10 and 11. Num
ber of new leaves per active vegetative meristem also decreased between
weeks 10 and 11 (Table 6). The number of active vegetative growing
points was derived from a study of the plant maps made of the 3 marked
plants harvested weekly. From week 9 on, some growing points were
being inactivated even as new ones were being initiated closer to the
exterior of the canopy. Presumably this was due to a lack of light
penetration to the interior of the canopy.
No consistent pattern of leaf loss could be determined from the
available data (Table 7). Even though an attempt was made to minimize
size differences between plants of the same age by hand planting the
seeds and by selecting only plants which met certain criteria at week
3, large differences still existed in plant size each week, and thus
larger samples would have been necessary to separate leaf loss from
sample variability. It appears in Table 7 that some stress between
weeks 7 and 8 caused the plants to lose about 20 leaves and then more
leaves were not lost until week 13.

Table 3-
Average
weekly
leaf growth
plant samples
for Florunner peanut plants
during the
1978 growing
season, as indicated by
Week
G rowth
of Leaves
During the Preceed
ing Week
Tota 1
F rom
No. New
Wt. New
Specific Leaf
Weight per
Number of
Total Leaf
Weight per
Planting
LA 1 *
Leaves
Leaves, g
Wt., mg/cm2
Leaf, mg
Leaves
Weight, g
Leaf, mq
3
0.04
10.8
0.2
4.66
20.4
10.8
0.2
20.4
4
0.08
7.4
0.2
4.92
28.4
16.8
0.4
25.6
5
0.16
11.8
0.6
5.05
50.0
28.0
0.9
31. r
6
0.73
24.0
2.0
3.66
81.2
60.8
3.3
54.6
7
1.49
36.5
3.6
4.00
99.3
80.7
6.5
80.3
8
2.05
41.8
3.4
3.68
80.4
109.7
8.7
79.3
9
3.62
50.8
5.0
3.73
98.1
164.1
15.0
91.7
10
3.49
30.7
2.6
3.78
84.1
162.7
13.8
85.1
11
4.97
35.5
2.6
3.27
72.1
223.1
17.6
79.0
12
6.55
50.0
3.5
3.09
69.2
277.8
25.0
89.9
13
5.68
20.7
1.5
3.39
71.1
280.3
21.7
77.4
Hi
6.23
20.7
1.6
4.02
76.4
261.5
24.8
94.7
15
6.43
3.0
0.2
3.17
50.0
276.5
24.7
89.3
16
6.09
3.3
0.2
3.51
60.0
229.7
22.8
99.3
17**
6.75
0.3



306.0
26.7
87.2
18
6.24
0.0



286.0
25.4
88.7
20
5.15
0.0



226.7
24.3
107.2
'-Leaf area index.
"Only 3 plants harvested this week.

19
Table 4. Average stem growth for Florunner peanut plants during the 1978
growing season, as Indicated by weekly plant samples.
Week
Ma1nstem
Length, cm
Total Stem
Length, cm
Stem
Weight, g
Ratio of Stem Weight
to Length, mg/cm
3
5.0
13.5
0. 1
9.4
4
5.9
21.5
0.2
8.0
5
7.1
35.1
0.4
9.9
6
9.9
101.2
1.5
13.7
7
12.0
199.5
2.9
14.4
8
18.1
403.8
7.0
16.1
9
23.9
609.2
13.2
18.7
10
29.1
787.4
14.9
18.4
11
35.7
1051.3
22.7
21.1
12
38.9
1267.4
27.4
19.6
13
44.6
1403.4
31.0
23.1
14
43.1
1245.0
30. 1
24.9
15
49.2
1483.8
33.6
22.2
16
46.4
1218.6
28.6
23.2
17-
38.8
1408.0
28.7
20.4
18
52.3
1471.7
35.0
22.5
20
40.1
1081.4
26.7
24.8
Only 3 plants harvested this week.

20
Table 5. Average numbers and weights of pods present on the Florunner
peanut plants harvested each week during the 1978 growing
season.
o"! No. No. o"! F4 No. P5 Kerne 1
Week PI P2 P3 P4 Wt. g P5 Wt. g Wt. g
7
2.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
8
3.3
6.3
1.6
0.0
0.0
0.0
0.0
0.0
9
12.8
13.9
11.1
2.3
0.6
0.8
0.3
0.4
10
18.6
13.2
16.4
8.8
1.9
1.0
0.4
0.4
11
20.3
27.9
34.4
10.4
1.9
18.9
9.3
5.6
12
17.8
44.0
46.7
17.2
2.3
23.0
14.1
9.7
13
16.0
24.3
47.6
20. 1
4.6
31.2
24.9
18.3
14
15.9
23.5
30.7
21.9
6.6
30.3
27.4
20.9
15
7.6
20.4
34.4
17.5
5.4
43.0
40.3
31.3
16
6.A
19.3
17.5
14.5
5.9
42.3
48.0
37.3
17*
16.3
22.3
43.7
30.3
11.0
58.3
61.5
49.1
18
9.6
17.5
26.3
22.4
6.5
57.1
63.7
51.4
20
7.7
14.3
14.3
17.6
6.0
55.4
63.6
49.8
:':0nly 3 plants harvested this week.

3
4
5
6
7
8
9
10
11
12
13
14
21
Number of new leaves per branch during the 1978 growing season,
as indicated by weekly plant samples.
Estimated Number of Active
Veg. Growing Points/Plant
4.6
7.8
16.4
26.8
30.1
34.6
28.0
31.3
39.1
17.8
20.7
Estimated Number of New Leaves/
Active Veg. Growing Point
1.6
1.5
1.5
1.4
1.4
1.5
1.6
1.1
1.3
1.2
1.0

22
Table 7.
Estimation of
1978 season,
leaf loss by
as indicated
Florunner peanut plants during the
by weekly plant samples.
Week
from
Planting
No. of New
Leaves Grown
During Week
Sum of
Leaves Added
Each Week
Actual Mean No.
Leaves Present
Plant 1 2 SE
of
per
Est¡mated
No. of Leaves
Lost to date*
3

10.8
10.8 + 2.2

4
7.4
18.2
16.8 + 2.7
1.4
3
11.8
30.0
28.0 + 6.2
2.0
6
24.0
54.0
60.8 + 12.5
6.8
7
36.5
90.5
80.7 + 17.2
9.8
8
41.8
132.3
109.7 + 28.0
22.6
9
50.8
183.0
164.1 + 36.5
18.9
10
30.7
213.7
162.7 + 40.2
51.0
11
35.5
249.2
223.1 + 66.2
26.1
12
50.0
299.2
277.8 + 48.4
21.5
13
20.7
319.9
280.3 + 64.6
39.6
14
20.7
340.6
261.5 + 63.8
79.1
15
3.0
343.6
276.5 + 49.0
67.1
16
0.0
343.6
229.7 + 33.8
113.9
17
0.0
343.6
306.0 + 45.6
37.6
18
0.0
343.6
286.0 + 72.4
57.6
20
0.0
343.6
226.7 + 38.1
116.9
-'Column 3 Column 4

23
Leaves continued to add weight for a time after they were con
sidered fully expanded in this study. The specific leaf weight of the
new leaves each week (Experiment 2) is compared in Table 8 with that of
leaves marked during the same week but not harvested until week 16
(Experiment 1).
Pegs were first present on plants harvested at week 7 (Table 5).
Pods first started to swell at week 8 and there were fully expanded
pods (PVs and P5's) present by week 9- The number and weight of pods
in the largest size category (P5's) continued to increase until week
17. The number of aerial pegs (Pi's) decreased after week lA.
The branching pattern of Florunner turned out to be more variable
than the literature indicated for Virginia peanuts (Gregory et al. 1951,
Wynne 1975). According to Gregory et al. (1951), the branching pat
tern should be vegetative in the first node, mostly vegetative in the
second node, then have alternating pairs of reproductive and vegetative
nodes. In a study of the first 2 nodes on the 2 cotyledonary laterals
and the first branches off the mainstem on 20 plants mapped when leaf
and stem growth had essentially stopped, only 72.5% of these branches
were vegetative in the first node, and 29.2% in the second node. For
the most part, however, the cotyledonary laterals and first h branches
off the mainstem had more vegetative nodes than expected. There were
frequently 3 or b vegetative nodes in a row, and sometimes as many as
6. A common pattern was 1 vegetative node, 1 reproductive node, then
3 or vegetative nodes, then alternating pairs of reproductive and
vegetative. Later branches for the most part exhibited the expected
branching pattern. This variation had the effect of making most early

24
Table 8. Comparison of specific leaf weights for leaves initiated at
the same time but harvested within a week or at week 16.
Interval of
Leaf Initiation,
Weeks
Spec ific Leaf
Weight, mg/cmz
Leaves Harvested at
End of Week
Leaves Marked at End
of Week but Harvested
at Week 16
0-3
4.66
5.48
3-4
4.92
5.96
4-5
5.05
5.42
5-6
3.66
4.11
6-7
4.00
3.82
CO
1
3.68
3.74
8-9
3.73
3.98
9-10
3.78
4.04
10-11
3.27
4.10
11-12
3.09
4.23
12-13
3.39
4.27
13-14
4.02
4.24
14-15
3.17
4.12

25
nodes vegetative, and this perhaps contributes to the high-yielding
capability of Florunner.
Although there was a large amount of variation between plants of
the same age in stem length and weight, the ratio of stem weight to
length was closely correlated to plant age; in fact, there was a much
higher correlation between this ratio and plant age than between it and
plant size, when total length of all stems was used as the measure of
plant size (Table 9)- Internode length and weight also depended more
on plant age than on plant size (Table 9)- Table 10 is a summary of
week versus internode length and internode weight. Both length and
weight per internode remained constant for the first 5 weeks after
planting, then began to increase. Weight increased steadily until
week 16, but average length was somewhat more variable from week to
week.
Figure 1 is a graph of the measured canopy light interception
versus LAI. The fitted equation has an value of 0.98.
The results of these experiments as they relate to the develop
ment of the plant growth model will be discussed in greater detail in
Chapter IV.

26
Table 9. Results of linear correlations of stem size to plant age and
plant size
for
F1orunner
peanuts.
Dependent
Variable
Independent Variable(s)
~rT~
Ratio of
stem weight
to
1ength
Week of the season
0.78
Ratio of
stem weight
to
1ength
Total stem length
0.40
Ratio of
stem weight
to
1ength
Week of the season,
total stem length
0.78
1 nternode
we ight*
Week of the season
0.80
Internode
length**
Week of the season
0.67
Internode
weight*
Number of leaves
(internodes)
0.46
*lnternode weight was estimated by dividing total stem weight by the
number of leaves on the plant.
''"Internode length was estimated by dividing total stem length by the
number of leaves on the plant.

27
Table 10.
Average size of stem internodes during
indicated by weekly plant samples.
the 1978 season, as
Week
Internode Length, cm*
Internode Weight, mg**
3
1.25
12.3
4
1.27
10.0
5
1.21
12.7
6
1.58
22.1
7
2.31
33.4
8
3.49
57.5
9
3.94
77.0
10
4.43
85.1
11
4.62
97.4
12
5.15
101.1
13
4.96
112.9
14
4.64
114.9
15
5.36
119.3
16
5.46
125.8
17
4.58
93.3
18
5.12
114.8
20
4.70
116.7
'Average internode length for each plant was estimated by dividing the
total stem length by the number of leaves (internodes) on the plant.
**Average internode weight for each plant was estimated by dividing the
total stem weight by the number of leaves (internodes) on the plant.

90
80
70
60
50
40
30
20
10
0
_J I
1.0 2.0
_J I I l l I
3.0 4.0 5.0 6.0 7.0 8.0
Leaf Area Index
1. Relationship between leaf area index and percent light interception for Florunner peanuts planted
on 24 May 1978.
OO

CHAPTER I I I
THE EFFECTS OF DEFOLIATION ON PEANUT PLANT GROWTH
I ntroduction
There have been several studies on the effect of various degrees
of defoliation upon final yield in peanuts. There is little in the
literature about the physiological response of peanut plants to leaf
remova1.
Greene and Gorbet (1973) defoliated Florunner peanuts with a mow
ing machine, approximating 10-15, 20, 33, and 50% defoliation by
changing wheel settings. They found that 33% defoliation at several
growth stages decreased yields. Since their method of defoliation also
removed petioles, stems, and pegs and cut across major trunks of the
vascular system of the plant, their results are not applicable in de
termining the effect of foliage-feeding insects upon the plant.
Enyi (1975), working in Africa, performed defoliation experiments
on the Dodoma edible variety of peanuts. In this experiment, flowering
began A weeks after sowing, pegging at 8 weeks, and podding at 11. He
removed either 50% (2 of the 4 leaflets on each leaf) or 100% of the
foliage at weekly intervals (plants were defoliated only once). Plants
were harvested at the end of the season and dry weights for stems, pods,
and seeds determined. Complete defoliation significantly reduced ker
nel weight and pod number, the greatest reduction occurring when leaves
were removed 12 weeks after sowing. Complete defoliation also reduced
weight of pods, dry weight of stems, and individual kernel size. Half
29

30
defoliation at 8 and 12 weeks significantly reduced the weight of 1000
kernels, while half defoliation at any time between ^ and 1^ weeks
(the extent of the experiment) significantly reduced pod number per
plant and dry weight of stems. In fact, in correlating pod number (N)
to stem dry weight (S) he found that a variation in S accounted for
about 80% of the variation in N between treatments (R=0.896). A simi
lar correlation existed between pod dry weight and stem dry weight
(R=0.913) Defoliation always significantly increased shelling per
centage. Enyi hypothesized that defoliation reduced pod number by
depressing growth of stems and consequently reducing the number of
flowering nodes, the number of pegs formed, and hence the number of
pods per plant.
Nickle (1977), working in Gainesville, Florida, defoliated the
Florunner variety of peanut from 25 to 100% by removing from 1 to k
leaflets from each leaf. He defoliated plants at 3, 6 (beginning of
flowering), 9 (pegging), 12 (beginning of pod filling), and 15 weeks
of age. Some plots were defoliated 50% 2 or more times. For example,
50% of the leaves were removed at 3 weeks and 50% of the new foliage
was removed 3 weeks later. He obtained dry weights for the leaves re
moved at each treatment period, and dry weight and quality of nuts per
treatment plot at harvest. For all single defoliation levels he found
greatest yield reduction at 9 weeks, followed by 12 weeks. A single
defoliation at 3 or 6 weeks resulted in a delay of flower production by
as much as 2 weeks. Defoliation at 9~12 weeks inhibited floral pro
duction or, if severe, caused flower drop and cessation of flower
production. It also resulted in a delay or cessation of the pegging

31
process. Yields from single defoliations of 50% or more at 9, 12, and
15 weeks had a higher percentage of split and damaged nuts than the
controls, but the percentage of sound, whole nuts from multiple defoli
ation treatments was significantly higher than that from the control.
A comparison of leaf biomass removed in single defoliations with
that removed in multiple defoliations indicates that defoliated plants
probably put on greater new leaf mass between treatments. For example,
35-6 g/plant total leaf weight was removed from plants defoliated at
9 and 12 weeks, whereas only 30.1 g was removed from plants defoliated
at 12 weeks.
Williams et al. (1976) studied the influence of defoliation and
pod removal on growth and dry matter distribution of the Makulu Red
variety of peanuts in Rhodesia. Normal growth of this variety in
Rhodesia, as reported by Williams et al. (1975), proceeds as follows:
flowering begins 55 days after planting, continuing until 100 days.
Stems increase in weight until 18 weeks after sowing, as does the plant
as a whole. Leaf area reaches a maximum at 16 weeks, kernels start to
form at 12 weeks, and pegs reach a maximum number at 20 weeks, as do
the pods. Kernel number is set at 22 weeks. In their defoliation and
depodding experiments, Williams et al. (1976) defoliated 0, 50, or 75%
and depodded either 0 or 50% at 3 stages of growth (17, 19, and 21
weeks). They defoliated by removing leaflets from each leaf and de
podded by severing at ground level all pegs on one half of the plant.
The plants were harvested and measured 2 weeks after the treatment.
Defoliation at all periods greatly increased leaf growth rate over the
control. At 17 and 19 weeks, defoliation of 75% increased leaf growth
rate more than 50% defoliation did. The reverse occurred at 21 weeks.

32
Stem growth rate was correspondingly slowed by defoliation. In plants
that were both depodded and defoliated, stem growth rate was not as
severely decreased as in plants with only defoliation. The results
also indicated that few if any pods were initiated when the plants
were depodded at 21 weeks--in fact the plants appeared to abort pods
at this stage if they were defoliated but not depodded. Williams et al.
(1976) hypothesized that the increased leaf growth with defoliation and
corresponding decrease in stem growth could be accounted for by in
creased mass per unit area of leaf, due possibly to greater accumulation
of assimilated material in leaves no more completely illuminated.
Differences in branching patterns between varieties of peanuts
may affect the response to leaf removal. Smith and Jackson (197^) found
that defoliation of Florunner decreased final yeild less than did an
equal percentage of defoliation of Starr peanuts (a Spanish variety).
This difference might be explained by the determinate branching system
of Spanish peanuts (Gregory et al. 1951) as opposed to an indeterminate
branching pattern in Florunner and the consequent ability of Florunner
to put on more new leaves when defoliated. Fehr et al. (1977) found
that defoliated determinate cultivars of soybeans had significantly
greater yield reduction than did indeterminate cultivars similarly
defoliated. They also found that the indeterminate cultivars put on
more new leaves following defoliation than did the determinate ones.
In addition, the number of new leaves produced after defoliation sig
nificantly exceeded the number for the untreated check at some growth
stages. Rudd et al. (1980), in modelling soybean growth, found that
their model overestimated the damage done to final yield by 1 mechanical

33
defoliation just prior to pod appearance unless they allowed the plant
to "compensate" for leaf loss by using photosynthate destined for
temporary storage in the stems to produce extra leaves instead.
The experiments discussed in this chapter were designed to deter
mine the effects of mechanical defoliation on certain aspects of plant
growth. Severe uniform defoliation (50% or more) appears to have the
effect of increasing growth of leaves (Nickle 1977, Williams et al.
1976) and decreasing stem growth (Enyi 1975, Williams et al. 1976), at
least until fairly late in the season. This could happen if leaves
left on the plant gain in weight (as suggested by Williams and his co
workers) and stems stop or slow down growth (as suggested by Enyi).
Alternatively, the plants might grow leaves at an increased rate at
current growing points and/or initiate new growing points at previously
inactive vegetative nodes. New growing points might be initiated only
in places where light penetrates due to the defoliation. This in
creased growth of leaves when photosynthetic supply has been decreased
could be accomplished by depletion of storage reserves (probably in the
stems) or by a change in the partitioning of available photosynthate
to the various plant organs.
It appeared likely that defoliation at different times in the
season would have different effects on plant growth. Early in the
season with the plants growing at a maximum rate, defoliation was ex
pected to have the effect of slowing down vegetative growth of the plant
and thus delaying the time of full ground cover, and podsetting during
pegging and podsetting. It was hypothesized that defoliation would de
crease the number of fruit set, due to a decrease in available photo
synthate and a shift in photosynthate partitioning to new leaves at a

3 ^
tme when vegetative growth would normally be decreasing. After the
pod load is set, defoliation was expected to result in the plant fill
ing fewer pods.
There are indications that defoliating caterpillars may attack
younger leaves or terminal buds (vegetative growing points) preferen
tially (Huffman 197^, Arthur et al. 1959, Morgan 1979). I anticipated
that the type of defoliation would make at least some difference in the
plant response. Most prior defoliation experiments on peanuts have
dealt with uniform defoliation (removing a certain number of leaflets
from each leaf). It appeared likely that this would change light in
terception and plant growth in a different manner than an equal amount
of non-uniform defoliation (removing an outer layer of leaves, for
example).
Four defoliation experiments were performed to investigate these
questions about plant response to defoliation. The purpose of the
early season defoliations was to determine the effect of several levels
of defoliation and the effect of removal of vegetative meristems alone
or in combination with partial or complete defoliation. The second and
third defoliations investigated the effect on subsequent plant growth
of severe defoliation (50%) by 2 different methods (removing 2 leaf
lets from each leaf, or removing 100% of the leaves from the outer 50%
of the canopy) at the pegging and podsetting stages of growth. The
final experiment dealt with the effect of 50% uniform and total defolia
tion late in the season. The 50% defoliation treatment was for com
parison with the earlier experiments; the 100% defoliation was intended
to reveal the presence or absence of storage reserves in the stems, as

35
vegetative growth should have ceased prior to defoliation time. All
the experiments were designed to determine growth of new leaves, growth
of pods, and growth of stems, as indicated by changes in length, weight,
and length to weight ratio, following defoliation.
Methods and Materials
First Defoliation
The first defoliation plot was planted on 22 May with a row and
intrarow spacing identical to that described in Chapter II. Other
aspects of crop management were identical also. The plants were de
foliated on 23 June, bj weeks after planting.
The experiment consisted of 7 treatments applied to 5 blocks.
Plants were blocked by row. Seven treatment plots were selected in
each row with at least 2 plants between treatments. Each treatment
plot consisted of 5 plants, but only the 3 interior plants were in
cluded in the sample.
The 7 treatments were:
1 Check
2. 25% uniform defoliation
3. 50% uniform defoliation
b. 100% uniform defoliation
5. 50% uniform defoliation + 100% of the vegetative growing
points
6. 100% defoliation + 100% of the vegetative growing points
7. 0% defoliation + 100% of the vegetative growing points.

36
Uniform defoliation refers to removing the same number of leaflets
from each ^-leaflet leaf on the plant. Only leaves which had another
leaf starting to open above them on the branch were defoliated or
marked. Growing points were removed by snapping off newly forming
leaves as far down within the stem as possible.
Plants in treatments 1 and 7 were marked with surgical wound clips
and acrylic paint as discussed in Chapter II. A surgical wound clip
was placed around the petiole of each fully expanded leaf, and all
stems were marked with a spot of paint. The stems of treatments 2-6
plants were also marked with paint and the defoliation process itself
adequately marked the leaves. Removed leaflets from each treatment
were measured and then dried and weighed.
The plants were harvested 7 weeks after planting--25 weeks follow
ing treatment. One plant from each treatment plot was selected for
mapping. This plant was the "average" plant in that it was intermedi
ate in size between the other 2 sample plants contained in the plot.
The positions of new and old leaves and branches were noted and each
stem was given a code number and measured. Each harvested plant was
broken down into the following parts: old leaves, new leaves, petioles,
stems, vegetative growing points, pegs and reproductive branches, and
pods. Leaves were counted and a subsample was measured for leaf area.
The numbers of new and old stems and number of pegs were obtained. All
stems were measured. The various plant parts were then dried and
weighed.
Canopy light interception was measured for each treatment plot
in 2 rows just before the plants were harvested, in the manner dis
cussed in Chapter I I.

37
Second Defoliation
Plants for this experiment were in the same field as those in
Chapter II, and all crop management practices were identical. The
plants were defoliated 9 weeks after planting, and half were harvested
2 weeks after treatment; the other half 6 weeks post treatment. The
experiment consisted of 6 treatments applied to 4 blocks. Plants were
again blocked by row, there being a buffer row between treatment rows
and at least 2 plants between treatment plots in a row. Again there
were 5 plants per treatment plot, but only the interior 3 were in
cluded in the sample. Plants were dug up by shovel to save as many
pods and roots as possible.
The 6 treatments were:
1. Check--harvested at 11 weeks
2. 50% uniform defoliation--harvested at 11 weeks
3. Removal of all leaves from the outer 50% of the canopy-
harvested at 11 weeks
4. Check--harvested at 15 weeks
5. 50% uniform defoliation--harvested at 15 weeks
6. Removal of all the leaves from the outer 50% of the canopy-
harvested at 15 weeks.
For treatments 3 and 6 the outer 50% of the canopy was determined on a
volume basis. Several measurements were made to determine the average
height and width of the canopy and the cross-sectional area was calcu
lated using the formula for an ellipse. The proper height and width
were then calculated to obtain a canopy with only ? the original cross-
sectional area. Wires were bent across the canopy delineating this

38
area and all leaves falling outside of the wires were removed; those
inside were left alone.
Leaves and stems were marked in a manner Similar to that of pre
vious experiments except only the last 2 leaves on each branch were
marked. Pegs that had entered the ground also were marked with wound
clips. In this experiment any newly emerging leaf also was removed if
the petiole was extended sufficiently for a wound clip to be placed
around it.
When the plants were harvested, plant parts were separated, weighed,
counted, and measured as in the other experiments and 1 plant from each
treatment plot was mapped. This time pods were divided into marked
versus unmarked and then into size categories P3~P5 After drying and
weighing, nuts in the P5 category (fully expanded shell which did not
shrink upon drying) were shelled and weighed.
Canopy light interception measurements were made in the treatment
plots the day after defoliation and just before the 2-week harvest.
Third Defoliation
The third defoliation was performed when the plants were 12 weeks
old. This experiment was identical to the second defoliation except
that pegs were not marked and plants were harvested 2 and b weeks after
treatment.
Fourth Defoliation
The last series of defoliations took place when the plants were 16
weeks of age. As it was late in the season, the treatments were 50%
uniform and 100% defoliation. All plants were harvested 2 weeks later.

39
As there was little vegetative growth at this late stage, no plant
maps were made.
Table 11 is a summary of the times and types of defoliations made
during the course of the season.
Results
First Defoliation
The results are summarized in Table 12. All plant parts appeared
to be affected equally by defoliation, i.e., if stem weight was re
duced, so were stem length and leaf number and weight (Table 13)- The
fact that the average values for the 50% defoliation treatment were
generally higher than those for the 25% defoliation treatment (Table
12) is perhaps due to the higher initial LAI for the 50% defoliation
plots. Mean LAI for the 25% defoliation plots was 0.10 just prior to
defoliation, whereas that for the 50% defoliation plots was 0.16. The
unevenness of planting depth caused some problems in that plants
emerged at different times and this had an effect upon plant size
throughout the season. Blocking by row partially overcame this prob
lem as is indicated by significant differences (a= .05) between rows
in average cotyledonary lateral length, total stem length, root weight,
and the number of old leaves. There was variation in plant emergence
and size within rows too and this resulted in the plants in some treat
ment plots being larger on average than those in other treatment plots
prior to defoliation.
Plant response to growing tip removal was quite uniform. Removing
the apical meristem destroyed apical dominance. If either of the first

40
Table 11. Summary of the defoliation experiments performed during the
1978 growing season on Florunner peanut plants.
Week from Treatment Week
Plant ing Number Treatment Type Harvested
9
12
16
1
2
3
4
5
6
7
Check
25% un i form
50% uniform
100%
50% uniform + veg. growing pts.
100% uniform + veg. growing pts.
0% + vegetative growing points
7
7
7
7
7
7
7
1 Check
2 50% uniform
3 Outer 50% of the canopy
4 Check
5 50% uniform
6 Outer 50% of the canopy
1 Check
2 50% uniform
3 Outer 50% of the canopy
4 Check
5 50% uniform
6 Outer 50% of the canopy
1 Check
2 50% uniform
3 100%
1 1
1 1
1 1
15
15
15
14
14
14
16
16
16
18
18
18

Table 12. The effect of various levels of defoliation at 4 weeks upon plant size at 7 weeks.
Mainstem Stem
Treatment Length, cm* Length, cm*
Check
17.5
(0.7)
298.5
(32.2)
25% uniform
14.8
(0.7)
216.8
(28.3)
50% uniform
16.7
(0.8)
250.0
(31.6)
100%
13.9
(0.9)
192.2
(26.8)
0% + vegetative
growing points
12.1*
(0.9)
206.3
(24.6)
50% + vegetative
growing points
12.2
(0.5)
143.8
06.2)
100% + vegetative
10.8
(0.5)
94.6
(10.8)
growing points
Avg. Cot. Lat. Stem Ratio of Stem Wt.
Length, cm*Weight, g* to Length, mg/cm*
23. 1
(1.1)
4.0
(0.6)
12.9
(0.4)
18.7
(1.5)
2.8
(0.5)
12.5
(0.4)
21.5
(1.2)
3.5
(0.5)
13.4
(0.5)
16.5
(1.6)
2.3
(0.4)
11.6
(0.4)
14.8
(1.1)
2.5
(0.4)
11.3
(0.7)
13.6
(1.1)
1.6
(0.2)
10.8
(0.5)
10.8
(0.7)
0.9
(0.1)
9.6
(0.5)
'Number in parentheses is standard error of the mean.

Table 12. Continued
T reatment
Numbe r
G rowin g
of Veg.
Points*
Number of
New Leaves
Check
31.8
(3.2)
72.2
(6.*t)
25% uniform
28.5
(2.0)
57.*4
(*4.7)
50| uniform
30.9
(3.0)
61.*4
(6.0)
100%
28.7
(3.M
5*4.1
(5.6)
0% + vegetative
growing points
25.7
( 1 *4)
52.6
(5.2)
50% + vegetative
growing points
2*4.5
(2.6)
*45.5
(*4.2)
100% + vegetative
18.7
(2.1)
32.6
(3.0)
growing points
-Number in parentheses is standard error of the mean.
Weight of Root Total Plant
New Leaves g*Weight, g*Weight, g*
5.2
(0.7)
0.6
(0.
1)
1*4.*4
(1.9)
3.9
(0.5)
0.6
(0.
1)
10.8
0.5)
5.0
(0.6)
0.6
(0.
1)
13.0
0.6)
3.*4
(0.5)
0.5
(0.
1)
8.3
0.2)
3.0
(0. *4)
0.5
(0.
.1)
9.2
0.3)
2.1
(0.3)
0. *4
(0.
1)
6.*4
(0.9)
1.0
(0.1)
0.3
(0.
.0)
3.*4
(0. *4)
-E-
tvj

43
Table 13.
Estimated leaf
defoliation at
and stem gains in
4 weeks.
the 2? weeks
following
Treatment
Estimated
Original
Stem Wt., g
Estimated
Gain in
Stem Wt. g
Gain in
Leaf Wt., g
ALeaf
ALeaf+AStem
Check
3.0
3.7
5.2
0.58
25% uniform
2.8
2.6
3.9
0.60
50% uniform
3.6
3.1
5.0
0.62
100%
3.6
1.9
3.4
0.64
0% + tips
3.5
2.1
3.0
0.58
50% + tips
3.2
1.3
2.1
0.62
100% + tips
4.8
0.4
1.0
0.70
-'Original stem weight was estimated by dividing the original leaf weight
by 0.70 to find stem weight + leaf weight. Subtracting leaf weight from
this gave original stem weight. (The ratio of leaf weight to leaf + stem
weight averaged 0.70 for non-defo1iated plants until week 8.)

2 nodes below the destroyed tip was vegetative, a new branch would grow
out of the end of the former branch, with only a scarred stub over to
one side to mark the end of the original branch and the beginning of the
new. The branching pattern of this new stem was that expected for a
vegetative branch, there being no leaf at the first node. If the 2
nodes directly below the destroyed tip were both reproductive then a
flower would emerge at both nodes, but there would be no vegetative
growth.
Table 14 is a summary of the light interception results for this
experiment. The weather was unsuitable for taking measurements for
several days prior to harvest and it was therefore not possible to make
as many readings as necessary to obtain an accurate picture of LAI ver
sus percent light interception.
Second Defoliation
Tables 15 and 16 are summaries of the results for plants harvested
at 11 and 15 weeks, respectively. In the removal of all the leaves
from the outer 50% of the canopy in treatments 3 and 6, more than 50%
of the leaf matter by weight was removed. Two weeks after treatment,
plants defoliated 50% uniformly had as many new leaves as non-defoli-
ated plants, and the ratio of stem weight to length was significantly
reduced. Plants from which the exterior 50% of the canopy was removed
had significantly more leaves than non-defoliated plants. They also had
significantly more new vegetative growing points and a significantly
reduced stem weight to length ratio. Weight of new leaves was also
significantly higher. A study of the plant maps indicated that the new

45
Table )4. Summary of light interception by plants 7 weeks of age which
had been defoliated at 4 weeks.
Treatment Type
Row
LAI
Percent Light
1 n te rcepted
Check
B
1.89
46.9
E
1.80
50.8
25% uniform
B
1.53
48.4
E
0.62
29.6
50% uniform
B
1.06
33.3
-
E
1.78
36.9
1 00%
B
0.77
32.0
E
0.68
36.6
50% uniform + tips
B
0.66
44.7
E
0.42
22.7
100% + growing tips
B
0.27
20.2
E
0.35
20.6
0% + growing tips
B
0.82
26.9
E
1.39
24.7

Table 15. The effect of 50% defoliation at week 9 upon plant size at
week 11.
T reatment
Plant Variable
Check
50% Uniform Outer
50% of Canopy
Number of new leaves
52.9b
56.7b
86,8a
Weight of new leaves, g
4. 4b
5.3ab
7.0a
Ratio of stem weight to
length, mg/cm
21.3a
18. lb
18.7b
Number of vegetative
growing points
*9.6b
58.lab
72.2a
Number of new vegetative
growing points
14.4b
14.1 b
25.9a
Number of PI*
19.3b
27.lab
35.1a
Number of P5
19.8a
1 3.9ab
7.7b
P5 weight, g
9.9a
7.0a
4.0b
Kernel weight, g*
6.0a
4.2ab
2.6b
Note: Means in a row followed by the same letter are not significantly
different according to a t-Test (a = 0.05 except for plant variables
marked with an *, in which case a = 0.10).

47
Table 16. The effect of
week 15.
501 defoliation at week 9
upon
plant size at
T reatment
Plant Variable
Check
50% Uniform
Outer
50x of Canopy
Number of new leaves'"
105.2b
107.3b
138.8a
Ratio of stem weight to
length, mg/cm
22.8a
20.9b
18.2c
Mainstem length, cm
51.9a
44.6b
44.3b
Average cotyledonary
lateral length, cm
71.3a
61.6b
60.7b
Number of new vegetative
growing points
12.4b
16.8ab
21.8a
Number of PI
4.6b
8.2ab
12.2a
Number of P3*
38.6a
27.2ab
20.0b
Weight of P3, g*
1.0a
0.6ab
0.5b
Number of P5*
47.1a
36.lab
31.6b
Weight of P5, g
44.8a
34.3ab
28.3b
Kernel weight, g
35.0a
27.2ab
22.6b
Note: Means in a row followed by the same letter are not significantly
different according to a t-Test (a = 0.05 except for plant variables
marked with an *, in which case a = 0.10).

vegetative growing points arose toward the exterior of the canopy,
frequently in the axils of defoliated leaves.
The results for plants harvested at week 15 were similar to those
for plants harvested at 11 weeks. By this time, mainstem length and
average cotyledonary lateral length were significantly lower for de-
foliated plants.
There was a significant effect (a=.05) of block (row) on mainstem
length, number of P2 (pegs in ground), number of P5 (fully expanded
pods which did not shrink when dried), P5 weight, kernel weight, and
weight of all pods (P3~P5) at 11 weeks. This was probably due again to
the difference in emergence times of different rows. By week 15, row
had a significant effect only on root weight and the ratio of stem
weight to length.
Light interception by plants harvested at week 11 is summarized in
Table 17- Average light interception immediately following defoliation
by plants defoliated uniformly was 83% of that of the check plants;
average light interception by plants defoliated non-uniformly was 69%
of that of the check plants at the same time. There was no difference
in light interception 2 weeks after treatment between defoliated and
non-defoliated plants.
Third Defoliat ion
The response of plants defoliated at week 12 was similar to that
of plants defoliated at week 9 in that the plants from which leaves
were removed had an equal or greater growth of leaves, as indicated by
number and weight of new leaves per plant, and a reduction in stem
weight to length ratio as compared to the check plants (Tables 18 and
19). More than half of the leaf material by weight was removed in

Table 17. Summary of light interception by plants defoliated at 9 weeks of age.
T reatment
Row
Estimated LAI
Immediately
After Defoliat ion
% Light Interception
Immedi ate 1y
After Defoiiation
LAI
at 1 1
weeks
% Light
1 nterception
at 11 weeks
Check
F
2.8
82.2
*.o
90. 1
G
A. 7
59.1
6.3
97.2
H


3.3
77.1
50| uniform
F
2.3
56.6
A. 1
91.0
G
1.5
56.8
2.9
96.0
H



71.5
Outer 50% of
F
1.0
56.0
2.7
Sk.k
canopy
G
1.7
kl.2
3.9
96. 1
H


2.9
79.9
-c-

50
Table 18. The effect of 50% defoliation at week 12 upon plant size at
14 weeks.
T rea tmen t
Plant Variable
Check
50% Uniform Outer
50% of Canopy
Number of new leaves
10.1b
15.1b
32.0a
Weight of new leaves, g
0.9b
1.3b
2.1a
Ratio of stem weight to
length, mg/cm
25.3a
22.5b
20.5c
Number of vegetative
growing points
45.5b
41.7b
60.6a
Number of new vegetative
growing points
6.2b
4.2b
10.8a
Number of P3
26.9b
29.9b
49.3a
Note: Means in a row followed by the same letter are not significantly
different according to a t-Test (a = 0.05).

51
Table 19. The effect of 50% defoliation at week 12 upon plant size at
week 16.
T reatment
Plant Variable
Check
50% Uniform Outer
50% of Canopy
Number of new leaves
22.3b
26.5b
55.0a
Weight of new leaves, g
1 .6b
1.9b
3.7a
Ratio of stem weight to
length, mg/cm
23.4a
21.8ab
20.6b
Average cotyledonary
lateral length, cm
67.9a
65.9ab
60.6b
Number of new vegetative
growing points
5.2b
3.8b
8.9a
Number of PI
5.7b
13.0a
13.9a
Number of P5
44.4a
39-9ab
28.2b
Weight of P5, g
51.8a
46.9ab
33.8b
Kernel weight, g
40.5a
36.7ab
27.2b
Total plant weight, g*
125.6a
1 10.5ab
90.5b
Note: Means in a row followed by the same letter are not significantly
different according to a t-Test (a = 0.05 except for plant variables
marked with an *, in which case a = 0.10).

52
Treatment 6, but in Treatments 2 and 3 essentially identical amounts of
leaf material were removed. Of the plants harvested at 1 ** weeks, plants
which were defoliated non-uniformly had an increase in number of grow
ing points and in number of small pods (P3)- By 16 weeks, defoliated
plants had significantly more aerial pegs, but the number and weight
of mature pods (P5) were lower, although the difference between check
and 50% uniform defoliation plants was not significant.
For the plants harvested at lA weeks, block (row) had a signifi
cant effect only on weight of PVs (fully expanded pods which shrivel).
For those removed at 16 weeks, there was a significant difference be
tween rows for number of new growing points and leaf weight prior to
treatment.
Light interception data are summarized in Table 20. Average light
interception immediately following defoliation by plants defoliated
uniformly was 86% of that by the check plants; average light inter
ception by plants defoliated non-uniformly was 81% of that of the check
plants at the same time. Again, there was no appreciable difference in
light interception between check and defoliated plots 2 weeks post
treatment, although LAI was much less in the defoliated plots than in
the check plots.
Fourth Defoliation
There was a significant difference between treatments for only 3
of the variables considered in this late season experiment. As can be
seen in Table 21, the only discernible differences were in number and
weight of new leaves and ratio of stem weight to length. The order of
response was the same as in the previous experiments--the more serious

Table 20. Summary of light
interception by plants
defoliated at week 12.
T reatment
Row
LAI Immediately
After Defoliation
% Light
1n te rception
After Defo1 i ation
LAI at
1*4 Weeks
% Light
1 nterception
at 1*4 Weeks
Check
J
*4.8
90.7
5.1
91 .6
K
3.1
85.2
3.3
75.2
L
7.3
92.9
7.5
92.6
M
7.1
92.6
7.3
90.6
50% uniform
J
2.3
69.9
2.5
8*4.9
K
2.2
81.1
2.5
9*.3
L
3.7
87.7
3.9
85.9
M
2.5
72.9
3.0
88.8
Outer 50% of
J
2.8
62.2
3. b
91.1
canopy
K
2.5
86.2
2.8
90.9
L
2.6
68.2
3.3
79.5
M
2.5
76.3
3.1
85.*4

5**
Tab 1e 21.
The effect of defoliation at 16 weeks
18 weeks.
upon plant size at
Treatment
Number of New
Leaves
Weight of
New Leaves,q
Ratio of Stem Weight
to Length, mg/cm
Check
6.1b
0.1b
22.5a
50% uniform
13.9b
0.3ab
21.2ab
100%
33.0a
0.6a
19.2b
Note: Means in a column followed by the same letter are not signifi
cantly different according to a t-Test (a = 0.05).

55
the level of defoliation, the more new leaves were grown and the more
the stem weight to length ratio was reduced. Plants defoliated 50%
intercepted 80% as much light immediately following defoliation as did
the check plants (Table 22). Plants from which all leaves had been
removed still intercepted 46% as much light as the check plants.
Plants did not put on sufficient new leaf matter following defoliation
for canopy light interception to recover.

Table 22. Summary of light interception by plants defoliated at 16 weeks.
Treatment
Row
LAI Immediately
After Defoliation
% Light Intercep
tion Immediately
After Defoliation
LAI at
18 Weeks
% Light
Intercept ion
at 18 Weeks
Check
R
6.7
9A.0
6.7
93.A
S
**.3
90.9
A.3
93.5
T
8.1
95.5
8.1

U
6.0
96.0
6.0
98.5
50% Un¡form
R
3.3
75. A
3.A
89.1
S
3.0
73.1
3.0
90.2
T
3.7
8A.A
3.8

U
2.6
68.6
2.6
80.0
100%
R
0.0
A0.8
0.1
33.1
S
0.0
51.8
0.3
61.1
T
0.0
Al.5


U
0.0
A0.1
0.03
A9.2
\n
on

CHAPTER IV
THE SIMULATION MODEL
Introduction
The experiments discussed in Chapters II and III yielded much of
the information necessary for modification of Duncan's (197M PENUTZ
model. From the experiments dealing with the normal growth of non-
defoliated plants, I was able to establish the branching pattern of an
average plant, the rate of initiation of leaves and vegetative and re
productive branches at different times in the season, the average size
of individual leaves and internodes at different times in the season,
and the relationship between LAI and percent light interception by the
canopy.
My overall conclusions from the defoliation experiments were that
the Florunner cultivar of peanuts does accumulate stem storage reserves,
and that defoliated plants draw upon these reserves and continue to
grow leaves of the same size as non-defoliated plants at active vegeta
tive nodes. If the level of defoliation is severe enough to expose to
the 1 ight inactive vegetative nodes that would normally be shaded,
some of these nodes are activated. Severe defoliation during the peg
ging and podsetting stages of growth results in fewer pods of the larg
est size category. When the defoliation occurs early in the pod filling
period, expansion of small pods (P3's) is curtailed. When defoliation
occurs late in the season after vegetative growth has almost ceased,
57

58
stem reserves are apparently used for seed growth, as very little new
leaf material is added.
The morphogenetic approach to crop modeling is based on the assump
tion that individual plant organs have maximum potential growth rates
or sink strengths which may vary with temperature and may not be
achieved on any given day if substrate is limiting. In order to con
struct a morphogenetic model, it is necessary to estimate the maximum
potential growth rates for the various plant organs, such as leaves and
pods, and to provide rules for the division or partitioning of the avail
able carbohydrate and nitrogen on any day when there are insufficient
amounts to fill all demands.
From the results of the experiments dealing with normal plant
growth, an estimate of maximum average leaf size could be obtained. Di
viding this by the number of days required for growth of the leaf pro
vided an estimate of the maximum potential growth rate for leaves.
PENUTZ contained estimates of the maximum growth rates for seeds and
shells. An estimate of maximum growth rate for individual stem inter
nodes was somewhat more difficult to obtain. In order to do so, I as
sumed that the ratio of leaf weight to stem weight of 2.15, which held
for the first 7 weeks of plant growth, was equal to the ratio of maximum
growth rate for an individual leaf to that for an individual stem inter-
node. Estimates were therefore available for maximum growth rates of
individual leaves, shells, seeds, and stem internodes.
Many small roots are lost when plants are harvested, and root
nodules require carbohydrate for nitrogen fixation. This makes calcu
lation of root demands difficult. A decision was made to exclude roots
from the daily balancing of potential growth versus available substrate

59
in the model being developed. The handling of root growth and nitrogen
fixation in the model will be discussed later in this chapter.
Establishing rules for the division of carbohydrate and nitrogen
each day was less clearcut than determining potential growth rates for
the various plant organs. Although it was clear from the field data
(Table 2) that the pod load was set by the end of week 12, it was not
clear by what mechanism the size of the pod load was determined. Nor
was it obvious by what means the gradual inactivation of growing points
could be programmed, especially in view of the increased leaf growth
following defoliation. My overall approach to balancing supply and
demand was to assume that leaf demands were given higher priority than
most other demands when LAI, as an indicator of canopy light intercep
tion, was low; but that this priority was moderated by increasing pod
demands later in the season. Several different sets of priority rules
were tried before one which produced realistic simulations for both
normal and defoliated plants was found.
Insofar as possible, parameter values used in PENUTZ were used in
itially in PMINUS, the morphogenetic model derived from PENUTZ. The
results of the experiments dealing with normal plant growth were used
for estimation of new parameters involved in computation of leaf and
stem growth. When there was no experimental information available for
estimation of a particular parameter value, such as the length of time
a peg could remain in the ground before becoming incapable of swelling
into a pod, a value was chosen which gave a good visual fit between sim
ulated and experimental plant growth. Changes were necessary in some
model parameters taken from PENUTZ in order for simulated plant growth
to match that observed in the field. New estimates for these parameters

60
were obtained from the results of the experiments dealing with normal
plant growth. After the model simulated normal plant growth satis
factorily, the defoliation experiments were simulated. These simula
tions produced some unrealistic results, such as too much pod growth
and too little stem growth following defoliation, and thus further
changes were made in the model so that it satisfactorily simulated not
only the growth of the non-defo1iated plants, but that of all defoliated
plants as well. The changes generally pertained to parameters or
processes for which there were no data available for direct calculation
of va 1ues.
Description of the Model
PMINUS is programmed in GASP IV, a combined continuous/discrete
FORTRAN based simulation language (Pritsker 1974). The short main pro
gram reads the climate cards for the growing season (which contain daily
values for radiation, maximum and minimum temperatures, and rainfall and
irrigation) and then calls the executive subroutine GASP, which handles
the calling of the other subroutines. A brief description of the user-
written subroutines included in PMINUS is given in Table 23. PHZDAZ
and RUTNOD are the same as their counterparts in PENUTZ except for
minor changes. The subroutines PTOTAL, PLTGRO, DIVIDE, and FRUFIL are
adapted from subroutines of the same name in PENUTZ but differ in some
major respects. INTLC, EVNTS, SCOND, STATE and OTPUT were added to con
vert PENUTZ from straight FORTRAN to GASP IV. BEGIN, LEAVES, GRPTS,
STEMS, and PNTLAI are new subroutines which calculate the growth of the
vegetative portions of the plant. INSECT and ATTAC simulate the effect

61
Table 23. A brief description of the user-written subroutines included
in PMINUS.
Subroutine
Description
INTLC
Initializes some model variables
EVNTS
Computes changes in system status which occur whenever an
event occurs
SCOND
Checks state variables at the end of each time step to
determine if any of them crossed a specified threshold,
thereby triggering a state event
BEGIN
Called at time of plant emergence to initialize plant
variables
STATE
Each day calls the subroutines which calculate environ
mental changes and plant growth
WATERX
Calculates water stress factoiat present a dummy sub
rout i ne
PTOTAL
Calculates carbohydrate and nitrogen available to each
plant each day
PLTGRO
Calculates sink demand for various plant organs, initiates
new leaves, branches, and pegs and calls the subroutines
which divide the available carbohydrate and nitrogen
LEAVES
Calculates daily growth of leaves
DIVIDE
Calculates amount of carbohydrate and nitrogen available
for pod growth and calls FRUFIL
FRUFIL
Calculates daily growth of pods
GRPTS
Initiates new vegetative growing points
STEMS
Calculates daily growth of stems
PNTLAI
Calculates percent light interception for use in photosyn
thetic equations
PHZDAZ
Calculates number of physiological days in each calendar
day
RUTNOD
Calculates daily growth of roots and nitrogen manufacture
ATTAC
Describes time and type of insect invasion or mechanical
defoliation and calls INSECT
INSECT
Calculates effect of defoliation each day on leaf area,
leaf weight, and canopy light interception and initiates
special growing points if damage is severe enough

62
Table 23
OTPUT
Cont¡nued
Prints results of the simulation
BLK DATA
Provides initial values for many model variables

63
of an insect invasion and defoliation on the plant. Flow charts of
the major subroutines are contained in Appendix 2. A complete listing of
PMINUS is given in Appendix 3, a description of model parameters in
Appendix 4, and a glossary of input parameters and variable names in
Appendi x 5-
PMINUS computes growth on a square meter basis. The growth of an
average plant is calculated each day and this is multiplied by the num
ber of plants/m^ to determine growth/m^. In actuality, program storage
and model structure are such that up to 7 plant types may be simulated.
Growth/m^ is then calculated by multiplying the amount of growth of
plants of a given type (l~7) by the number of plants of that type/m^,
and then summing over all 7 plant types. This structure was originally
devised so that seedling emergence could be spread over several days,
giving plants of different sizes. It could also be used to simulate
the effect of uneven defoliation over a field.
Subroutine STATE is called by GASP on a daily basis and it in turn
calls the other subroutines to calculate plant growth each day. Most
plant growth processes are dependent upon physiological time, which is
calculated each day by PHZDAZ. The daily minimum and maximum tempera
tures are used to compute the number of physiological days in a given
calendar day. One physiological day equals 75F. If the average of
the maximum and minimum temperature is greater than 75F then there is
more than 1 physiological day in that calendar day. There are an aver
age of 1.2 physiological days per calendar day during the summertime in
this part of Florida.

Initiation of New Leaves and Branches
Plants emerge 11 physiological days after planting with a fully
expanded leaf on the mainstem, 3 partially developed leaves on the
mainstem, and 2 partially developed leaves on each cotyledonary lateral.
In the field experiments, plant emergence began on the fifth day follow
ing planting, and plants continued to emerge for more than 2 weeks, al
though the plants used in the experiments were those that emerged during
the first 9 days of the emergence period. The earliest leaves expanded
more quickly than later leaves. It was easier to simulate this by
having the plants emerge later than they did in actuality with some
leaves already forming, than by having the earliest leaves grow more
rapidly than later ones and draw upon seed reserves.
The program keeps track of the number of branches, both vegetative
and reproductive, on each plant, and the date of initiation of the last
2 leaves on each vegetative stem. When the first leaf on a branch is
half-grown, a new leaf is initiated on that stem. When a leaf com
pletes development then a new leaf is initiated, and a new branch,
either vegetative or reproductive, may be initiated 2 nodes back on
the stem. Whether the new branch is vegetative or reproductive de
pends on the fixed branching pattern of the plant. Suppose, for ex
ample, that the stem in question is the first lateral off the mainstem
and that it has 1 node with no attached leaf, ^ fully developed leaves
at nodes 2-5, a leaf completing development at node 6, and a half-
grown leaf at node 7 on day K. There should already be a vegetative
branch at node 1, a reproductive branch at node 2, and another vegeta
tive branch at node 3. On day K the leaf at node 6 completes develop
ment, and a branch can be initiated at node k. This branch will be

65
vegetative according to the plant's branching pattern. A new leaf is
also set to start development the next day at node 8.
Each leaf grows for a set number of physiological days. This
number depends on the stage of development of the plant. Up until 82
physiological days (about 68 calendar days) after planting, a leaf
takes 10.8 physiological days (about 9 calendar days) to develop. This
rate of growth yields about 1.4 leaves/branch/week, in keeping with the
field results for weeks 4-10 presented in Table 6. Late in the season
(after day 82), leaves take 14.4 physiological days to complete devel
opment. This yields approximately 1.1 leaves/branch/week, again in
accordance with the results in Table 6. The underlying cause for this
apparent decrease in growth rate could not be determined, and it may
have been due to non-linearity in the leaf growth versus temperature
response curve.
In the model a maximum of 333 vegetative growing points/m^ are
allowed. In the field there may be many more than this present, but in
my plot this was the maximum number of active ones present at any one
time (35/plant, on the average). It was simpler to stop the initiation
of growing points when the maximum/m^ was reached, rather than to pro
gram the simultaneous initiation and shutdown of branches.
The length of time between nodes on a reproductive branch is set
at 6.0 physiological days in the model. A maximum of 4 nodes is allowed
per reproductive branch. In the field there are occasionally more than
4 nodes per branch. The model does not keep track of flowers and pegs
separately; rather, once a reproductive node has been activated, a pod
may start to swell at that node 27.0 physiological days later.

66
Calculation of the Day's Net Photosynthate
The photosynthetic equations used in PMINUS are essentially the
same as those used in PENUTZ. First, gross photosynthate is calculated
by the following equation:
PTS = PLTLAI CL I MAT(NOW,1) PS LOPE PTSFAC (l)
where PLTLAI is a measure of canopy light interception, CLIMAT(N0W,1)
is total radiation in langleys, PSLOPE is the slope of the photosyn
thetic equation (0.0836g/1ang1ey), and PTSFAC is a factor which changes
with cultivar, as some cultivars have higher photosynthetic rates than
others. Photosynthate is then reduced as follows:
PTS = PTS STRESF DECFCT (2)
where STRESF denotes reduction in photosynthesis due to water stress
and DECFCT represents lost photosynthetic efficiency of an aging can-
opy. Net photosynthate/m is then calculated by the equation
PTS = PTS PTS RESPFC BMETFC STLFRT (3)
where RESPFC is a growth respiration factor (0.30), BMETFC is the main
tenance respiration coefficient (0.01), and STLFRT is the dry weight
of stems, leaves, and petioles. This calculation of net photosynthate
differs from Duncan's in that it is calculated on a square meter rather
than per plant basis. PLTLAI is also calculated in a different manner.
In PENUTZ, PLTLAI is the ground area covered by 1 plant. In PMINUS,
PLTLAI is a measure of percent light interception and it is determined
from the LAI versus percent light interception equation developed in
Chapter I I:
PLTLAI = (11.767 + 27.167 SS(1) 2.192 SS(1) SS(1))/100 (k)
where S S (1) is the state variable representing "effective" leaf area

67
index. Generally speaking, "effective" LAI is the same as LAI, but
after defoliation it may differ from real LAI. This will be explained
in the description of the INSECT subroutine.
Equation (A) was derived from light interception readings made
when the plants were 6 or more weeks of age and cannot be used for
younger plants, as it has a Y-intercept of 0.11767; i.e., plants with
zero leaf area intercept nearly 12% of the incident radiation, accord
ing to this equation. Light interception for young plants was assumed
to equa1 LAI, or,
PLTLAI = SS (1) (5)
until an LAI of 0.16. (Equations (A) and (5) intersect at an LAI of
0.16.) In essence this assumes that in young plants all leaves are
fully exposed to the light with no shading. When the LAI Is above 0.16,
shading causes light interception to be lower than LAI. I changed
PTSFAC in equation (I) from the 1.05 used for Florunner in PENUTZ to
1.10 to correct for the fact that the maximum value for PLTLAI in
equation (4) is about 0.95 rather than the 1.00 maximum for PLTLAI used
in PENUTZ.
The amount of photosynthate going to any one plant is calculated
by dividing the plant's leaf area by the total leaf area/m^. For the
purpose of calculating leaf area index and thus light interception and
photosynthesis, leaves are not counted as leaves until they are fully
grown. Not until a leaf has completed development is its area computed
by dividing its weight by the specific leaf weight of new leaves at
that point in the season. Specific leaf weight is 4.98 until physio
logical day 40 (calendar day 34), 3-77 from day 41 to day 82 (calendar
day 68), and 3-28 for the remainder of the season. These were the

68
average specific leaf weights for weeks 35, 6-10, and 11-16 (exclud
ing week 14), respectively (Table 3)- These specific leaf weights are
used for defoliated as well as non-defoliated plants.
Division of Day's Net Photosynthate
The amount of carbohydrate allocated to the roots each day for
root growth and nitrogen fixation depends on time in the growing season.
The roots receive 15% of the day's net photosynthate for nitrogen fixa
tion for the first 82 physiological days, and 13% thereafter. The
additional amount allocated for root growth is 28% until week 4, 15%
from week 4 until week 7, and 0% thereafter. The decision to allocate
15% to roots from week 4 until week 7 for root growth rather than the
lower amount indicated in Table 24 was based on balancing top growth
during this time period against photosynthetic supply. Allocating at
least 12% of the net carbohydrate to roots for nitrogen fixation pre
vents any nitrogen shortage from occurring, if 100% efficiency of con
version is assumed.
The remainder of each day's photosynthate is apportioned according
to demand from leaves, stem internodes, seeds, and expanding pods.
Leaf demand for carbohydrate is based on the number of developing
leaves and the amount each leaf can add on a given day. Demands for
the attached petiole and internode are also calculated and included in
the leaf demand variable, WANTLF. Maximum new leaf size is set at 88
mg, the average weight per leaf for new leaves for weeks 6-10 (Table
3). Leaves grow for either 10.8 or 14.4 physiological days, depending
on the point in the season, and thus leaves and petioles only demand
carbohydrate for that length of time. Stem internodes continue to

69
Table 2k. Root growth during the 1978 growing season, as indicated by
weekly plant samples.
Week from
Planting
Root Weight,
g/m2
Root Growth as % of
Total Plant Growth
1.3
25.3
3.3
28.1
k.2
7.0
5.3
2.2
12.2
9.2
17.7
11. k
11.5
--
13.1

10

70
grow and demand carbohydrate until 32.4 physiological days (27 calendar
days) after initiation.
Shell demand is calculated according to the formula
WANT = (10.0 + 0.25 PODWGT(J,K)) DAY INC (6)
where P0DWGT(J,K) is the weight of an individual pod initiated on day
K on plant J and DAYINC is the number of physiological days in the
given calendar day. About 85% of this demand is for carbohydrate
(McGraw 1977) When the pod reaches 17% of its capacity it is consid
ered to be fully expanded and shell growth stops and seed growth begins
If there is no shortage of carbohydrate it takes approximately 8 cal
endar days for the first pods to become fully expanded.
In this model, as in PENUTZ, pods that are filling seeds may grow
at a maximum rate of 22 mg/physiological day. Since more energy is
expended in making kernels than in making other plant parts, 35-9 mg of
carbohydrate are required to produce this 22 mg of kernel dry weight.
This is a result of the higher oil and protein concentration in seeds
than in other plant parts (McGraw 1977). Each developing pod that is
filling seeds thus demands 35-9 mg/day until it reaches 80% of its
capacity. It then continues to grow at half this rate until fully
grown. Schenk (1961) noted that pod growth rate declines in the later
stages of seed enlargement. In both PMINUS and PENUTZ, the later in
the season a pod is initiated, the smaller is its capacity.
If there is a surplus of carbohydrate after all growth demands are
filled on any day, then the excess is sent to stems for storage. If
there is a shortage, then allocation of the available photosynthate is
determined on a priority basis. The system of priorities is based

71
partially on canopy LAI, as an indicator of light interception. Devel
oping seeds have priority over all other plant parts, and after podset,
they may draw from stem storage, if necessary, to fill their demands.
This is based on my own field results and the observations of Hang An
(1978) who performed plant shading experiments. There is a limit to the
amount of photosynthate which seeds assimilate on any day. In PMINUS,
this limit is 65% of the day's net photosynthate or, after podset, 65%
of the maximum 5day-average net photosynthate. Thus, once the pod load
is set, pods may get more than 65% of the day's net photosynthate if it
is less than the maximum 5day-average. In PENUTZ, a maximum was set
in a similar manner on amount of photosynthate allocated to all pods,
rather than to seeds. On any day when there is insufficient carbohy
drate available for seeds to satisfy total seed demand, priority is
g i ven to older pods.
If the effective LAI (E LA I) is less than 2.5, then developing
leaves and their attached petioles and internodes have priority over
all plant parts except seeds. If ELAI is less than 2.0, the leaves
which are more than half-grown may draw from stem storage, if necessary,
to meet their demands. If there is excess carbohydrate after leaf
demand is met (ELAI < 2.5), then the initiation of new vegetative
branches has next priority.
Early in the season (before LAI reaches 0.16 for the first time)
vegetative growing points become active automatically without carbohy
drate and nitrogen availability being taken into account. Once LAI
reaches 0.16 for the first time, growing points are initiated only if
there is excess carbohydrate left after root, seed, and leaf demands

72
are filled. The model keeps track of potential new growing points each
day and each one is allowed 3 days to be activated. If there is in
sufficient photosynthate to activate it within this time, then it is
relegated to the permanently inactive file of growing points. Once
there are 333 vegetative branches, no new growing points may become
active, except in the event of severe defoliation. Growing point ini
tiation is cut off when ELAI reaches 2.5, even if there are fewer than
333 vegetative branches.
Any carbohydrate left after new branches are initiated goes to
meet stem internode and expanding pod demand. When ELAI is above 2.5,
any shortage in carbohydrate supply is allocated uniformly to leaves,
stems, and expanding pods. Older pods have priority over younger ones,
although PENUTZ and PMINUS are set up so that older pods can be given
from 0 to 100% priority.
PENUTZ was structured so that if a nitrogen shortage occurred, at
any time, the rest of the day's carbohydrate supply would be allocated
to the roots to fix nitrogen. This feature was retained in PMINUS, but
the amount of carbohydrate allocated to roots is set sufficiently high
that a nitrogen shortage never occurs.
Calculation of Increases in Total Dry Weight per Unit of Carbohydrate
The ratio of carbohydrate to nitrogen and the proportion of total
weight which is either carbohydrate or nitrogen are different for
different plant structures. In PENUTZ, Duncan assumed that 12% of
leaf, stem, and shell dry weights was protein, 85% was carbohydrate,
and 3% was other constituents. For nuts he assumed that 25% of total
dry weight was protein, 50% was oil, 20% was carbohydrate, and 5% was

73
other constituents. He further assumed that it required 2.85 units
of carbohydrate to produce 1 unit of oil. The same assumptions are
made in PMINUS.
Once the amount of carbohydrate available for leaf, stem, or shell
growth on a given day has been calculated, the total dry weight added
to that portion of the plant is calculated by
dWv =(dCv + ^1) / 0.97 (7)
dt dt dt
where dCv/dt is the change in carbohydrate for the given plant struc
ture, dNv/dt is the change for nitrogen, and the subscript v refers to
either leaf, stem, or shell. The amount of nitrogen needed is calcu
lated by assuming a nitrogen:carbohydrate ratio of 12:85.
For nut growth, the total dry weight added on a given day is calcu
lated by the equation
dWn = (dCn + d£n + dNn) / 0.95 (8)
dt dt dt dt
where dCn/dt is the weight of carbohydrate added to nuts, dOn/dt is the
weight of oil, and dNn/dt is the weight of nitrogen in the form of pro
tein. The ratio of carbohydrate:o¡1:nitrogen used is 20:50:25, and
2.85 units of carbohydrate are used to produce 1 unit of oil.
Inactivation of Vegetative Growing Points
The cessation of active growth by any branch is controlled by
time in the growing season and the size of the last leaf on the branch.
No stem may stop growing until after day 82, when leaf development time
is increased from 10.8 to 14.4 days. Maximum leaf size remains 88 mg,
but daily demand/leaf is reduced at this point due to the increased

7^
development time. Lack of sufficient carbohydrate to meet total demands
from pods, stems, and leaves on any given day may result in leaves that
are smaller than the maximum size. After day 82, the weight/leaf of
all leaves completing development on day K is checked against SIZMIN
(70.0 mg). If WTLEAF(J,l), the weight of a single leaf initiated on
day I on plant J, is greater than SIZMIN, then no growing points are
inactivated. If WTLEAF(J,l) is less than SIZMIN, growing points are
shut down in the proportion of WTLEAF(J,I)/SIZMIN; i.e., the smaller
the leaves that are just completing development, the greater the number
of growing points which are shut down.
Cessation of Peg and Pod Initiation
Reproductive nodes continue to be activated and pegs continue to
grow until the time the pod load is set. This point is reached when
seeds have demanded more photosynthate than is available to them for 5
days. When this occurs, flowering ceases and all pegs which have not
developed to the point that they can expand as pods (i.e., they are
less than 27.0 physiological days old) are removed from the system. On
any day from the time the first pod starts to swell until podset, no
new reproductive nodes are activated if there is no photosynthate avail
able on that day for stem growth and pod expansion. This was based on
the observation by Hang An (1978) that 75% shade (and the resulting
shortage of photosynthate) reduced flowering and reduced peg formation
after 7 days.
If a peg has not started swelling (i.e., its weight is still zero)
after 32 physiological days as a potential pod, then it is deleted from

75
the system. A shell that is not fully expanded after ^2 physiological
days ceases to grow and make demands for carbohydrate.
INSECT Subroutine
INSECT is the subroutine developed to link PMINUS to an insect
development model. Each day that simulated insect damage occurs, it is
called to compute changes in leaf weight and area and in canopy light
interception due to defoliation. The type of defoliation must be speci
fied. At present, INSECT can simulate the effects of 3 types of defoli
at ion: 1) removal of the same proportion of leaf material from each
leaf on the plant; 2) removal of whole leaves, starting with the young
est; and 3) removal of portions of leaves as in 1) plus removal of
some or all of the active vegetative growing points on the plant. Only
minor changes would be required to combine leaf removal as in 2) with
remova1 o f g rowing points.
The effect of defoliation on canopy light interception and photo
synthesis is handled differently in the model depending on the type of
defoliation. The data collected by Jones et al. (1980 and personal
communication) were used to estimate the effect of uniform defoliation
on photosynthesis. The regression line
2
Y = 99.^5 0.0715 DEFPER 0.00816 DEFPER (9)
2
with an R value of 0.96 relates DEFPER, percent defoliation, to Y,
percent of photosynthesis of defoliated versus non-defoliated plants.
(For the purposes of the regression, only readings that were made 1-3
days after defoliation or that were made after week 15, when leaf
growth had essentially stopped, were used.) For example, a plant
which is defoliated 50% on a given day will have, immediately after

76
defoliation, a photosynthetic rate 75.48% of its rate before defoliation
according to the equation. This value (Y) is multiplied by PLTLAI (pro
portion of the available light intercepted by the canopy prior to defoli
ation) to find the effective canopy light interception (Y1). This value
(Y1) is then inserted into equation (4) to find the normal canopy LAI
which photosynthesizes at the same rate as the defoliated plants now
do. This becomes the "effective" LAI for the defoliated plants and is
used as the baseline for any increases or decreases in LAI in the future
Going back to the example of the plants defoliated 50% on a given day,
if the plants had an LAI of 2.15 and were intercepting 60% of the avail
able light just prior to defoliation, then they would now intercept
45.28% of the available light (75-48 0.60) and have an effective LAI
of 1.39. In actuality, the LAI is half of 2.15, or 1.08, but these
plants are photosynthesizing at the same rate as normal, non-defo1iated
plants with an LAI of 1.39* In summary, effective LAI is a variable
to relate percent interception of defoliated canopies to percent inter
ception of non-defo]iated canopies.
The removal of leaves from the outer portion of the canopy was
equated with removal of the youngest leaves. Since there were no data
to relate light interception by plants defoliated in this manner to
rate of photosynthesis, the assumption was made that the photosynthetic
rate of plants defoliated in this manner is the same as the photosyn
thetic rate of non-defoliated plants with an LAI equal to the reduced
LAI. For example, if 50% of the total leaf area is removed in this
manner from a plant with an initial LAI of 3*0, then, after treatment,
the plant will photosynthesize at the same rate as a normal plant with
an LAI of 1.5. By removal of the outer envelope of leaves from the

77
canopy, the canopy is effectively returned to the size of a normal
canopy with the lower LAI, as photosynthesis by bare stems is negli
gible (Jones et al. 1980).
If the level of defoliation is severe enough that percent light
interception is reduced by more than 40% from its level when INSECT is
first called, new vegetative growing points may be initiated, if there
are any potentially active ones present. These growing points are of
a special type in that they may only grow 1 leaf before shutting down.
I assume that the normal maximum number of active growing points is
2
333/m and that only when stems are exposed to light may this number
be temporarily exceeded until the canopy closes over again. The selec
tion of 40% as the trigger point for this reaction was based on the
fact that the 50% uniform defoliations (which reduced light intercep
tion by 25%) caused no increase in vegetative growing points, whereas
the literature indicates (Mangold 1979, Williams et al. 1976) that
75% defoliation (50% decrease in light interception) resulted in in
creased leaf growth, which was probably due to an increase in the
number of growing points.
If growing points are destroyed, then the last 2 nodes on the
affected branch are checked to determine if they are vegetative or
reproductive. If either of them is vegetative, then a new branch is
initiated to replace the one destroyed.
Subroutine ATTAC
This is the subroutine which simulates insect entry into the sys
tem. It may do nothing more than call the subroutine INSECT on a
given day to remove a certain portion of the leaves on that day, or it
may be considerably more complicated.

78
Each of the defoliation experiments was simulated by calling
INSECT on the day the plants were defoliated, and by specifying the
percent and type of defoliation. For the simulations of removal of
leaves from the outer portion of the canopy, a sufficient amount of
defoliation was specified to bring the simulated LAI down to the same
level as that of the experimental plants after treatment.
I also simulated defoliation experiments performed by Mangold
(1979) in a field adjacent to mine. His peanuts were planted 1 or 2
days earlier than mine but the plant spacing and crop management were
identical. The defoliations simulated were as follows:
1. 75% uniform at week 8
2. 75% uniform at week 8 plus 75% defoliation of new leaves for
the next 7 days
3. 75% uniform at week 11
4. 75% uniform at week 11 and 75% defoliation of all new leaves
at week 15-
In order to demonstrate the coupling of PMINUS to an insect develop
ment model, I constructed a simplistic model of an insect cohort enter
ing the system, growing and eating for a certain number of days, and
then leaving the system. One of the power curves derived by Huffman
(197*0 for consumption of peanut foliage by the bollworm, He 1ioth i s zea
(Boddie) was used in calculation of leaf material eaten each day:
Y = 0.011 X2-995 (10)
where X is the age of the larva in days and Y is the cumulative foliage
consumption to date, in cm^. I assumed all larvae emerged on the same
day; the same number attacked each plant; they grew and fed for 26 days;

79
no mortality occurred; and they all left the system after 26 days. The
simulated attacks were as follows:
1. 10 larvae per plant, entering the field on day 21, and feed
ing randomly on the plant (the effect of this on light inter
ception was assumed to be the same as uniform defoliation)
2. 10 larvae per plant, entering the field on day 21, and feeding
on the youngest leaves
3. 10 larvae per plant, entering the field on day 35, and feeding
randomly on the plant
k. 10 larvae per plant, entering the field on day 35, and feeding
randomly
5. 10 larvae per plant, entering the field on day 56, and feeding
randomly
6. 10 larvae per plant, entering the field on day 56, and feeding
on the youngest leaves
7. 20 larvae per plant, entering the field on day 35, and feeding
randomly
8. 20 larvae per plant, entering the field on day 35, and feeding
on the youngest leaves.
Results and Discussion
Comparison of Model Predictions with Growth of Non-defoliated Plants
in the Field
Figures 2 through 9 are graphs of time versus LAI, number of
leaves, leaf dry weight, stem dry weight, number of pods, pod dry weight,
number of fully expanded pods (PVs and P5's), and weight of fully ex
panded pods, according to the weekly plant samples and according to the

Leaf Area Index
Figure 2
Simulated and experimental leaf area index for Florunner peanuts planted on 2k May 1978.

Number of Leaves/m
gure 3. Simulated and experimental change in leaf numbers for Florunner peanuts planted on 2k May 1978.

Weight of Leaves, g/m
C\J
Simulated and experimenta1 leaf growth for Florunner peanuts planted on 24 May 1978.
Figure 4.
CD
1-0

Stem Weight, g/m
Figure 5.
Simulated and experimental stem growth for Florunner peanuts planted on 2k May 1978.

Figure
O
O
C\J
a)
CL
tn
"O
O
CL
o
-O
E
r>
16 r
14
12
10
8
6
4
2
0
0
simulation
mean +_ 2 SE for
field samples
J L
J I L
Simulated and experimental changes in pod numbers for Florunner peanuts planted on 24 May 1978.
oo

Pod Dry Weight, g/m
CM
1000
900
800
700
600
500
400
300
200
100^
0
0 1
simulation
mean +_ 2 SE for
field samples
Simulated and experimental pod growth for Florunner peanuts planted on 2h May 1978.
oo
vn
Figure 7.

10
Figure
O
O
c\)
to
~o
o
CI
TO
O)
"O
c
o
CL
X
UJ
O)
-Q
E
D
9
8
7
6
5
4
3
2
1 k
0
0 1
simulation
mean + 2 SE for
field samples
f

L
7 89 10 11 12 13
Weeks from Planting
18 19 20
8. Simulated and experimental change in number of fully expanded pods for Florunner peanuts planted
on 2k May 1978.
oo
o>

900
800
700
600
500
400
300
200
100
0
S nu
2U t-
simulation
Weeks from Planting
lated and
ay 1978.
experimental growth of fruit filling seeds for Florunner peanuts planted on

88
model predictions. For all variables the average plant means from the
weekly sampels were converted to a square meter basis by multiplying by
9 ...
9.5 plants/m Simulated leaf, stem, and pod dry weights are within the
35% confidence intervals for the experimental means at all times during
the season.
Simulated and experimental leaf area indexes match until the very
end of the season, when LAI of the field plants declines, but that of
the model plants does not. Rather than model leaf loss, I chose to use
the results of Jones et al. (1980), obtained in a plot adjoining mine,
to model the decrease in gross photosynthesis late in the season. They
noted a h0% drop in P]500 (gross photosynthesis at a light intensity of
1500 pE/m^) between weeks 17 and 19; a drop that was due to the combined
effects of decreased LAI and decreased efficiency of aging leaves.
The fact that the model does not deal with loss of leaves due to
age or stress conditions leads to another difference between simulation
and field results, as shown in Figure 3- Number of leaves/m^ is over
estimated by the model after week 7 since at this point in the season
plants in the field started to lose leaves. The model does a fairly
good job of matching field results for the growth of new leaves each
week (Table 25), except between weeks 8 and 9- Simulated leaf weight
and LAI match those of the sample plants because the model adds less
weight to new leaves many weeks than do the sample plants (Table 25).
If leaf loss were to be included in the model, it would be necessary
to increase the photosynthate available for vegetative growth to
account for the extra leaf weight.
There are 3 points in the season when simulated pod numbers do not
correspond to those of the sample plants--at weeks 12, 16, and 17

89
Table 25. Comparison of
leaf growth
in the field
with model
predictions.
Period of Time,
No. of New Leaves/m^
Wt. of New
Leaves,g/m^
Weeks from Planting
Field
Mode 1
Field
Mode 1
0 3
102.6
104.5
2. 1
1.9
3 4
70.3
47.5
2.0
2.0
4 5
112.1
142.6
5.6
9.0
5 6
228.0
142.5
18.5
13.1
6 7
346.8
370.6
34.4
30.3
7 8
397.1
323.1
31.9
26.7
8 9
482.6
627.2
47.3
53.5
9 -10*
291.6
370.6
24.5
28.9
10 -11
337.2
332.6
24.3
20.6
11 -12
475.0
465.7
32.9
28.5
12.-13
196.6
199.5
14.0
8.4
13 -14
196.6
114.1
15.0
6.8
14 -15
28.5
38.0
1.4
2.8
15 -16
31.4
19.0
1.9
1.0
16 -17
2.8
0.0


Leaves were marked 2 days late this week, so this is the number and
weight of leaves grown in a 5~day period.

90
(Figure 6). The difference at week 17 can probably be explained by the
small sample size (3 plants). I cannot explain the difference at week
16. There were 15 plants in the sample, but for some reason they were
smaller than average, as indicated by pod number, leaf number, and leaf
and stem weight. The difference at week 12 is probably due to the way
photosynthate is distributed in the model. The stepwise increase in
pod numbers after week 11 is due to the fact that in the model available
carbohydrate is distributed to expanding pods on an oldest-first basis.
Only on a day when radiation and photosynthesis are extremely high is
there sufficient carbohydrate left over, after the demand of existing
pods is met, to initiate new pods. Distribution of photosynthate may
not be quite so cut and dried in reality. Giving 100% priority to the
oldest fruits does result in a good correspondence between field and
model of number and weight of fully expanded pods (Figures 8 and 9)
Comparison of Model Predictions with Results of the Field Defoliations
Table 26 is a summary of plant growth in the 2\ weeks following
defoliation at week k?, as indicated by model simulation and by the
field experiment. There was a large amount of variation between treat
ments in the average LAI just prior to defoliation. This variation
seemed to affect the model's ability to simulate the effect of defolia
tion on leaf growth. The closer the initial LAI of the field plots
was to the initial model LAI of 0.1**, the closer was the correspond
ence between field and simulated LAI and leaf weight at harvest. The
model underestimated the stem weight at harvest for the control plants
and for the plants which were defoliated 50% and 100%. Otherwise,
model and field stem weights matched well except for the plants from

Table 26. Comparison of model predictions with field results for plants defoliated at 4i weeks and har
vested at 7 weeks.
Initial
LAI
LAI ;
after Defoliat ion
LAI
at Harvest
Leaf Weight at
Harvest, g/m2
T reatment
Field
*
Mode 1
Field*
Mode 1
Field*
Mode 1
Field*
Mode 1
Check
0.14
(0.02)
0. 14
0. 14
(0.02)
0.14
1.42
(0.17)
1.42
56.7
(7.1)
56.2
25% uni form
0.10
(0.02)
0.14
0.08
(0.01)
0.10
1.07
(0.15)
1.36
42.0
(5.8)
55.2
501 uniform
0.16
(0.02)
0.14
OO
O
O
(0.01)
0.07
1.32
(0.17)
1.27
51.7
(6.5)
51.3
1001
0.15
(0.02)
0.14
0.00
(0.00)
0.00
0.90
(0.15)
0.93
32.7
(5.0)
35.9
0% + veg.
0.22
(0.03)
0.14
0.22
(0.03)
0.14
0.97
(0.14)
0.79
36.4
(4.8)
31.6
growing points
50% + veg.
0.14
(0.02)
0.14
0.07
(0.01)
0.07
0.59
(0.08)
0.63
23.6
(3.1)
24.7
growing points
100% + veg.
0.20
(0.03)
0.14
0.00
(0.00)
0.00
0.25
(0.04)
0.10
9.3
(1.4)
3.8
growing points
''Number in parentheses is standard error of the mean.

Table 26. Continued
T reatment
Weight of
Leaves,
New
g/m2
Stem
Weight,
g/m2
Gain in
Weight,
Stem
g/m2
Number of
Leaves per
New
m2
Field*
Model
Fiel d*.
Mode 1
Field
Mode 1
Field*
Mode 1
Check
49.8 (6.3)
49.4
38.2
(5.2)
27.6
35.2
24.7
686.0 (61.1)
598.6
25% uni form
37.1 (5.0)
49.9
27.0
(4.3)
26.7
24.2
23.8
545.3 (44.6)
589.1
50% uniform
^7-5 (6.1)
47.8
33.1
(5.1)
25.2
29.4
22.3
583.3 (56.6)
579.6
100%
32.7 (5.0)
35.9
21.7
(3.4)
17.8
18.1
14.8
513.7 (53.1)
589.1
0% + veg.
28.1 (4.0)
24.8
23.7
(3.8)
24. 1
20.1
21.2
499.7 (49.7)
285.0
growing points
50% + veg.
19.8.(2.6)
21.3
15.5
(2.1)
15.8
12.3
12.9
432.0 (40.2)
285.0
growing points
100% + veg.
9.3 (1.4)
3.8
8.8
(1.2)
4.3
4.0
1.4
309.7 (28.8)
285.0
growing points
"Number in parentheses is standard error of the mean.

93
which all leaves and all vegetative growing points were removed. In
this case the model underestimated leaf growth as well. It may be that
the plants in the field were able to draw some carbohydrate from stems
to make leaves. In the model, leaf and stem demands are so high in
comparison to available photosynthate that there is no storage of car
bohydrate in the stems until week 8.
The simulated number of new leaves initiated after treatment was
within the confidence interval (+_ 2 SE) for the experimental mean
except in the case of plants defoliated 0 or 50% from which the vege
tative growing points were removed. This can probably be attributed,
at least in part, to a failure to remove all of the small new leaves
beginning in the axils of fully grown leaves.
Tables 27 and 28 are comparisons of field results and model pre
dictions for plants defoliated at week 9- Figures 10 and 11 are graph
ical representations of the comparisons for LAI and pod dry weight.
The simulated values for all plant variables are within the 95% confi
dence intervals for the experimental means except for the number of
pods at 15 weeks on plants from which all the leaves were removed from
the outer half of the canopy. In this case simulated pod weight was
also somewhat higher than the experimental mean, but it was well within
the confidence interval. For this experiment there was a good corre
spondence generally between simulated and field results in weight of
new leaves and gain in stem weight.
Comparisons of model predictions with field results of the week
12 defoliation are summarized in Tables 29 and 30 and Figures 12 and
13- There is again some problem with matching number of pods/m^.

Table 27. Comparison of model
vested at 11 weeks.
predictions with
field results for plants
defoliated at 9 weeks and
ha r-
Plant Variable
Treatment
Control
50% Uniform
Outer
50%, of
Canopy
Field*
Mode 1
Field*
Mode 1
Field*
Mode 1
Original LAI
4.0
(0.9)
3.6
4.6
(0.7)
3-6
4.3
(0.5)
3.6
LAI after defoliation
4.0
3.6
2.0
1.8
1.2
1.3
LAI at harvest
5.2
(1.1)
5.1
3.6
(0.4)
3.3
3.4
(0.3)
3.1
Leaf weight at harvest, g/m^
188.9
(40.1)
189.9
126.2
(15.3)
121.7
119.5
(n.o)
112.8
2
Weight of new leaves, g/m
41.7
(6.3)
53.5
50.4
(5.0)
51.1
66.1
(6.1)
61.6
2
Stem weight, g/m
212.4
(47.3)
221.9
213.4
(33.5)
192.4
218.0
(27.8)
162.8
2
Gain in stem weight, g/m
85.3
92.9
67.0
63.8
43.8
35.4
2
Number of pods/m
656.4(173.7)
598.7
697.6(121.0)
598.7
562.9
(64.3)
598.7
2
Weight of pods, g/m
118.1
(33.2)
109.0
91.5
(18.3)
100.2
70.3
(11.4)
79.2
o
Number of P4-P5/m
286.7
(72.4)
237.6
215.0
(44.4)
285.1
201.1
(25.8)
161.6
Weight of P4-P5, g/m^
112.3
(31.4)
87.5
81.5
(17.4)
89.1
62.6
(17.5)
57.2

Table 28. Comparison of model
vested at 15 weeks.
predictions with
i field
results for plants
defoliated
at 9 weeks and
ha r-
Plant Variable
T reatment
Control
50% Uniform
Outer
502. of
Canopy
Field*
Mode 1
Field*
Model
Field*
Mode 1
Original LAI
4.4 (0.6)
3.6
4.1 (0.7)
3.6
3.5
(0.4)
3.6
LAI after defoliation
A. 4
3.6
2.0
1.8
1.2
1.3
LAI at harvest
7.0 (0.9)
6.5
4.6 (0.6)
4.7
4.3
(0.3)
4.3
2
Leaf weight at harvest, g/m
257.1 (31.8)
236.3
183.5 (23.6)
166.5
157.8
(12.2)
154.5
. 2
Weight of new leaves, g/m
108.2 (12.1)
99.9
108.2 (13.9)
95.8
113.9
(9.1)
103.3
2
Stem we¡ght, g/m
345.7 (43.9)
298.3
272.1 (40.2)
278.6
243.6
(24.8)
249.0
2
Gain in stem weight, g/m
210.0
169.3
143.1
150.0
114.0
120.4
2
Number of pods/m
960.4(117.1)
959.8
781.1(141.8)
826.7
682.9
(61.2)
826.7
2
Weight of pods, g/m
479.4 (51.9)
435.2
394.4 (54.7)
412.4
354.0
(35.0
379.4
Number of P4-P5/m2
594.2 (69.8)
598.7
522.5 (68.6)
598.7
492.9
(47.9)
503.6
Weight of P4-P5, g/m2
469.6 (50.1)
422.6
388.6 (53.3)
405.1
349.6
(34.4)
360.6
Number in parentheses is standard error of the mean.

POD DRY WEIGHT, g/m2 LEAF AREA INDEX
96
7.0
Figure 10.
The simulated and experimental effect of 50% uniform defoliation
at 9 weeks after planting on LAI (a) and pod dry weight (b).

POD DRY WEIGHT, g/m2 LEAF AREA INDEX
97
Figure 11. The simulated and experimental effect of removal of all leaves
from the outer 50% of the canopy at 9 weeks after planting on
LAI (a) and pod dry weight (b).

Table 29. Comparison of model
vested at 14 weeks.
predictions with
field
results for plants
defoliated
at 1 2 weeks and
ha r-
Plant Variable
T reatment
Control
50% Uniform
Outer
50% of
Canopy
Field*
Mode 1
Field*
Model
Field*
Mode 1
Original LAI
5.6
(0.9)
5.9
6.1 (0.9)
5.9
6.7
(0.6)
5.9
LAI after defoliation
5.6
5.9
2.7
3.0
2.6
2.7
LAI at harvest
5.8
(0.9)
6.4
3.0 (0.5)
3.4
3.1
(0.3)
3.0
2
Leaf weight at harvest, g/m
216.6
(34.*4)
233.5
122.3 (18.3)
121.8
116.3
(12.1)
114.5
2
Weight of new leaves, g/m
8.5
(1.2)
15.2
12.1 (2.4)
11.2
19.6
(3.0)
10.3
2
Stem weight, g/m
26*4.6
(41.3)
291.4
251.9 (38.2)
283.5
280.5
(34.4)
276.3
2
Gain in stem weight, g/m
*49.8
49.6
25.2
42.7
8.5
35.5
2
Number of pods/m
708.5(135.8)
855.3
711.7(120.7)
598.7
897.0(101.2)
598.7
2
Weight of pods, g/m
3^0.3
(61.0)
343.3
335.6 (55.5)
293.2
349.7
(39.8)
287.9
2
Number of P4-P5/m
*452.8
(74.3)
503.6
427.5 (68.4)
418.1
428.3
(55.0)
418.1
Weight of P4-P5, g/m^
313.1
(58.2)
329.6
327.4 (54.3)
286.0
338.8
(38.7)
281.9
"Number in parentheses is standard error of the mean.

Table 30. Comparison of model
vested at 16 weeks.
predictions with
i field
results for pi ants
defoliated
at 12
weeks and har-
Plant Variable
T reatment
Control
50? Uniform
Outer
50? of
Canopy
Field*
Mode 1
Field*
Model
Field*
Model
Original LAI
5.6
(0.4)
5.9
5.8
5.9
5.0
5.9
LAI after defoliation
5.6
(0.4)
5.9
3.0 (0.3)
3.0
1.8
(0.3)
2.0
LAI at harvest
6.0
(0.5)
6.5
3.5 (0.3)
3.5
2.6
(0.3)
2.5
2
Leaf weight at harvest, g/m
213.1
(19.9)
237.3
123.2 (9.6)
125.7
101.9
(12.5)
93.6
. 2
Weight of new leaves, g/m
15.3
(2.6)
19.0
19.8 (2.7)
15.1
36.4
(3.7)
17.2
2
Stem weight, g/m
269.9
(25.9)
295.2
246.0 (24.1)
286.8
196.3
(23.2)
265.6
2
Gain in stem weight, g/m
79.5
53.4
33.4
46.1
0.5
24.8
2
Number of pods/m
729.1
(67.0)
959.8
795.2(121.9)
826.7
654.6(108.6)
598.7
2
Weight of pods, g/m
552.0
(45.5)
520.8
511.9 (53.1)
443.1
417.7
(57.0)
385.8
2
Number of P4-P5/m
558.1
(43.6)
674.7
549.3 (62.9)
598.7
411.1
(58.7)
503.6
2
Weight of P^-P5, g/m
546.0
(44.6)
511.2
505.9 (52.1)
439.6
362.9
(55.3)
383.6
* Number in parentheses is standard error of the mean.

POD DRY WEIGHT, g/m2 LEAF AREA INDEX
100
Figure 12. The simulated and experimental effect of 50% uniform defolia
tion at 12 weeks of age on LAI (a) and pod dry weight (b).

POD DRY WEIGHT, g/m2 LEAF AREA INDEX
101
Figure 13.
The simulated and experimental effect of removal of all leaves
from the outer 50% of the canopy at 12 weeks of age on LAI (a)
and pod dry weight (b).

102
There is a great deal of variability between plants in this respect.
Also, the problem is perhaps partially due to the cut and dried method
of allocating available photosynthate to oldest pods first. As pod
dry weight/m2 is usually well within the confidence limits for the
experimental means, the difference in pod number between field re
sults and model simulation is a difference mainly in number of small
pods.
O
The model estimate of weight of new leaves/m for the control
plants is higher than the field average for plants marked at 9 weeks
and harvested at 11 weeks (Table 27) and for plants marked at 12 weeks
and harvested at 14 weeks (Table 29). This is due to a difference in
the marking system for plants used as controls in the defoliation ex
periments as opposed to that for plants marked weekly for determination
of weekly growth of leaves, as used in model development. In the de-
foliation experiments a leaf was marked if the petiole was sufficiently
extended for a surgical wound clip to fit around it, whereas in the
weekly plant markings a leaf was marked if the leaf above it was
starting to unfold. When the plants were harvested, in both cases a
leaf was included in the count of new leaves only if the leaf above it
was starting to unfold. This had the effect of decreasing the number
of new leaves per branch by one in the 2 weeks following marking in the
defoliation experiments, as compared to the weekly plant samples. The
difference in leaf weight between model and field control diminished
in the following 2 or 3 weeks (Tables 28 and 30) due to the fact that
the specific leaf weight and weight/leaf of leaves initiated after the
field plants were marked increased as the leaves aged, whereas these
remained constant in the model.

103
2
The weight of new leaves/m is lower for the simulated removal of
all leaves from the outer 50% of the canopy at 12 weeks than for the
field experiment (Tables 29 and 30). This is due to the fact that in
the model developing leaves may only draw carbohydrate from storage if
the LAI is less than 2.0. Even though leaves have priority over stems
and expanding pods if the LAI is below 2.5, at this point in the season
there is a sufficient number of developing seeds to use all of the
photosynthate produced by the defoliated plants on most days. It
would appear from the differences in stem weight gains between the field
experiment and the simulation that in actuality the plants can draw
upon reserves to a greater extent than is allowed in the model. I
used the 2.0 LAI limit for drawing upon stem storage because it worked
well for the defoliation experiment at 9 weeks (Tables 27 and 28) and
because higher limits caused the plants defoliated at 9 weeks in the
simulated experiments to seriously overshoot the LAI of the field
plants defoliated at 9 weeks and harvested at 15 weeks. In order to
use the higher limit, which would work better at 12 weeks, it would be
necessary to change the method of inactivating growing points in the
model, making it dependent upon some factor other than the weight/leaf
of the leaves completing development on a given day. The fact that the
specific leaf weight and size of new leaves are essentially the same
for the check and defoliated plants for the last 3 experiments (Table
31) indicates that once a leaf is initiated it gets as much photosyn
thate as it wants, if at all possible. Therefore, growing point in
activation should probably not be tied to leaf size. This is something
which needs to be investigated further.

Table 31* Specific leaf weights and average size of new leaves grown
in the 2 weeks following defoliation.
Defoliation
Date, Week
T reatment
Type
SLW-of
New Leaves,
mg/cm^
Average Wt.
per Leaf, mg
Average Area
per Leaf, cm'
9
Check
5.kb
83.0
24. 1
50% uniform
3.5k
93-5
28.0
50% outer
3.46
80.2
23.2
12
Check
3.88
88.3
22.8
50% uniform
*4.25
84.2
19-8
50% outer
3.66
64.7
17.7
16
Check
2.60
14.8
5.7
50% uniform
4.09
20.8
5.1
100%
3.45
17.6
5.1
^Specific leaf weight

105
Table 32 and Figure 14 are comparisons of model and field results
for plants defoliated at 16 weeks and harvested 2 weeks later. Experi
mental and simulated results match well except for the weight of new
leaves/m^. The model plants have already shut down all vegetative
growing points by week 16, whereas a few are still active on the field
plants at 16 weeks.
The simulations of 4 of the defoliations performed by Mangold
(1979) fit field results well in some respects and not so well in
others (Tables 33 and 34). The model underestimated the weight of new
leaves 2 weeks after treatment for the plants defoliated 75% (Table 33)*
According to the model there was little carbohydrate in stem storage at
8 weeks which could be drawn upon to grow leaves, but apparently in
the field the plants were able to draw upon reserves to grow leaves.
A more rapid increase in LAI during the first week following defolia
tion would yield a higher level of photosynthesis during the following
week which could produce the higher stem and pod weights observed in the
field at 10 weeks.
The model did a good job of fitting weight of new leaves for
plants defoliated 75% at 8 weeks with 75% of new leaves removed for 7
days subsequently (Table 33). Simulated stem and pod dry weights at
10 weeks are low. The plants may have been larger than the simulated
plants prior to defoliation, but I don't have the information necessary
to determine whether this was the case.
The model underestimated the amount of damage to final yield done
by the 75% defoliation at 8 weeks and the 75% defoliation plus new
leaves for 7 days at 8 weeks (Table 34). This is probably due to the
fact that in the simulations the defoliated plants were slower in

Table 32. Comparison of model predictions with field results for plants defoliated at 16 weeks and har
vested at 18 weeks.
Plant Variable
T reatment
Control
50
% Uniform
Outer
50'.? of
Canopy
Field*
Mode 1
Field*
Model
Field*
Mode 1
Original LAI
6.2
(0.8)
6.5
6.9
(0.6)
6.5
5.8
(0.5)
6.5
LAI after defoliation
6.2
6.5
3.1
3.2
0.0
0.0
LAI at harvest
6.2
(0.8)
6.5
3.2
(0.3)
3.2
0.2
(0.1)
0.0
2
Leaf weight at harvest, g/m
241.5
(30.9)
237.3
127.5
(11.8)
121.6
5.7
(1.9)
0.0
2
Weight of new leaves, g/m
0.9
(0.3)
0.0
2.8
(0.7)
0.0
5.5
(1.9)
0.0
2
Stem weight, g/m
309.9
(40.5)
290.0
271.4
(29.7)
244.3
243.1
(27.0)
209.0
2
Gain in stem weight, g/m
-20.9
-5.1
-51.1
-51.0
-90.2
-86.4
2
Number of pods/m
1037.2(129.6)
959.8
874.8
(94.4)
959.8
802.2
959.8
2
Weight of pods, g/m
674.0
(83.6)
653.3
629.9
(57.7)
645.8
492.8
(77.5)
581.1
Number of P4-P5/m^
CO
(95.2)
674.7
665.8
(65.9)
674.7
522.5
(90.9)
674.7
2
Weight of P4-P5, g/m
667.0
(82.5)
637.0
621.4
(57.3)
636.4
484.2
(76.2)
571.6
'Number in parentheses is standard error of the mean.

POD DRY WEIGHT, g/rn2 LEAF AREA INDEX
Figure 14. The simulated and experimental effect of 50% uniform and
100% defoliation at 16 weeks after planting on LAI (a) and
pod dry weight (b).

Table 33.
Comparison of
2 weeks immed
simulated and experimental
iately following defoliation
(Mangold, 1979)
at 8 weeks.
growth of Florunner
peanuts
in the
Wt. of New
Leaves, g/m^
Wt. of Stems,* g/m2
Wt. of
Pods, g/m2
Treatment
Field
Mode 1
Field
Mode 1
Field
Mode 1
Check
52.1
56.6
21*8.5
222.0
1*1*.1
1*1 .1*
75% uniform
76.3
58.1
181.7
152.5
26. 1
19.8
75% uniform
+ buds**
33.^
37.0
182.6
126.9
23.4
5.5
'"Includes weight of leaf petioles.
'""Buds removed for 7 days.

109
Table 34. Comparison of simulated and experimental (Mangold, 1979)
yields for Florunner peanuts defoliated at various points in
the season.
Pod Dry Wei
ght, g/m2
% Reduction in Yield
T reatment
Field*
Mode 1
Field
Model
Check
495.1 a
460.9

--
75%, week 8
429.5ab
461.8
13
0
75% + buds, week 8**
365.4b
404.5
26
12
75%, week 11
349.0b
346.2
30
25
75%, weeks 11, 15
366.1b
346.0
26
25
'"Values in the column
different ( p < 0.05),
fol1 owed by
Duncan's new
the same letter
1 multiple range
are not
test.
s ign i ficant1y
**Buds removed for 7 days.

no
inactivating vegetative growing points than non-defoliated plants,
with the result that final photosynthetic rates for defoliated and non-
defol iated plants were almost equal. This was due to the mechanism used
to determine growing point inactivation in the model. Further experi
ments need to be performed to determine the true mechanism for growing
point inactivation.
The model predicted no difference in yield between plants defoli
ated only at 11 weeks and those defoliated at 11 weeks and again at 15
weeks, and this was in agreement with the field results (Table 3^).
The predicted level of yield reduction was also close to the actual
amount.
Simulation of Insect Cohort Entering the Field
The simulations of an insect cohort entering the field at 3 dif
ferent points in the growing season and at 2 different population lev
els indicate that the plants can tolerate larger infestations at some
times than at others and that the location of feeding damage does make
a difference. When 10 larvae/plant were introduced at 21 days after
planting, the plants were destroyed. When the same number was intro
duced at 35 days post planting, no damage to final pod weight was sus
tained by plants on which feeding occurred randomly, whereas final
pod weight was reduced by 6% when feeding was on the youngest leaves
(Figure 15). Although LAI was essentially the same for the 2 types of
feeding, effective LAI and consequently photosynthetic rate were higher
for the plants defoliated randomly. When 10 larvae/plant entered the
system at day 56 (feeding until day 82), the results were essentially
the same as those for entry at day 35--less than \% reduction in final

POD DRY WEIGHT, g/m2 LEAF AREA INDEX
111
Figure 15- The simulated effect of 10 larvae/plant entering the field
on day 35 after planting and feeding for 26 days at an
increasing rate.

112
pod dry weight if the plants were fed upon randomly, but 6% reduction if
the feeding was on the youngest leaves (Figure 16). When the population
was increased to 20/plant (Figure 17) a much more serious reduction in
yield occurred when the insects entered the field at day 35- Final
pod dry weight was 27% lower than the check for the plants defoliated
randomly and 23% lower for plants on which the youngest leaves were
eaten. There was less of a difference in final yield between types of
feeding damage in this case because LAI was reduced to almost zero by
either type of feeding.

POD DRY WEIGHT, g/m2 LEAF AREA INDEX
113
WEEKS FROM PLANTING
Figure 16. The simulated effect on LAI (a) and pod dry weight (b) of
10 larvae/plant entering the field on day 56 and feeding for
26 days at an increasing rate.

POD DRY WEIGHT, g/m2 LEAF AREA INDEX
114
Figure 17- The simulated effect on LAI (a) and pod dry weight (b) of
20 larvae/plant entering the field on day 35 and feeding for
26 days at an increasing rate.

CHAPTER V
SUMMARY AND CONCLUSIONS
The growth of Florunner peanuts was followed on a weekly basis
during the summer of 1978. For these plants leaf growth slowed down
after week 12 and ceased after week 17- Stem growth, as indicated
by the ratio of stem weight to length, continued until week ]k, and
there was a high correlation between stem weight to length ratio and
plant age. The pod load was set by week 12, in that very few pegs
that entered the ground after week 12 had expanded into pods by week
16.
A series of defoliation experiments was also performed. For the
plants defoliated at H weeks, all plant parts appeared to be equally
affected by defoliation; i.e., if stem weight was reduced, so were
root weight and leaf number and weight. In the later experiments, stem
growth was affected more than leaf growth. Leaf weight for the defoli
ated plants increased as much as or more than did that for the check
plants in the 2 weeks immediately following treatment. Removal of
leaves from the outer portion of the canopy resulted in a greater num
ber of new vegetative branches and in more new leaves 2 weeks following
treatment. This high level of leaf growth following defoliation was at
the expense of stem and pod growth. In all cases the ratio of stem
weight to length for defoliated plants was lower than for the control
plants. Even at week 16, when stem elongation had ceased, this ratio
was negatively affected by defoliation, indicating that the plants
115

116
were drawing upon reserves in the stem to grow leaves and pods. Gener
ally, the effect of defoliation upon pod growth appeared to be to slow
or stop the expansion of young pods, thereby resulting in fewer pods of
the largest size category.
In general, the computer model developed on the basis of these
experiments, PMINUS, satisfactorily simulates changes in LAI and weight
of stems, pods, and fully expanded pods for both defoliated and control
plants. Further work needs to be done on determining factors which
cause the plants to lose leaves and to decrease growth of leaves. Fur
ther experimentation aimed at determining the mechanisms involved in
setting the size of the pod load would also be helpful. It would also
be of value to know how long a peg that has entered the ground can re
main inactive before it loses the capacity for expansion. A series of
defoliation and depodding experiments could shed light on some of these
questions. In particular, 100% defoliations and 100% depoddings per
formed at frequent intervals during the season on 2 or more varieties
of peanuts could provide the necessary information on what factors de
termine the cessation of vegetative growth and the partitioning of
photosynthate to pods.
The fact that simulated plant growth following defoliation for the
most part matched plant growth in the field indicates that the assump
tions made about light interception and photosynthesis in the model are
realistic. Further experiments still need to be performed to determine
the effect of non-uniform defoliation on canopy photosynthesis. Work
also needs to be done on the related problem of feeding site location
for different foliage-consuming insects and the effect of natural in
festations of insects on canopy photosynthesis. The simulations of an

117
insect cohort entering the system support the view that time in the
season and distribution of feeding damage do influence the plants'
ability to tolerate an insect attack.
The model structure is such that the influence of other compon
ents of the crop system which affect plant growth and final yield,
such as disease and water stress, can be incorporated fairly easily.
There is already a water stress subroutine developed by Ritchie (1972)
included in PENUTZ. With minor changes it could be incorporated into
PMINUS. GASP IV, the simulation language used in construction of this
model, allows for the easy programming of events. This makes it pos
sible to simulate insect or disease attacks of some complexity with
relative ease.
More research is needed to refine the model for use in a pest
management program. At present, it can be a useful research tool in
the study of plant response to pest damage. With further comparisons
between results of field experiments and model predictions, it should
become clearer which of the various hypotheses incorporated in the
model are in need of modification.

APPENDIX 1
WEATHER DATA
FOR THE 1978 GROWING SEASON
Solar
Rad¡at ion,
Temperature
(0
Rainfall and
DAY
1ang1eys
Max.
Min.
Irrigation, mm
23 Hay
449
33.9
21.1
24 May
545
31.7
21.7
25 May
487
32.8
20.6
5.1
26 May
593
32.8
20.0
27 May
614
31.7
16. 1
28 May
566
31.7
18.3
29 May
533
31.7
18.3
30 May
550
32.2
20.0
5.8
3 1 May
397
32.2
19.4
1 June
550
32.8
20.0
2 June
392
31.1
22.2
6.3
3 June
292
30.0
21.7
25.9
4 June
277
28.3
22.2
8.8
5 June
368
28.3
21 1
6 June
485
31.1
22.2
7 June
540
31.1
23.3
.5
8 June
502
33.3
24.4
9 June
425
32.2
23.9
2.5
10 June
449
31.7
23.9
14.7
1 1 June
449
31.7
23.3
.3
12 June
461
31.1
20.6
13 June
576
32.2
23.3
1b June
456
31.1
23.3
7.9
15 June
464
28.3
20.0
16 June
519
30.6
18.9
17 June
619
30.6
18.9
18 June
614
30.6
17.8
19 June
507
30.6
22.2
20 June
313
29.4
22.2
21 June
406
32.2
21 1
10.2
22 June
447
30.6
22.2
1.0
23 June
578
32.8
22.2
2b June
478
34.4
20.6
26.9
25 June
600
32.2
22.8
26 June
597
33.9
22.2
27 June
571
33.3
23.9
28 June
497
35.0
23.9
29 June
554
35.0
23.9
30 June
600
35.0
23.9
118

119
Day
Solar
Rad 1 at¡on,
1ang1eys
Temperature
Max.
(c)
Min.
Rainfa
1 rrigat
1 July
62A
33.9
23.3
2 July
636
3 A. A
23.3
3 July
638
33.9
25.0
A July
29A
28.3
23.9
3.3
5 July
A30
31.1
23.9
6. A
6 July
258
27.8
21.1
5.3
7 July
335
22.8
20.0
8.A
8 July
A78
31.1
22.2
1.2
9 July
609
31.1
22.2
3.8
10 July
590
33.3
23.3
11 July
kk3
33.3
23.3
12 July
270
30.6
22.2
9.9
13 July
370
27.8
22.3
. 8
1A July
A25
30.0
22.8
15 July
A80
31.1
23.3
16 July
103
31.1
23.3
37.6
17 July
392
30.6
22.8
8.A
18 July
A85
30.0
23.3
10.1
19 July
397
30.6
21.7
A.3
20 July
k] 1
28.9
22.2
.3
21 July
519
32.2
22.2
. 8
22 July
533
32.2
23.3
6.6
23 July
62A
32.2
23.3
2 A July
628
32.2
22.2
.3
25 July
583
33.9
22.8
2.0
26 July
337
30.6
21.7
1.3
27 July
A5A
31.1
22.8
77.5
28 July
220
27.8
23.3
7.1
29 July
330
29.A
22.8
9.1
30 July
All
31.1
23.9
6.6
31 July
2A9
30.6
21 1
1 August
A32
30.6
21.1
82.8
2 August
502
31.7
22.2
11.9
3 August
61A
31.7
21.1
k August
51A
31.1
22.2
5 August
A78
30.6
22.8
2.3
6 August
313
31.7
22.2
7 August
571
33.3
21.7
8 August
311
30.0
23.9
.3
9 August
633
31.7
21.7
A.6
10 August
387
30.6
22.2
. 8
11 August
280
30.0
22.8
12.2
12 August
3A2
31.7
23.3
2.8
13 August
2A9
28.9
22.8
i .0
lA August
380
30.0
22.2
15 August
A 85
33.3
22.8
50.1

120
Solar
Day
Radiation,
1ang1eys
Temperature
Max.
(C)
Min.
Rainfal1 and
Irrigation, mm
16 August
387
31.7
22.8
.5
17 August
464
32.8
21.7
2.3
18 August
576
33.9
21 1
2.3
19 August
382
31.7
20.0
20 August
516
33.3
23.9
21 August
542
32.2
21.1
22 August
428
31.7
22.2
23 August
473
31.1
22.2
24 August
547
31.7
21 1
25 August
456
31.7
20.0
12.7
26 August
499
32.2
21.1
27 August
593
33.9
22.2
28 August
476
35.0
22.2
29 August
571
32.2
22.2
30 August
573
32.8
22.8
31 August
509
32.8
21.7
19.1
1 September
466
35.0
21.7
2 September
413
33.3
21.7
1.8
3 September
511
32.8
21.7
4 September
516
33.3
20.0
5 September
437
33.9
19.4
6 September
459
31.1
18.3
7 September
535
32.2
20.0
8 September
425
32.8
23.3
19.1
9 September
378
32.8
22.8
10 September
217
31.7
20.0
.8
11 September
487
31.7
18.9
12 September
499
32.2
21.7
13 September
449
32.8
20.0
14 September
411
32.8
20.6
19.1
15 September
416
33.3
21 1
16 September
410
33.3
20.6
17 September
490
32.8
20.0
18 September
509
32.8
20.6
19 September
468
33.3
16.1
20 September
483
32.2
20.6
19.1
21 September
380
32.2
20.9
22 September
459
33.9
20.6
23 September
251
32.2
21.1
7.6
24 September
385
31.1
21.7
25 September
435
31.7
20.6
.8
26 September
354
30.0
20.6
12.7
27 September
292
29.4
20.0
28 September
378
28.3
18.3
29 September
170
27.2
20.6
30 September
129
25.6
22.2
7.9

121
Solar
Radiation, Temperature (C) Rainfall and
'ay
1ang1eys
Max.
Min.
Irrigation
1 October
306
28.9
17.2
2 October
456
28.9
16.1
12.7
3 October
485
29.4
19.4
4 October
308
29.4
15.6

APPENDIX 2
FLOW CHARTS OF THE MAJOR SUBROUTINES IN PMINUS

WATERX
LEAVES
N>
UO
MAIN
GASP
INTLC
EVNTS
ATTAC
INSECT
BEGIN
PNTLAI
FRUFIL
PNTLAI
Systems flow diagram showing the relationships between GASP IV (Pritsker 197*0 and PMINUS subroutines.
(See Table 23 for a functional description of these subroutines.)

}2k

125

126

no
yes
Change proportion of
daily photosynthate
which goes to roots.
no
1NIT >
ndex:
TNOW
> = 1
Call
¡EG IN.

128

129

130

131

132

PLTC5R0
yes
yes

13^

135
Calculate shell and nut demands for photosynthate.
no
Set the
pod load.
7
N.
Calculate stem sink demand.
Calculate
AVLCON.
V

136

137

138

139

\kO

141
Return

FRUFIL )
Return

1*3

I Mi

145

11*6

1^7

148

\U3

APPENDIX 3
COMPUTER PRINTOUT OF PMINUS

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3UI3ROUT I Nil EVNTSU X)
COMMON /('.COM 1 / A TR I (3 ( 25 ) JtVNT.Mf AiMFE(ldO) ML L ( l f) 0 ) M3 TOO ,M CUDK N
1 APO, NNAPT NNATR ,NNF II. NNG( 1 00 ) NNTR Y. Mf?M T, OP AR M ( 5 0.4 ) TMOW T T3CG
2 T TCLR. TTF I N ,TTRI O (25 ) TT5ET
COMMON /GCO M2/ ().)( 100), DDL (100), DTFUL DHL) W, I SC t 5 LF L AG ( 50 ) NFL AG,
1 NNFQD, 11 NEOS NNF.OT, 55 ( 1 00) SSL( 1 00 ) TTNEX
COMMON /UCO Ml /NDL'X 1 N )CX2 NO EX 3 NDCX5 NOW O T 3Y N { 7 ) OTS OUT ( 7) ,
1 A 50 G5 T ( 7 ) DA Y INC J, MERGE MOR Oil W
COMMON /UCOM2/HFT1 ME,T 1 MEL F
COMMON /UCOM3/INIT
COMMON /DC )M A/ADOS T M
1
COMMON
1
2
3
COMMON
1
2
COMMON
/UC 0 MS/ I 5 r r. M ( 7,350) NOD h ( 7 33 0 ) XL E AFN ( 7 ) 5 IZ EL F ( 7, 20 0) ,
H TLE AF ( 7,200) W T I NOD ( 7,200) W1 P E T ( 7.2 0 0 ) A RE AL F ( 7 ) ,
GHTLK (7 > *T5t EM( 7 ) XNLEAF ( 7,200) WTROUT 7 ) ICOUNI ( 7,350)
PDAY (200) A G R11T 5 (7 )
/UCO A 21/PODWGT( 7,200) ,MORE,PL UUMZ(7,200) KPEGST ,
PEGNO ( 7.20 0 ) PD PST ( 7 ) OCJDCAO ( 7, 20 0 ) A Gt: MA X( 7, 20 0 ) GRA TEK ,
KOOD5T GRRA TE ,OOPO.) 3(7) PQNUT 5(7 ) POO AGE (200 )
/UC ) M2 ? / HE *VE G( 7,200), ADOLF
COMMON / UCOM24/XNUNOD( 7) NC OU N T ( 2 0 0 ) SURF AC ( 7
VLGNIT VEGNCR. A5VEGF, VEGCI1R PflULF PORPT
COMMON /UCOM31 /ROO IF,SMA INF
COMMON /UCO M 35/N DE X
COMMON /UCOM37/NDEX9
GO TO ( 1,2,3 ) I X
CALL AT TAC
GO TO 3
CALL flE GIN
,200),VEGCRO.
,PORNJ, SL W
GO TO 900
5 IF (LFL AG{ 1 ) ) 1 0 0,100,1 0
10 CONTINUE
IF (N0EXS.EQ.1 ) GO T) 100
NOE XI = 2
NOEX 5 1
NOEX6 = 1
100 IF (LFLAG(2)) 200,200,110
110 SL W = 3.26
5 MAINF = 0,13
ADOLF (10.57 0.97) / (1.0 F VEGNCR)
P()RL F = 6.16 0.9 7
PORI1 T = 2.16 0.9 7
PL) RM i JO = 2.2 5 0.57
XX = T I MELE
I IF T 1 ME = 7.2
TIMELE = 14.4
00 220 I = l.NOW
IF (PDA Y( I ) .LE.0.0) 50 TO 220
rDAY(l) = rlMELF (TIMELF/XXl (XX -
PDAY( I 1 )

220
CONTINUE
NDEX9 = i
2 0 0
IE (LFLAG(B)
)
300.
30 0, 21 0
21 0
NOE XI = 3
300
IF (L FLAG (4)
)
3 1 0,
400.400
3 1 0
NOEX 1 = 3
40 0
IF ( L F L A G ( 5 )
)
5 00 ,
500,410
4 10
HOOT F = 0.0 1
5MAINF = 0.1
5
*">0 0
I F: ILFL A G ( 6 )
)
n 0 0 .
6 0 0,6 10
51 0
IN IT = TNOal
NOCX2 = 1
CALL OF GIN
C 0 0
IF (L FL AG( 7 )
)
700.
7 0 0. 6 1 0
61 0
RL'TF = 0.4 3
5M A IN F = 0.30
70 0
IF (LFLAGCJ)
)
BOO.
BOO, 7 10
7 1 0
MOEX 1 = 4
NO f£X 6 = 2
B00
IF (LFLAG(O)
)
cUO.
900,900
Ml 0
NOEXI = 2
00 0
CUNT INO E
IF (LFLAG(10
) 1
1 950
,950,910
0 10
SL m 3.77
05 0
CONT INU E
RETURN
E NO
x-

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COMMON /GO) 42/ r>.> C 1 JO) ,IJOL( 1 OJ ) ,!)TFUl. .DTNMW
1 NNFGD, NNflOG, NNEOT SG { 1 0 0 ) GSL ( 100), T THE X
DATA EMERGE/ 11.0/
LFLAG( 1 )
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0
9
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0
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1
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)
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9
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l-vl TURN
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5 = <24X)NDbl
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JO-IWIJ 4 3N I 1311/cV L DO/ NOMOD
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ARCALF(K > =
ARFANW
WGMTLF(K) =
WT NEW /
(1000. *
0 .07)
WT3TEM(K) =
STEMNW /
(1000. *
0.57)
PETWT(K) =
: ETNE/r /
(1000. 0
0.97)
WTROGT(K) =
ROOT NW /
1000 .
XNLFAF K J )
= l 0
X I nodi: ( K J )
= l 0
XX = { T I
F 2.0)
/ TIMELF
s i 2!.:lh k m )
= W T NT. 1*
* XX
WTLTAP ( K > -1 )
= WT NEW
* XX
W T I NOO ( K I)
= 3 T F M N W
* XX
WTPF.T (K -U
- P f TN E Vi
* XX
XNLFAF{K,M)
- 1.0
XI NODE( K ,M)
= 1.0
IF (;>OAY(M)
L T .TI MEL
F 3.0)
POAY(M) =
T I
XNLi: AF ( K ,L )
- 3.0
X INODtK K ,L )
= 3.0
SIZELF(K,L )
= (WTNEW
/ 2. ) *
XNLFAF(X.L
)
WTLFAf ( K ,L )
= W T NE A
/ 2 .
WT INI) 0( K L. )
= STEMNW
/ 2.
WTPT.TI K ,L )
= (PFTNEW
/ 2. ) *
X NL FA F ( K L
)
IF ( lDAYU. ) .LT.HFT I ME > POAY(L) UPTIME
XX = (UPTIME -2.0) / TIMELF
XNLFAF(K.N) = 3.0
X I NO Or. ( K i N ) = 3.0
WTPET (KH) = PET NEW XX
SIZL'LF(K.N) = 3.0 wTNEW 3 XX
WTLCAr(KiM) = W TN E W XX
WTINDD(K.N> = 5TEMNW T XX
IF ( DA Y( M) L T. I IF T l Mia-2.0 ) P)AY(N) = UPTIME 2.0
I COUNT (K,
1 ) =
N
ICUUNT( K .
2 ) -
N
ICO UN T( K .
1 ) =
N
NCOUNT(J )
- NOW
AGRPT 9( K)
- 3.
S>( 1 ) 3
5(1)

( AREALT(K )
PROPOR(K))
/
1 0 00 0 .
33(3) S
5(3)
( AREAL T (K )
* 3 ROPOR { K ) )
/
10000.
CALL PUT LA I
5 00 RETURN
I; NO
i

oo
LTV
X I! 1 VMO
lVlOld 11V3 C2
0 2 V 10 S 10 (2XJGN) dl
ZVUZIld 11VD il
l = Z XION
< l )N31 I J 11 VD
* I = ( 2)UIM1V
KI1JLK1 4 MOM = ( 1)01 ill V
0*99 = WJ1J30
MINI = AVOlid
SI U J O V (C* 3N*ZX3(JN) dl Cl
Cl *CT *0C6 (AVUlld (9*MUN>1VWI1D) II
XUdlVf* llVD
f'U N1 = MON
0G6 Cll DO ( C C* l J MON1G ) dl
X3CNI V IS IV dV?l IV Hi I = (DCS
llVl! UNIJNVld TJN15 AVI* 1 V D 11. UK) I S AM d = (2)SS
XUClf I VIIV :IV31 JAllDlddl = ( nss
/0//X3ON VIVO
loon 3NO1S/0 VK UDO/ NOV KOD
( 0Cc)I Vlddd/Vf V UDO/ NOWKOD
2dAl 1 HI J JO JlOkOD/Ol KUJO/ NOf.K'UD
( L ) COlK'l S ( Z ) N 1 K W1S /1 2 W 0 Dn / NOWKOD
(COZ ) I'D VOUd 4 ( Z )S in NO cl ( Z.) GCOdOd 3 1VHMD J SOOcOl 2
( 0 02* L ) XV Wl'DV ( 002 ) c IV DUOc ( Z )i GOOd ( COT L ) U NT lid l
4IGDldX 4( 002 4 Z ) Z M1U1U *D MOW ( CCS L ) IPWClllcl/ l 2K ODO/ NOWWUD
1WJ11S/SlKUDO/NOWKOD
( Z )3GU1U l/k l MIDO/ NIJKKOD
AVO lid 4OA V WX/C IKUDf*/
(Z ) 1 Wild ( L ) 3cl mid ( Z ) H
* { Z ) SD3d ( L) Id dlGH ( />OUdISO* ( L ) llllMJ* ( Z ) ZION Id/ OK 100/
OCJVAVu 4 ( Z ) dUdUdd/tl UDn/
(002 JoWiOOU 4 (002 ) A V Ci I
4 ( C C 2 ) I V1X 4 ( C 02 ) KWfKIlM 4 < 0 C2 )Kd I dNd 4 cWd 1UM 4 ( CC2 ) 21 Old
4 ( 00Z ) WM 110 M4 (00 2 ) WCill'JII 4 ( 0 02 ) K1 10 id 4 ( OC 2 ) K'lf'NHd 4 ( 0 02 )2W 1U1
4 ( 0 02 ) WdlPNX4 ( 002 ) WG Id 19 4 ( 0 0 2 ) 2 Kill M 4 ( 0 02 )2 1 WIG/MODO/
(9*002)1V111D/9KIDU/
( Z ) S 1 c¡?JD V 4 ( 0 02 ) A V(Id
NOWKOD
NOOKOD
NOWKOD
MOWKOD
h O K M O D
4( OGf 4 Z) IN ODD I 4 ( Z ) IOIUI 1M 4 ( 0 0 24 7. ) dV 21N X 4 ( Z ) W 111 1 4 (Z ) dll I IDd 2
4 (Z)dlVlIV4( 0 02 4Z ) 1 LldlM 4 ( 0 02 Z ICCMI 1/1 4 ( 00 2 4 Z ) dV31 It* l
* ( 0 02* Z ) 1117 IS4 ( Z )N JV ¡IX < 0 S 2 4 Z ) ICON 4 (091 4 Z M* 211 1/0 1 ODO/ NOW KOD
A'ONiiUW 4 I'jMIiN *r 4 DM I AVO 4 (Z)lSDdSV I
4 (Z )inIEld4 (Z )NASJ X JN11* (001 ) 1GS 4 (00! )SS 4 10.7NH4 S 01N N 4 <1OIIMN I
4 OVldN 4 ( OS ) D V1 d 1 4 S13 S I 4 M! IM10 in J lO 4 ( 00 l ) 100 4 < 0 0 I ) CIO /2KUDD/ NOWKOD
11)51 1 4 ( S2 ) OI Ml 1 4 Ml dll *il ID 11*2
030 1 1 4 i*UN 1 4 ( *? 4 OS ) IDIV dd 4 INIJdN 4 Ad INN 4 < CC l ) CNN 4 II dNN 4 Ml VNN 4 1 d VON 4 Od VN l
N 4 NO ID N 4 dUlSW 4 (CC l ) 11K 4 ( 001 ) 3.1 K 4 VdW J NA1 0 4 ( 9 2)01 HIV /l KUDO/ NUWKOD
31 vi r, ini inufjtinc
IJ IjU

CALL PLTGRD
riOTPM2 = o.o
PET =0 .0
TO SJ J = 1 MERGE
L>0
F WTROOT(J) PRDPOR(J)
WTSTEM1 J) PRUPOR ( J )
( > T M M I N ( J ) l'IUin.'lil J ) ) / 1 000.
F WSHTLF(J) F PPOPOR(J)
* AS f F XL [ A r N ( J ) HUOPflKl J)
F PENUT/J) F PROPOR(J)
F FiiUI T( J ) PRUPOR ( J >
F ULOOMZ ( J NOW ) <> PF-iOPOE ( J )
I IISTPOOtJ) PROP i ii J )
F IIS TR r ( J ) F IMOIOH ( J )
F PEGS ( J ) F PUSH MR ( J )
HO TP M2 = 1(0 TPM 1 {< c J PROPOR(J)
NH I PM( NOW ) = PNNIPM(N)W) P JN IPi\ ( J ) F PROPONJ)
PI'T = PE T PETWT7) PRUPOHJ)
GO CONTINUE
TOTM2UOW) STMM2INOW) f WTL FM2 ( NOW ) f fin I TM( MO.V ) F ROO TM2 ( : UJ W)
1 f PF
STLFNT = STM M 2! NO W > WTLF M2! NOW ) F PET
SS(1 ) = S 'SI (1 ) F PAY ADI) F DT NOW
SSI T) = SSL ( 1) F MAYADO F DTNOV
DAY ADD = 0.0
CALL ROTNOD
CALL PM TLA 1
30 TO 100
000 CONTINUE
ss!2) s:si_( .?)
DIG CONTINUE
Soil) = Sr.L(l)
S ( 1 ) = SDL ( 3)
200 CONTINUE
I DAY!NOW) = SD(2) F O.b
XL A I (NOW > = DD ( 3)
EFFL A I (NOW) DS( 1 )
DDO CONTINUE
RETURN
END
IF ( I MERGE! J ) .LE. 0) r,;j TO
ROOT M2 { NOW )
ST MM2 ( NOW)
STORE(NOW)
.v TLF M2 ( NO .<)
GRP TSMI NOW )
X NOLFM ( N' )W )
PE N'JTMI NOW )
F ROI T 1 (NO W)
3LOOMM(NOW)
OS TP DM! NO t)
h s r rr1(now )
PEGSM?(NOW)
= ROOTM2(NOW)
SI MM2(NOw) F
D T OR E ( N )W ) F
- WTLFM2(NOW)
= ORPTSM(NOW)
- XNOLFM(NOW)
- i*r: NUT M ( NOW )
= FRUITM = ULl'iClMM (NOW )
= 11S TPi) M ( NOW)
= 115 T FRM (NOW )
- PEGS M2 (IU1W)

'iUUHOUT INC WATtIRX
COMMON / ijC DM2./ OO ( 1 0 0 ) DDL ( 1 00 ) OTf-UL .0 TWO W I SEE 5 LF LA G ( 50 ) NFLAG .
1 NNFOO NNcQG, NNFQT, S5 { 1 0 0 ) SSL( 1 0 0 ) TTNEX
COMMON /UCOM1/NDEX1 ,NOEX2.NDEX3,NOEX5.NOW,PTSYN(7) ,PTSRUT(7)
1 ASPOSr (7 ) ,DAY INC. J, 1ER C.E M OR NO W
COMMON /UCO 16/CL I MAT(TOO ,6)
COMMON / U COM 1 1/STRE5F
RETURN
CN O
CTN
o

SUOROUTINE PTOTAL
O I MENS I ON AV GP T S{ 10)
COMMON /GCOM1/ AT R I O (2 5 ) J i: V N X ME A M P E ( 100 ) ML E( 100 ) MS TOP N CRON N
INAPO NN APT. NINA TR NNF It. I1NO (100). Nil TRY, NPRN T I'M* ARM (50 .4 ) T NOW T TUEG
2 r r clw r t f- in. r r r i j (2 5 >, t t set
COMMON /SCO M2 / DO ( 1 0 0) DDL ( 1 0 J ) D TFOL OT NOW, I SEES, LFL A G ( 50 ) NFL AS,
1 NNEOD, IINEO >, NNECI l, SSI 100), SSL ( 1 00 > T rME X
COMMON /UCn M 1 /NDEX 1 NOEX2 NDEX .1, NDF X 5, NOV* PTSYN ( 7 ) P T SR UT 1 7) ,
1 A Si> S S T ( 7 ) O A Y I NC J ME RGE MOR R OW
COMMON ZOOMS/ IST£M( 7, S50) NOTE ( 7, OSO) XLLAFNI 7) S I ZELL 7,20 0) .
1 WTLE AE (7,2 0 0 ) UT I NODI 7.20 0 ) WT PET ( 7. 20 0 ) ,AREAL E( 7 ) ,
2 WGlITLf ( 7 ) WT 5TF M( 7 ) XiiLE AF I 7 ,2 00) WTROOT (7 ) I COUNT (7 3 50 ) .
3 POAY(200),AGRPTS(7)
COMMON /OC0M6/CL I MAT (200, 6> )
COMMON /UCOMD/PROPUR( 7 ) O A Y A D )
COMMON /U C O M10/XM ATOP, PLT DAY
COMMON /OCOMl 1ZSTRESF
COMMON /DCOM 1 2/PL TLA I PTS
COMMON /UCOM13/PN(200)
CO MMON /UCOM14/I MERGE( 7)
COMMON/UCGM1 5/STLERT
COMMON /OCO Ml (S/POR T( 7 )
COMMON /OCOM1 7/XL IM T( 7)
COMMON /UCOM1O/AS JGEN(7 )
COMMON /OCO M3 1/ROO IF SMAlNF
COMMON /UCO M 3.5/PODLM, XL MM AZ
DA TA H STOY STDECL PTSSUM AV G >TS K AV G. AK/0 .3 J 1 1 ) 0 .0 1 0 =0.0, 6,
1 0.0/
DATA DECFCT/1.0/
DA TA PS LOPE ,PTSF AC RESPFC IJMF if C ,P AR FAC/0 .H3t.d-0 5, 1.10,
1 0.30,0.01,0.65/
DATA AVG/5./
DECR T!£ = (1.0 HSTCPY)/{XMATUR STOlfCL)
DECS T = TNOW STDcCL
IF ( DECST.LE.O .0 ) GO TO 9
DECFCT = 1.0 DLCRT.I DEC ST
CONT INOE
PTS = PL TLA I 1.0 E4 CL I MAT ( NOW, 1 ) PSLOPE PTSE'AC
PTS = PTS STRESF DECFCT
PI S = PTS PTS RESPFC M r_ TFC STL FR T
IF' (PTS.LE.0.0) PTS = 0.0
AK = AK 4 1.
AK = AM INI ( AK, AVG )
A V 3 P T S ( 1 > = PTS
PTOSUM = P T S SUM 4 AVGPTS(l) AVSPTS(KAVG)
PTSMEN = PT3SOM / AK
KL = KAVG 1
DO 50 I l.KL

L = KAVG 14-1
5 0 AVC.PTr,(L) = AVGPTS(L-l)
X L M M A Z = AMAX 1 C PTSMEN, POOLM )
IF ( PODLM. G r O. 0) POOL M = XLI-MAZ
DO 110 J = l.MFRGE
if ( lMfinr.c( j ) .Ltz.o ) c,u to iio
IF ( SOL ( il .Lf-.o. 0) r.o TO 15
A = AOCALF(J) / ( SSL ( 3 > 10010. )
GO TO 16
15 A PORK J) / POOP OP(J)
16 CONTINUE
PTSYN(J) ~ i'Tfi A 1 0 00.
XL = PA OF AC XL MO A Z A 1 000.
XN .= PA OF AC PTS A 1 0 00.
IF (A.iru.0.0) GO TO 00
XL IMT { J ) = AMAXl(XL.XM)
IF ( NI1FX3.LT mZ ) XLIMT(J) = XN
00 CONTINUE
PTSOUT(J) = PTSYN(J) SMAINF
PTSYN(J) PTSYNtJ ) PTSOUT( J )
100 ASPGST(J) = ASPGST(J) F ASPGEI(J)
110 CONTINUE
Pf) (NOW ) = PTS
OETUON
r.¡ j d
cr>
ro

subroutine rltgro
DIMENSION PG,>£D(7 )
i> I VC NSI ON NEW REP (7.200)
COMMON /DCOM 1 /N DEX 1 NOE X2 NDF KJ NOE XO NOW RT SY Ni 7 ) ,PTSUUr( 7) ,
1 A SP (1ST (7 ) O A Y INC, J, MERGE.MORROW
COMMON /OCIO M2 /HF TI ME T 1 Mr'LF
COMMON /UCOM4/ADDSTM
SO
COMMON
1
2
2
COMMON
1
COMMON
COMMON
COMMON
COMMON
1
2
CO MMO N
COMMON
o
#_
COMMON
C OMMON
COMMON
COMMON
/UCC! MS / I STEM (7,350), NO )F ( 7, 350 ) XL E AFN ( 7 ) 5 I Z EL F ( 7.20 0 ) ,
WTLEAF ( 7,2 00 ) W T I NOO { 7,200) wTPI'.T ( 7,200 ) ARE ALE (7 ) ,
WGIITLF ( 7 ) WT ST L.M( 7 ) XNLEAE ( 7,2 00) WTROO T ( 7 ) I COUNT ( 7,050)
PDAY (200) A G R n T 5 (7 )
/UClH S/R ENUTZ ( 7 ) ,PUIJ I T ( 7 ) ,11 S TROD ( 7 ) ,1ISTERT ( 7 ) ,PEGS ( 7 ) ,
R ( 7 ) RIM R I RE ( 7 ) P E T W T ( 7 )
/UCOM1 7/XL I MT{ 7 )
/UCtlM 1 G/RHZUAY 200 )
/DC )M20 /WANTLE( 7 ), NUMO.l ( 7 ) X INOOE 7, 200 )
/UCO M2 1/ROO*G T( 7,300) MORE,OLGOMZC 7 ,200 ) KREoST,
REGNO (7, 200 ). ROOST (7).RONCAR{ 7, 20 0) AGE MA X( 7,200) GliA T E K ,
K ROO ST,GRRAT E.RQROOS(7 ) RGNOTS(7 ) ,RODAGEi 20 0 )
/iJC OM 22/Nt: W VE G ( 7,200) \DOl.F
/ U CO M2 4 / X NGNOO( 7 ), NC OJNT (200 ) .SURFACi 7, 200 ),VEGGRO,
VEGNI I VEGNCR ASVEGF VEoC NR,RORLF,RGRRI PORNOO,SLW
/OCOM26/WGT TNZ( 7, 200) H ANOT,RATIO ,RTGS
/UCOM27/RCTC,ROOC,RCTN, PGDN, A5RRRO,OIL FAC
/ UC O M 2 0 /LC O UN T ( 7, ISO)
/UCOM 3 i/PODLM, XL MM A Z
COMMON /OC O M35/NOEXG
COMMON /IJCUM 17/NDEX9
COMMON /UC O M43/W NT NO I (7 ) WNTR ) l)( 7 ) .
COMMON /UCOM4M/WANTOG7)
OAT A 3 I ZM IN.NEWRER,RERT IM,ROD 1A X, SI
1 .013/
DATA CONS1/27.0/
DATA NOEX11/0/
OAT A PC GDI. 0/7 *0.0/
MORRO V = NOW + 1
DO 50 J =
WANTOG(J) =
WNTSTM(J) =
WNT ROD( J ) =
WNTNUT(J) =
WNTS TO(J ) =
VJANTLF(J) =
NYES ~ NOW -
1 MERGE
= 0.0
= 0.0
= 0.1)
= 0.0
= 0.0
= 0.0
1
DO 200 I = l.NYES
RilZOAY ( I ) = PH ZD AY ( I )
Ir (Pl)AY( I ) .LE .0. 0)
I 0 AY ( I ) = RD AY ( I )
I
DAY I Ns
GO TO 200
DAY INC
NT GTO( 7 ) ;.'N T ST¡M ( 7 )
ZRED/70.0,1400*0,6.
, AVLCONt 7)
O 1 3 jO t

IF (fDAY( I ).LT.MFTIM2) GO TO l 60
DO 149 J = 1.MERGE
NKE EP .VTLEAFt J, I )/SI 2MIN X INUOIIU, I )
XKEFP = NKEEP
IF ( XKEEP. GT .X INODE ( J I ) ) XKEEP = XlNOUE(J.l)
XOPOP = XI NODE! J, I ) XKEEP
N=NUMUR { J )
IF ( N > 149.149,118
113 DO 149 K = 1,0
IF ( I STFM( J.K ) .NE / ) GO TO 70
IF ( PDA Y ( I ) .LT .T l MEI.F ) GO TO 70
IF ( ICOUNTI J ,K ) .ED.I ) AGRPT5IJ) AGRPTG(J) 1.
7 0 CONT I NOF.
IF ( 1 *',TEM( J K) G.I. 5 ) GO TO 149
IF (PDA Y( 1 ) .LT.TIMELF ) GO TO 10
IF (LCnUNT(J.K) I) 14 9,121.149
1 2 1 MO I SHI-A ( J K)
NODE ( J K ) = NU.)E(J.K) T 1
L = NOOE(J.K)
IF
( L- 3)
14 3, 122.122
1 2 2
GO
TO ( 1
2 3, 1 30, 140, 1 46), MN
1 2 3
IF
( L7 >
126,148,143
126
NUM3R(J)
-- NUMOR(J) f 1
AGHPTS(J) = AGOPTS(J) F 1.
I STEM! J,NOM3H1 J) ) = 3
NODE < J NUMO. ( J ) ) = 1
I COUNT ( J NOM 3R ( J ) ) = NOW
XNLEAF(J,NOW) XNLEAFlJ,NOW) F 1.
XINODE! J .NOW ) = XI NODE( J,NOW) 1.
GO TO 143
130 IF (L-6) 141,12*3,142
12 3 NUMOR(J) = NUMUR(J) F 1
IS T E M(J NOMORJ ) ) = 6
NUDE ( J NON OR ( J) ) = 1
I COUNT ( J.NiMi Jf< ( J ) ) = NOW
OLCOMZ ( J NO V ) = LOOMZ J NOW ) F 1.
IF (KPCGST.EQ.0) KPEG6T = NOW
GO TO 143
141 IF (L-4) 143,143,143
143 IF ((((LH)/2)/2)2 KL4D/.0) 14 4,143,144
14.3 NE JVEG J NOW ) = NLWV EG( J MOW ) F 1
IF ( NOE X 3 G T 0 ) GO TO 14 !3
NU.M\3K(J) = NOM3IUJ) 1
AGR"*I S( J I = AGRPTS(J) FI. ~
I STEM* J ,NUM.3W( J) ) =4 -c-
NODE(J.NOMUR(J)) = 1
NF WVEG ( J Mf'V ) = NEWVEG J NOW ) -
ICOUN I ( J NUN IP ( J ) ) NOW
1

1 -44
1 40
1 45
1 4 6
143
10
1 1 5
1 1 5
1 1
1 1 7
120
1 4 1
1 5 0
XNLEAF ( J.NOW ) = XNLEAF! J.N.IN) + 1.
XI NODE ( J .NOW) = XI nodi: l J .NOW ) 1.
30 TO 143
NF WRCP J, NOW) = NEWREP ( J. NOW ) 1
if c Morx.i.n.2) r,o to i 48
NUM01HJ ) = NUMORtJ) + 1
I S Til M ( J NO MOR ( J ) ) =5
NODE ( J NO O 1!1 ( J ) ) = 1
I COUNT ( J, NU MOR 1J ) ) -= NOW
ni: w'?e p j now) = newrep ( j. now ) i
riLOOMZ ( J NOW ) = 5LUOMZ ( J.IIJW) t 1.
IF (KPEGST.EO.O ) KPEGST = NOW
50 TO 1 4 3
IF (L-6) 148,146,148
l F { 1.-4 ) 145,144,143
IF tt!L/2)/2)+2 CL/2)) 143,144,143
CUNT IN'JF.
= I COUNT( J,K)
(NDEX6.LT. 1) GO TO 116
( V/TLEAF J, I ) ,LT .3 I Z.M IN )
TO 116
)
GO TO 11
K )-
I )
1
>
i
3
. 1
15,1
20
X) .
NE
. 0
)
GO
I 0
120
1 )
GO
T
O
1 1
6
I ) .
LT
1)
I z
MI
N/3 .
0) GO TO 117
I C
OUST
(
J
, K
)
LX
IF
IF
GO
IF (ICOUNT(
CONTI HUE
IF (LCOUN T(
IF (NDEXO.L
LX = I
IF ( WTLEAFC
CUNT INUf
LCOUNT(J,K)
I COUNT! J,K)
XNLEAFt J,MORROW ) =
XI MODI'< J .MORRO W) -
GO TO 1 2 D
I F (XDUOP.LE. J. 31 ) G O
XDROP = XDRDP 1.0
I S T EM ( J K ) = 6
LCCUNT(J.K) = ICDJNTCJ,K)
A50iT5(J) = AGRPTG(J) 1.
If- ( WTL EAF( J ,LX ) GE .20.0 )
aTPJTC J.I.X) = W TPl-IT { J ,LX )
XNLF.Af ( J ,L X ) = XNL HA F ( J 1. X )
WT PET ( J LX ) = wTPE T ( ) ,L X ) <
SI 7EI.FC J ,LX) = SIZE LF ( J LX )
X I NONE(J,LX) = X I NODE(J,LX)
CON TI NOE
CONTI HUE
DO 160 J = 1,MERGE
IF {POAY(I ).5u.HFrI ME) WANTJGIJ) =
= MORROW
XNLEAF(J,MORROW ) -
X I NODE( J,MORROW) l
TO 116
GO TO 120
/ XNLL AF( J,LX )
- 1.0
XNLEAF( I ,L X )
- wTLEAF! J.LX )
- 1.0
O'
W ANT !li. ( J ) X NLLAFC J I ) AODL F

1 DAY INC
16) WANTLF(J) = *ANTLf ( J ) F XNLEAF(J.I) A DDL E DAY INC
20 0 CONTINUE-'
PH 20AY (NOW) = DAY INC
DO 210 J = 1,MERGE
IF (XNLEAFIJ.NOW) .LT .0.01 ) GO TO 210
Pi) AY (NOW) = DAY INC
WANTLF(J) = WANTLF(J) F XNLF. AF (J NOW ) ADOLF DAY INC
2 10 CUNT INUF
IF INDEX 3 2 ) 3 00 ,5 00,3 00
300 DO 3 DO J = 1 .MERGE
N = NUM HR ( J )
IF ( N ) 3 5 0,3 5 0.3 1 0
310 DO 150 K -- 1 N
IF { 1ST CM ( J K ) ,NF. 5) G(J TO ISO
IF { NODE ( J K ) <312 4 ) GO TO 3f>0
LI. I COON T ( .), <)
IF (FHZDAY (LL ) .LT .lU'iH IM ) GO TO 350
ND>E(J,K) NODL(J.K) F 1
IC O UN T ( J K ) = MOR R O W
OLCOMZ(J,MORROW) = HLOOM2(J,MORROW) F 1.
3D J CONTINUE
500 CONTINUE
IF ( KPET.SI .cl.O > GO TO 60 0
DO 50 1 J = 1, MERGE
50 1 13 E G 5 ( J ) = 0.0
DO 310 K = KPEGGT, NOW
DO 510 J = 1, MERGE
IF (OLOOMZ(J,K) 0.01) 510,510.303
5 03 1F ( PH2D AY(K ) CONS 1 ) 509,506,3 06
503 PEGNO(J,MORROW) = PE'GNO ( J MOR; O W ) f ULOOMZ(J.K)
OLniMZ(J.K) = 0.0
IF (POO ST( J) .LL.0.0) PODST(J) = MORROW
RED = MORROW
RED = WED PO)ST(J)
IF (KPODST.EO.0) KPODST NOW
1JODCAP( J MORROW ) POVMAX SI.'RED -> RED I'lJOMAX
ASEMAX(J,MORROW) = 35.0 1.2
50) PEGS(J) = P E G 3 ( J ) f fH.nOIZ(J.K)
510 CONTINUE
IE (KPODST.50.0) GO TO 600
GRRATE = GR ATE K DAY INC
DO 512 J 1,MERGE
POPOOS ( J) = 0. 0
512 PDNOTS(J) 0.0
DO 530 K = KPODST, NOW
PODAGE(K) PODAGEIK) F DAY INC
>0 530 J 1, MERGE

IF (PEG NO(J,K).EG.0.0) GO TO 5 30
IF (POOWGT { J,K ) .GT.IMiiCAlM J.K) ) GO TO 510
POOS I 2 = 0.17 PODCAP(J.K)
IF ( PQOAvGE ( K ) .GT. AGEMAX ( J K ) A NO. PODWCJT ( .), K ) .L 1 PUDS I L ) GO TO 527
IF (PUOWGK J,K).LT.PUI)SI2) GO TO 525
IF ( PDOhGT ( J.K) GT .0 .clFPOOCAPi J. K ) ) GO TO 5.26
520 COOT INUE
PONUTS(J)
GO TO 530
-
P0NUT5(J)
F
PLGMO J
. K >
*
6RRATL
52 5
CONTINUE
WANT 1 = P
on
512 POO W
GT
(J.K)
H\ N T 2 = (
1 0
.0 J.2 5
A
POO WG T( J
. Is ) )
*
DAY 1NC
WANT = AM IN 1 (WANT 1 ,WA
NT
2)
POPOOS! J)
GO TO 530
-
POPOOS(J)
F
PEGN 1 (J
. K )
*
W AN 1
52 5
PQNUT5{J)
PQNU1S(J )
F
PEGNO(J
. K )
*
GURAT E
52 7
CONTINUF
5 10
CONT INUE
600
CONT I MUE
>0 5:3 0 J
_
1.MERGE
WNTNUT (J )

PONUTS(J )
*
PC TC /
O1LFAC
wn r poo(j >
r.
POPOOS(J)
*
PiJOC
IF ( WNTNUT( J) LE. XL I MT( J> ) GO TO 610
PEGOEDJ ) Pl-.GDEO(J) F 1.0
fttO'lUl (J) = XLIMT(J)
WNTPOO(J) = 0.0
IF ( PFGDFI) ( 1 ) Oil > ) GO TO 5 0 1
POOLM = XLMMAZ
MDCXJ = 2
00 60 K = KPEGGT.MORROW
GO 1LOO A7A J.K) = 0.0
601 CONTINUE
610 CONTINUE
5 3 5 0 0 5 4 0 I = ] N )W
IF (NCOUNT( I ) .60.0 ) GO TO 540
IF (PMZOAY( I ) .GT .32.4 > GO TO 540
WNTGTM(J) = WNTSIM(J) F XI NOOL ( J I ) AODGTM DAY INC
540 CONTINUE
A WANTLIM J I F WNTGTO(J) F WNTPO!)(J> F WNTSTM(J)
i = PTSYM(J) WNTNUT(J)
I F ( NDEX 1 .1- T .4 ) A = A WAN TL ( J )
IF ( Morix 1 L T .4 ) 0=1- WANTLf'(J)
IF (A.LF. 1.030 1) 6 0 TO 5 50
AVLCONI J > = 1 / A
GO TO 560
550 AVLCON J ) = 0.0
560 CONTINUE
IF (AVLCOIH J) .GE.1 .0 ) AVLCON(J) = 1.0
O'
-^i

IF ( AVL. CON ( J ) tLF.a 0.0) AVLCON(J) = 0
IF (KPOD5T.GT.0.AND.AVLCDN(J).LO.O.0
5S0 CONTINUE
IF (KPODST.NE.O) CALL DIVIDE
CALL LEAVES
IF (NDHXb.FO.l ) CALL GRPT S
KK = 0
DO 710 J = 1.MERGE
710 IF (PTSYN (J ) .GT .0.00 1 ) KK = KK F 1
IF (KK.NE.O) CALL STEMS
900 CUNTINUE
RETURN
END
0
PHZDAY(NOW) = 0.0
oo

SUO-DUTINE LEAVES
O I MENS I ON A DO OLD ( 7 ) ADD 2( 7)
DIMENSION AD OU AT (7)
COMMON /GC0M2/ ODdOOl.MLUOJi, DFUL NT NOW IS EES L FLAG ( SO ). NIL AG.
1 NNE'IO NNIiOSi NNEOT SS ( l 0 0 > 5SL 1 0 0 > T TME X
COMMON /UCDM1/NDLX1.NDEX2,NOEX3,NDLX5,NOW,PTSYN( 7).PTSRUT( 7) ,
1 A Sr* G ST ( 7) ,DA Y I NC J MERGE MOD ROW
COMMON /UCC1M2/HFT IMC.T l MELF
COMMON /UCOM5/I STEM! 7) NO Ju ( 7, 3SJ ) XL C A F N ( 7 ) S I Z EL F ( 7,2 O'JI,
1 >V T L F A F ( 7,300) WTI NIDI 7 ,200) WTPF.1 ( 7,20 0 ) ARE ALT ( 7 ) ,
2 WGIITLI- ( 7 ) wTSTEMl 7 ) XNLi'.AF ( 7, 200) WTROOTI 7) ICflUNT ( 7 350) .
3
PD AY(2 0 0) ,A G R P T S(7)
COMMON /UCOM3/PROPUR(7),GAYADO
COMMON /OCOM v/PENU T Z (7 ) FRO I T ( 7 ) (1ST POL) ( 7 ) 11 5 TFR T ( 7 ) PE G S ( 7) ,
1 R( 7) .PNRIPE C 7 ) PE Tw 1 { 7)
COMMON /OCOM 1 4 / IM ER GE ( 7 )
COMMON /l) CO M2 0/WANTL E ( 7 ) NO MOM ( 7 ) X I NU DE ( 7 200 )
COMMON /UCOM2J/GTMMINC7),STMLJS(7)
COMMON / JC 0M2 4/XNONOD ( 7 ) MCOII T { 200 ) SORT AC ( 7.200) VEGGRO ,
VFGNI T VEGNCR ASVEGF V2GCNR, POILF, PORPT .PORNOD, SLW
COMMON /UCOM 25/A SI* RED
COM ION /UCOM 4 J/,.NT NUT ( 7 ) WNTPJl) ( 7 ) WNTSTl) ( 7 ) ,*'NTSTM( 7 ) A VL CON ( 7)
COMMON /UCOM4J/WANTDGI7)
DO 450 J 1,MERGE
ADD2(J) = 0.0
IF ( WAN It F( J ) .Lfc* 0.0 ) Gf) TO 4 4 5
IF CNDEX1.GE.4) AVLLF = AVLCON(J) WAIMTLKI J)
IF (NDEX1.GE.4) GO TO 410
AVLLF = AM IN 1( WAN TLF C J ) ,PTSYN( J) )
413 CUNTINUF
IF ( AVLLF.LT. 0. 00 01 ) GU TO 44j
VEGGRO = AVLLF
430 VEGNIT = VEGGRO VEGNCR
ASPKFQ = VEGNI T ASVEGF
IF (ASPGST(J ) .GF .ASPUFQ ) GO TU 4m0
VEGNIT = AS
PGS
T ( J ) /
ASVEGF
VEGGRO = VK
GN I
T VE G
C NR
PTSYNJ) =
PT5
YN(J) -
V F.GGRO
A SPSST( J) =
0.
0
PTSRUT(J)
p r
SHUT ( J )
* PT5YN
PT SY N ( J ) =
GU TO 445
0 .0
440
PTSYN(J) =
P T S
YN( J ) -
VEGGRi 1
ASPGST(J) =
AG
PGS I ( J )
- ASPRI'.O
44 5
AGORA 1 (J) =
GO TO 447
VC
CGRO /
WANTLF ( J)
4 4 4
ADDP AT( J ) =
.) .
0
44 7
CONTINUE
O'
VX>

IF (NDEX1 GE .3 ) GO TO 45J
IF ( 3TMMIN ( J) .LE. 0.0001 ) GO TO 450
AI)!)1LD( J ) = 1.0 AO OH A T ( J )
W A N T L F ( J ) ADOOLO(J) WANTiT (J }
IF ( WANTLFI J) .LT. 0.000 1 ) GO I) 450
AG REQ WANTl.F(J) VEGNCR A ASVEGF
IF (A SPRE O. GT. A3P3ST ( J> ) GO TO 450
IF (STMMIN(J) WANTLF(J)) 500,550,550
500 VEGGRO = GIMMIN(J)
GO TO 600
55 0 VEGGRO = WAMIL Ft J )
60 0 CO NT I NO li
WT GTL. M ( J )
ST'MINt J)
A5PGGT(J)
AD02(J) =
= WTSTEM(J) VEGGOO/1000.
- STMMIM(J) VEGGR )
= A5PGSTJ) VEGGRO A VEGNCR A
VEGGRO / WAN TLF ( J) ADOIILOt J)
ASVEGF
450 CONTINUE
10 4 3 0 I
=
1 .NOW
IF (PDAYI
l
)
.LE.0.0 ) G n
TO
4 0 0
DO 460 J
1 lERGE
Ir (I MERGE
I
J ) L E 0 ) G U
TO
4 60
jCTLEAFI J,
I
)
= WTLEAF(J
. I )
A PORL.F
<' ADDEAT t J)
A DAY INC
GlZELF( J ,
I
)
= 5 IZELF ( J
. I )
+- P )I!LF
4 AODR AT (J )
A DA Y INC A
1
X nle AF( J
, I )
WT PET(J, I
)
= WTPET I J I
) A
P0I6* T *
ADDI'A T( 0)
A
XNLE AF ( J I )
w T I N 010 ( J ,
I
)
= WT IN00 ( J
. I )
A PORNO!)
* AODR AT
( J
) A DAY INC
460 CONTINUE
IF {POAYI
I )
.L T .MF r I ME )
GO
TO 4 3 0
DO 455 J
=
1 .ME ROE
wTL E AF( J .
I
J
= W TLE AF( J
. I )
A PJOLF
* A 1)02 ( J )
A
DAY I NC
5 I ZELF ( J ,
I
)
= SIZELF(J
. 1 )
A >0 OL F
AOD2J)
**
DAY INC A
1
XNLEAF( J ,
I )
W TOUT(J I
)
= :J T P E T ( J 1
) A
POUPT A
AO 02 ( J) A
XNLEAEJ.I) *
WT INOD< J,
I
)
- wriNOOIJ
1 >
A ri 1 0 NOD
A A 00 2(J
)
A D A Y I N C
455 CONTINUE
IF (POAYI
I
)
.LT .T I MELE )
G')
TO 4 30
POAY(I) =
0
. 0
NCfJUNT ( I )
=
NO w
DO 470 J
=
1 I LT: Gt
IF ( IMERG
1.7
(J).LE.O) GO
TO
40 )
5 I ZELF( J ,
I
)
= 51 ZELF ( J
. I )
/ 0. 0 7
XLEAFNJ)
-
XLEAFN(J)
A XNL E AF ( J .
l
)
XNONIHX J)
XNONU ) { J )
A X I NODE ( J ,
I
)
SURF AC ( J ,
1
)
= GIZELF( J
. I )
/ SL a
0AY ALO =
NAY A ) 0 (SURFACIJ, I) A
1
GO OR IJ ) )
/
1 J ) 0 0 .
>>(. I WT I J )
-
PET W T( .) f
W T PE
T ( J. I )
/
(1000. A
0
. f )
ARF.ALFl J )
=
Ail;al r ( j )
A GUiiF AC ( J,
I
)
wGOTLF(J)
WGMf LF< J )
A SI
ZELF ( J ,
1
) / 1000.
A DAY INC
DAYINC
o

VTSTEM(J) = ITSTEM ( J ) + { rf T I! IJi) ( J 1 ) + XML'.AT (J.I )>/( 1 00 0. 07 )
470 CONTINUE
400 CONTINUE
WITUPN
EN')

sum OUT I Nr: DIVIDE
COMMON /UCDM 1 /N DC XI* NOE X.'?* NDEX .3 NDE X 6, NOW PT SYN( 7 > P TSRUT ( 7)
1 ASP OS T (7)iOAYl NC J MliRS.: MOUND W
COMMON /UCOM2/UF TI Mu r I MELF
COMMON /UCOM 5/ 13TEM( 7, 3150) NJOE ( 7. 360) XLLAFNt 7 ) S I 2l£LF C 7.2 0 0) .
1 WTLF AF (7 ,200 ) w T INOD(7,200 ) WTPfT (7, 200 ) ,AREAL F( 7 ) ,
2 WGHTLF ( 7 > WT 5TEM( 7 ) XNLE AF < 7 ,2 0 0) WTROUT ( 7 ) I COUNT (7 3 60 ) ,
3 PC) AY ( 20 0 ), AGRPTS ( 7 )
COMMON / U C M 2 0/WANTLF(7) NUM'iK ( 7 ) X I NODE (7,200 )
COMMON /UCflM 2 1 /Pi) D'wGT ( 7, 100) 30RK ,ULflf)MZ( 7,200) KPEGST ,
1 P E < J N I ( 7,200 ), PO 1) jT ( 7 ) .60 DC AIM 7, 200 ) ACEMA X( 7, 200) SIM TEK ,
2 KPIIDOI ,GRRA TE .POPOOS ( 7 ) PONUT S ( 7 ) PODASE ( 200 )
COMMON /UCOM22/NEWVCG(7,200),ADDLE
COM MON /UCOM2 I/STMMlN(7).STMLOS<7)
COMMON / OCO M24/XNONUO( 7) ,NC 0 ) N T(200) ,SUUFAC(7 ,200 ) ,VESGKO,
2 VESNir .VEGNCR. ASVEGF. VE GCNR PORLF .PORPT PORNlJO, SL W
/UC O'M 2 6/ AS PRC 0
/UCOM26/WG r:)N2 ( 7,200) PEANUT ,RA 1 I i), PT S3
/UCOM2 7/PCT C, ;>ODC, PCTM, PODN, A SPPRO, O ILF AC
/UCDM 31/R0!) 7F ,SMAINF
/UCOM43/WN TNUT(7).WNTPOD(7) ,WNTSTO 7) ,WNT STM(7) .AVLC0N 7)
J = 1.MERGE
= 0.0
C DMMON
COMMON
COMMON
COMMON
COMMON
DO 2 CO
FR UC HO
FRUN IT
PNTCHO
PODCHO
IF
IF
1 0
1 5
1 6
IF
I F
PT
0,0
PON ITS (J) PC T C / OIL F A C
PQPODS(J) POOC
( WNT NOT ( J ) *- WNTPO.)( J ) .LE.O .001 )
( WNTNUT(J).LE. 0.0001 ) GO TO 100
(PTSYN(J) WNTNUri))) 10,20,20
( STM M IN ( J ) -WNTNUT (J ) FTSYMt J ) ) 1
YN ( J ) P T S Y ,N( J ) M ST MM I N ( J )
GO TO 200
16, 1 o
VTSTrM( J )
0.0
WTSTEM ( .1 )
S T M M I N ( J )
GO TO 0
ST MM IN( J) = STMMIN(J) -
wTSTEM(J) = WTSTEM(J) -
JTSYN( J ) = WNTNUT ( J )
IF (PTSYNIJ) .LE.O. 000 1 )
FRUCHO = AMIN1(PTSYN(J)
- GTMMIN(J) / 1000.
WNTNUT(J)
(WNTNJT(J)
GO TO 200
WNTNUT(J))
- PTSYN(J)
- PTSYN(J ) )/ 1 000
1 0 J
FRUNIT = (TRUCHO + OIL FAC /
FRUCHO = FKOCHO AVLCON(J)
IF (TRUCHO.LE.0.0001) GO TO
PC TC ) PC T N
* WNT POD(J)
20 0
+ WNTPUD(J)
FRUN IT = FRJNIT AVLCON(J)
F RUNG R = FRUNIT / FRUCHO
FR UCNR = FRUCHO / FRUNI T
ASPREQ = FRUN IT ASPPRO
IF {ASPGST(J).GT.ASPREQ) GO TO 110
FRUCHO = (ASPCGT(J) / ASPPR> + F R UC NR
* PODN
N)

FRUNIT = ASPGST(J) / ASPPH
A jPGSn J ) = 0.0
PTSRUT(J) = PTMRUT(J) PTSYM(J) FRUCHU
PTSYN(J) =0.0
GOTO 115
110 CONTINUE
PTSYN(J) = PTSYtH J) EPUCHO
AS PGM r ( J ) = AriPGSr(J) A SPHl: 0
115 CONTINUE
PEANUT = FRUCUO
IF ( PCDCll l ) 1 20, 120. 1 1 U
110 IF (FOUCH1 PflTCHO) 120.120,125
12 0 P A fIO = 1.0
GO TO 1J0
125 NATIO = (EPUCHQ PNTCHO) / POOCMU
150 CONTINUE
IT (PATIO.GT.1.0) RATIO = 1.0
IF (RAI lfl.LZ.0.0) RATIO = 0. 0001
CALL FRUF 1L
PTSYN(J) = P T > Y N( J) f P T MS
AM PGM T (J 1 = A3PGSMJ) PTSS FRUMCR
'T SM = 0.0
200 CONTINUE
RETURN
END

3 0
3 3
4 0
SUBROUTINE FliUF IL
O l VE NSI ON PNNI PX (7 ) GNPCT ( 7.20 0 ) PEG NO r (7 200 )
COMMON /UCO M 1 /¡M!)F.X 1 NDE X2.NDEX 3 NDEX 5, NOW PT SYN ( 7 ) PT5RUT ( 7 ) .
1 ASPGST (7 ) DAY INC. J. MERGE MONRO M
COMMON /UCOMD/PENUTZ C 7) ,FNO T ( 7 ) ,HST PUD(7 )MSTF NT (7 ) .PEGS(7) .
1 N( 7) PNR IP E ( 7 ),PETWT( 7)
COMMON /Cn.CM /POOWGT (7, 20 0 ) M ONE* OLOOM2( 7, 200) KPEGST,
1 PEG NO ( 7.200) POD ST ( 7 ) .POD CAP (7.200 ) AGE. MAX (7.200). GRATEK.
2 KPOD jT.GRN ATE.POPOOS( 7) ,PONUT S( 7) ,PODAGE( 200)
COMMON /UCOM2o/WGT MNZ ( 7 ? 0 0 ) PEANDT NAT IO.PTSS
COMMON /UCO M2 7/ PC TC POlOC .PC T N, PODO. A SPPRO O 1 LE AC
DATA AVLGTD, AVLGR.X, PNNIPX. Sit PC T, PE GNO T .PEGLST/ 0.0. O. 0. 1 407*0. 0,
1 1 4 0 0* 0. 0 3 S 0 /
DA T A PR IE AC/0.0/
AVLGRO = PEANUT F AVLGRO
GROW = NA T III** PR I r AC
AVLGRX = 0.0
PE NUT Z(J) = 0.0
MSTFPTt J ) = 0.0
HSTPUD(J) = 0.0
F R UIT ( J ) = 0.0
PNRIPX(J) = 0.0
00 1 1 K = KPJDST, NO V)
IF ( P£"GNO( J.K) .EO. 0.0) GO TO 11
PODS IZ 0.17 PODCAP(J.K)
IF (POOWGT (J,K ) .GT .POOCAP(J,K ) ) GO TO 20
IF ( POD AGE ( K ). G T. 32.0 AN >. POOwGT ( I K ) EE 0.0 00 1 ) GO TO SI
IF (PODAGi;(K ) .GT .A GEMAX ( J K ). \ NO .PUD WG T ( J K) .IT. PDSI Z ) GO TO 12
IF ( A VL GN X.2Q.1 .0) GO TO 12
IF ( AVLGRO .LE .0. 0) GO TO 12
IF (POOWGT (J .K ) .LT .POOS I /) GO TO SO
PN TC 110 -- F.RRATE PEGNO ( J.K) PCTC / OIL FAC
IF { POD WGT ( J .K ) GT 0. ) PODCAP J K) ) GO TO MS
AVLGRO = AVLGRO PNTCIIO
IF (A VL GR O .0 fl 0 0 ) C. G TO 40
O = (PNTCIIO F AVLGRO) / PN TCI JO GRN ATE
CONTI NOE
POVWGT(J.K) PODrtGT(J.K) F Q
WGTMNZ(J.K) = W GTONZ(J.K) F PZCNO(J.K) 0
AVLGNO 0.0
A VL GR X = I 0
GO TO 12
PNTCIIO = PNTCHO / 2.0
GNOTII = GNPArC / 2.0
GO T O 5 S
CONTI NOE
POOWGT(J.K) = POOWGT (J.K) F 2,URATE
WGTONZ(J.K) TiJNZt J.K) F GN NATE PLGNU(J.K)
or-

CO TO 12
'3 0 CONTINUE
WANT 1 = PUD 31 2 PODWGTtJ.K)
ANT 2 = ( 10.) F 0.25 F POD WG T{ J K 1 ) DAY INC
WANT = A MINI (XANT1.WANT2)
GUO Til = WANT GOO w
"NT C HO = GUO T U PEGNJ(J.K) F PODC
55 CONTINUE
A VI.G 10 = A VL jlii) PN ICON
IF C AVL GUO Gil .0.0) GO TO 60
0 (PNTCMO F AVLGRO) / PNTCH) GUO T11
GO TO 5 0
60 CONTINUE
PODWGT(J.K) PODwGT(J.K) GUETH
WGT 1NZ( J. K 1 = WGTUNZ(J.K) f GUO Til *
GO TO 12
20 PNHfPX(J) = PNRIPX(J) F wGTONZ(J.K)
PE GOUT ( J K ) = PE GUO T ( J K ) F 1.
IF (PCGRUT(J ,K ) ,LT .PEGL3T ) GO TO 12
R(J> = R ( J ) F WGTUNZ(J.K) / 1000 .
51 SHPCT(J.K) 0.0
WG TO NZ ( J K ) 0.0
"ODWGT(J,K) = 0.0
PEGNO(J.K) = 0.0
12 CONTINUE
IF (POOWGT{J.K) .LE. 0.0001 ) GO TO 11
FRUIT (J) = FUUIT(J) F WGTONZ(J.K) /
PENUTZ(J) = PLMUTZ(J) F PEGNO(J.K)
IF ( PODVi j T ( J K ) .LT .POD-3 I Z ) GO TO 11
UGTPOD(J) = HGTPOO(J) F PEC.NO(J.K)
ilJTFI T( J) USTFKT(J) F WGTUNZ(J.K)
1 1 CO NT I NU E
IF (PNUIPC(J). GE.PNU IPX(J) ) GO TO 65
p.n u i p r: t j ) = pnripx(j)
65 CONTINUE
PT S 3 = AVLGRO
AVLGRO = 0.0
RETURN
END
PE G Nil ( J iK)
/ 1000.
10 0 0.
/ 1000.
--j

COMMON
SUOPOUT IN¡: Glll'rs
C OMMQN /UC OM l /NDEX 1 N >L X? NDEX 3 NDEX5 NOW
1 A SPGG r ( 7 ) DA YI NC J MERGE .MDlUiOW
COMMON /UC0M5/ 1STEM(7,350), NODE! 7,350),XLEAFN 7 ) .
1 WTL.EAF' ( 7.2 0 0 ) WT1 NOi)( 7 .200) WT PET (7.200 ),
2 WGMTLF 7 >.WTSTEMI7 > ,XMLFAF( 7.20 0) .WTROUT (
3 PDAY(200),AGUPTS(7)
/UC O-4 7/ OTMM 2 ( 20 0) W TLFM2 ( 20 0 ) GRPT SM (2 00 ) .
T OTME(20 0) PE NU T M( 2 00 ) FRUI TM (2 00) HlPwMl
PFG3M2 (200 ) RUT PM2 PMU IPM (200 ) QLOOMMI 200
I )A Y( 20 0 ) ROO TM 2( 200)
/UC.nM 1/ P COPtJiT ( 7 ) PAYADO
/UC0M20/W AN IL F ( 7 ) NUM.Iii ( 7 ) X I NODE ( 7,200 )
/Cf ) 4 22/NEWVEG( 7,20 0 > ,Ai)l)LF
/ O CuM24/XNOND( 7 ) NCOUNT ( 20 0 ) SU)
VEGNI T.VCGNCS ,ASVEGF ViiGCNii POPLF ,
/UCUM 16/PLTPU2
/UCOM43/WNTNUT (7) ,WNT PHD(7).W NT 5TU(7 )
1.0 GRPT SM( NUU- 1 )
PTSY N( 7), PTS RUT ( 7)
S IZELF- ( 7, 20 0) .
ARE AL F(7 ) ,
7) ICUUNTI7,3SO )
XNULFM(200 ) .
200 ) US TF RM (200)
) X L A I ( 2 O 0 ) ,
COMMON
COMMON
COMMON
COMMON
>
COM TON
COMMON
P = 33'
! r AC ( 7,
PflRPT ,
200),VE'GGRO,
PORNO O, SLW
WN TSTM( 7),A VLCONI 7 )
00 200 J = 1.MERGE
IF (PTSYN(J).LT.0.001) GO TO 200
KK = NOW 2
SUM = 0.0
I SUM = 0
IF ( P ) 200, 200. 5
5 CONTINUE
00 10 = KK, NOW
10 I SUM = I SUM F NEWVeG(J.I)
SUM = ISUM
XI = SUM PROPOR(J)
IF (XI ~> ) 16, 1 5, 15
15 CONTINUE
SUM A INT(P/PROPOR J) )
NDEX6 = 2
16 CO N TINUF
IF (SUM.LE.0.1) GO TO 200
A = SUM F ADOLF* F DAY INC
X = SUM
LL = SUM
IF (PTSYN(J) A) 30.20,20
20 O ADOLF VLGNCR F ASVEGF F SUM F DAY INC
? 5 IF (ASPGST(J) :n 4 0.50,50
7.0 LL = (PTSYN(J) / A) F SUM
X = LL
O = ADOLF F VLGNCR F ASVEGF F X F DA Y l NC
IF (O.LE.3.)) GO TO 170
A = X A)DLF F DAY INC
GO TO 2 5
i

4 0 LL = (ASPinr(J) / tl X
X = LL
U = ADOLF V L (>N CP A5V EGF X DAY INC
\ = X ADOLF DAY INC
SO IF (LL ) 1 70, 170, 55
55 PT5YNIJ) = PTSYN(J) A
A5'GGT(J> ASPGST(J) )
WILHAH J.MO/J ) = PORLF << DA Y I NC
SI ZITLF ( J ,ND0 ) = SI ZELF { J, NOW ) POOL r X
WT PF T ( J N) W ) = WriIITt J.NOW) ¥ ODD! T X *
.vr INOOt J, NOW ) = PORN Of) DAY INC
XI NODE( J NO0 ) = X I NODE( J,NOW) X
XNLEAFl J.NOV ) = XNLF A-F ( J NO W ) + X
AGROTS(J) = AGRPTS(J) X
PDAY(MOW) = DAY INC
DO 7 0 JK = 1,IL
NUMf)R(J) = NUMDIX ( J ) ¥ 1
I S T : M ( J N'-JM 10 ( J ) ) = 4
NO OF. ( J NO MU < ( J ) ) 1
(COUNT ( J ,IL MOO ( J) ) = NOW
70 CONTINUE
DO 16S I = M NE W Vi ; G ( J I )
IF (M.F.0) GO TO 1 5
DO 160 JK = 1 M
IF (LL) 170,170,105
1 5 5
LL = LL -
1
NEWVEGIJ.
I )
= NE iV V E G ( J
16 0
CONTI NOF.
1 6 5
cont indi:
1 7 3
CO NT I NUF
' = P X
*
Pl< IPOD ( J )
2 0 0
CONT ItlUt:
PE URN
FN D
DA Y INC
DAY INC

GUI ROUT I NE STEMS
COMMON /UCO-I 1 /NDuX l NOF X2 NO EX 3 NDFXS MOW PTSYN ( 7 ) RTS RUT ( 7 ) .
1 ASPOST (7) .DAY INC, J,MERGE,MORROW
C OMMON /UCOM4 /ADDS TM
COMMON
1
->
l
3
COMMON
COMMON
COMMON
1
2
COMMON
COMMON
o
C OMMON
/UCO 4 5/ I S TEM 7,350), NO>E ( 7,350) XL E AF N ( 7) ,S I 7cLF ( 7 ,0 O) .
VtiT LEAt ( 7,200 ) WT !NOI)( 7,2 JO ) W T P E T ( 7, 200), ARE ALE ( 7) ,
WSO TU ( 7) #T 'jR- M( 7 ) XNLE AF ( 7 ,2 00 ) WT ROOT (7 ) I COUNT (7,350
IOAY ( 20 0 ) A GR P T 3 ( 7 )
/UC O M1 7/PH 20AY(2 00 )
/UCO I 20/ t A N TL f- ( 7) NOM3R ( 7) X1 NODE( 7 20 0 >
/UC O 12 l/PODWG T ( 7, ?0 0 ) -lORE OLOOMZ ( 7.200), KPEG ST ,
pro NO ( 7.20 0) POOST ( 7 ) POC AP ( 7.200 ) AGE MAX ( 7, 20 0 ) OR AT .-IK,
KPOD i T. GRRATE,POPOOS( 7) .PONUT S( 7) ,POOAGE ( 200)
/UCOM2 3/ST mm 1 N(7 ) STMLUS(7)
/ JCU 424/XNONU) ( 7 ) NC.OUNT (200) SURI AC ( 7 ,200 ) V EGGED,
VEGNIT.VEGNCR. ASVEGF, VEGCNR.PORLF.PORPT.PORNOO, SL W
/UC 11 M2 5/ASPREO
COMMON /UCOM4 3/ WN T N U T ( 7 ) ,rtNTPOD(7) ,WNTS TO( 7 ) W NT ST M ( 7 ) AVLCON 7 )
00 E00 J = 1, MERGE
VEGGRO PTSYN(J)
IF (PTSYM( JJ.LT.O.OOl) GO TO O00
200 VEGNIT = VEGSRO < VEGNCR
ASPREQ VEGNIT ASVEGF
IF ( ASPC3T ( J ) .Gu .ASPREIO ) GO TO 300
VEGNIT = ASPGST(J) / ASVEGF
VEGGRO = VEGNIT VEGCNR
PTSYN(J) PTSYN(J) VEGGRO
A SPGST(J ) = 0.0
T Sli U T( J ) = 'TGIMJTI J) PTSYN(J)
PTSYN (J ) = 0.0
GO TO 400
300 ">TSYN(J) = PTSYN(J) VEGGRO
AS r,GS T ( J ) = ASPGST(J) ASPRC.l
400 A = (VEGGRO f VEGNIT) / O.U7
WTSTEM(J) = WTSTEM(J) + A / 1000.
STORE = A (wNTSTV( J ) AVLCON(J) )*( 1 .0VIGNCR ) / 0.07
STORE = AMA X 1 ( ST ORE,0.0)
STMMIN(J) = STMMIN(J) + STORE
C = XNONOO(J) 40.0
IF ( S r M M I N ( J ) L L C. ) GO TO 60 0
WTSTEM(J) = WTSTEM(J) (C GTMMIN(J ) )/l000.
S T M T I N ( J ) = C
GOO CONTINUE
RETU RN
END
-j
oo

5 LOR OUT IMIE tNTLA 1
COMMON /GCOM2/ IX)( 10 0), DDL ( 1 00 ) DTI UL I) IN.) W I St US, LF LA G( 50) Nr' LAG,
1NNLOD .NNLOS,NNLOT, SS(1 OO) ,SSL( 100) ,T XNLX
COMMON /UCOM 1/NDUX l ,NOLX2.NDLX3,N >LX5,NOW,PT6YN( 7) .PTSUUK7) .
1 A SOOS T {7 ),DAY INC, J,MLR Gil,MORROW
COMMON /UCO.M1 2/PLTLAI PTS
COMMON /UCDM32/AMTLT(200)
IF ( NOFX 1 LT .2 ) GO TO 10
L TLA 1 = (11.767 2 7.167 V SKI) 2.1^2 4 SS(1) S3(l))/100.
GO TO 20
1 0 PL IL A I = SS( 1 )
20 AMTLT(NOW) PL TLA I 100. 4 1.05
RCTURN
END

SU.')¡3HUT I Nil >IIZHA2
COMMON /GCO A ?./ Df>{ 1 0 0) DDL ( 1 00 ) .DfFUL ,OTN()W, I GEES L.F LAG (00 ) Nr LAG.
1 NNr'OD, NNEGS NNEQT SS ( 1 0 0 ) SSL ( 1 00 ) T TNH X
C (jMMON /UCOM 1 /NOEXI NOT. X2 .NDEX 3 NDl.XG NO* PT GY N 7 > PT5 RUT < 7 ) .
1 ASPGST ( 7), DA Y INC. J,MERGE .MORROW
COMMON /UCDA6/CL 13 AT(200,6 )
REAL MAX, MIN
DATA GLIM IN. IMPORT .OAYdEG/OO.0.90.O. 20. 0/
MAX = CL IMA T ( NOW ,2 )
MIN = CL IMA( NO W,3)
IF
(MIN.LT.GETMIN)
I I! J
= GETMIN
IF
(MAX.LT.GET MI N)
MAX
= GET MIN
I F
( MAX .GT T 1POPT)
MAX
= TMPOPT
DEGREE (MAX 6 MIN) / 2.0 .GETMIN
PAYINC = DEGREZ / OAYDEG
SS(2> = G>L(2) 6 PAYING DTNDW
RETURN
END

gn n
Nan 13?i
coc / jocuk.c! + (r)j(ioiiw = (Dochih o i
NX-13 J:J CIlINGc ( r JN3'. d5V
JLOlNKic! ( C } 11.U Id GCNOc!
ucnnj 3DI3WM = r 01 r.)CI
/O l/NX 33 31 vivo
ziNi vws* urna/ if worn/ nonwoi
( JNIDdSV/OI KI.O1/ NONN03
(OGF/)J NON 3 I ( )
< Z)31V3dV*
(CO? > 31171 S*
( L ) 10)1 G1 c) ( l
(l ISidaOV* (00? )AV(lrJ
10UH1M ( 00? 4 L ) JV11NX ( L )W-11S1I<' ( l ) rJUHVIi
( 0 02* / ) J IctlM ( 00 2 4 L JOHN I 1M (00 Z *1 ) 3V DU M
( / )M3V11X ( OSK )ICON (0SC*)W3JLS 1/00030/ NONNO 3
flOilHOKTlIOH'r 3 N I AVG ( ) JSOcJSV
)NA ciONina iNiinoanni;
i
i
CM

sunnnuTfne attac
D I ME NS I ON A .CLAK ( 7 )
DIMENSION S JML A R I 7 )
COMMON / GC0 41/ AT R I 1 (25 ) J EVN T MFA MET. ( 10 .)), MEE ( 100) M STOP .NCRDR N
1 NA PD, 1-IN A(> T .fJNATH NNF IL NNO ( 1 00 ) NNT RY NPRI1T PP AKM( 50 4 ) T NO*! T TilEG
?. rTCLR.T rrM,TTf)r..)( 25), ttset
COMMON /SCO a;?/ Of) ( 1 0 0 ) DDL t 1 00 ) OT | |JL DTNOW I SEE5. LEL AG ( 50 ) NK L AC. ,
1NNEOD MNEO S, NNEQ r SS( 100) SSI ( 1 00) T OCX
COMMON /UCOM 1/NOEX 1, NDEX2.NUE X 3 NOE X 5 NO *1 P T SYN { 7 ) .PTSKUTI /) .
1 A Si") ST (7 ) DAY I NC, J, MERGE MORROW
COMMON /UCO 4 5/1 ST 2 4 ( 7.150) NO )E ( 7,35 0) XLF AF N( 7 ) 5 I Zl'LF C 7.2 0 0 ) ,
1 OH. 0 AF ( 7,2 00 ). W T I NODI 7 2 0 0 ) WTPLT ( 7, CO 0 ) ARLALE ( 7 ) ,
2 WGM TLT ( 7 ) W T STL M( 7 ) X Nl.E AF < 7 20 0 ) W T ROOT { 7 ) I CHUN 1 ( 7 150 ) ,
3 P DA Y ( ? 0 0 ) A GRP T S ( 7)
COMMON /UCO A J/PROPOR ( 7 ) DAY ADD
CO -1MOM/UCD11 2/PL T LA l PT S
COMMON / UCO-124/XNONOD ( 7 ) NC HUNT I 200). SURE AC I 7,200) VEGGRO ,
2 VuC.NI T VEGNCR ASV.FGE, V2GCNR, POP.L F, POR PI PRN. 31. W
COMMON /UCO A JO/COl IDLE,DEE I 1M,NTYPE
COMMON /UCO4O/TOTEAT
DATA AGE LAE/7* 0. 0/
DATA SUMLAR/20. 0, b*0,0/
DATA A/0.011/
DATA 0/2.093/
DATA CUNSUM/0.0/
EATEN = 0.0
DO 10 J = 1,MERGE
AGELARIJ) AGFLAP(J ) + 1.0
IE ( AGE LARI J) .GE.27.0) GO TO 10
E A TEN = CATEN *- A SUMLAR(J) AGELAI (.))**!) PKOPORIJ)
10 CONTINUE
CONGUM = EATEN TOT FAT
IE ( CONSUM .L 2 0.0 ) COM SUM = 0.0
TOTEAT = TOT EAT T CONSUM
IF I SSI 3) .11.0.0) GO TO 15
CON DEE = 1.0- (CONSUM / (SSI 1) 10 000.))
GO TO 16
15 CONTINUE
CONDEE O.J
16 CONTINUE
IE (CUMOEi'.LT. 0.0) CONDF.F = 0.0
KK = 0
)0 20 J = 1,MERGE
IE I SUMLAI! (J).EO.O.O) GO TO 20
IE { AGCL AN I J ) GE .2 7.0 ) GO TO 20
KK = KK 1
20 CONTINUE
IE (KK) 40,40,30
03
to

3) CALL INSECT
ATrUIJ( 1 ) = T
A TR It) ( 2 ) = 1
CALL F ILL 1( 1
40 CONTINUE
J?E TURN
E N'T
NOW + 1.0
)
oo

SUBROUTINE INSECT
COMMON /'.COM 1 / A TR I M ( 25) JE. VNT MF A Ml;t <100). ML fl ( 1 00 ) MS TOP NCRDR. N
1 NAi'd NI4APT NNAT R, NNF IL NMD ( 1 00 ).NN T ¡(Y. NPRU T ,PP AR -1(50.4) T III*' TTIItO
2 T TC L R T TF I 1 T T R I i) ( 2 5 ) T T 3L T
COMMON /GCO A 2/ D 0( 1 0 G) D")L ( 1 00 ) .O IF UL ,l) 1 NOW I 3F.L 5, LF LAG (50 ) NFL AG.
1 NNF00, NNFQG NNLOT S3 ( 1 0 0 ) SSI ( 1 0 0 > TTNIIX
COMMON /GCO 1 1 / A AERO ,0 T MAX ,O TMIN DT3 AV 1 1 r l!S LLEUd, LLS AV.LLS EV ,Kl(E
1FU.TTLAS, rr ov
COMMON / GC CM* / OT PI. T ( 1 0 ) MIILO.V l 25 ) MOV. ID( 23 ) 1 ICIO I I T AP( 10) .JJCLL
1 ( 500 ) LL. AJC ( 5,2) LL ADI I ( 2 5.2 ) l.l. A) IM 1 1 ,2) .LLAflT (25,2 ) LLPi ll( 10 ),LL
2 PL 'll 10),l LPL.LL GUO ( 15) L L 3 Y M ( 10). MMIT 5 MHCi'L ( 25 ) .NNCL 1 .NUIII 5 NNIL
3 T NNPTS (10), DUST A NNV Al< ( 1 0 ) PHI (10), l'i'l. (10)
COMMON /GC OM 5/ I I L V T 1 I Si'O ( 6 ) J JOiZG J JCLII, M M N I T MMON NNAML ( 3 ) NNC F
1 1 NND AY NUPT NNSCT NNPP: J NNPR 3 MURNG, NOR UN NN5 TR .NMYft, SSLF.iX 6)
COMMON /GCOMG/ LLNGi 1 00 ) I I NN( 1 00 ) ,KKIiNN ( 100 ) MMAX Q( 100 ), OUT IM ( 1 00
1 ) j > 011 V ( 25, 5 ) 33TP V( 25. 6) VV I 1(100)
COMMON /UCO -11 /NDEX 1 ,N9LX2, NOFX 5 NO OX 5, NO, PT5YN ( 7 ) P T 30 UT ( 7) ,
1 A SPG 3 T < 7) O A Y I NC J.MERGE MAURO
CO 3MON /UO H2/HFTI Mr. T I MCL.F
COMMON /UCOM 3/ GT M ( 7 ,350 ) NO HI ( 7. AGO ) XL L APU ( 7 ) 3 IZ EL F < 7,20 0 ) .
1 WTLi-AF ( 7.2 00) WTI NOD ( 7,2 00) W I PlT ( 7,200 ) AliF. ALF (7 ) ,
2 .V GI (T L F (7 ), JTSTFM( 7 ), XNLLAF ( 7,200). WTROUT ( 7) I COUNT ( 7 35 0) ,
.'3 P!)AY( 200) AGRPT3 (7)
COMMON /UGOM J/PRPOR ( 7), TAYA), >
CO MMO N/UCOM1 2/PLTL A I ,PTS
COMMON /UCO 120/WANTLF 7) NUM1FU7) X I NUDE ( 7 ,2 )
CO AMON /UCOM 2 2/N EW V E G ( 7. 200 ) ADOLF
COMMON / UCOM24/XNONOU(7) NCOJN1 {200 ),SURFAC(7,200 ) ,VCGGRO,
2 Vi" GN I T VEGNCR A5VCGF, VIGOUR Pi JR IF ,1ONPT POUNOO ,3 LW
COMMON /UC.C M2U/LCOUNT (7, 350)
C O M MON / UC OM JO/CRN OFF .DEPTH, NTYPLI
COMMON /UC.) -3 5 1 /COUGRO
DAI A IUAM/0/
DA TA PLT 3A X /0. 0/
XY = PL TL A I 0.6
PLTMAX = AMAX 1 (PLTMAX, XY )
lit FPL R = (1.0 CUNOEF) + 100.
NO a' = T NOW
MORROW = NOW 3- 1
1 F ( CONGRI).£0.0.0)
M = 1.0/CON GUO
CONTINUE
IF INTYPE -
GO TO 9
50.10
10 OO 20 J 1
aGMTLF(J) =
ARCALF(J) =
OU 20 I =
IF ( NCriUUT ( I
2 ) 10
M FRGE
= WGI IT LF ( J )
= AREALF( J )
1 NOW
).EQ.0> GO
CONOFF
COUOLF
TO 20
oo
-tr

5 l 2 EL F ( J I )
s i zi:l f i j
. I >
*
CUNDE!
W IL L A F ( J I )
-
WTLL AF l J
. I )
4-
CONOEF
SURFAC(J I )
=
SURF AC I J
. I )
*
CONDEF
2 0
CONT INUE
SSI 3) = SSI i)
* COND.EF
50
IF IN TYPE -
2)
140,55,
1 0 0
55
ALEFT = 0.0
no 95 J = 1 ,
mi:
RGE
AMTOCF = AREALF(J) CUN!)t£F
on no r i,now
jk = now i <-1
IF ( NCOUU r ( JK ) .EG 0 ) GO TO 90
Cl = SURF AC( J,JK)
C2 = AR CALFl J > Cl
IF (C2.LT
. AM f L)EF ) GO TO
GO
WTLEAFIJ,
JK )
= 0.0
WGMTLFIJ)
-
WGIITLF I J ) -
31ZELF I J ,
JK )
/
1000.
S I 2El.F I J.
JK )
= 0.0
AREiALFIJ)

ARuALF I J ) -
SURF AC IJ .
JK )
SURF AC I J,
GO TO 90
JK )
= 0.0
C2 = ARE ALT(
J) AMTLOEF
C3 = 1.0
c
2/SURFACIJ,
JK )
SURF AC I J ,
JK )
= SURF AC IJ
, JK) C2
wgutlrI J )
r:
WGIITLF I J ) -
51 ZE LE ( J ,
IK)
/
10 0 0.
SI2ELFIJ,
JK )
= S I Z EL F I J
. JK ) C3
IfcTLEAF( J ,
JK)
= W TLC AF(J
, JK) A C 3
iVGHTLF I J )
=
WGHTLFIJ) +
SIZELF I J ,
JK )
/
1 0 0 0.
AREALFI J )
AMTDLF
GO TO 91
90 CONTINUF
91 CONTINUO
AL£F T = ALFF r + (AREAL! (J) 1 RUPi !R( J ) ) / 1 0 0 0 0 .
9-3 CONTINUE
3SI3) = ALEF T
GO TO 140
100 CONT INUE
OO 130 J = 1.MERGE
N NUMHR(J)
no 125 I = l, NOW
IF (NCOUNI(I).NL.3) GO TO 125
IF {XNLIAF(J,I).LE.0.01) GO TO 125
UO 120 K = 1,N.M
IF ( I STEM! J,K).GE.5) GO TO 120
IF (ICOUNT!J, K).NE.I) GO TO 120
SIZELFIJ,I) = 5 I ZELF (J. I > WTLEAF(J.I)
UTP.CTIJ.IJ = WT iT ( J I ) / XNLtAFI Jil )
XNLEAFIJ.I) XNLEAFIJ.I) 1.0

XI NODE(J, I) XI NODE(J. I ) 1.0
WTPET(J.I) = WTPifTt J, I) XNL.IAFiJ.l)
AGn1S(J> = AGRPTSCJ) 1.0
L L CO UN T(
J
. K )
IF ( L.r0.0 )
GO TO
1 1
5
5 I zr. LF ( J L )
= 51 Z
1.
LF
(
J
*
L
)
-
TLE
AT ( J,L )
WTP.ZT ( J ,L )
=
W I PII
r ( j

L
)
/
XNL
I AF
( J L )
X NLi: AF { J L )
= XNL
AF
(
J

L
)
i
. 0
XI NODE ( J L )
= XI N
1 )
of:
(
J
*
l
)

i
. 0
WTPET(J,L)

wtp r.
r
i j
t
L
)
*
XNL
2 AF
( J L )
1
1
5
MN I5TEM
J
,K )
I GTEM (J.K)
=
6
L = NODE(J,
K
)
1
1
4
GO TO (116,
1
17,11
3
. i
1
0
)
*
M
N
1
1
f,
NUMTR(J) =
N
UMDK (
J
>
4-
1
AGRPT5(J) =
AGRPT
j
( j
)

1
.0
I STEK{ J NUM )R ( J) ) =4
IF (L .Lt:.4 .AND.M.N.EO 1 ) (STr'K J.NOM'ikl JJ 1 J
NOr>£ ( J NUMTIR ( J ) ) 1
(COUNT(J.NUM3R(J)) MORROW
XNLEAF ( J MORROW ) = XNLL AF ( J M J f?RO W ) 4 1.
XI NllO: ( J, MORROW) = X 1 Nil OIK J MORROW ) ^ 1.
GO TO 121
117 IF (L.LE..ANI).L .NC.2) GO TO li
IF ( ( ( ( L 4 1 ) /'? ) /2 ) 2 ( ( L H ) /2 ) ) 12 1,116,121
113 IF (L.LT.6.ANO .L .Nfi,2) GO TO 116
110 IF { ( (L/2 )/2 )*2-(L/2 ) ) 12 1,110,121
121 IF (L.NF:.000F( J.K)) GO TO 120
1. = NOTE ( J < ) 1
IF (L.NE.O) GO TO 114
120 CONTINUE
125 CONTINUE
130 CUNT I NOE
140 CONTINUE
IF (NTYPC 2) 200,150.200
150 CONTINUE
GS { 1 ) = ~j 5 ( J )
GO I O 3 00
200 Y = 00. 45 0. 071 5 DEEPER 0. OOO1 6 OCF PER* OI.FPCR
Y = ->L TLA I Y
IF (Y.IE.16.1) GO TO 250
Y = Y 11.767
55(1 ) = (27.167 S3RT( 27. 167* *2 4.0 2. 1 02* Y ) ) / ( 2 *2.1 W: )
GO TO 3 0 0
2 5 0 5 5(1) = Y / 100.
.300 CALL PMTL A I
IF ( PLT1.AI LC.PLTMAX ) I DAM = 1
IF (K)AM) 400,400, 350
oo

15 0 CONTINUE
KK = NOW
DO 390 J = 1 MilHGE
I SUM = 0
DO 3 60 I = KK NO W
I SUM = I SUM i NI1WV EG( J I )
NE V.VCGI J,I ) = 0
36 T CONTINUE
IE (ISUV.LF.O) GO TO 390
>0 370 JK 1,1 SUM
NJMMFKJ) = NUMUW(J) 1
1 S T M ( J,NUMT!( J ) ) = 7
MOD-: { J NUMI3R ( J ) ) 1
I COUNT ( J ,NUM 0.9 { J ) ) = MORROW
XNLiTAE ( J MORRO/;) = XNLF.AIT( J, M JlillOW )
ASRPTStJ) = A'iKPTSI J) + 1.
370 CONTINUE
390 CONTINUE
400 CONTINUE
RETURN
E NO
1 .
oo
i

1
o
3
SUOROUT I NI: OTPUT
COMMON / UC ) M 7/STMM2C 200) W TLF -12(200) GRP T 5 M ( 2 0 0 ) X N OL F M (200 ) .
TOT M2(20 0) PCNUT Ml 200)> fROI IM(2 00) .HSTPDM(200) .MSTERM(2 00) .
PEGS M2 ( 2 0 0 ) ROT PM2 PN.< I PM (200), 13LOUMM ( 200 ) XL A I ( 200 ) .
I D A Y ( 200) ROOTM2 200)
COMMON /UC0M10/XMATUR,PLTOAY
C OMMON /UCOM1 3/PN(20 0)
COMMON /IJCOM .2/TTL (.20)
COMMON /U COM3 O/CON IT E F, DEFT 1M.NTYPE
COMMON /IJCOM 52/A MIL T { 2 0 0 )
COMMON /UCOM34/CFFLA l( 200)
COMMON /UCOM40/STORE(200)
COMMON /UCO -15 1 /CONGNO
COMMON /UCMMoO/T O T EAT
VnK TE ( 6,1 0 ) TTL
10 FORMAT ( 1 H 1 / / / / 2 0 X 2 0 A 4 / / )
WRITE (6,20)
2 0 FORMAT! 70X,' PEANUTS )
WRITE (6,30)
3 0 FORMAT(GXPHYS )K, NF.T 3X L lAVF.S ',3X.STEM,3X,
1 'GROW 3 X '.') A ILY' 3X STORE TOTAL' JX TOTAL' ,4X K IPE ,
2 3 X H A RV .' 2 X IIAffV 3 X 'TOTAL* )
WRITE (6,40)
4 0 FORMAT( IX, 'DAY', 2X, 'DAY', 3X, 'LAI ,4X 'PT5* ,4 X, NO. ,3X, WEIGHT ,
1 2X 'WEIGHT* ,2X, P r 5 3 X 'FLflWEKS 2X, C A R13 3 X NUMOER 2X ,
2 WE IGH I* ,2X, WEIGHT' ,3X NO. ,JX 'WEI GMT ,2X, WEIGHT )
WP. ITE (6, GO)
5 0 FORMAT (IX.' 2 X 2X 2X 2X, 2X ,
1 2X 2X 2X ,2X, .
2 3 ( 2 X ). 2 X 2 X. 2 X /)
K = 0
LJ = PLTDAY
M XMATUR + PL TOAY
no 100 I = L J,M
WR I TE ( 6,60) K IDAY( I ) ,XLA I ( I ) ,PN( I ) ,XNOLFMI 1 ) ,W TLFM2( I ) .
1 ST MM2 I I ) ,GRPTSM( I ) ,OLOOMM( I ) STORE( I ) ,PENOTM I ) ,
2 FRUI T M ( I ) P N R I PM( I), HSTPDM ( I ) MS T FRM ( 1 ), TOT M2( I )
60 FORMAT ( 1 X 1 3, 2X, I 3, 3X, F *. 2,2X ,F 5. 2 I X,F6. 1 2X F6.2.2X F6.2 1 X ,
1 F6.1,2 X FF> 1,2X F. 1,2< ,F6.1,2X, F6. ,2. 2X,F 6.2, 2X.F5. 1 2X ,
2 F 6 2.2 X F 7 2 )
K = K + 1
100 CONTINUE
WRITE (6,70)
70 FORM AT ( 1 H1////20X, 'DAY ">X. 'RE AL L A I OX EFFFC T I VE LAI'.SX,
1 'LIGHT INTERCEP1 I ON/ )
K 0
DO 150 I = LJ.M
*1(1 TE (6,ri0) K X LA 1(1), EFTL A I ( I ) AMT LT ( I )
oo
co

3 0 FORMAT ( 20 X I .7X.F4.2. 1 1X.F4.-2. 16X.F6.2)
K. = K 1
150 CONTINUE
FACTOR = (1.0 CONI1EF) 100.
CONG RO = CO N>T RO 10 0.
WRITE (6,050) FAC TOR OFF TI M ,M TYRE
250 FORMAT (1 X////20X 'PERCENT OFF C)L l AT I ON = F 1 0 1 / 20 X,
1 DAYS FROM PLANTING T1 START OF OFF OLl AT 1 ON =',F6.0/
2 .? OX, TYP E OF DEFOLIATION =',I2///I
WRITE (6,255) C.ONGRO
FORMAT ( 2 0 X 'PERCENT OF GROWING TIPS REMOVED =',F10.1///>
WR I TE (,260 )
260 F ORMAT ( 2 0 X TY IF 1 OEFNI IATKiN MEANS UNIFORM THROUGHOUT T I IF CANOPY
1 / 2 0 X, TYPE 2 ME AN 3 OUTER PORTION OF CANOPY ONLY'/
2 POX.'TYPL 3 MEANS UNIFORM DEFOLIATION OF FULLY DEVELOPED
ILF A VES AND DEVELOPING LEAVES AND GROWING POINTS')
WR IT E (6,270) TOTEAT
270 FORMAT(20X,'TOTAL FOLIAGE CONiUMED HY LARVAE. CM2 =',F12.2)
RE TURN
CNC

NOW PT SYN ( 7 ) P T SR UT ( 7)
MLOCK DATA
COMMON /UCO Ml / MDEX 1 NDEX2 N Dr!X .3, NDKX
1 A SPG S T ( 7) DA Y 1 NC J ML' RG I MOP HO W
COMMON /UCOM2/UF TI ME. T I MI L F
COMMON /UCO Mi/ 1ST EM( 7,300 ) NO )L ( 7,350 J XL IE A F N ( 7),SIZELF(7,200) .
1 WTLEAF ( 7,20 0 ) W T I NOD ( 7,2 00) .W1 PC T( 7.200 ) ARE ALF ( 7 ) ,
2 W 3 Pi) AY ( 20 0 ) A GR PT S ( 7 )
COMMON / UCO 3 7/ST MM 2( 20 0) wTLEM 2( 200 ) (j E P T 3 M ( 2 0 0 ) XNOLFM (200) .
1 TOTM2 (200 ), PIEN) T M( 200 ), F RU I TM ( 200 ) US TP DM ( 2 0 0 ) M 5 TERM (2 00)
2 PCG SM2 (200) ROT PM2 PNR1 PM ( 200 ) ,UL GCMM(200 ),XL A I (200) ,
3 ID AY ( 20 0 ). ROOT M2 ( 2 00 )
COMMON /UCOMU/PROPOR(7) ,DAY A ) >
COMMON /UCO 3 S/PE NU TZ ( 7 ) F RU I T ( 7 ) ,11 STPOIX 7 ) ,UGTF RT(7) ,PEGS(7) ,
1 R ( 7 ) PNMIPE(7 > PET W T(7)
COMMON /UCO M1 0/X3ATUR,PLTOAY
COMMON /NCtiM 1 1/STRESF
COMMON /UCI1M1 2/PL TL A I PT 3
COM ION /UC M 1 3/PN 200)
COMMON / UCO I 14/IMERGE 7)
C O M M 0 N / U C O M1 5 / S T L F U T
COMMON /UCOM 16/PORT( 7)
COMMON /UCCMl 7/XLIMT (7)
COMMON /UCOM1/ASPGEN(7)
COM ION /UCOM1O/PHZOAY( 200)
COM AON /UCU320/W ANTL K 7 ) NU.MOR 1 / ) X l NODE ( 7, 200 )
COMMON /OCOM21 /POOVkGTi 7 ,200 ) MORE,OLOOMZ(7 ,200 ) ,KPEGST.
1 P EGflll ( 7,20 0 ) PODST ( 7 ) ,.'I)I)CAP ( 7, 20 0) A GEMA X( 7.2-00) GRA TC K ,
2 KPODS T GRRATE .PQP0D5 ( 7 ) PQNUT S ( 7 ) POOAGE( 200 )
COMMON /UCO3 22/NC*VEG( 7,200) ADOLF
CGMMON /UC ) 123/ST MM £N( 7 ) ,ST ML US( 7 )
COMMON / OC O M2 4 /XNONOD ( 7 ) NCO.JNT (200 ) SUR F AC ( 7,20 0 ) VLGGRD ,
2 VE >N I T VE'GNCR A 5VEG V IGC NR PORLF I'OliPT POP NOD 3 l. W
/UCO M3 6 / W GT l)N 7(7,200 ) LAN J T R AT IO, PT SS
COMMON
COMMON
COMMON
COMMON
COMMON
COMMON
COMMON
COMMON
COMMON
/UCO M20/I.C0UN T( 7.350 )
/UCO M30/CONDEF,DEFT I M
/UCO M3 1/ROTF,SMAINF
/UCO 332/AMTLT 300)
/U CO M3 3/ Pi )0 L M XL M M A Z
/UCOM34/CFFL A 1 (2 00)
/UCO3 05/NOE X6
/UCOM37/NDEXO
IT YPE
rommon /urn 34o/storc 200 )
COMMON /UCOM51 /CONGRO
COMMON /UCOMOO/TOTEAT
DATA TOTEA 1/0.0/
DAI A PL T DAY/ 1 4 ./
DAI A jTRESF/1 0/
VJ3
O

DATA
1
DATA
DATA
1
DA TA
1
2
DATA
DATA
DATA
DAT A
DATA
DA TA
DATA
DA TA
DATA
DATA
1
i
DATA
DA rA
DATA
DATA
DA TA
DATA
DA TA
.DAT A
DATA
DATA
DAI A
DATA
DA TA
DAT A
DA TA
DATA
DATA
DA TA
DATA
DA TA
END
NDEX1 N TEX 2, NDCX J. NDE. X5 T S YN P T SR U T A SPj ST. DA Y I NC /
0,0,1 ,0,14*0.0,7*25.8,0.3/
UPTIME, T I ME LP / 5.4 1 0 ?. /
1ST FZM, NODE, XLE AFN. S [ l EL E. W TLP AP WT I NOD W T PL T ANEALE ,
WGMTLF WT5TEM XNLF.AP wTFiOUT 1 COilNI P DAY AGNPTS/ 2450*0,
2450*0,7*0.0,1400*0,0.200*0.0,1400*0.0.21*0.0,1407*0.0
2450*0.207*0.0/
STM 12 WTLF M2, GRPTSM ,X NOLF M.TOTM!, PITNUTM P MU I TM EtSTPDM ,
MS T PM M, DEOS M2. OUT DM2. DM MI DM DLIUIMM XL A 1 IDA Y/26 01 O. 0 .
200+0/
DAYADD/J.0/
I MERGE/7*100/
pl:nu r / *-mui r, ms t pod, ms tfm i pegs m pnm I PE. Pc T WT/56*0.0/
XM A Tl JIT / 140./
PI TLA I. i3/2*0.0/
PN/20 0* O.0/
STLPMT/0.0/
ASPGEM PMZDAY/2 0 7+0.0/
WANTLP,NUMDN, XI NODE/7*0. C, 7* 0, 1 400*0.0/
PDDW OT MMM.l. DLOOMZ. KPEGS T PEGMD POD5T POOL AD AGE MA X GMA Tr.K
KPODST,PODODS.DONUTS.POOAGE/14 00*0 .0,0.1400*0 .0.0. 1400*0.0
7*0.0, 2 SO 0*0.0, 22.0,0, 14*0.0,20 0*0.0/
ST MM IN,ST ML 05/7 0.0,7 *0.0/
XNONilD NCUUNT SUME AC/7 *0.0,200*0,1400*0.0/
WGTUMZ.PTSS/1401*0.0/
LCGUNT/2450 *0/
MOO TM2/20 0*0. 0/
NEWVEG/1400*0/
XL IMT/7+0.0/
ROMTF, SMA INF/0.6H. 0.40/
MERGE/1/
I'DRT/l.O.ft+O. 0/
PDDLM/0 .0/
XLMMAZ/0.0/
FFELA1/200*0.0/
AMTLT/20 0*0 .0/
NDE X6/0/
NDEXD/O/
STORE/200*0.0/
NTYPF/2/
CONDEP/l.O/
CONGMU/O.0/

APPENDIX 4
DESCRIPTION OF MODEL PARAMETERS

Parameter
Descr¡pt¡on
Numerical Value(s)
Source
ADOLF
Amount of carbohydrate necessary for maximum
growth each physiological day by a growing leaf
and its attendant petiole and internode, mg
12.0
9.0
p.t. < 82
p.t. > 82
Table 3
ADDSTM
Amount of carbohydrate necessary for maximum
growth of a developing stem internode each
physiological day after the attached leaf has
ceased growing, mg
2.55
field results
AGEMAX(J,1)
Number of physiological days a developing peanut
initiated on day 1 on plant J has to complete
shell expansion--growth ceases is shell is not
fully expanded at end of this time period
k2
calibration,
field results
ASPPRO
Conversion factor for asparagine to protein in
the seeds
0.863
Duncan (197^
and personal
communication)
ASVEGF
Conversion factor for asparagine to protein in
the vegetative portion of the plant
0.786
Duncan (197^
and personal
communication)
BMETFC
Maintenance respiration coefficient
0.01
Duncan (197^
and personal
commun¡cation)
CONS 1
Number of physiological days between flower and
beginning of pod expansion at a reproductive
27.0
ca1ibration,
field results

Pa rameter
Description
Numerica1
JL
Value (s)
Source
DAYDEG
Number of F in a physiological day
25.0
Duncan (197**
S pers. comm.)
DECRTE
Coefficient for linear decline in canopy
photosynthesis after day 119
0.33
Jones et a 1.
(1980)
GRATEK
Maximum potential growth rate for kernels in
1 pod, mg/physiological day
22.0
Duncan (197**
& pers. comm.)
HFTIME
Number of physiological days for a leaf to
be ha If-grown
5.** P-t
7.2 p.t
. < 82
> 82
Table 6
HSTCPY
Ratio of photosynthetic efficiency of canopy
at maximum to efficiency at harvest
0.30
Jones et a 1.
(1980)
01LFAC
Ratio of weight of oil + carbohydrate in seed
to weight of carbohydrate necessary to produce it
0.A3
Duncan (197**
& pers. comm.)
PARFAC
Proportion of maximum 5-day-average of photosyn-
thate which may go to seeds
0.65
calibra tion,
field results
PCTC
Proportion of seed weight which is oil or
carbohydrate
0.70
Duncan (197**
& pers. comm.)
PCTN
Proportion of seed weight which is nitrogen
0.25
Duncan (197^
& pers. comm.)
PNTCNR
Ratio of carbohydrate + oil to nitrogen in seeds
0.36
Duncan (197**
& pers. comm.)

Parameter
Descript¡on
Numerical Value(s)
Source
PNTNCR
Ratio of nitrogen to carbohydrate + oil in seeds
2.80
Duncan (197^
& pers. comm.)
PNTOIL
Percent oil in seed
50.0
Duncan (197^
& pers. comm.)
PNTPRO
Percent protein in seed
25.0
Duncan (197^
& pers. comm.)
PODC
Percent carbohydrate in pod shell
0.85
Duncan (197^
& pers. comm.)
PODMAX
Maximum pod size, mg
1350
ca1ibration,
field results
PODN
Proportion of shell which is nitrogen
0.12
Duncan (197^
& pers. comm.)
PORLF
Maximum amount of weight a growing leaf can
7.96
p. t. <
82
field results
add each physiological day, mg
5.98
p. t. >
82
PORNOD
Maximum amount of weight a growing internode can
2.91
p. t. <
82
field results
add each physiological day, mg
2.18
p. t. >
82
PORPT
Maximum amount of weight a growing petiole can
2.79
p. t. <
82
field results
add each physiological day, mg
2.10
p. t. >
82

Parameter
Description
Source
Numerical Value(s)
PR 1 FAC
Priority factor for assignment of available
photosynthate to expanding pods (0.0 = complete
priority to older pods, 1.0 = each pod receives
equal percentage of its demands)
0.0
Duncan (197^
£ pers. comm.
PSLOPE
Slope of the photosynthetic equation, g/langley
0.0836
Duncan (197^
& pers. comm.)
PTSFAC
Factor related to photosynthetic efficiency of
different cultivars
1.10
Duncan (197^
& pers. comm.)
REPTIM
Number of physiological days between nodes on
a reproductive branch
6.0
field results
RESPFC
Growth respiration factor
0.30
Duncan (197^
& pers. comm.)
ROOTF
Proportion of photosynthate allocated to roots
which is used for root growth and maintenance
respiration
0.68
0.43
0.01
p.t. £ 3^
3** < p. t. <.60
p. t. > 60
calibration,
field results
SETMIN
Temperature below which development does not
occur, UF
50.0
Duncan (197^
6 pers. comm.)
S1ZM1N
If leaf completing development after day 82
weighs less than this amount, growing points
70.0
calibration,
field results
are inactivated, mg

Pa rameter
DescriptIon
Numeri
ical Value(s)
Source
SIZRED
Slope of line for decrease in pod capacity with
day of initiation
0.013
Duncan (1974
& pers. comm.)
SLW
2
Specific leaf weight for new leaves, mg/cm
4.98
3.77
3.28
p.t.
40 <
p.t.
£ 40
p.t. <.
> 82
82
Table 3
SMAINF
Proportion of net photosynthate allocated to
roots
0.43
0.30
0.15
p.t.
34 <
p.t.
<_ 34
p.t. £
> 60
60
calibration,
field results
STDECL
Days from planting until photosynthetic
efficiency of canopy begins to decline
119
Jones et a 1.
(1980)
TIMELF
Physiological days for a leaf to complete
development
10.8
14.4
p.t.
p.t.
< 82
> 82
Table 6
TMPOPT
Temperature above which the rate of development
does not increase, UF
90.0
Duncan (1974
& pers. comm.)
VEGCNR
Ratio of carbohydrate to nitrogen in the
vegetative portion of the plant
7.1
Duncan (1974
& pers. comm.)
VEGNCR
Ratio of nitrogen to carbohydrate in the
vegetative portion of the plant
0.14
Duncan (1974
& pers. comm.)
VEGPRO
Percent protein in the vegetative portion of
the plant
12.0
Duncan (1974
& pers. comm.)
* p.t. stands for physiological time in days from planting

APPENDIX 5
INPUT PARAMETERS AND
VARIABLES DESCRIBING THE DYNAMICS OF
PEANUT PLANT GROWTH
Input Parameters
CL I MAT(1,1) total radiation on day I in langleys
CLIMAT(!,2) maximum temperature on day I, to the nearest F
CLIMAT(l,3) ~ minimum temperature on day I, to the nearest F
C LI MAT(1,4) rainfall and irrigation on day I, 0.01 in
CL I MAT(1,5) not used
CL1 MAT(1,6) Julian day
CONDEF proportion of leaf matter left after defoliation (1.0 -
portion defoliated)
C0NGR0 proportion of active vegetative meristems destroyed by an insect
attack
DEFTIM number of days from planting until defoliation begins
EMERGE number of physiological days from planting until plants start
to emerge
NTYPE an indicator of type of defoliation (1 = uniform throughout the
canopy, only fully developed leaves; 2 = outer portion of canopy;
3 = uniform + partially formed leaves + vegetative meristems)
PLTDAY Julian day of planting
PLTPOP number of plants/m^
198

199
2
PROPOR(J) number of plants/m which emerge on day J
PORT(J) proportion of plants which emerge on day J
ROWMID distance between rows, cm
ROWSPC distance between plants within a row, cm
TMETRC indicator for metric weather data (if it equals 1.0, data is
metric, otherwise it is not)
TTL a title for the simulation run
XMATUR number of calendar days from planting until harvesting
Variables Describing the
Dynamics of Peanut Plant Growth
ADDRAT(J) ratio of photosynthate available to a developing leaf on
plant J from the daily photosynthate pool to the amount necessary
for maximum potential growth
ADD2(J) proportion of the demand for photosynthate by a leaf that is
more than half-grown that is filled from stem storage on plant J
AGELAR(J) age of larvae feeding on plant J
AGRPTS(J) number of active vegetative growing points on plant J
AMTLT(l) percent of available light intercepted by the canopy on day I
AREALF(J) leaf area of plant J
ASPGEN(J) amount of nitrogen (asparagine) manufactured each day by
plant J
ASPGST(J) amount of nitrogen (asparagine) available for growth each
day by plant J
ASPREQ amount of nitrogen (asparagine) required for a certain amount
of growth
AVLCON(J) ratio of amount of carbohydrate available for growth of
various plant parts on plant J to amount needed for maximum growth
on a given day

200
2
BL00MM(I) number of flowers per m on day I
BL00MZ(J,l) number of flowers on plant J on day I
2 2
CONSUM leaf area consumed by larvae on a given day, cm /m
DAYADD change in LAI from one day to the next
DAYINC number of physiological days in one calenday day (computed each
day)
DECFCT ratio of photosynthetic efficiency of aging canopy to maximum
efficiency
EFFLAl(l) effective leaf area index on day I
FRUCHO amount of carbohydrate used in seed and shell growth on a given
day, mg
FRUIT(J) weight of peanuts on plant J, g
2
FRUITM(l) weight of peanuts in g/m on day I
FRUNIT amount of nitrogen allocated to seeds and shells on a given
day, mg
2
GRPTSM(I) number of active vegetative growing points/m on day I
GRRATE amount added to each growing peanut in rag on a calendar day
o
HSTFRM(l) weight of fruit that are filling seeds on day I, g/m
HSTFRT(J) weight of fruit that are filling seeds on plant J on a
given day, g
HSTPDM(I) number of fruit that are filling seeds per rn on day I
HSTPOD(J) number of fruit that are filling seeds on plant J on a
given day
I COUNT(J,K) day of initiat ion of the most recent leaf on plant J,
stem K, starting from beginning of simulation
I DAY(I) day from planting on day I

201
I MERGE(J) date of emergence of plant J
INIT day plants start emerging
I STEM(J,K) type of stem K on plant J (1 = mainstem, 2 = cotyledonary
lateral, 3 = one of first 4 laterals off the mainstem, 4 = other
vegetative branch, 5 = reproductive branch, 6 = branch that has
stopped growing)
J index for plants that emerged on same day (from 1 7)
KPEGST date flowering starts
KPODST date pods start to form
LC0UNT(J,K) date of initiation of the next-to-the-last leaf on plant J,
stem K
MERGE number of days on which plants emerge
MORE not used at this time
MORROW current simulation day + 1, counting from start of the simulation
NCOUNT(l) date leaves initiated on day I completed development
NDEX1 an indicator of ELAI ( 0 = less than 0.161, 2 = less than 2.0,
3 = less than 2.5, 4 = greater than 2.5)
NDEX2 an indicator that enough physiological days have passed that
plants can start emerging
NDEX3 an indicator that the pod load has been set
NDEX5 ~ an indicator that a given ELAI has been surpassed at least one
time
NDEX6 an indicator of whether GRPTS should be called to initiate new
vegetative branches on a given day
NDEX9 an indicator of whether vegetative growing points may be inacti
vated

202
NEWREP(J,I) number of potentially active reproductive nodes on plant J
which were added to plant on day I not used at present
NEWVEG(J,l) number of potentially active vegetative nodes on plant J
which were added to plant on day I
N0DE(J,K) number of nodes on stem K of plant J
NOW integer equivalent of TNOW
NUMBR(J) number of vegetative and reproductive branches on plant J
PDAY(l) physiological days from day I ( only non-zero when there are
growing leaves initiated on day l)
PEANUT amount of carbohydrate available for fruit growth on a given
day
PEGDED(J) number of days there has been no photosynthate available to
fill demand from expanding pods on plant J
PEGN0(J,1) number of peanuts on plant J initiated on day I
PEGS(J) total number of pegs on plant J on a given day
2
PEGSM2(l) number of pegs per m on day I
2
PENUTM(l) number of peanuts per m on day I
PENUTZ(J) number of peanuts on plant J on a given day
PETWT(J) weight of petioles on plant J on a given day
PHZDAY(l) physiological days since day I (used for turning flowers
into peanuts)
PN(I) net photosynthesis on day 1, g/m
PNRIPE(J) weight of ripe peanuts on plant J on a given day
PNRIPM(l) maximum weight of ripe peanuts per m up until day I
PNTCHO amount of carbohydrate used in seed growth on a given day, mg
P0DCH0 total amount of carbohydrate required by shells for maximum
growth on a given day, mg

203
PODAGE(l) physiological age of pods initiated on day I
P0DCAP(J,I) pod capacity for peanuts initiated on day I on plant J
PODLM maximum five-day-average net photosynthate
PODST(J) date of pod initiation on plant J
P0DWGT(J,l) weight of an individual peanut initiated on day I on
plant J
PQNUTS(J) total amount of weight developing nuts require for maximum
growth on a given day on plant J
PQPODS(j) total amount of weight developing pods require for maximum
growth on a given day on plant J
2
PTS net photosynthesis in g/m each day
PTSRUT(J) amount of daily photosynthate which goes to roots of plant J,
i n mg
PTSYN(J) amount of daily photosynthate which goes to plant J, in mg
PTSS used to carry leftover carbohydrate from FRUFIL to DIVIDE
R(J) weight of fruit lost from plant J due to pegs rotting
RATIO ratio of carbohydrate available to developing shells to amount
necessary for maximum growth
O
R00TM2(|) weight of roots in g/m on day I
2
R0TPM2 weight of pods lost per m due to pegs rotting
SIZELF(J,I) weight of leaves initiated on day I on plant J (total)
SS(1) effect ive leaf area index
SS(2) physiological day since planting date
SS(3) real leaf area index
O
STLFRT weight of stems, leaves, and petioles, in g/m
STMLOS(j) not used at present

20
STMMIN(J) amount of carbohydrate in stem storage for plant J, mg
2
STMM2(I) weight of stems on day 1, g/m
STRESF water stress factor
SUMLAR(J) number of larvae feeding on plant J
SURFAC(J I) leaf area of fully developed leaves on plant J initiated
on day I
TNOW current simulation day, counting from start of simulation
TOTEAT total amount of foliage consumed by insects attacking the crop,
2, 2
cm /m
2
T0TM2(l) total plant weight in g/m on day I
WANTBG(J) amount of carbohydrate needed for maximum growth by leaves
developing on plant J which are more than half-grown on a given
day, mg
WANTLF(j) amount of carbohydrate necessary for maximum growth of leaves
developing on plant J on a given day, mg
WGHTLF(J) weight of leaves on plant J, g
WGTBNZ(J,l) weight of peanuts on plant J initiated on day I, mg
WNTNUT(J) amount of carbohydrate needed by seeds on plant J for
maximum growth on a given day, mg
WNTPOD(J) amount of carbohydrate needed by expanding pods on plant J
for maximum growth on a given day, mg
WNTSTM(J) amount of carbohydrate needed by developing stem internodes
on plant J for maximum growth on a given day, mg
WNTSTO(J) amount of carbohydrate "wanted" by stems for storage on
plant J on a given day--always zero at present
WTIN0D(J,l) weight in mg of an individual internode initiated on day I
on plant J

205
WTLEAF(J,I) weight in mg of an individual leaf initiated on day 1 on
plant J
2
WTLFM2(l) weight of leaves in g/m on day I
WTPET(J,l) total weight in mg of all petioles initiated on day I on
plant J
WTROOT(J) weight of roots on plant J, g
WTSTEM(J) weight of stems on plant J, g
XI NODE(J,I) number of internodes on plant J initiated on day I
XLAl(l) leaf area index on day I
XLEAFN(J) number of leaves on plant J on a given day
XLIMT(J) proportion of day's photosynthate which may be used by
plant J for seed development
XLMMAZ maximum average of 5 days' photosynthate
XNLEAF(J,I) number of leaves on plant J which were initiated on day I
2
XNOLFM(l) number of leaves per m on day I
XNONOD(J) number of internodes on plant J on a given day

REFERENCES CITED
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red-necked peanutworm on peanuts. J. Econ. Entomol. 52: 468-70.
Bhagsari, A.S., and R.H. Brown. 1973. Photosynthesis in peanut
genotypes. Amer. Peanut Res. Ed. Assoc. J. 5: 194.
Bhagsari, A.S., and R.H. Brown. 1976. Photosynthesis in peanut
(Arachis) genotypes. Peanut Sci. 3: 1-5.
Bolhuis, G.G. 1958. Observations on the flowering and fructification
of the groundnut, Arachis hypogaea L. II. Neth. J. Agrie. Sci.
6: 245-8.
Bolhuis, G.G., and W. DeGroot. 1959. Observations on the effect of
varying temperatures on the flowering and fruit set in three
varieties of groundnut. Neth. J. Agrie. Sci. 7 317-26.
Cahaner, A., and A. Ashri. 1974. Vegetative and reproductive devel
opment of Virginia-type peanut varieties in different stand
densities. Crop Sci. 14: 412-6.
Cox, F.R. 1978. Effect of quantity of light on the early growth and
development of the peanut. Peanut Sci. 5: 2730.
Cox, F.R. 1979. Effect of temperature treatment on peanut vegeta
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Duncan, W.G. 1974. PENUTZ, a simulation model for predicting growth,
development, and yield of a peanut plant. Amer. Peanut Res. Ed.
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Duncan, W.G., D.E. McCloud, R.L. McGraw, and K.J. Boote. 1978.
Physiological aspects of peanut yield improvement. Crop Sci.
18: 1015-20.
Enyi, B.A.C. 1975. Effects of defoliation on growth and yield in
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(Glycine max) and green gram (Vigna aurens). Ann. Appl. Biol. 79
55^
Fehr, W.R., C.E. Caviness, and J.J. Vorst. 1977. Response of in
determinate and determinate soybean cultivars to defoliation and
half-plant cut-off. Crop Sci. 17: 913-7.
206

207
Gautreau, J. 1973. Influence of climatic factors on the growth and
development of early groundnut. (French). Oleagineux 28: 567"77.
Greene, G.L., and D.W. Gorbet. 1973- Peanut yields following defoli
ation to assimilate insect damage. J. Amer. Peanut Res. Ed. Assoc.
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Gupton, C.L., D.A. Emery, and J.A. Benson. 1968. Reproductive
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Hackett, C. 1972. An exploration of the carbon economy of the tobacco
plant. I. Inferences from a simulation. Aust. J. Biol. Sci. 26:
1057-71.
Hang Ngoc An. 1976. Low light intensity at different stages of growth
as affecting peanut yield components. M.S. thesis, Univ. Fla.
76 pp.
Hang Ngoc An. 1978. Light intensity effects on metabolism, growth, and
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208
Linker, H.M. 1980. An analysis of seasonal abundance and sampling
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209
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BIOGRAPHICAL SKETCH
Gail Ellen Geier Wilkerson was born on 12 November 1946 in Nashville,
Tennessee. She attended public schools in Nashville until graduation from
John Overton High School in 1964. She then entered Duke University in
Durham, North Carolina, and received a B. S. degree in mathematics in 1968
In 1967 she and Richard Wilkerson were married. She received a Na
tional Science Foundation Traineeship and began graduate studies in math
ematics at the University of Florida in the fall of 1968. Upon the in
duction of her husband into the U. S. Army in the summer of 1969, she
moved to San Antonio, Texas, where she worked as a technical secretary
and teacher until 1972. She then returned to Gainesville to pursue gra
duate studies in entomology, and she received her Master of Science degree
in 1974.
She then moved to Cali, Colombia, and worked as a computer programmer
for the International Center for Medical Research until the summer of 1976
when she again returned to Gainesville to begin work toward the degree of
Doctor of Philosophy in the Department of Entomology and Nematology, Uni
versity of Florida, under the auspices of a CSRS pest management grant.
She had a son, Trevor Alan, in November 1976. Her marriage ended in di
vorce in 1978.
Gail Wilkerson is a member of the Phi Kappa Phi Honor Society.
210

I certify that I have read this study and that in my opinion it
conforms to acceptable standards of scholarly presentation and is fully
adequate, in scope and quality, as a dissertation for the degree of
Doctor of Philosophy.
S. H. Kerr, Chairman
Professor of Entomology and
Nematology
I certify that I have read this study and that in my opinion it
conforms to acceptable standards of scholarly presentation and is fully
adequate, in scope and quality, as a dissertation for the degree of
Doctor of Philosophy.
7trm 7?.
T. R. Ashley
Assistant Professor of Entomology
and Nematology
I certify that I have read this study and that in my opinion it
conforms to acceptable standards of scholarly presentation and is fully
adequate, in scope and quality, as a dissertation for the degree of
Doctor of Philosophy.
few v-
Jone?
/Associate Professor of
Agricultural Engineering
I certify that I have read this study and that in my opinion it
conforms to acceptable standards of scholarly presentation and is fully
adequate, in scope and quality, as a dissertation for the degree of
Doctor of Philosophy.
//
R. C. Littell
Associate Professor of
Stat i stics

This dissertation was submitted to the Graduate Faculty of the
College of Agriculture and the the Graduate Council, and was accepted
as partial fulfillment of the requirements for the degree of Doctor
of Philosophy.
June 1980
coJ\ X.
i cu 1 tyr
Deany College of Agr
Dean, Graduate School



88
model predictions. For all variables the average plant means from the
weekly sampels were converted to a square meter basis by multiplying by
9 ...
9.5 plants/m Simulated leaf, stem, and pod dry weights are within the
35% confidence intervals for the experimental means at all times during
the season.
Simulated and experimental leaf area indexes match until the very
end of the season, when LAI of the field plants declines, but that of
the model plants does not. Rather than model leaf loss, I chose to use
the results of Jones et al. (1980), obtained in a plot adjoining mine,
to model the decrease in gross photosynthesis late in the season. They
noted a h0% drop in P]500 (gross photosynthesis at a light intensity of
1500 pE/m^) between weeks 17 and 19; a drop that was due to the combined
effects of decreased LAI and decreased efficiency of aging leaves.
The fact that the model does not deal with loss of leaves due to
age or stress conditions leads to another difference between simulation
and field results, as shown in Figure 3- Number of leaves/m^ is over
estimated by the model after week 7 since at this point in the season
plants in the field started to lose leaves. The model does a fairly
good job of matching field results for the growth of new leaves each
week (Table 25), except between weeks 8 and 9- Simulated leaf weight
and LAI match those of the sample plants because the model adds less
weight to new leaves many weeks than do the sample plants (Table 25).
If leaf loss were to be included in the model, it would be necessary
to increase the photosynthate available for vegetative growth to
account for the extra leaf weight.
There are 3 points in the season when simulated pod numbers do not
correspond to those of the sample plants--at weeks 12, 16, and 17


TABLE OF CONTENTS
CHAPTER PAGE
ACKNOWLEDGEMENTS '
LIST OF TABLES v
LIST OF FIGURES vil ¡
ABSTRACT.
x
I INTRODUCTION 1
II GROWTH OF NON-DEFOLIATED PEANUT PLANTS. 6
Introduction
Effect of Temperature on Plant Growth
Photosynthesis
Methods and Materials
Crop Management
First Experiment
Second Experiment
Results
First Experiment
Second Experiment
6
8
8
10
10
1 1
13
1 4
14
17
THE EFFECTS OF DEFOLIATION ON PEANUT PLANT GROWTH .... 29
Introduction 29
Methods and Materials 35
First Defol iation 35
Second Defoliation 37
Third Defoliation 38
Fourth Defoliation 38
Results 39
First Defoliation 39
Second Defoliation 44
Third Defoliation 48
Fourth Defoliation 52
IV THE SIMULATION MODEL 57
Introduction 57
Description of the Model 60
Initiation of New Leaves and Branches 64
Calculation of the Day's Net Photosynthate 66
i i i


Table 26. Continued
T reatment
Weight of
Leaves,
New
g/m2
Stem
Weight,
g/m2
Gain in
Weight,
Stem
g/m2
Number of
Leaves per
New
m2
Field*
Model
Fiel d*.
Mode 1
Field
Mode 1
Field*
Mode 1
Check
49.8 (6.3)
49.4
38.2
(5.2)
27.6
35.2
24.7
686.0 (61.1)
598.6
25% uni form
37.1 (5.0)
49.9
27.0
(4.3)
26.7
24.2
23.8
545.3 (44.6)
589.1
50% uniform
^7-5 (6.1)
47.8
33.1
(5.1)
25.2
29.4
22.3
583.3 (56.6)
579.6
100%
32.7 (5.0)
35.9
21.7
(3.4)
17.8
18.1
14.8
513.7 (53.1)
589.1
0% + veg.
28.1 (4.0)
24.8
23.7
(3.8)
24. 1
20.1
21.2
499.7 (49.7)
285.0
growing points
50% + veg.
19.8.(2.6)
21.3
15.5
(2.1)
15.8
12.3
12.9
432.0 (40.2)
285.0
growing points
100% + veg.
9.3 (1.4)
3.8
8.8
(1.2)
4.3
4.0
1.4
309.7 (28.8)
285.0
growing points
"Number in parentheses is standard error of the mean.


203
PODAGE(l) physiological age of pods initiated on day I
P0DCAP(J,I) pod capacity for peanuts initiated on day I on plant J
PODLM maximum five-day-average net photosynthate
PODST(J) date of pod initiation on plant J
P0DWGT(J,l) weight of an individual peanut initiated on day I on
plant J
PQNUTS(J) total amount of weight developing nuts require for maximum
growth on a given day on plant J
PQPODS(j) total amount of weight developing pods require for maximum
growth on a given day on plant J
2
PTS net photosynthesis in g/m each day
PTSRUT(J) amount of daily photosynthate which goes to roots of plant J,
i n mg
PTSYN(J) amount of daily photosynthate which goes to plant J, in mg
PTSS used to carry leftover carbohydrate from FRUFIL to DIVIDE
R(J) weight of fruit lost from plant J due to pegs rotting
RATIO ratio of carbohydrate available to developing shells to amount
necessary for maximum growth
O
R00TM2(|) weight of roots in g/m on day I
2
R0TPM2 weight of pods lost per m due to pegs rotting
SIZELF(J,I) weight of leaves initiated on day I on plant J (total)
SS(1) effect ive leaf area index
SS(2) physiological day since planting date
SS(3) real leaf area index
O
STLFRT weight of stems, leaves, and petioles, in g/m
STMLOS(j) not used at present


SUBROUTINE INSECT
COMMON /'.COM 1 / A TR I M ( 25) JE. VNT MF A Ml;t <100). ML fl ( 1 00 ) MS TOP NCRDR. N
1 NAi'd NI4APT NNAT R, NNF IL NMD ( 1 00 ).NN T ¡(Y. NPRU T ,PP AR -1(50.4) T III*' TTIItO
2 T TC L R T TF I 1 T T R I i) ( 2 5 ) T T 3L T
COMMON /GCO A 2/ D 0( 1 0 G) D")L ( 1 00 ) .O IF UL ,l) 1 NOW I 3F.L 5, LF LAG (50 ) NFL AG.
1 NNF00, NNFQG NNLOT S3 ( 1 0 0 ) SSI ( 1 0 0 > TTNIIX
COMMON /GCO 1 1 / A AERO ,0 T MAX ,O TMIN DT3 AV 1 1 r l!S LLEUd, LLS AV.LLS EV ,Kl(E
1FU.TTLAS, rr ov
COMMON / GC CM* / OT PI. T ( 1 0 ) MIILO.V l 25 ) MOV. ID( 23 ) 1 ICIO I I T AP( 10) .JJCLL
1 ( 500 ) LL. AJC ( 5,2) LL ADI I ( 2 5.2 ) l.l. A) IM 1 1 ,2) .LLAflT (25,2 ) LLPi ll( 10 ),LL
2 PL 'll 10),l LPL.LL GUO ( 15) L L 3 Y M ( 10). MMIT 5 MHCi'L ( 25 ) .NNCL 1 .NUIII 5 NNIL
3 T NNPTS (10), DUST A NNV Al< ( 1 0 ) PHI (10), l'i'l. (10)
COMMON /GC OM 5/ I I L V T 1 I Si'O ( 6 ) J JOiZG J JCLII, M M N I T MMON NNAML ( 3 ) NNC F
1 1 NND AY NUPT NNSCT NNPP: J NNPR 3 MURNG, NOR UN NN5 TR .NMYft, SSLF.iX 6)
COMMON /GCOMG/ LLNGi 1 00 ) I I NN( 1 00 ) ,KKIiNN ( 100 ) MMAX Q( 100 ), OUT IM ( 1 00
1 ) j > 011 V ( 25, 5 ) 33TP V( 25. 6) VV I 1(100)
COMMON /UCO -11 /NDEX 1 ,N9LX2, NOFX 5 NO OX 5, NO, PT5YN ( 7 ) P T 30 UT ( 7) ,
1 A SPG 3 T < 7) O A Y I NC J.MERGE MAURO
CO 3MON /UO H2/HFTI Mr. T I MCL.F
COMMON /UCOM 3/ GT M ( 7 ,350 ) NO HI ( 7. AGO ) XL L APU ( 7 ) 3 IZ EL F < 7,20 0 ) .
1 WTLi-AF ( 7.2 00) WTI NOD ( 7,2 00) W I PlT ( 7,200 ) AliF. ALF (7 ) ,
2 .V GI (T L F (7 ), JTSTFM( 7 ), XNLLAF ( 7,200). WTROUT ( 7) I COUNT ( 7 35 0) ,
.'3 P!)AY( 200) AGRPT3 (7)
COMMON /UGOM J/PRPOR ( 7), TAYA), >
CO MMO N/UCOM1 2/PLTL A I ,PTS
COMMON /UCO 120/WANTLF 7) NUM1FU7) X I NUDE ( 7 ,2 )
CO AMON /UCOM 2 2/N EW V E G ( 7. 200 ) ADOLF
COMMON / UCOM24/XNONOU(7) NCOJN1 {200 ),SURFAC(7,200 ) ,VCGGRO,
2 Vi" GN I T VEGNCR A5VCGF, VIGOUR Pi JR IF ,1ONPT POUNOO ,3 LW
COMMON /UC.C M2U/LCOUNT (7, 350)
C O M MON / UC OM JO/CRN OFF .DEPTH, NTYPLI
COMMON /UC.) -3 5 1 /COUGRO
DAI A IUAM/0/
DA TA PLT 3A X /0. 0/
XY = PL TL A I 0.6
PLTMAX = AMAX 1 (PLTMAX, XY )
lit FPL R = (1.0 CUNOEF) + 100.
NO a' = T NOW
MORROW = NOW 3- 1
1 F ( CONGRI).£0.0.0)
M = 1.0/CON GUO
CONTINUE
IF INTYPE -
GO TO 9
50.10
10 OO 20 J 1
aGMTLF(J) =
ARCALF(J) =
OU 20 I =
IF ( NCriUUT ( I
2 ) 10
M FRGE
= WGI IT LF ( J )
= AREALF( J )
1 NOW
).EQ.0> GO
CONOFF
COUOLF
TO 20
oo
-tr


78
Each of the defoliation experiments was simulated by calling
INSECT on the day the plants were defoliated, and by specifying the
percent and type of defoliation. For the simulations of removal of
leaves from the outer portion of the canopy, a sufficient amount of
defoliation was specified to bring the simulated LAI down to the same
level as that of the experimental plants after treatment.
I also simulated defoliation experiments performed by Mangold
(1979) in a field adjacent to mine. His peanuts were planted 1 or 2
days earlier than mine but the plant spacing and crop management were
identical. The defoliations simulated were as follows:
1. 75% uniform at week 8
2. 75% uniform at week 8 plus 75% defoliation of new leaves for
the next 7 days
3. 75% uniform at week 11
4. 75% uniform at week 11 and 75% defoliation of all new leaves
at week 15-
In order to demonstrate the coupling of PMINUS to an insect develop
ment model, I constructed a simplistic model of an insect cohort enter
ing the system, growing and eating for a certain number of days, and
then leaving the system. One of the power curves derived by Huffman
(197*0 for consumption of peanut foliage by the bollworm, He 1ioth i s zea
(Boddie) was used in calculation of leaf material eaten each day:
Y = 0.011 X2-995 (10)
where X is the age of the larva in days and Y is the cumulative foliage
consumption to date, in cm^. I assumed all larvae emerged on the same
day; the same number attacked each plant; they grew and fed for 26 days;


76
defoliation, a photosynthetic rate 75.48% of its rate before defoliation
according to the equation. This value (Y) is multiplied by PLTLAI (pro
portion of the available light intercepted by the canopy prior to defoli
ation) to find the effective canopy light interception (Y1). This value
(Y1) is then inserted into equation (4) to find the normal canopy LAI
which photosynthesizes at the same rate as the defoliated plants now
do. This becomes the "effective" LAI for the defoliated plants and is
used as the baseline for any increases or decreases in LAI in the future
Going back to the example of the plants defoliated 50% on a given day,
if the plants had an LAI of 2.15 and were intercepting 60% of the avail
able light just prior to defoliation, then they would now intercept
45.28% of the available light (75-48 0.60) and have an effective LAI
of 1.39. In actuality, the LAI is half of 2.15, or 1.08, but these
plants are photosynthesizing at the same rate as normal, non-defo1iated
plants with an LAI of 1.39* In summary, effective LAI is a variable
to relate percent interception of defoliated canopies to percent inter
ception of non-defo]iated canopies.
The removal of leaves from the outer portion of the canopy was
equated with removal of the youngest leaves. Since there were no data
to relate light interception by plants defoliated in this manner to
rate of photosynthesis, the assumption was made that the photosynthetic
rate of plants defoliated in this manner is the same as the photosyn
thetic rate of non-defoliated plants with an LAI equal to the reduced
LAI. For example, if 50% of the total leaf area is removed in this
manner from a plant with an initial LAI of 3*0, then, after treatment,
the plant will photosynthesize at the same rate as a normal plant with
an LAI of 1.5. By removal of the outer envelope of leaves from the


1
o
3
SUOROUT I NI: OTPUT
COMMON / UC ) M 7/STMM2C 200) W TLF -12(200) GRP T 5 M ( 2 0 0 ) X N OL F M (200 ) .
TOT M2(20 0) PCNUT Ml 200)> fROI IM(2 00) .HSTPDM(200) .MSTERM(2 00) .
PEGS M2 ( 2 0 0 ) ROT PM2 PN.< I PM (200), 13LOUMM ( 200 ) XL A I ( 200 ) .
I D A Y ( 200) ROOTM2 200)
COMMON /UC0M10/XMATUR,PLTOAY
C OMMON /UCOM1 3/PN(20 0)
COMMON /IJCOM .2/TTL (.20)
COMMON /U COM3 O/CON IT E F, DEFT 1M.NTYPE
COMMON /IJCOM 52/A MIL T { 2 0 0 )
COMMON /UCOM34/CFFLA l( 200)
COMMON /UCOM40/STORE(200)
COMMON /UCO -15 1 /CONGNO
COMMON /UCMMoO/T O T EAT
VnK TE ( 6,1 0 ) TTL
10 FORMAT ( 1 H 1 / / / / 2 0 X 2 0 A 4 / / )
WRITE (6,20)
2 0 FORMAT! 70X,' PEANUTS )
WRITE (6,30)
3 0 FORMAT(GXPHYS )K, NF.T 3X L lAVF.S ',3X.STEM,3X,
1 'GROW 3 X '.') A ILY' 3X STORE TOTAL' JX TOTAL' ,4X K IPE ,
2 3 X H A RV .' 2 X IIAffV 3 X 'TOTAL* )
WRITE (6,40)
4 0 FORMAT( IX, 'DAY', 2X, 'DAY', 3X, 'LAI ,4X 'PT5* ,4 X, NO. ,3X, WEIGHT ,
1 2X 'WEIGHT* ,2X, P r 5 3 X 'FLflWEKS 2X, C A R13 3 X NUMOER 2X ,
2 WE IGH I* ,2X, WEIGHT' ,3X NO. ,JX 'WEI GMT ,2X, WEIGHT )
WP. ITE (6, GO)
5 0 FORMAT (IX.' 2 X 2X 2X 2X, 2X ,
1 2X 2X 2X ,2X, .
2 3 ( 2 X ). 2 X 2 X. 2 X /)
K = 0
LJ = PLTDAY
M XMATUR + PL TOAY
no 100 I = L J,M
WR I TE ( 6,60) K IDAY( I ) ,XLA I ( I ) ,PN( I ) ,XNOLFMI 1 ) ,W TLFM2( I ) .
1 ST MM2 I I ) ,GRPTSM( I ) ,OLOOMM( I ) STORE( I ) ,PENOTM I ) ,
2 FRUI T M ( I ) P N R I PM( I), HSTPDM ( I ) MS T FRM ( 1 ), TOT M2( I )
60 FORMAT ( 1 X 1 3, 2X, I 3, 3X, F *. 2,2X ,F 5. 2 I X,F6. 1 2X F6.2.2X F6.2 1 X ,
1 F6.1,2 X FF> 1,2X F. 1,2< ,F6.1,2X, F6. ,2. 2X,F 6.2, 2X.F5. 1 2X ,
2 F 6 2.2 X F 7 2 )
K = K + 1
100 CONTINUE
WRITE (6,70)
70 FORM AT ( 1 H1////20X, 'DAY ">X. 'RE AL L A I OX EFFFC T I VE LAI'.SX,
1 'LIGHT INTERCEP1 I ON/ )
K 0
DO 150 I = LJ.M
*1(1 TE (6,ri0) K X LA 1(1), EFTL A I ( I ) AMT LT ( I )
oo
co


IF ( AVL. CON ( J ) tLF.a 0.0) AVLCON(J) = 0
IF (KPOD5T.GT.0.AND.AVLCDN(J).LO.O.0
5S0 CONTINUE
IF (KPODST.NE.O) CALL DIVIDE
CALL LEAVES
IF (NDHXb.FO.l ) CALL GRPT S
KK = 0
DO 710 J = 1.MERGE
710 IF (PTSYN (J ) .GT .0.00 1 ) KK = KK F 1
IF (KK.NE.O) CALL STEMS
900 CUNTINUE
RETURN
END
0
PHZDAY(NOW) = 0.0
oo


Table 12. The effect of various levels of defoliation at 4 weeks upon plant size at 7 weeks.
Mainstem Stem
Treatment Length, cm* Length, cm*
Check
17.5
(0.7)
298.5
(32.2)
25% uniform
14.8
(0.7)
216.8
(28.3)
50% uniform
16.7
(0.8)
250.0
(31.6)
100%
13.9
(0.9)
192.2
(26.8)
0% + vegetative
growing points
12.1*
(0.9)
206.3
(24.6)
50% + vegetative
growing points
12.2
(0.5)
143.8
06.2)
100% + vegetative
10.8
(0.5)
94.6
(10.8)
growing points
Avg. Cot. Lat. Stem Ratio of Stem Wt.
Length, cm*Weight, g* to Length, mg/cm*
23. 1
(1.1)
4.0
(0.6)
12.9
(0.4)
18.7
(1.5)
2.8
(0.5)
12.5
(0.4)
21.5
(1.2)
3.5
(0.5)
13.4
(0.5)
16.5
(1.6)
2.3
(0.4)
11.6
(0.4)
14.8
(1.1)
2.5
(0.4)
11.3
(0.7)
13.6
(1.1)
1.6
(0.2)
10.8
(0.5)
10.8
(0.7)
0.9
(0.1)
9.6
(0.5)
'Number in parentheses is standard error of the mean.


Table 22. Summary of light interception by plants defoliated at 16 weeks.
Treatment
Row
LAI Immediately
After Defoliation
% Light Intercep
tion Immediately
After Defoliation
LAI at
18 Weeks
% Light
Intercept ion
at 18 Weeks
Check
R
6.7
9A.0
6.7
93.A
S
**.3
90.9
A.3
93.5
T
8.1
95.5
8.1

U
6.0
96.0
6.0
98.5
50% Un¡form
R
3.3
75. A
3.A
89.1
S
3.0
73.1
3.0
90.2
T
3.7
8A.A
3.8

U
2.6
68.6
2.6
80.0
100%
R
0.0
A0.8
0.1
33.1
S
0.0
51.8
0.3
61.1
T
0.0
Al.5


U
0.0
A0.1
0.03
A9.2
\n
on


126


4 0 LL = (ASPinr(J) / tl X
X = LL
U = ADOLF V L (>N CP A5V EGF X DAY INC
\ = X ADOLF DAY INC
SO IF (LL ) 1 70, 170, 55
55 PT5YNIJ) = PTSYN(J) A
A5'GGT(J> ASPGST(J) )
WILHAH J.MO/J ) = PORLF << DA Y I NC
SI ZITLF ( J ,ND0 ) = SI ZELF { J, NOW ) POOL r X
WT PF T ( J N) W ) = WriIITt J.NOW) ¥ ODD! T X *
.vr INOOt J, NOW ) = PORN Of) DAY INC
XI NODE( J NO0 ) = X I NODE( J,NOW) X
XNLEAFl J.NOV ) = XNLF A-F ( J NO W ) + X
AGROTS(J) = AGRPTS(J) X
PDAY(MOW) = DAY INC
DO 7 0 JK = 1,IL
NUMf)R(J) = NUMDIX ( J ) ¥ 1
I S T : M ( J N'-JM 10 ( J ) ) = 4
NO OF. ( J NO MU < ( J ) ) 1
(COUNT ( J ,IL MOO ( J) ) = NOW
70 CONTINUE
DO 16S I = M NE W Vi ; G ( J I )
IF (M.F.0) GO TO 1 5
DO 160 JK = 1 M
IF (LL) 170,170,105
1 5 5
LL = LL -
1
NEWVEGIJ.
I )
= NE iV V E G ( J
16 0
CONTI NOF.
1 6 5
cont indi:
1 7 3
CO NT I NUF
' = P X
*
Pl< IPOD ( J )
2 0 0
CONT ItlUt:
PE URN
FN D
DA Y INC
DAY INC


3 ^
tme when vegetative growth would normally be decreasing. After the
pod load is set, defoliation was expected to result in the plant fill
ing fewer pods.
There are indications that defoliating caterpillars may attack
younger leaves or terminal buds (vegetative growing points) preferen
tially (Huffman 197^, Arthur et al. 1959, Morgan 1979). I anticipated
that the type of defoliation would make at least some difference in the
plant response. Most prior defoliation experiments on peanuts have
dealt with uniform defoliation (removing a certain number of leaflets
from each leaf). It appeared likely that this would change light in
terception and plant growth in a different manner than an equal amount
of non-uniform defoliation (removing an outer layer of leaves, for
example).
Four defoliation experiments were performed to investigate these
questions about plant response to defoliation. The purpose of the
early season defoliations was to determine the effect of several levels
of defoliation and the effect of removal of vegetative meristems alone
or in combination with partial or complete defoliation. The second and
third defoliations investigated the effect on subsequent plant growth
of severe defoliation (50%) by 2 different methods (removing 2 leaf
lets from each leaf, or removing 100% of the leaves from the outer 50%
of the canopy) at the pegging and podsetting stages of growth. The
final experiment dealt with the effect of 50% uniform and total defolia
tion late in the season. The 50% defoliation treatment was for com
parison with the earlier experiments; the 100% defoliation was intended
to reveal the presence or absence of storage reserves in the stems, as


Table 12. Continued
T reatment
Numbe r
G rowin g
of Veg.
Points*
Number of
New Leaves
Check
31.8
(3.2)
72.2
(6.*t)
25% uniform
28.5
(2.0)
57.*4
(*4.7)
50| uniform
30.9
(3.0)
61.*4
(6.0)
100%
28.7
(3.M
5*4.1
(5.6)
0% + vegetative
growing points
25.7
( 1 *4)
52.6
(5.2)
50% + vegetative
growing points
2*4.5
(2.6)
*45.5
(*4.2)
100% + vegetative
18.7
(2.1)
32.6
(3.0)
growing points
-Number in parentheses is standard error of the mean.
Weight of Root Total Plant
New Leaves g*Weight, g*Weight, g*
5.2
(0.7)
0.6
(0.
1)
1*4.*4
(1.9)
3.9
(0.5)
0.6
(0.
1)
10.8
0.5)
5.0
(0.6)
0.6
(0.
1)
13.0
0.6)
3.*4
(0.5)
0.5
(0.
1)
8.3
0.2)
3.0
(0. *4)
0.5
(0.
.1)
9.2
0.3)
2.1
(0.3)
0. *4
(0.
1)
6.*4
(0.9)
1.0
(0.1)
0.3
(0.
.0)
3.*4
(0. *4)
-E-
tvj


43
Table 13.
Estimated leaf
defoliation at
and stem gains in
4 weeks.
the 2? weeks
following
Treatment
Estimated
Original
Stem Wt., g
Estimated
Gain in
Stem Wt. g
Gain in
Leaf Wt., g
ALeaf
ALeaf+AStem
Check
3.0
3.7
5.2
0.58
25% uniform
2.8
2.6
3.9
0.60
50% uniform
3.6
3.1
5.0
0.62
100%
3.6
1.9
3.4
0.64
0% + tips
3.5
2.1
3.0
0.58
50% + tips
3.2
1.3
2.1
0.62
100% + tips
4.8
0.4
1.0
0.70
-'Original stem weight was estimated by dividing the original leaf weight
by 0.70 to find stem weight + leaf weight. Subtracting leaf weight from
this gave original stem weight. (The ratio of leaf weight to leaf + stem
weight averaged 0.70 for non-defo1iated plants until week 8.)


POD DRY WEIGHT, g/m2 LEAF AREA INDEX
113
WEEKS FROM PLANTING
Figure 16. The simulated effect on LAI (a) and pod dry weight (b) of
10 larvae/plant entering the field on day 56 and feeding for
26 days at an increasing rate.


CHAPTER IV
THE SIMULATION MODEL
Introduction
The experiments discussed in Chapters II and III yielded much of
the information necessary for modification of Duncan's (197M PENUTZ
model. From the experiments dealing with the normal growth of non-
defoliated plants, I was able to establish the branching pattern of an
average plant, the rate of initiation of leaves and vegetative and re
productive branches at different times in the season, the average size
of individual leaves and internodes at different times in the season,
and the relationship between LAI and percent light interception by the
canopy.
My overall conclusions from the defoliation experiments were that
the Florunner cultivar of peanuts does accumulate stem storage reserves,
and that defoliated plants draw upon these reserves and continue to
grow leaves of the same size as non-defoliated plants at active vegeta
tive nodes. If the level of defoliation is severe enough to expose to
the 1 ight inactive vegetative nodes that would normally be shaded,
some of these nodes are activated. Severe defoliation during the peg
ging and podsetting stages of growth results in fewer pods of the larg
est size category. When the defoliation occurs early in the pod filling
period, expansion of small pods (P3's) is curtailed. When defoliation
occurs late in the season after vegetative growth has almost ceased,
57


207
Gautreau, J. 1973. Influence of climatic factors on the growth and
development of early groundnut. (French). Oleagineux 28: 567"77.
Greene, G.L., and D.W. Gorbet. 1973- Peanut yields following defoli
ation to assimilate insect damage. J. Amer. Peanut Res. Ed. Assoc.
5: 141-2.
Gregory, W.C., B.W. Smith, and H.A. Yarbrough. 1951. Morphology,
genetics and breeding, p. 28-88. _l_n The Peanut--The Unpredictable
Legume. Nat. Fert. Assoc., Washington, D.C.
Gupton, C.L., D.A. Emery, and J.A. Benson. 1968. Reproductive
efficiency of Virginia type peanuts. III. Relating the time of
peg placement to the branching pattern of the plant. Oleagineux
23: 247-50.
Hackett, C. 1972. An exploration of the carbon economy of the tobacco
plant. I. Inferences from a simulation. Aust. J. Biol. Sci. 26:
1057-71.
Hang Ngoc An. 1976. Low light intensity at different stages of growth
as affecting peanut yield components. M.S. thesis, Univ. Fla.
76 pp.
Hang Ngoc An. 1978. Light intensity effects on metabolism, growth, and
yield components of peanuts. Ph.D. Dissertation, Univ. Fla. 119 pp.
Henning, R.J., R.H. Brown, and D.A. Ashley. 1979. Effects of leaf
position and plant age on photosynthesj^ and translocation in pea
nut. I. Apparent photosynthesis and 4C translocation. Peanut
Sci. 6: 46-50.
Huffman, F.R. 1974. Consumption of peanut foliage by the bollworm,
Heliothis zea (Boddie) (Lepidoptera:Noctuidae). M.S. thesis,
Texas A & M Univ. 40 pp.
Jacobs, W.P. 1951. The growth of peanut plants at various diurnal and
nocturnal temperatures. Sci. 114: 205-6.
Jones, J.W., C.S. Barfield, K.J. Boote, G.H. Smerage, and J. Mangold.
1980. Photosynthetic recovery of peanuts to defoliation at var
ious growth stages. Crop Sci. (in review).
Jones, J.W., L.G. Brown, J.D. Hesketh. 1980. C0TCR0P: A simulation
of cotton growth and yield, p. 209-41. _[n^ Predicting Photosynthesis
for Ecosystem Models, Vol. II. CRC Press, Inc., Boca Raton, Fla.
Jones, J.W., and G.H. Smerage. 1978. Representation of plant/crop
physiology. ASAE Tech. Paper No. 78-4024. 11 pp.


75
the system. A shell that is not fully expanded after ^2 physiological
days ceases to grow and make demands for carbohydrate.
INSECT Subroutine
INSECT is the subroutine developed to link PMINUS to an insect
development model. Each day that simulated insect damage occurs, it is
called to compute changes in leaf weight and area and in canopy light
interception due to defoliation. The type of defoliation must be speci
fied. At present, INSECT can simulate the effects of 3 types of defoli
at ion: 1) removal of the same proportion of leaf material from each
leaf on the plant; 2) removal of whole leaves, starting with the young
est; and 3) removal of portions of leaves as in 1) plus removal of
some or all of the active vegetative growing points on the plant. Only
minor changes would be required to combine leaf removal as in 2) with
remova1 o f g rowing points.
The effect of defoliation on canopy light interception and photo
synthesis is handled differently in the model depending on the type of
defoliation. The data collected by Jones et al. (1980 and personal
communication) were used to estimate the effect of uniform defoliation
on photosynthesis. The regression line
2
Y = 99.^5 0.0715 DEFPER 0.00816 DEFPER (9)
2
with an R value of 0.96 relates DEFPER, percent defoliation, to Y,
percent of photosynthesis of defoliated versus non-defoliated plants.
(For the purposes of the regression, only readings that were made 1-3
days after defoliation or that were made after week 15, when leaf
growth had essentially stopped, were used.) For example, a plant
which is defoliated 50% on a given day will have, immediately after


12
A leaf was considered fully expanded if the next leaf on the branch was
starting to unfold. New vegetative branches were marked by placing a
spot of acrylic paint on the axil of the leaf at the node from which
the branch was emerging. Pegs that had entered the ground during the
preceding week also were marked with colored surgical wound clips.
The color of paint and clips was different each week so that at the end
of the experiment the age of each leaf, stem, and pod could be deter
mined. The numbers of marked pegs, leaves, and stems were recorded
each week.
When the plants were brought in from the field, the location and
age of leaves, stems, and pods were mapped. The leaves were separated
by age and counted; leaf area was determined by use of a Lambda^ leaf
area meter; and after drying the leaves were weighed. Marked pods also
were separated by age and further divided into categories of P3, P4,
and P5. A P3 pod is defined as one that is slightly swollen; a P4 as
one that is fully expanded but which shrinks when dried; and a P5 is
one that is fully expanded which does not shrink when dried (Hang An
1976). The pods in the various categories were counted, then dried and
we ighed.
All plant parts in all experiments were dried at 60C for at least
48 hr prior to weighing. Data were analyzed using the Statistical
Analysis System on an Amdahl 470 V/6-11 with OS/MVS Release 3.8 and
JES2/NJE Release 3- Computing was done using the facilities of the
Northeast Regional Data Center of the State University System of Flori
da, located on the campus of the University of Florida in Gainesville.
^Lambda Instruments Corporation, Lincoln, NE.


135
Calculate shell and nut demands for photosynthate.
no
Set the
pod load.
7
N.
Calculate stem sink demand.
Calculate
AVLCON.
V


3) CALL INSECT
ATrUIJ( 1 ) = T
A TR It) ( 2 ) = 1
CALL F ILL 1( 1
40 CONTINUE
J?E TURN
E N'T
NOW + 1.0
)
oo


viD
ln
P3N1J*J = ( r 50 lilr.lP
MNN.31S (r x jctiNiir
wdn i* = ( r x ) jv?,3 jm
m 3Nin ( f 4 X ) 3 311 z i >
i = (> khinunx
*i = (x)njv3 3>;
C (E4X)3C>0N
c = (o'X)DCION
X = < I 4X ) DOOM
E = < xhkjnon
2 = ( £ 4 X ) N DI S I
5 = <24X)NDbl
I = ( I X )NJ1S I
Mf IN = (X)39iJ3Wl
x r
i + x = N
T + UNI MON = X
*7*2 i 3 K113! MONI = N
0*1 -t 3NI1JM MUNI *- 3
( 1)1 Vi3 I 3 33 VD
l = ( L ) 0 I N IV
* i + m(.-ni = ( i ) v111;i v
C06 01 OO ( 303W3*. 1IN1 MON) 31
T X */ *£/ *0 V E *0;
RDN1 = AON
/9t? *10 l
y E <7 /MMllJOM 4 M ?N13d *KNE 3 1 S 4 M3M l M M.NV3LJV VIVO
(CSE )lNnf03/62M0it/ NUKNOD
M3S 4 OONMf' d 4 IfJMOd *3 3>!Ut' *0ND93A 4 39JASV 4 U JN93 A 4 1 1 NO. A Z
4 OXJ993A 4 (CC 3 4 L ) JVJdOS *(003)1 MOLON 4 ( L ). 3 HJf'NX / *7 J N O J O / NON NOD
( C 0 3 4 / ) 3li(JN 1 X 4 ( / ) Oil ON ( J. HOlNVM/Ocl.ODO/ NULhOD
( L ) 3011301 /*7 IKUDfV NUNNOD
U ) 1 Ml 30 4 ( ) 3 4 f'CVAVG 4 ( L ) Ul dOMc'/ONODO/ NONNOD
< )J1 dXJDV4 (002 ) A VGd f
(OSE 4 / )1 MOOD I 4 C l) lnon 1M 4(0 0 3 4)3V33NX4 ( L)W31S1M 4 (L)33J MOM 2
4 ( y.) J3V3HV 4 ( 0 0 2 *Z )1 Idle 4 (00 2 4/ ) CON 1 1 M 4 ( 0 0 2 4/ ) 3VJ 3.1 M I
4 ( O C2 ) 3 337 I S 4 ( y. )N:JV 33 X 4 ( OSE 4 L ) 3 CON 4 ( OSE 4 L H 31 S I/Sl-ODO/ NOES OD
J I NI /EWUDn/ NONNIJD
JO-IWIJ 4 3N I 1311/cV L DO/ NOMOD
MOmtC'N4 30XI.3N 4T DM I A VO 4 ( L ) iffdSV I
4 (y ) inns Id 4 (/ ) MAS IcJ4 MON 4SX ION 4E X3(!N 4 2X31 h 4 I X3C1N/X V 030/ NONNOD
X 3N1 1 4 (OC l ) 1ST 4 (0 0 I ) fS 4 1 OIJN'tJ 4 9 ODN N 4 OC3MM l
4 O V3 IN 4 ( C S ) 9 V 3 3 3 4 S O 3 f 1 4 (INK 4 3f i )1U 4 ( CO X ) 3C,U 4 (OCX ) (l 13f.ll 4 (Sc Mil Mil 4 Ml 311 *0331 1 4c
0 301 1 4 MONI 4 ( <7 4 OS )NMV dd 4 IHUtlM 4 AH INN 4 ( CC I ) CNN 4 31 3NN 4 111 VNN 4 1 dV NN 4 OdVN X
N 4 MCI 1ID N 4 dOlS N 4 (OO X )3 IN 4 ( OCX ) 3 J N 4 V JN 4 IN AD T 4 ( S 2 ) U I IIIV / I NO DO / NONNOD
Ml 930 3NI 1001:0 OS


120
Solar
Day
Radiation,
1ang1eys
Temperature
Max.
(C)
Min.
Rainfal1 and
Irrigation, mm
16 August
387
31.7
22.8
.5
17 August
464
32.8
21.7
2.3
18 August
576
33.9
21 1
2.3
19 August
382
31.7
20.0
20 August
516
33.3
23.9
21 August
542
32.2
21.1
22 August
428
31.7
22.2
23 August
473
31.1
22.2
24 August
547
31.7
21 1
25 August
456
31.7
20.0
12.7
26 August
499
32.2
21.1
27 August
593
33.9
22.2
28 August
476
35.0
22.2
29 August
571
32.2
22.2
30 August
573
32.8
22.8
31 August
509
32.8
21.7
19.1
1 September
466
35.0
21.7
2 September
413
33.3
21.7
1.8
3 September
511
32.8
21.7
4 September
516
33.3
20.0
5 September
437
33.9
19.4
6 September
459
31.1
18.3
7 September
535
32.2
20.0
8 September
425
32.8
23.3
19.1
9 September
378
32.8
22.8
10 September
217
31.7
20.0
.8
11 September
487
31.7
18.9
12 September
499
32.2
21.7
13 September
449
32.8
20.0
14 September
411
32.8
20.6
19.1
15 September
416
33.3
21 1
16 September
410
33.3
20.6
17 September
490
32.8
20.0
18 September
509
32.8
20.6
19 September
468
33.3
16.1
20 September
483
32.2
20.6
19.1
21 September
380
32.2
20.9
22 September
459
33.9
20.6
23 September
251
32.2
21.1
7.6
24 September
385
31.1
21.7
25 September
435
31.7
20.6
.8
26 September
354
30.0
20.6
12.7
27 September
292
29.4
20.0
28 September
378
28.3
18.3
29 September
170
27.2
20.6
30 September
129
25.6
22.2
7.9


116
were drawing upon reserves in the stem to grow leaves and pods. Gener
ally, the effect of defoliation upon pod growth appeared to be to slow
or stop the expansion of young pods, thereby resulting in fewer pods of
the largest size category.
In general, the computer model developed on the basis of these
experiments, PMINUS, satisfactorily simulates changes in LAI and weight
of stems, pods, and fully expanded pods for both defoliated and control
plants. Further work needs to be done on determining factors which
cause the plants to lose leaves and to decrease growth of leaves. Fur
ther experimentation aimed at determining the mechanisms involved in
setting the size of the pod load would also be helpful. It would also
be of value to know how long a peg that has entered the ground can re
main inactive before it loses the capacity for expansion. A series of
defoliation and depodding experiments could shed light on some of these
questions. In particular, 100% defoliations and 100% depoddings per
formed at frequent intervals during the season on 2 or more varieties
of peanuts could provide the necessary information on what factors de
termine the cessation of vegetative growth and the partitioning of
photosynthate to pods.
The fact that simulated plant growth following defoliation for the
most part matched plant growth in the field indicates that the assump
tions made about light interception and photosynthesis in the model are
realistic. Further experiments still need to be performed to determine
the effect of non-uniform defoliation on canopy photosynthesis. Work
also needs to be done on the related problem of feeding site location
for different foliage-consuming insects and the effect of natural in
festations of insects on canopy photosynthesis. The simulations of an


39
As there was little vegetative growth at this late stage, no plant
maps were made.
Table 11 is a summary of the times and types of defoliations made
during the course of the season.
Results
First Defoliation
The results are summarized in Table 12. All plant parts appeared
to be affected equally by defoliation, i.e., if stem weight was re
duced, so were stem length and leaf number and weight (Table 13)- The
fact that the average values for the 50% defoliation treatment were
generally higher than those for the 25% defoliation treatment (Table
12) is perhaps due to the higher initial LAI for the 50% defoliation
plots. Mean LAI for the 25% defoliation plots was 0.10 just prior to
defoliation, whereas that for the 50% defoliation plots was 0.16. The
unevenness of planting depth caused some problems in that plants
emerged at different times and this had an effect upon plant size
throughout the season. Blocking by row partially overcame this prob
lem as is indicated by significant differences (a= .05) between rows
in average cotyledonary lateral length, total stem length, root weight,
and the number of old leaves. There was variation in plant emergence
and size within rows too and this resulted in the plants in some treat
ment plots being larger on average than those in other treatment plots
prior to defoliation.
Plant response to growing tip removal was quite uniform. Removing
the apical meristem destroyed apical dominance. If either of the first


73
other constituents. He further assumed that it required 2.85 units
of carbohydrate to produce 1 unit of oil. The same assumptions are
made in PMINUS.
Once the amount of carbohydrate available for leaf, stem, or shell
growth on a given day has been calculated, the total dry weight added
to that portion of the plant is calculated by
dWv =(dCv + ^1) / 0.97 (7)
dt dt dt
where dCv/dt is the change in carbohydrate for the given plant struc
ture, dNv/dt is the change for nitrogen, and the subscript v refers to
either leaf, stem, or shell. The amount of nitrogen needed is calcu
lated by assuming a nitrogen:carbohydrate ratio of 12:85.
For nut growth, the total dry weight added on a given day is calcu
lated by the equation
dWn = (dCn + d£n + dNn) / 0.95 (8)
dt dt dt dt
where dCn/dt is the weight of carbohydrate added to nuts, dOn/dt is the
weight of oil, and dNn/dt is the weight of nitrogen in the form of pro
tein. The ratio of carbohydrate:o¡1:nitrogen used is 20:50:25, and
2.85 units of carbohydrate are used to produce 1 unit of oil.
Inactivation of Vegetative Growing Points
The cessation of active growth by any branch is controlled by
time in the growing season and the size of the last leaf on the branch.
No stem may stop growing until after day 82, when leaf development time
is increased from 10.8 to 14.4 days. Maximum leaf size remains 88 mg,
but daily demand/leaf is reduced at this point due to the increased


Pa rameter
DescriptIon
Numeri
ical Value(s)
Source
SIZRED
Slope of line for decrease in pod capacity with
day of initiation
0.013
Duncan (1974
& pers. comm.)
SLW
2
Specific leaf weight for new leaves, mg/cm
4.98
3.77
3.28
p.t.
40 <
p.t.
£ 40
p.t. <.
> 82
82
Table 3
SMAINF
Proportion of net photosynthate allocated to
roots
0.43
0.30
0.15
p.t.
34 <
p.t.
<_ 34
p.t. £
> 60
60
calibration,
field results
STDECL
Days from planting until photosynthetic
efficiency of canopy begins to decline
119
Jones et a 1.
(1980)
TIMELF
Physiological days for a leaf to complete
development
10.8
14.4
p.t.
p.t.
< 82
> 82
Table 6
TMPOPT
Temperature above which the rate of development
does not increase, UF
90.0
Duncan (1974
& pers. comm.)
VEGCNR
Ratio of carbohydrate to nitrogen in the
vegetative portion of the plant
7.1
Duncan (1974
& pers. comm.)
VEGNCR
Ratio of nitrogen to carbohydrate in the
vegetative portion of the plant
0.14
Duncan (1974
& pers. comm.)
VEGPRO
Percent protein in the vegetative portion of
the plant
12.0
Duncan (1974
& pers. comm.)
* p.t. stands for physiological time in days from planting


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151


199
2
PROPOR(J) number of plants/m which emerge on day J
PORT(J) proportion of plants which emerge on day J
ROWMID distance between rows, cm
ROWSPC distance between plants within a row, cm
TMETRC indicator for metric weather data (if it equals 1.0, data is
metric, otherwise it is not)
TTL a title for the simulation run
XMATUR number of calendar days from planting until harvesting
Variables Describing the
Dynamics of Peanut Plant Growth
ADDRAT(J) ratio of photosynthate available to a developing leaf on
plant J from the daily photosynthate pool to the amount necessary
for maximum potential growth
ADD2(J) proportion of the demand for photosynthate by a leaf that is
more than half-grown that is filled from stem storage on plant J
AGELAR(J) age of larvae feeding on plant J
AGRPTS(J) number of active vegetative growing points on plant J
AMTLT(l) percent of available light intercepted by the canopy on day I
AREALF(J) leaf area of plant J
ASPGEN(J) amount of nitrogen (asparagine) manufactured each day by
plant J
ASPGST(J) amount of nitrogen (asparagine) available for growth each
day by plant J
ASPREQ amount of nitrogen (asparagine) required for a certain amount
of growth
AVLCON(J) ratio of amount of carbohydrate available for growth of
various plant parts on plant J to amount needed for maximum growth
on a given day


Table 2.
Average numbers and
marked on a weekly
weights of pods of various size
basis during 1978 and harvested
categories
at 16 weeks
from 4
of age.
Florunner peanut plants
Week Peg
Entered
P3 at
Harvest
P4 at
Harvest
P5 at
Harvest
Total
at
Pods Present
Harvest
Kernel Weight
Ground
Numbe r
Weight, g
Number
Weight, g
Numbe r
Weight, g
Number
Weight, g
at Harvest, g
6-7
0.0

0.6
0. 1
2.4
3.0
3.0
3.0
2.5
CO
0.2
0.0
1 .2
0.7
5.0
6.7
6.4
7.4
LA
LA
8-9
o
OO
0.0
1.2
0.4
6.0
6.5
8.0
6.9
5.4
9-10
2.0
0. 1
3.6
1.7
1 1.4
11.7
17.0
13.4
9.6
10-11
1.8
0. 1
OO
1.8
6.8
5.5
12.4
7.4
4.3
11-12
1.2
0.0
2.0
0.7
2.0
1.6
5.2
2.4
1.2
12-13
0.0

0.6
0.1
0.4
0.3
1.0
0.4
0.3
13-14
0.2
0.0
0.2
0.0
0.0

0.4
0.1
0.0
14-15
0.0

0.0

0.0

0.0


15-16*
6.8
0.2
2.2
0.5
11.4
12.5
20.4
13.2
10.2
Actually pods that were not marked.


CHAPTER I
INTRODUCTION
Peanuts are an important food and oil crop. During the period
1967_1969, an average of nearly 45 million acres of peanuts was grown
annually throughout the world and over 1.4 million acres were grown in
the United States (McGill, 1973). The peanut agroecosystem is complex,
in that there are numerous arthropods, weeds, and diseases which attack
peanut plants and affect crop growth and yield. In addition, growth and
yield are influenced by soil and weather conditions, and by crop manage
ment practices. The effects of many of these factors are dynamic--for
example, final yield may be less affected by a given level of moisture
stress or defoliation at one time in the season than at another. Fur
thermore, there is interaction between factors; a plant that has been
weakened by disease may be less able to withstand insect defoliation.
Linker (1980), working in north Florida, noted an interaction between a
crop management practice (date of planting) and numbers of fall army-
worm, Spodoptera frugiperda (J.E. Smith), and corn earworm, Heliothis
zea Boddie, larvae obtained in his field samples. As a result of this
interaction, in 1975 and 1976 the later in the season the crop was
planted, the more insecticide treatments were required for crop pro
tection.
Given the dynamic nature of the different factors involved in de
termination of final yield, and the difficulty of designing and
1


subroutine rltgro
DIMENSION PG,>£D(7 )
i> I VC NSI ON NEW REP (7.200)
COMMON /DCOM 1 /N DEX 1 NOE X2 NDF KJ NOE XO NOW RT SY Ni 7 ) ,PTSUUr( 7) ,
1 A SP (1ST (7 ) O A Y INC, J, MERGE.MORROW
COMMON /OCIO M2 /HF TI ME T 1 Mr'LF
COMMON /UCOM4/ADDSTM
SO
COMMON
1
2
2
COMMON
1
COMMON
COMMON
COMMON
COMMON
1
2
CO MMO N
COMMON
o
#_
COMMON
C OMMON
COMMON
COMMON
/UCC! MS / I STEM (7,350), NO )F ( 7, 350 ) XL E AFN ( 7 ) 5 I Z EL F ( 7.20 0 ) ,
WTLEAF ( 7,2 00 ) W T I NOO { 7,200) wTPI'.T ( 7,200 ) ARE ALE (7 ) ,
WGIITLF ( 7 ) WT ST L.M( 7 ) XNLEAE ( 7,2 00) WTROO T ( 7 ) I COUNT ( 7,050)
PDAY (200) A G R n T 5 (7 )
/UClH S/R ENUTZ ( 7 ) ,PUIJ I T ( 7 ) ,11 S TROD ( 7 ) ,1ISTERT ( 7 ) ,PEGS ( 7 ) ,
R ( 7 ) RIM R I RE ( 7 ) P E T W T ( 7 )
/UCOM1 7/XL I MT{ 7 )
/UCtlM 1 G/RHZUAY 200 )
/DC )M20 /WANTLE( 7 ), NUMO.l ( 7 ) X INOOE 7, 200 )
/UCO M2 1/ROO*G T( 7,300) MORE,OLGOMZC 7 ,200 ) KREoST,
REGNO (7, 200 ). ROOST (7).RONCAR{ 7, 20 0) AGE MA X( 7,200) GliA T E K ,
K ROO ST,GRRAT E.RQROOS(7 ) RGNOTS(7 ) ,RODAGEi 20 0 )
/iJC OM 22/Nt: W VE G ( 7,200) \DOl.F
/ U CO M2 4 / X NGNOO( 7 ), NC OJNT (200 ) .SURFACi 7, 200 ),VEGGRO,
VEGNI I VEGNCR ASVEGF VEoC NR,RORLF,RGRRI PORNOO,SLW
/OCOM26/WGT TNZ( 7, 200) H ANOT,RATIO ,RTGS
/UCOM27/RCTC,ROOC,RCTN, PGDN, A5RRRO,OIL FAC
/ UC O M 2 0 /LC O UN T ( 7, ISO)
/UCOM 3 i/PODLM, XL MM A Z
COMMON /OC O M35/NOEXG
COMMON /IJCUM 17/NDEX9
COMMON /UC O M43/W NT NO I (7 ) WNTR ) l)( 7 ) .
COMMON /UCOM4M/WANTOG7)
OAT A 3 I ZM IN.NEWRER,RERT IM,ROD 1A X, SI
1 .013/
DATA CONS1/27.0/
DATA NOEX11/0/
OAT A PC GDI. 0/7 *0.0/
MORRO V = NOW + 1
DO 50 J =
WANTOG(J) =
WNTSTM(J) =
WNT ROD( J ) =
WNTNUT(J) =
WNTS TO(J ) =
VJANTLF(J) =
NYES ~ NOW -
1 MERGE
= 0.0
= 0.0
= 0.1)
= 0.0
= 0.0
= 0.0
1
DO 200 I = l.NYES
RilZOAY ( I ) = PH ZD AY ( I )
Ir (Pl)AY( I ) .LE .0. 0)
I 0 AY ( I ) = RD AY ( I )
I
DAY I Ns
GO TO 200
DAY INC
NT GTO( 7 ) ;.'N T ST¡M ( 7 )
ZRED/70.0,1400*0,6.
, AVLCONt 7)
O 1 3 jO t


109
Table 34. Comparison of simulated and experimental (Mangold, 1979)
yields for Florunner peanuts defoliated at various points in
the season.
Pod Dry Wei
ght, g/m2
% Reduction in Yield
T reatment
Field*
Mode 1
Field
Model
Check
495.1 a
460.9

--
75%, week 8
429.5ab
461.8
13
0
75% + buds, week 8**
365.4b
404.5
26
12
75%, week 11
349.0b
346.2
30
25
75%, weeks 11, 15
366.1b
346.0
26
25
'"Values in the column
different ( p < 0.05),
fol1 owed by
Duncan's new
the same letter
1 multiple range
are not
test.
s ign i ficant1y
**Buds removed for 7 days.


27
Table 10.
Average size of stem internodes during
indicated by weekly plant samples.
the 1978 season, as
Week
Internode Length, cm*
Internode Weight, mg**
3
1.25
12.3
4
1.27
10.0
5
1.21
12.7
6
1.58
22.1
7
2.31
33.4
8
3.49
57.5
9
3.94
77.0
10
4.43
85.1
11
4.62
97.4
12
5.15
101.1
13
4.96
112.9
14
4.64
114.9
15
5.36
119.3
16
5.46
125.8
17
4.58
93.3
18
5.12
114.8
20
4.70
116.7
'Average internode length for each plant was estimated by dividing the
total stem length by the number of leaves (internodes) on the plant.
**Average internode weight for each plant was estimated by dividing the
total stem weight by the number of leaves (internodes) on the plant.


3 0
3 3
4 0
SUBROUTINE FliUF IL
O l VE NSI ON PNNI PX (7 ) GNPCT ( 7.20 0 ) PEG NO r (7 200 )
COMMON /UCO M 1 /¡M!)F.X 1 NDE X2.NDEX 3 NDEX 5, NOW PT SYN ( 7 ) PT5RUT ( 7 ) .
1 ASPGST (7 ) DAY INC. J. MERGE MONRO M
COMMON /UCOMD/PENUTZ C 7) ,FNO T ( 7 ) ,HST PUD(7 )MSTF NT (7 ) .PEGS(7) .
1 N( 7) PNR IP E ( 7 ),PETWT( 7)
COMMON /Cn.CM /POOWGT (7, 20 0 ) M ONE* OLOOM2( 7, 200) KPEGST,
1 PEG NO ( 7.200) POD ST ( 7 ) .POD CAP (7.200 ) AGE. MAX (7.200). GRATEK.
2 KPOD jT.GRN ATE.POPOOS( 7) ,PONUT S( 7) ,PODAGE( 200)
COMMON /UCOM2o/WGT MNZ ( 7 ? 0 0 ) PEANDT NAT IO.PTSS
COMMON /UCO M2 7/ PC TC POlOC .PC T N, PODO. A SPPRO O 1 LE AC
DATA AVLGTD, AVLGR.X, PNNIPX. Sit PC T, PE GNO T .PEGLST/ 0.0. O. 0. 1 407*0. 0,
1 1 4 0 0* 0. 0 3 S 0 /
DA T A PR IE AC/0.0/
AVLGRO = PEANUT F AVLGRO
GROW = NA T III** PR I r AC
AVLGRX = 0.0
PE NUT Z(J) = 0.0
MSTFPTt J ) = 0.0
HSTPUD(J) = 0.0
F R UIT ( J ) = 0.0
PNRIPX(J) = 0.0
00 1 1 K = KPJDST, NO V)
IF ( P£"GNO( J.K) .EO. 0.0) GO TO 11
PODS IZ 0.17 PODCAP(J.K)
IF (POOWGT (J,K ) .GT .POOCAP(J,K ) ) GO TO 20
IF ( POD AGE ( K ). G T. 32.0 AN >. POOwGT ( I K ) EE 0.0 00 1 ) GO TO SI
IF (PODAGi;(K ) .GT .A GEMAX ( J K ). \ NO .PUD WG T ( J K) .IT. PDSI Z ) GO TO 12
IF ( A VL GN X.2Q.1 .0) GO TO 12
IF ( AVLGRO .LE .0. 0) GO TO 12
IF (POOWGT (J .K ) .LT .POOS I /) GO TO SO
PN TC 110 -- F.RRATE PEGNO ( J.K) PCTC / OIL FAC
IF { POD WGT ( J .K ) GT 0. ) PODCAP J K) ) GO TO MS
AVLGRO = AVLGRO PNTCIIO
IF (A VL GR O .0 fl 0 0 ) C. G TO 40
O = (PNTCIIO F AVLGRO) / PN TCI JO GRN ATE
CONTI NOE
POVWGT(J.K) PODrtGT(J.K) F Q
WGTMNZ(J.K) = W GTONZ(J.K) F PZCNO(J.K) 0
AVLGNO 0.0
A VL GR X = I 0
GO TO 12
PNTCIIO = PNTCHO / 2.0
GNOTII = GNPArC / 2.0
GO T O 5 S
CONTI NOE
POOWGT(J.K) = POOWGT (J.K) F 2,URATE
WGTONZ(J.K) TiJNZt J.K) F GN NATE PLGNU(J.K)
or-


125


50
Table 18. The effect of 50% defoliation at week 12 upon plant size at
14 weeks.
T rea tmen t
Plant Variable
Check
50% Uniform Outer
50% of Canopy
Number of new leaves
10.1b
15.1b
32.0a
Weight of new leaves, g
0.9b
1.3b
2.1a
Ratio of stem weight to
length, mg/cm
25.3a
22.5b
20.5c
Number of vegetative
growing points
45.5b
41.7b
60.6a
Number of new vegetative
growing points
6.2b
4.2b
10.8a
Number of P3
26.9b
29.9b
49.3a
Note: Means in a row followed by the same letter are not significantly
different according to a t-Test (a = 0.05).


GUI ROUT I NE STEMS
COMMON /UCO-I 1 /NDuX l NOF X2 NO EX 3 NDFXS MOW PTSYN ( 7 ) RTS RUT ( 7 ) .
1 ASPOST (7) .DAY INC, J,MERGE,MORROW
C OMMON /UCOM4 /ADDS TM
COMMON
1
->
l
3
COMMON
COMMON
COMMON
1
2
COMMON
COMMON
o
C OMMON
/UCO 4 5/ I S TEM 7,350), NO>E ( 7,350) XL E AF N ( 7) ,S I 7cLF ( 7 ,0 O) .
VtiT LEAt ( 7,200 ) WT !NOI)( 7,2 JO ) W T P E T ( 7, 200), ARE ALE ( 7) ,
WSO TU ( 7) #T 'jR- M( 7 ) XNLE AF ( 7 ,2 00 ) WT ROOT (7 ) I COUNT (7,350
IOAY ( 20 0 ) A GR P T 3 ( 7 )
/UC O M1 7/PH 20AY(2 00 )
/UCO I 20/ t A N TL f- ( 7) NOM3R ( 7) X1 NODE( 7 20 0 >
/UC O 12 l/PODWG T ( 7, ?0 0 ) -lORE OLOOMZ ( 7.200), KPEG ST ,
pro NO ( 7.20 0) POOST ( 7 ) POC AP ( 7.200 ) AGE MAX ( 7, 20 0 ) OR AT .-IK,
KPOD i T. GRRATE,POPOOS( 7) .PONUT S( 7) ,POOAGE ( 200)
/UCOM2 3/ST mm 1 N(7 ) STMLUS(7)
/ JCU 424/XNONU) ( 7 ) NC.OUNT (200) SURI AC ( 7 ,200 ) V EGGED,
VEGNIT.VEGNCR. ASVEGF, VEGCNR.PORLF.PORPT.PORNOO, SL W
/UC 11 M2 5/ASPREO
COMMON /UCOM4 3/ WN T N U T ( 7 ) ,rtNTPOD(7) ,WNTS TO( 7 ) W NT ST M ( 7 ) AVLCON 7 )
00 E00 J = 1, MERGE
VEGGRO PTSYN(J)
IF (PTSYM( JJ.LT.O.OOl) GO TO O00
200 VEGNIT = VEGSRO < VEGNCR
ASPREQ VEGNIT ASVEGF
IF ( ASPC3T ( J ) .Gu .ASPREIO ) GO TO 300
VEGNIT = ASPGST(J) / ASVEGF
VEGGRO = VEGNIT VEGCNR
PTSYN(J) PTSYN(J) VEGGRO
A SPGST(J ) = 0.0
T Sli U T( J ) = 'TGIMJTI J) PTSYN(J)
PTSYN (J ) = 0.0
GO TO 400
300 ">TSYN(J) = PTSYN(J) VEGGRO
AS r,GS T ( J ) = ASPGST(J) ASPRC.l
400 A = (VEGGRO f VEGNIT) / O.U7
WTSTEM(J) = WTSTEM(J) + A / 1000.
STORE = A (wNTSTV( J ) AVLCON(J) )*( 1 .0VIGNCR ) / 0.07
STORE = AMA X 1 ( ST ORE,0.0)
STMMIN(J) = STMMIN(J) + STORE
C = XNONOO(J) 40.0
IF ( S r M M I N ( J ) L L C. ) GO TO 60 0
WTSTEM(J) = WTSTEM(J) (C GTMMIN(J ) )/l000.
S T M T I N ( J ) = C
GOO CONTINUE
RETU RN
END
-j
oo


}2k


79
no mortality occurred; and they all left the system after 26 days. The
simulated attacks were as follows:
1. 10 larvae per plant, entering the field on day 21, and feed
ing randomly on the plant (the effect of this on light inter
ception was assumed to be the same as uniform defoliation)
2. 10 larvae per plant, entering the field on day 21, and feeding
on the youngest leaves
3. 10 larvae per plant, entering the field on day 35, and feeding
randomly on the plant
k. 10 larvae per plant, entering the field on day 35, and feeding
randomly
5. 10 larvae per plant, entering the field on day 56, and feeding
randomly
6. 10 larvae per plant, entering the field on day 56, and feeding
on the youngest leaves
7. 20 larvae per plant, entering the field on day 35, and feeding
randomly
8. 20 larvae per plant, entering the field on day 35, and feeding
on the youngest leaves.
Results and Discussion
Comparison of Model Predictions with Growth of Non-defoliated Plants
in the Field
Figures 2 through 9 are graphs of time versus LAI, number of
leaves, leaf dry weight, stem dry weight, number of pods, pod dry weight,
number of fully expanded pods (PVs and P5's), and weight of fully ex
panded pods, according to the weekly plant samples and according to the


COMMON
SUOPOUT IN¡: Glll'rs
C OMMQN /UC OM l /NDEX 1 N >L X? NDEX 3 NDEX5 NOW
1 A SPGG r ( 7 ) DA YI NC J MERGE .MDlUiOW
COMMON /UC0M5/ 1STEM(7,350), NODE! 7,350),XLEAFN 7 ) .
1 WTL.EAF' ( 7.2 0 0 ) WT1 NOi)( 7 .200) WT PET (7.200 ),
2 WGMTLF 7 >.WTSTEMI7 > ,XMLFAF( 7.20 0) .WTROUT (
3 PDAY(200),AGUPTS(7)
/UC O-4 7/ OTMM 2 ( 20 0) W TLFM2 ( 20 0 ) GRPT SM (2 00 ) .
T OTME(20 0) PE NU T M( 2 00 ) FRUI TM (2 00) HlPwMl
PFG3M2 (200 ) RUT PM2 PMU IPM (200 ) QLOOMMI 200
I )A Y( 20 0 ) ROO TM 2( 200)
/UC.nM 1/ P COPtJiT ( 7 ) PAYADO
/UC0M20/W AN IL F ( 7 ) NUM.Iii ( 7 ) X I NODE ( 7,200 )
/Cf ) 4 22/NEWVEG( 7,20 0 > ,Ai)l)LF
/ O CuM24/XNOND( 7 ) NCOUNT ( 20 0 ) SU)
VEGNI T.VCGNCS ,ASVEGF ViiGCNii POPLF ,
/UCUM 16/PLTPU2
/UCOM43/WNTNUT (7) ,WNT PHD(7).W NT 5TU(7 )
1.0 GRPT SM( NUU- 1 )
PTSY N( 7), PTS RUT ( 7)
S IZELF- ( 7, 20 0) .
ARE AL F(7 ) ,
7) ICUUNTI7,3SO )
XNULFM(200 ) .
200 ) US TF RM (200)
) X L A I ( 2 O 0 ) ,
COMMON
COMMON
COMMON
COMMON
>
COM TON
COMMON
P = 33'
! r AC ( 7,
PflRPT ,
200),VE'GGRO,
PORNO O, SLW
WN TSTM( 7),A VLCONI 7 )
00 200 J = 1.MERGE
IF (PTSYN(J).LT.0.001) GO TO 200
KK = NOW 2
SUM = 0.0
I SUM = 0
IF ( P ) 200, 200. 5
5 CONTINUE
00 10 = KK, NOW
10 I SUM = I SUM F NEWVeG(J.I)
SUM = ISUM
XI = SUM PROPOR(J)
IF (XI ~> ) 16, 1 5, 15
15 CONTINUE
SUM A INT(P/PROPOR J) )
NDEX6 = 2
16 CO N TINUF
IF (SUM.LE.0.1) GO TO 200
A = SUM F ADOLF* F DAY INC
X = SUM
LL = SUM
IF (PTSYN(J) A) 30.20,20
20 O ADOLF VLGNCR F ASVEGF F SUM F DAY INC
? 5 IF (ASPGST(J) :n 4 0.50,50
7.0 LL = (PTSYN(J) / A) F SUM
X = LL
O = ADOLF F VLGNCR F ASVEGF F X F DA Y l NC
IF (O.LE.3.)) GO TO 170
A = X A)DLF F DAY INC
GO TO 2 5
i


oo
LTV
X I! 1 VMO
lVlOld 11V3 C2
0 2 V 10 S 10 (2XJGN) dl
ZVUZIld 11VD il
l = Z XION
< l )N31 I J 11 VD
* I = ( 2)UIM1V
KI1JLK1 4 MOM = ( 1)01 ill V
0*99 = WJ1J30
MINI = AVOlid
SI U J O V (C* 3N*ZX3(JN) dl Cl
Cl *CT *0C6 (AVUlld (9*MUN>1VWI1D) II
XUdlVf* llVD
f'U N1 = MON
0G6 Cll DO ( C C* l J MON1G ) dl
X3CNI V IS IV dV?l IV Hi I = (DCS
llVl! UNIJNVld TJN15 AVI* 1 V D 11. UK) I S AM d = (2)SS
XUClf I VIIV :IV31 JAllDlddl = ( nss
/0//X3ON VIVO
loon 3NO1S/0 VK UDO/ NOV KOD
( 0Cc)I Vlddd/Vf V UDO/ NOWKOD
2dAl 1 HI J JO JlOkOD/Ol KUJO/ NOf.K'UD
( L ) COlK'l S ( Z ) N 1 K W1S /1 2 W 0 Dn / NOWKOD
(COZ ) I'D VOUd 4 ( Z )S in NO cl ( Z.) GCOdOd 3 1VHMD J SOOcOl 2
( 0 02* L ) XV Wl'DV ( 002 ) c IV DUOc ( Z )i GOOd ( COT L ) U NT lid l
4IGDldX 4( 002 4 Z ) Z M1U1U *D MOW ( CCS L ) IPWClllcl/ l 2K ODO/ NOWWUD
1WJ11S/SlKUDO/NOWKOD
( Z )3GU1U l/k l MIDO/ NIJKKOD
AVO lid 4OA V WX/C IKUDf*/
(Z ) 1 Wild ( L ) 3cl mid ( Z ) H
* { Z ) SD3d ( L) Id dlGH ( />OUdISO* ( L ) llllMJ* ( Z ) ZION Id/ OK 100/
OCJVAVu 4 ( Z ) dUdUdd/tl UDn/
(002 JoWiOOU 4 (002 ) A V Ci I
4 ( C C 2 ) I V1X 4 ( C 02 ) KWfKIlM 4 < 0 C2 )Kd I dNd 4 cWd 1UM 4 ( CC2 ) 21 Old
4 ( 00Z ) WM 110 M4 (00 2 ) WCill'JII 4 ( 0 02 ) K1 10 id 4 ( OC 2 ) K'lf'NHd 4 ( 0 02 )2W 1U1
4 ( 0 02 ) WdlPNX4 ( 002 ) WG Id 19 4 ( 0 0 2 ) 2 Kill M 4 ( 0 02 )2 1 WIG/MODO/
(9*002)1V111D/9KIDU/
( Z ) S 1 c¡?JD V 4 ( 0 02 ) A V(Id
NOWKOD
NOOKOD
NOWKOD
MOWKOD
h O K M O D
4( OGf 4 Z) IN ODD I 4 ( Z ) IOIUI 1M 4 ( 0 0 24 7. ) dV 21N X 4 ( Z ) W 111 1 4 (Z ) dll I IDd 2
4 (Z)dlVlIV4( 0 02 4Z ) 1 LldlM 4 ( 0 02 Z ICCMI 1/1 4 ( 00 2 4 Z ) dV31 It* l
* ( 0 02* Z ) 1117 IS4 ( Z )N JV ¡IX < 0 S 2 4 Z ) ICON 4 (091 4 Z M* 211 1/0 1 ODO/ NOW KOD
A'ONiiUW 4 I'jMIiN *r 4 DM I AVO 4 (Z)lSDdSV I
4 (Z )inIEld4 (Z )NASJ X JN11* (001 ) 1GS 4 (00! )SS 4 10.7NH4 S 01N N 4 <1OIIMN I
4 OVldN 4 ( OS ) D V1 d 1 4 S13 S I 4 M! IM10 in J lO 4 ( 00 l ) 100 4 < 0 0 I ) CIO /2KUDD/ NOWKOD
11)51 1 4 ( S2 ) OI Ml 1 4 Ml dll *il ID 11*2
030 1 1 4 i*UN 1 4 ( *? 4 OS ) IDIV dd 4 INIJdN 4 Ad INN 4 < CC l ) CNN 4 II dNN 4 Ml VNN 4 1 d VON 4 Od VN l
N 4 NO ID N 4 dUlSW 4 (CC l ) 11K 4 ( 001 ) 3.1 K 4 VdW J NA1 0 4 ( 9 2)01 HIV /l KUDO/ NUWKOD
31 vi r, ini inufjtinc
IJ IjU


no
yes
Change proportion of
daily photosynthate
which goes to roots.
no
1NIT >
ndex:
TNOW
> = 1
Call
¡EG IN.


220
CONTINUE
NDEX9 = i
2 0 0
IE (LFLAG(B)
)
300.
30 0, 21 0
21 0
NOE XI = 3
300
IF (L FLAG (4)
)
3 1 0,
400.400
3 1 0
NOEX 1 = 3
40 0
IF ( L F L A G ( 5 )
)
5 00 ,
500,410
4 10
HOOT F = 0.0 1
5MAINF = 0.1
5
*">0 0
I F: ILFL A G ( 6 )
)
n 0 0 .
6 0 0,6 10
51 0
IN IT = TNOal
NOCX2 = 1
CALL OF GIN
C 0 0
IF (L FL AG( 7 )
)
700.
7 0 0. 6 1 0
61 0
RL'TF = 0.4 3
5M A IN F = 0.30
70 0
IF (LFLAGCJ)
)
BOO.
BOO, 7 10
7 1 0
MOEX 1 = 4
NO f£X 6 = 2
B00
IF (LFLAG(O)
)
cUO.
900,900
Ml 0
NOEXI = 2
00 0
CUNT INO E
IF (LFLAG(10
) 1
1 950
,950,910
0 10
SL m 3.77
05 0
CONT INU E
RETURN
E NO
x-


45
Table )4. Summary of light interception by plants 7 weeks of age which
had been defoliated at 4 weeks.
Treatment Type
Row
LAI
Percent Light
1 n te rcepted
Check
B
1.89
46.9
E
1.80
50.8
25% uniform
B
1.53
48.4
E
0.62
29.6
50% uniform
B
1.06
33.3
-
E
1.78
36.9
1 00%
B
0.77
32.0
E
0.68
36.6
50% uniform + tips
B
0.66
44.7
E
0.42
22.7
100% + growing tips
B
0.27
20.2
E
0.35
20.6
0% + growing tips
B
0.82
26.9
E
1.39
24.7


POD DRY WEIGHT, g/m2 LEAF AREA INDEX
96
7.0
Figure 10.
The simulated and experimental effect of 50% uniform defoliation
at 9 weeks after planting on LAI (a) and pod dry weight (b).


19
Table 4. Average stem growth for Florunner peanut plants during the 1978
growing season, as Indicated by weekly plant samples.
Week
Ma1nstem
Length, cm
Total Stem
Length, cm
Stem
Weight, g
Ratio of Stem Weight
to Length, mg/cm
3
5.0
13.5
0. 1
9.4
4
5.9
21.5
0.2
8.0
5
7.1
35.1
0.4
9.9
6
9.9
101.2
1.5
13.7
7
12.0
199.5
2.9
14.4
8
18.1
403.8
7.0
16.1
9
23.9
609.2
13.2
18.7
10
29.1
787.4
14.9
18.4
11
35.7
1051.3
22.7
21.1
12
38.9
1267.4
27.4
19.6
13
44.6
1403.4
31.0
23.1
14
43.1
1245.0
30. 1
24.9
15
49.2
1483.8
33.6
22.2
16
46.4
1218.6
28.6
23.2
17-
38.8
1408.0
28.7
20.4
18
52.3
1471.7
35.0
22.5
20
40.1
1081.4
26.7
24.8
Only 3 plants harvested this week.


Table
1. Average leaf
growth for 4 Florunner
peanut plants
marked weekly and
harvested at
l6 weeks.
Week
No. Leaves
Marked
No. Leaves Still
Present at 16 Weeks
Leaf
Area, cm^
Specific Leaf
Wt., mg/cm^
Weight per
Leaf, mg
No. New Veg.
Growing Pts.
3
8.5
1.8
24.3
5.48
73.9
4.6
4
11.0
7.3
50.8
5.96
41.5
3.2
5
21.0
15.5
129.7
5.42
45.4
8.6
6
34.2
31.2
484.9
4. 1 1
63.9
10.4
7
34.8
33.0
777.5
3.82
90.0
5.8
8
34.2
33.0
941.4
3.74
106.7
6.0
9
44.8
39.8
1220.8
3.98
122.1
5.4
10
42.8
40.8
1097.3
4.04
108.7
1.8
11
39.5
39.0
995.3
4.10
104.6
5.0
12
34.8
34.8
833.6
4.23
101.3
1.4
13
25.2
25.0
492.3
4.27
84.1
1.2
14
18.2
16.5
280.7
4.24
72.1
0.0
15
10.5
10.5
164.6
4.12
64.6
0.0
16
10.2
10.2
167.4
4.17
68.5
0.0


67
index. Generally speaking, "effective" LAI is the same as LAI, but
after defoliation it may differ from real LAI. This will be explained
in the description of the INSECT subroutine.
Equation (A) was derived from light interception readings made
when the plants were 6 or more weeks of age and cannot be used for
younger plants, as it has a Y-intercept of 0.11767; i.e., plants with
zero leaf area intercept nearly 12% of the incident radiation, accord
ing to this equation. Light interception for young plants was assumed
to equa1 LAI, or,
PLTLAI = SS (1) (5)
until an LAI of 0.16. (Equations (A) and (5) intersect at an LAI of
0.16.) In essence this assumes that in young plants all leaves are
fully exposed to the light with no shading. When the LAI Is above 0.16,
shading causes light interception to be lower than LAI. I changed
PTSFAC in equation (I) from the 1.05 used for Florunner in PENUTZ to
1.10 to correct for the fact that the maximum value for PLTLAI in
equation (4) is about 0.95 rather than the 1.00 maximum for PLTLAI used
in PENUTZ.
The amount of photosynthate going to any one plant is calculated
by dividing the plant's leaf area by the total leaf area/m^. For the
purpose of calculating leaf area index and thus light interception and
photosynthesis, leaves are not counted as leaves until they are fully
grown. Not until a leaf has completed development is its area computed
by dividing its weight by the specific leaf weight of new leaves at
that point in the season. Specific leaf weight is 4.98 until physio
logical day 40 (calendar day 34), 3-77 from day 41 to day 82 (calendar
day 68), and 3-28 for the remainder of the season. These were the


35
vegetative growth should have ceased prior to defoliation time. All
the experiments were designed to determine growth of new leaves, growth
of pods, and growth of stems, as indicated by changes in length, weight,
and length to weight ratio, following defoliation.
Methods and Materials
First Defoliation
The first defoliation plot was planted on 22 May with a row and
intrarow spacing identical to that described in Chapter II. Other
aspects of crop management were identical also. The plants were de
foliated on 23 June, bj weeks after planting.
The experiment consisted of 7 treatments applied to 5 blocks.
Plants were blocked by row. Seven treatment plots were selected in
each row with at least 2 plants between treatments. Each treatment
plot consisted of 5 plants, but only the 3 interior plants were in
cluded in the sample.
The 7 treatments were:
1 Check
2. 25% uniform defoliation
3. 50% uniform defoliation
b. 100% uniform defoliation
5. 50% uniform defoliation + 100% of the vegetative growing
points
6. 100% defoliation + 100% of the vegetative growing points
7. 0% defoliation + 100% of the vegetative growing points.


22
Table 7.
Estimation of
1978 season,
leaf loss by
as indicated
Florunner peanut plants during the
by weekly plant samples.
Week
from
Planting
No. of New
Leaves Grown
During Week
Sum of
Leaves Added
Each Week
Actual Mean No.
Leaves Present
Plant 1 2 SE
of
per
Est¡mated
No. of Leaves
Lost to date*
3

10.8
10.8 + 2.2

4
7.4
18.2
16.8 + 2.7
1.4
3
11.8
30.0
28.0 + 6.2
2.0
6
24.0
54.0
60.8 + 12.5
6.8
7
36.5
90.5
80.7 + 17.2
9.8
8
41.8
132.3
109.7 + 28.0
22.6
9
50.8
183.0
164.1 + 36.5
18.9
10
30.7
213.7
162.7 + 40.2
51.0
11
35.5
249.2
223.1 + 66.2
26.1
12
50.0
299.2
277.8 + 48.4
21.5
13
20.7
319.9
280.3 + 64.6
39.6
14
20.7
340.6
261.5 + 63.8
79.1
15
3.0
343.6
276.5 + 49.0
67.1
16
0.0
343.6
229.7 + 33.8
113.9
17
0.0
343.6
306.0 + 45.6
37.6
18
0.0
343.6
286.0 + 72.4
57.6
20
0.0
343.6
226.7 + 38.1
116.9
-'Column 3 Column 4


SU.')¡3HUT I Nil >IIZHA2
COMMON /GCO A ?./ Df>{ 1 0 0) DDL ( 1 00 ) .DfFUL ,OTN()W, I GEES L.F LAG (00 ) Nr LAG.
1 NNr'OD, NNEGS NNEQT SS ( 1 0 0 ) SSL ( 1 00 ) T TNH X
C (jMMON /UCOM 1 /NOEXI NOT. X2 .NDEX 3 NDl.XG NO* PT GY N 7 > PT5 RUT < 7 ) .
1 ASPGST ( 7), DA Y INC. J,MERGE .MORROW
COMMON /UCDA6/CL 13 AT(200,6 )
REAL MAX, MIN
DATA GLIM IN. IMPORT .OAYdEG/OO.0.90.O. 20. 0/
MAX = CL IMA T ( NOW ,2 )
MIN = CL IMA( NO W,3)
IF
(MIN.LT.GETMIN)
I I! J
= GETMIN
IF
(MAX.LT.GET MI N)
MAX
= GET MIN
I F
( MAX .GT T 1POPT)
MAX
= TMPOPT
DEGREE (MAX 6 MIN) / 2.0 .GETMIN
PAYINC = DEGREZ / OAYDEG
SS(2> = G>L(2) 6 PAYING DTNDW
RETURN
END


1^7


\U3


IF (PEG NO(J,K).EG.0.0) GO TO 5 30
IF (POOWGT { J,K ) .GT.IMiiCAlM J.K) ) GO TO 510
POOS I 2 = 0.17 PODCAP(J.K)
IF ( PQOAvGE ( K ) .GT. AGEMAX ( J K ) A NO. PODWCJT ( .), K ) .L 1 PUDS I L ) GO TO 527
IF (PUOWGK J,K).LT.PUI)SI2) GO TO 525
IF ( PDOhGT ( J.K) GT .0 .clFPOOCAPi J. K ) ) GO TO 5.26
520 COOT INUE
PONUTS(J)
GO TO 530
-
P0NUT5(J)
F
PLGMO J
. K >
*
6RRATL
52 5
CONTINUE
WANT 1 = P
on
512 POO W
GT
(J.K)
H\ N T 2 = (
1 0
.0 J.2 5
A
POO WG T( J
. Is ) )
*
DAY 1NC
WANT = AM IN 1 (WANT 1 ,WA
NT
2)
POPOOS! J)
GO TO 530
-
POPOOS(J)
F
PEGN 1 (J
. K )
*
W AN 1
52 5
PQNUT5{J)
PQNU1S(J )
F
PEGNO(J
. K )
*
GURAT E
52 7
CONTINUF
5 10
CONT INUE
600
CONT I MUE
>0 5:3 0 J
_
1.MERGE
WNTNUT (J )

PONUTS(J )
*
PC TC /
O1LFAC
wn r poo(j >
r.
POPOOS(J)
*
PiJOC
IF ( WNTNUT( J) LE. XL I MT( J> ) GO TO 610
PEGOEDJ ) Pl-.GDEO(J) F 1.0
fttO'lUl (J) = XLIMT(J)
WNTPOO(J) = 0.0
IF ( PFGDFI) ( 1 ) Oil > ) GO TO 5 0 1
POOLM = XLMMAZ
MDCXJ = 2
00 60 K = KPEGGT.MORROW
GO 1LOO A7A J.K) = 0.0
601 CONTINUE
610 CONTINUE
5 3 5 0 0 5 4 0 I = ] N )W
IF (NCOUNT( I ) .60.0 ) GO TO 540
IF (PMZOAY( I ) .GT .32.4 > GO TO 540
WNTGTM(J) = WNTSIM(J) F XI NOOL ( J I ) AODGTM DAY INC
540 CONTINUE
A WANTLIM J I F WNTGTO(J) F WNTPO!)(J> F WNTSTM(J)
i = PTSYM(J) WNTNUT(J)
I F ( NDEX 1 .1- T .4 ) A = A WAN TL ( J )
IF ( Morix 1 L T .4 ) 0=1- WANTLf'(J)
IF (A.LF. 1.030 1) 6 0 TO 5 50
AVLCONI J > = 1 / A
GO TO 560
550 AVLCON J ) = 0.0
560 CONTINUE
IF (AVLCOIH J) .GE.1 .0 ) AVLCON(J) = 1.0
O'
-^i


13
Second Experiment
In this experiment 11 rows of plants were used. Sample plants
were selected from rows 2, 4, 6, 8, and 10. The other rows were left
undisturbed. Three weeks after planting, healthy plants which had a
healthy plant on each side were selected, numbered, and marked with a
flag. There were always at least 2 plants between sample plants. A
random number table was used to select the plants to be harvested each
week. Nine or 10 plants were harvested 3, 5, 6, 7, 8, 9, 10, 12, 13,
and 20 weeks after planting. On weeks 11, 14, 15, 16, and 18 the con
trol plants from the defoliation experiments performed in the same
field were used in determination of plant growth for those weeks. Each
week 3 plants were marked in a manner similar to that described in the
first experiment, and the plants were harvested the following week so
that number of new leaves, stems, and pods could be determined on a
weekly basis. These 3 plants were mapped as to location of branches,
both reproductive and vegetative, old and new leaves, and pegs and
pods. Old and new leaves were counted and weighed. A 50 or 100 leaf
let sample was measured for determination of specific leaf weight.
All the plants harvested each week were taken apart and leaves,
P1-P5, and growing points were counted. All stems were measured and
dry weights were obtained for leaves, stems, roots, vegetative growing
points, reproductive branches and pegs, petioles, P3-P5, and kernels.
Beginning when the plants were 6 weeks old, canopy interception of
photosynthetica11y active radiation (PAR) was measured periodically in
the following manner: a metal track 3 cm wide with 3 cm sides was in
serted perpendicular to the row between plants and a pyranometer^
k
Lambda Instruments Corporation, Lincoln, NE.


128


2 nodes below the destroyed tip was vegetative, a new branch would grow
out of the end of the former branch, with only a scarred stub over to
one side to mark the end of the original branch and the beginning of the
new. The branching pattern of this new stem was that expected for a
vegetative branch, there being no leaf at the first node. If the 2
nodes directly below the destroyed tip were both reproductive then a
flower would emerge at both nodes, but there would be no vegetative
growth.
Table 14 is a summary of the light interception results for this
experiment. The weather was unsuitable for taking measurements for
several days prior to harvest and it was therefore not possible to make
as many readings as necessary to obtain an accurate picture of LAI ver
sus percent light interception.
Second Defoliation
Tables 15 and 16 are summaries of the results for plants harvested
at 11 and 15 weeks, respectively. In the removal of all the leaves
from the outer 50% of the canopy in treatments 3 and 6, more than 50%
of the leaf matter by weight was removed. Two weeks after treatment,
plants defoliated 50% uniformly had as many new leaves as non-defoli-
ated plants, and the ratio of stem weight to length was significantly
reduced. Plants from which the exterior 50% of the canopy was removed
had significantly more leaves than non-defoliated plants. They also had
significantly more new vegetative growing points and a significantly
reduced stem weight to length ratio. Weight of new leaves was also
significantly higher. A study of the plant maps indicated that the new


9
rate of photosynthesis by Bhagsari and Brown (1973) In an expanded
study of 31 peanut genotypes, Bhagsari and Brown (1976) again found
Florunner to have the highest photosynthetic rates. Pallas and Samish
(197*0 also found Florunner to have one of the highest rates of photo
synthesis of the extensively cultivated varieties. Even though their
plants were grown at low light intensity, they did not photosaturate at
the highest light intensity tested, which was slightly less than full
sunlight.
Pallas and Samish (197*+) noted that the photosynthetic rate of an
individual peanut leaf dropped after it was 3 or *+ weeks of age. Henning
et al. (1979) obtained similar results, with younger leaves exhibiting
higher apparent photosynthetic (AP) rates. In addition, they noted that
the mean AP rate decreased in a nearly linear fashion with increasing
plant age from 80 to l*+0 days. Trachtenberg (1976) found that leaf net
photosynthetic rates increase with leaf age until peanut leaves are
less than 2 weeks old, then decline with leaf age. The P (theoreti-
max
cal maximum photosynthesis) for individual peanut leaves in his experi-
2.
ment was calculated at 77 mg CO2 dm hr' and the Pmax for leaves
over 6 weeks old was *+3.5 mg CO2 dm"2 hr-'.
Gautreau (1973) found that differences in climatic factors greatly
affected the growth of all plant parts. He felt that differences in
light intensity were particularly responsible for differences in length
of stem internodes and of the mainstem and other branches. Cox (1978)
determined that mainstems were quite elongated under low light treat
ments and the number of flowers was markedly reduced. Hang An (1S78)
found that shading affected flowering, pegging, and size of fruit load.


NOW PT SYN ( 7 ) P T SR UT ( 7)
MLOCK DATA
COMMON /UCO Ml / MDEX 1 NDEX2 N Dr!X .3, NDKX
1 A SPG S T ( 7) DA Y 1 NC J ML' RG I MOP HO W
COMMON /UCOM2/UF TI ME. T I MI L F
COMMON /UCO Mi/ 1ST EM( 7,300 ) NO )L ( 7,350 J XL IE A F N ( 7),SIZELF(7,200) .
1 WTLEAF ( 7,20 0 ) W T I NOD ( 7,2 00) .W1 PC T( 7.200 ) ARE ALF ( 7 ) ,
2 W 3 Pi) AY ( 20 0 ) A GR PT S ( 7 )
COMMON / UCO 3 7/ST MM 2( 20 0) wTLEM 2( 200 ) (j E P T 3 M ( 2 0 0 ) XNOLFM (200) .
1 TOTM2 (200 ), PIEN) T M( 200 ), F RU I TM ( 200 ) US TP DM ( 2 0 0 ) M 5 TERM (2 00)
2 PCG SM2 (200) ROT PM2 PNR1 PM ( 200 ) ,UL GCMM(200 ),XL A I (200) ,
3 ID AY ( 20 0 ). ROOT M2 ( 2 00 )
COMMON /UCOMU/PROPOR(7) ,DAY A ) >
COMMON /UCO 3 S/PE NU TZ ( 7 ) F RU I T ( 7 ) ,11 STPOIX 7 ) ,UGTF RT(7) ,PEGS(7) ,
1 R ( 7 ) PNMIPE(7 > PET W T(7)
COMMON /UCO M1 0/X3ATUR,PLTOAY
COMMON /NCtiM 1 1/STRESF
COMMON /UCI1M1 2/PL TL A I PT 3
COM ION /UC M 1 3/PN 200)
COMMON / UCO I 14/IMERGE 7)
C O M M 0 N / U C O M1 5 / S T L F U T
COMMON /UCOM 16/PORT( 7)
COMMON /UCCMl 7/XLIMT (7)
COMMON /UCOM1/ASPGEN(7)
COM ION /UCOM1O/PHZOAY( 200)
COM AON /UCU320/W ANTL K 7 ) NU.MOR 1 / ) X l NODE ( 7, 200 )
COMMON /OCOM21 /POOVkGTi 7 ,200 ) MORE,OLOOMZ(7 ,200 ) ,KPEGST.
1 P EGflll ( 7,20 0 ) PODST ( 7 ) ,.'I)I)CAP ( 7, 20 0) A GEMA X( 7.2-00) GRA TC K ,
2 KPODS T GRRATE .PQP0D5 ( 7 ) PQNUT S ( 7 ) POOAGE( 200 )
COMMON /UCO3 22/NC*VEG( 7,200) ADOLF
CGMMON /UC ) 123/ST MM £N( 7 ) ,ST ML US( 7 )
COMMON / OC O M2 4 /XNONOD ( 7 ) NCO.JNT (200 ) SUR F AC ( 7,20 0 ) VLGGRD ,
2 VE >N I T VE'GNCR A 5VEG V IGC NR PORLF I'OliPT POP NOD 3 l. W
/UCO M3 6 / W GT l)N 7(7,200 ) LAN J T R AT IO, PT SS
COMMON
COMMON
COMMON
COMMON
COMMON
COMMON
COMMON
COMMON
COMMON
/UCO M20/I.C0UN T( 7.350 )
/UCO M30/CONDEF,DEFT I M
/UCO M3 1/ROTF,SMAINF
/UCO 332/AMTLT 300)
/U CO M3 3/ Pi )0 L M XL M M A Z
/UCOM34/CFFL A 1 (2 00)
/UCO3 05/NOE X6
/UCOM37/NDEXO
IT YPE
rommon /urn 34o/storc 200 )
COMMON /UCOM51 /CONGRO
COMMON /UCOMOO/TOTEAT
DATA TOTEA 1/0.0/
DAI A PL T DAY/ 1 4 ./
DAI A jTRESF/1 0/
VJ3
O


60
were obtained from the results of the experiments dealing with normal
plant growth. After the model simulated normal plant growth satis
factorily, the defoliation experiments were simulated. These simula
tions produced some unrealistic results, such as too much pod growth
and too little stem growth following defoliation, and thus further
changes were made in the model so that it satisfactorily simulated not
only the growth of the non-defo1iated plants, but that of all defoliated
plants as well. The changes generally pertained to parameters or
processes for which there were no data available for direct calculation
of va 1ues.
Description of the Model
PMINUS is programmed in GASP IV, a combined continuous/discrete
FORTRAN based simulation language (Pritsker 1974). The short main pro
gram reads the climate cards for the growing season (which contain daily
values for radiation, maximum and minimum temperatures, and rainfall and
irrigation) and then calls the executive subroutine GASP, which handles
the calling of the other subroutines. A brief description of the user-
written subroutines included in PMINUS is given in Table 23. PHZDAZ
and RUTNOD are the same as their counterparts in PENUTZ except for
minor changes. The subroutines PTOTAL, PLTGRO, DIVIDE, and FRUFIL are
adapted from subroutines of the same name in PENUTZ but differ in some
major respects. INTLC, EVNTS, SCOND, STATE and OTPUT were added to con
vert PENUTZ from straight FORTRAN to GASP IV. BEGIN, LEAVES, GRPTS,
STEMS, and PNTLAI are new subroutines which calculate the growth of the
vegetative portions of the plant. INSECT and ATTAC simulate the effect


93
which all leaves and all vegetative growing points were removed. In
this case the model underestimated leaf growth as well. It may be that
the plants in the field were able to draw some carbohydrate from stems
to make leaves. In the model, leaf and stem demands are so high in
comparison to available photosynthate that there is no storage of car
bohydrate in the stems until week 8.
The simulated number of new leaves initiated after treatment was
within the confidence interval (+_ 2 SE) for the experimental mean
except in the case of plants defoliated 0 or 50% from which the vege
tative growing points were removed. This can probably be attributed,
at least in part, to a failure to remove all of the small new leaves
beginning in the axils of fully grown leaves.
Tables 27 and 28 are comparisons of field results and model pre
dictions for plants defoliated at week 9- Figures 10 and 11 are graph
ical representations of the comparisons for LAI and pod dry weight.
The simulated values for all plant variables are within the 95% confi
dence intervals for the experimental means except for the number of
pods at 15 weeks on plants from which all the leaves were removed from
the outer half of the canopy. In this case simulated pod weight was
also somewhat higher than the experimental mean, but it was well within
the confidence interval. For this experiment there was a good corre
spondence generally between simulated and field results in weight of
new leaves and gain in stem weight.
Comparisons of model predictions with field results of the week
12 defoliation are summarized in Tables 29 and 30 and Figures 12 and
13- There is again some problem with matching number of pods/m^.


Leaf Area Index
Figure 2
Simulated and experimental leaf area index for Florunner peanuts planted on 2k May 1978.


90
80
70
60
50
40
30
20
10
0
_J I
1.0 2.0
_J I I l l I
3.0 4.0 5.0 6.0 7.0 8.0
Leaf Area Index
1. Relationship between leaf area index and percent light interception for Florunner peanuts planted
on 24 May 1978.
OO


APPENDIX 4
DESCRIPTION OF MODEL PARAMETERS


63
of an insect invasion and defoliation on the plant. Flow charts of
the major subroutines are contained in Appendix 2. A complete listing of
PMINUS is given in Appendix 3, a description of model parameters in
Appendix 4, and a glossary of input parameters and variable names in
Appendi x 5-
PMINUS computes growth on a square meter basis. The growth of an
average plant is calculated each day and this is multiplied by the num
ber of plants/m^ to determine growth/m^. In actuality, program storage
and model structure are such that up to 7 plant types may be simulated.
Growth/m^ is then calculated by multiplying the amount of growth of
plants of a given type (l~7) by the number of plants of that type/m^,
and then summing over all 7 plant types. This structure was originally
devised so that seedling emergence could be spread over several days,
giving plants of different sizes. It could also be used to simulate
the effect of uneven defoliation over a field.
Subroutine STATE is called by GASP on a daily basis and it in turn
calls the other subroutines to calculate plant growth each day. Most
plant growth processes are dependent upon physiological time, which is
calculated each day by PHZDAZ. The daily minimum and maximum tempera
tures are used to compute the number of physiological days in a given
calendar day. One physiological day equals 75F. If the average of
the maximum and minimum temperature is greater than 75F then there is
more than 1 physiological day in that calendar day. There are an aver
age of 1.2 physiological days per calendar day during the summertime in
this part of Florida.


APPENDIX 5
INPUT PARAMETERS AND
VARIABLES DESCRIBING THE DYNAMICS OF
PEANUT PLANT GROWTH
Input Parameters
CL I MAT(1,1) total radiation on day I in langleys
CLIMAT(!,2) maximum temperature on day I, to the nearest F
CLIMAT(l,3) ~ minimum temperature on day I, to the nearest F
C LI MAT(1,4) rainfall and irrigation on day I, 0.01 in
CL I MAT(1,5) not used
CL1 MAT(1,6) Julian day
CONDEF proportion of leaf matter left after defoliation (1.0 -
portion defoliated)
C0NGR0 proportion of active vegetative meristems destroyed by an insect
attack
DEFTIM number of days from planting until defoliation begins
EMERGE number of physiological days from planting until plants start
to emerge
NTYPE an indicator of type of defoliation (1 = uniform throughout the
canopy, only fully developed leaves; 2 = outer portion of canopy;
3 = uniform + partially formed leaves + vegetative meristems)
PLTDAY Julian day of planting
PLTPOP number of plants/m^
198


26
Table 9. Results of linear correlations of stem size to plant age and
plant size
for
F1orunner
peanuts.
Dependent
Variable
Independent Variable(s)
~rT~
Ratio of
stem weight
to
1ength
Week of the season
0.78
Ratio of
stem weight
to
1ength
Total stem length
0.40
Ratio of
stem weight
to
1ength
Week of the season,
total stem length
0.78
1 nternode
we ight*
Week of the season
0.80
Internode
length**
Week of the season
0.67
Internode
weight*
Number of leaves
(internodes)
0.46
*lnternode weight was estimated by dividing total stem weight by the
number of leaves on the plant.
''"Internode length was estimated by dividing total stem length by the
number of leaves on the plant.


LIST OF FIGURES
FIGURE PAGE
1 Relationship between leaf area index and percent
light interception for Florunner peanuts planted
on 2k May 1978 28
2 Simulated and experimental leaf area index for
Florunner peanuts planted on 2k May 1978 80
3 Simulated and experimental change in leaf numbers
for Florunner peanuts planted on 2k May 1978 8l
k Simulated and experimental leaf growth for
Florunner peanuts planted on 2k May 1978 82
5 Simulated and experimental stem growth for
Florunner peanuts planted on 2k May 1978 83
6 Simulated and experimental changes in pod numbers
for Florunner peanuts planted on 2k May 1978 8k
7 Simulated and experimental pod growth for Florunner
peanuts planted on 2k May 1978 85
8 Simulated and experimental change in number of
fully expanded pods for Florunner peanuts planted
on 2k May 1978 86
9 Simulated and experimental growth of fruit filling
seeds for Florunner peanuts planted on 24 May 1978. 87
10 The simulated and experimental effect of 50% uni
form defoliation at 9 weeks after planting on LAI
(a) and pod dry weight (b) 96
11 The simulated and experimental effect of removal
of all leaves from the outer 50% of the canopy at
9 weeks after planting on LAI (a) and pod dry
weight(b) 97
12 The simulated and experimental effect of 50% uni
form defoliation at 12 weeks after planting on
LAI (a) and pod dry weight (b) 100
VI i i


i*
Of the 3 general approaches for partitioning growth into crop
components discussed by Jones and Smerage (1978), the morphogenetic
approach seemed the most applicable for the purposes of this study. In
this view of growth, individual plant organs (such as leaves and pods)
are initiated and grow for a finite time. Potential growth rates of
individual organs are calculated, sink demand is calculated for each
crop component, and growth is limited by substrate availability. A
tobacco model (Hackett 1972) and several cotton models (Stapleton and
Meyers 1971, McKinion et al. 1975, and Jones et al. 1980) have used the
morphogenetic approach to partitioning.
Duncan's PENUTZ model is based on the philosophy that the peanut
plant partitions a certain amount of the available photosynthate to the
reproductive portion of the plant and that this amount varies with cul
tivar. Since it calculates pod demand each day, it was only necessary
to add the initiation of vegetative organs and the calculation of vege
tative demands each day to develop the morphogenetic model, PMINUS, from
PENUTZ. As there were insufficient data available in the literature to
do this, experiments were designed to provide information on initiation
and rate of growth of leaves and branches and the weight and area of
individual leaves throughout the season on plants without insect damage.
The development of stems, roots, and pods was also followed in these ex
periments so that model predictions of plant growth could be verified.
Since Florunner is the most commonly grown cultivar in the United States
(Duncan et al. 1978), it was used in all experiments. These experiments
dealing with the normal growth of non-defoliated plants are discussed in
Chapter I I.


'iUUHOUT INC WATtIRX
COMMON / ijC DM2./ OO ( 1 0 0 ) DDL ( 1 00 ) OTf-UL .0 TWO W I SEE 5 LF LA G ( 50 ) NFLAG .
1 NNFOO NNcQG, NNFQT, S5 { 1 0 0 ) SSL( 1 0 0 ) TTNEX
COMMON /UCOM1/NDEX1 ,NOEX2.NDEX3,NOEX5.NOW,PTSYN(7) ,PTSRUT(7)
1 ASPOSr (7 ) ,DAY INC. J, 1ER C.E M OR NO W
COMMON /UCO 16/CL I MAT(TOO ,6)
COMMON / U COM 1 1/STRE5F
RETURN
CN O
CTN
o


xml version 1.0 encoding UTF-8
REPORT xmlns http:www.fcla.edudlsmddaitss xmlns:xsi http:www.w3.org2001XMLSchema-instance xsi:schemaLocation http:www.fcla.edudlsmddaitssdaitssReport.xsd
INGEST IEID EZTJ3BZ5Y_5YJ9UZ INGEST_TIME 2015-03-27T19:05:36Z PACKAGE AA00029794_00001
AGREEMENT_INFO ACCOUNT UF PROJECT UFDC
FILES


CHAPTER I I I
THE EFFECTS OF DEFOLIATION ON PEANUT PLANT GROWTH
I ntroduction
There have been several studies on the effect of various degrees
of defoliation upon final yield in peanuts. There is little in the
literature about the physiological response of peanut plants to leaf
remova1.
Greene and Gorbet (1973) defoliated Florunner peanuts with a mow
ing machine, approximating 10-15, 20, 33, and 50% defoliation by
changing wheel settings. They found that 33% defoliation at several
growth stages decreased yields. Since their method of defoliation also
removed petioles, stems, and pegs and cut across major trunks of the
vascular system of the plant, their results are not applicable in de
termining the effect of foliage-feeding insects upon the plant.
Enyi (1975), working in Africa, performed defoliation experiments
on the Dodoma edible variety of peanuts. In this experiment, flowering
began A weeks after sowing, pegging at 8 weeks, and podding at 11. He
removed either 50% (2 of the 4 leaflets on each leaf) or 100% of the
foliage at weekly intervals (plants were defoliated only once). Plants
were harvested at the end of the season and dry weights for stems, pods,
and seeds determined. Complete defoliation significantly reduced ker
nel weight and pod number, the greatest reduction occurring when leaves
were removed 12 weeks after sowing. Complete defoliation also reduced
weight of pods, dry weight of stems, and individual kernel size. Half
29


121
Solar
Radiation, Temperature (C) Rainfall and
'ay
1ang1eys
Max.
Min.
Irrigation
1 October
306
28.9
17.2
2 October
456
28.9
16.1
12.7
3 October
485
29.4
19.4
4 October
308
29.4
15.6


Table 27. Comparison of model
vested at 11 weeks.
predictions with
field results for plants
defoliated at 9 weeks and
ha r-
Plant Variable
Treatment
Control
50% Uniform
Outer
50%, of
Canopy
Field*
Mode 1
Field*
Mode 1
Field*
Mode 1
Original LAI
4.0
(0.9)
3.6
4.6
(0.7)
3-6
4.3
(0.5)
3.6
LAI after defoliation
4.0
3.6
2.0
1.8
1.2
1.3
LAI at harvest
5.2
(1.1)
5.1
3.6
(0.4)
3.3
3.4
(0.3)
3.1
Leaf weight at harvest, g/m^
188.9
(40.1)
189.9
126.2
(15.3)
121.7
119.5
(n.o)
112.8
2
Weight of new leaves, g/m
41.7
(6.3)
53.5
50.4
(5.0)
51.1
66.1
(6.1)
61.6
2
Stem weight, g/m
212.4
(47.3)
221.9
213.4
(33.5)
192.4
218.0
(27.8)
162.8
2
Gain in stem weight, g/m
85.3
92.9
67.0
63.8
43.8
35.4
2
Number of pods/m
656.4(173.7)
598.7
697.6(121.0)
598.7
562.9
(64.3)
598.7
2
Weight of pods, g/m
118.1
(33.2)
109.0
91.5
(18.3)
100.2
70.3
(11.4)
79.2
o
Number of P4-P5/m
286.7
(72.4)
237.6
215.0
(44.4)
285.1
201.1
(25.8)
161.6
Weight of P4-P5, g/m^
112.3
(31.4)
87.5
81.5
(17.4)
89.1
62.6
(17.5)
57.2


CALL PLTGRD
riOTPM2 = o.o
PET =0 .0
TO SJ J = 1 MERGE
L>0
F WTROOT(J) PRDPOR(J)
WTSTEM1 J) PRUPOR ( J )
( > T M M I N ( J ) l'IUin.'lil J ) ) / 1 000.
F WSHTLF(J) F PPOPOR(J)
* AS f F XL [ A r N ( J ) HUOPflKl J)
F PENUT/J) F PROPOR(J)
F FiiUI T( J ) PRUPOR ( J >
F ULOOMZ ( J NOW ) <> PF-iOPOE ( J )
I IISTPOOtJ) PROP i ii J )
F IIS TR r ( J ) F IMOIOH ( J )
F PEGS ( J ) F PUSH MR ( J )
HO TP M2 = 1(0 TPM 1 {< c J PROPOR(J)
NH I PM( NOW ) = PNNIPM(N)W) P JN IPi\ ( J ) F PROPONJ)
PI'T = PE T PETWT7) PRUPOHJ)
GO CONTINUE
TOTM2UOW) STMM2INOW) f WTL FM2 ( NOW ) f fin I TM( MO.V ) F ROO TM2 ( : UJ W)
1 f PF
STLFNT = STM M 2! NO W > WTLF M2! NOW ) F PET
SS(1 ) = S 'SI (1 ) F PAY ADI) F DT NOW
SSI T) = SSL ( 1) F MAYADO F DTNOV
DAY ADD = 0.0
CALL ROTNOD
CALL PM TLA 1
30 TO 100
000 CONTINUE
ss!2) s:si_( .?)
DIG CONTINUE
Soil) = Sr.L(l)
S ( 1 ) = SDL ( 3)
200 CONTINUE
I DAY!NOW) = SD(2) F O.b
XL A I (NOW > = DD ( 3)
EFFL A I (NOW) DS( 1 )
DDO CONTINUE
RETURN
END
IF ( I MERGE! J ) .LE. 0) r,;j TO
ROOT M2 { NOW )
ST MM2 ( NOW)
STORE(NOW)
.v TLF M2 ( NO .<)
GRP TSMI NOW )
X NOLFM ( N' )W )
PE N'JTMI NOW )
F ROI T 1 (NO W)
3LOOMM(NOW)
OS TP DM! NO t)
h s r rr1(now )
PEGSM?(NOW)
= ROOTM2(NOW)
SI MM2(NOw) F
D T OR E ( N )W ) F
- WTLFM2(NOW)
= ORPTSM(NOW)
- XNOLFM(NOW)
- i*r: NUT M ( NOW )
= FRUITM = ULl'iClMM (NOW )
= 11S TPi) M ( NOW)
= 115 T FRM (NOW )
- PEGS M2 (IU1W)


\kO


Table 28. Comparison of model
vested at 15 weeks.
predictions with
i field
results for plants
defoliated
at 9 weeks and
ha r-
Plant Variable
T reatment
Control
50% Uniform
Outer
502. of
Canopy
Field*
Mode 1
Field*
Model
Field*
Mode 1
Original LAI
4.4 (0.6)
3.6
4.1 (0.7)
3.6
3.5
(0.4)
3.6
LAI after defoliation
A. 4
3.6
2.0
1.8
1.2
1.3
LAI at harvest
7.0 (0.9)
6.5
4.6 (0.6)
4.7
4.3
(0.3)
4.3
2
Leaf weight at harvest, g/m
257.1 (31.8)
236.3
183.5 (23.6)
166.5
157.8
(12.2)
154.5
. 2
Weight of new leaves, g/m
108.2 (12.1)
99.9
108.2 (13.9)
95.8
113.9
(9.1)
103.3
2
Stem we¡ght, g/m
345.7 (43.9)
298.3
272.1 (40.2)
278.6
243.6
(24.8)
249.0
2
Gain in stem weight, g/m
210.0
169.3
143.1
150.0
114.0
120.4
2
Number of pods/m
960.4(117.1)
959.8
781.1(141.8)
826.7
682.9
(61.2)
826.7
2
Weight of pods, g/m
479.4 (51.9)
435.2
394.4 (54.7)
412.4
354.0
(35.0
379.4
Number of P4-P5/m2
594.2 (69.8)
598.7
522.5 (68.6)
598.7
492.9
(47.9)
503.6
Weight of P4-P5, g/m2
469.6 (50.1)
422.6
388.6 (53.3)
405.1
349.6
(34.4)
360.6
Number in parentheses is standard error of the mean.


SUOROUTINE PTOTAL
O I MENS I ON AV GP T S{ 10)
COMMON /GCOM1/ AT R I O (2 5 ) J i: V N X ME A M P E ( 100 ) ML E( 100 ) MS TOP N CRON N
INAPO NN APT. NINA TR NNF It. I1NO (100). Nil TRY, NPRN T I'M* ARM (50 .4 ) T NOW T TUEG
2 r r clw r t f- in. r r r i j (2 5 >, t t set
COMMON /SCO M2 / DO ( 1 0 0) DDL ( 1 0 J ) D TFOL OT NOW, I SEES, LFL A G ( 50 ) NFL AS,
1 NNEOD, IINEO >, NNECI l, SSI 100), SSL ( 1 00 > T rME X
COMMON /UCn M 1 /NDEX 1 NOEX2 NDEX .1, NDF X 5, NOV* PTSYN ( 7 ) P T SR UT 1 7) ,
1 A Si> S S T ( 7 ) O A Y I NC J ME RGE MOR R OW
COMMON ZOOMS/ IST£M( 7, S50) NOTE ( 7, OSO) XLLAFNI 7) S I ZELL 7,20 0) .
1 WTLE AE (7,2 0 0 ) UT I NODI 7.20 0 ) WT PET ( 7. 20 0 ) ,AREAL E( 7 ) ,
2 WGlITLf ( 7 ) WT 5TF M( 7 ) XiiLE AF I 7 ,2 00) WTROOT (7 ) I COUNT (7 3 50 ) .
3 POAY(200),AGRPTS(7)
COMMON /OC0M6/CL I MAT (200, 6> )
COMMON /UCOMD/PROPUR( 7 ) O A Y A D )
COMMON /U C O M10/XM ATOP, PLT DAY
COMMON /OCOMl 1ZSTRESF
COMMON /DCOM 1 2/PL TLA I PTS
COMMON /UCOM13/PN(200)
CO MMON /UCOM14/I MERGE( 7)
COMMON/UCGM1 5/STLERT
COMMON /OCO Ml (S/POR T( 7 )
COMMON /OCOM1 7/XL IM T( 7)
COMMON /UCOM1O/AS JGEN(7 )
COMMON /OCO M3 1/ROO IF SMAlNF
COMMON /UCO M 3.5/PODLM, XL MM AZ
DA TA H STOY STDECL PTSSUM AV G >TS K AV G. AK/0 .3 J 1 1 ) 0 .0 1 0 =0.0, 6,
1 0.0/
DATA DECFCT/1.0/
DA TA PS LOPE ,PTSF AC RESPFC IJMF if C ,P AR FAC/0 .H3t.d-0 5, 1.10,
1 0.30,0.01,0.65/
DATA AVG/5./
DECR T!£ = (1.0 HSTCPY)/{XMATUR STOlfCL)
DECS T = TNOW STDcCL
IF ( DECST.LE.O .0 ) GO TO 9
DECFCT = 1.0 DLCRT.I DEC ST
CONT INOE
PTS = PL TLA I 1.0 E4 CL I MAT ( NOW, 1 ) PSLOPE PTSE'AC
PTS = PTS STRESF DECFCT
PI S = PTS PTS RESPFC M r_ TFC STL FR T
IF' (PTS.LE.0.0) PTS = 0.0
AK = AK 4 1.
AK = AM INI ( AK, AVG )
A V 3 P T S ( 1 > = PTS
PTOSUM = P T S SUM 4 AVGPTS(l) AVSPTS(KAVG)
PTSMEN = PT3SOM / AK
KL = KAVG 1
DO 50 I l.KL


Parameter
Descr¡pt¡on
Numerical Value(s)
Source
ADOLF
Amount of carbohydrate necessary for maximum
growth each physiological day by a growing leaf
and its attendant petiole and internode, mg
12.0
9.0
p.t. < 82
p.t. > 82
Table 3
ADDSTM
Amount of carbohydrate necessary for maximum
growth of a developing stem internode each
physiological day after the attached leaf has
ceased growing, mg
2.55
field results
AGEMAX(J,1)
Number of physiological days a developing peanut
initiated on day 1 on plant J has to complete
shell expansion--growth ceases is shell is not
fully expanded at end of this time period
k2
calibration,
field results
ASPPRO
Conversion factor for asparagine to protein in
the seeds
0.863
Duncan (197^
and personal
communication)
ASVEGF
Conversion factor for asparagine to protein in
the vegetative portion of the plant
0.786
Duncan (197^
and personal
communication)
BMETFC
Maintenance respiration coefficient
0.01
Duncan (197^
and personal
commun¡cation)
CONS 1
Number of physiological days between flower and
beginning of pod expansion at a reproductive
27.0
ca1ibration,
field results


103
2
The weight of new leaves/m is lower for the simulated removal of
all leaves from the outer 50% of the canopy at 12 weeks than for the
field experiment (Tables 29 and 30). This is due to the fact that in
the model developing leaves may only draw carbohydrate from storage if
the LAI is less than 2.0. Even though leaves have priority over stems
and expanding pods if the LAI is below 2.5, at this point in the season
there is a sufficient number of developing seeds to use all of the
photosynthate produced by the defoliated plants on most days. It
would appear from the differences in stem weight gains between the field
experiment and the simulation that in actuality the plants can draw
upon reserves to a greater extent than is allowed in the model. I
used the 2.0 LAI limit for drawing upon stem storage because it worked
well for the defoliation experiment at 9 weeks (Tables 27 and 28) and
because higher limits caused the plants defoliated at 9 weeks in the
simulated experiments to seriously overshoot the LAI of the field
plants defoliated at 9 weeks and harvested at 15 weeks. In order to
use the higher limit, which would work better at 12 weeks, it would be
necessary to change the method of inactivating growing points in the
model, making it dependent upon some factor other than the weight/leaf
of the leaves completing development on a given day. The fact that the
specific leaf weight and size of new leaves are essentially the same
for the check and defoliated plants for the last 3 experiments (Table
31) indicates that once a leaf is initiated it gets as much photosyn
thate as it wants, if at all possible. Therefore, growing point in
activation should probably not be tied to leaf size. This is something
which needs to be investigated further.


51
Table 19. The effect of 50% defoliation at week 12 upon plant size at
week 16.
T reatment
Plant Variable
Check
50% Uniform Outer
50% of Canopy
Number of new leaves
22.3b
26.5b
55.0a
Weight of new leaves, g
1 .6b
1.9b
3.7a
Ratio of stem weight to
length, mg/cm
23.4a
21.8ab
20.6b
Average cotyledonary
lateral length, cm
67.9a
65.9ab
60.6b
Number of new vegetative
growing points
5.2b
3.8b
8.9a
Number of PI
5.7b
13.0a
13.9a
Number of P5
44.4a
39-9ab
28.2b
Weight of P5, g
51.8a
46.9ab
33.8b
Kernel weight, g
40.5a
36.7ab
27.2b
Total plant weight, g*
125.6a
1 10.5ab
90.5b
Note: Means in a row followed by the same letter are not significantly
different according to a t-Test (a = 0.05 except for plant variables
marked with an *, in which case a = 0.10).


POD DRY WEIGHT, g/m2 LEAF AREA INDEX
114
Figure 17- The simulated effect on LAI (a) and pod dry weight (b) of
20 larvae/plant entering the field on day 35 and feeding for
26 days at an increasing rate.


TABLE PAGE
28 Comparison of model predictions with field
results for plants defoliated at 9 weeks and
harvested at 15 weeks 95
29 Comparison of model predictions with field
results for plants defoliated at 9 weeks and
harvested at 14 weeks 98
30 Comparison of model predictions with field
results for plants defoliated at 12 weeks and
harvested at 16 weeks 99
31 Specific leaf weights and average size of new
leaves grown in the 2 weeks following defoliation. .104
32 Comparison of model predictions with field
results for plants defoliated at 16 weeks and
harvested at 18 weeks 106
33 Comparison of simulated and experimental (Mangold,
1979) growth of Florunner peanuts in the 2 weeks
immediately following defoliation at 8 weeks 108
34 Comparison of simulated and experimental (Mangold,
1979) yields for Florunner peanuts defoliated at
various points in the season 109
v 1 1


APPENDIX 1
WEATHER DATA
FOR THE 1978 GROWING SEASON
Solar
Rad¡at ion,
Temperature
(0
Rainfall and
DAY
1ang1eys
Max.
Min.
Irrigation, mm
23 Hay
449
33.9
21.1
24 May
545
31.7
21.7
25 May
487
32.8
20.6
5.1
26 May
593
32.8
20.0
27 May
614
31.7
16. 1
28 May
566
31.7
18.3
29 May
533
31.7
18.3
30 May
550
32.2
20.0
5.8
3 1 May
397
32.2
19.4
1 June
550
32.8
20.0
2 June
392
31.1
22.2
6.3
3 June
292
30.0
21.7
25.9
4 June
277
28.3
22.2
8.8
5 June
368
28.3
21 1
6 June
485
31.1
22.2
7 June
540
31.1
23.3
.5
8 June
502
33.3
24.4
9 June
425
32.2
23.9
2.5
10 June
449
31.7
23.9
14.7
1 1 June
449
31.7
23.3
.3
12 June
461
31.1
20.6
13 June
576
32.2
23.3
1b June
456
31.1
23.3
7.9
15 June
464
28.3
20.0
16 June
519
30.6
18.9
17 June
619
30.6
18.9
18 June
614
30.6
17.8
19 June
507
30.6
22.2
20 June
313
29.4
22.2
21 June
406
32.2
21 1
10.2
22 June
447
30.6
22.2
1.0
23 June
578
32.8
22.2
2b June
478
34.4
20.6
26.9
25 June
600
32.2
22.8
26 June
597
33.9
22.2
27 June
571
33.3
23.9
28 June
497
35.0
23.9
29 June
554
35.0
23.9
30 June
600
35.0
23.9
118


59
in the model being developed. The handling of root growth and nitrogen
fixation in the model will be discussed later in this chapter.
Establishing rules for the division of carbohydrate and nitrogen
each day was less clearcut than determining potential growth rates for
the various plant organs. Although it was clear from the field data
(Table 2) that the pod load was set by the end of week 12, it was not
clear by what mechanism the size of the pod load was determined. Nor
was it obvious by what means the gradual inactivation of growing points
could be programmed, especially in view of the increased leaf growth
following defoliation. My overall approach to balancing supply and
demand was to assume that leaf demands were given higher priority than
most other demands when LAI, as an indicator of canopy light intercep
tion, was low; but that this priority was moderated by increasing pod
demands later in the season. Several different sets of priority rules
were tried before one which produced realistic simulations for both
normal and defoliated plants was found.
Insofar as possible, parameter values used in PENUTZ were used in
itially in PMINUS, the morphogenetic model derived from PENUTZ. The
results of the experiments dealing with normal plant growth were used
for estimation of new parameters involved in computation of leaf and
stem growth. When there was no experimental information available for
estimation of a particular parameter value, such as the length of time
a peg could remain in the ground before becoming incapable of swelling
into a pod, a value was chosen which gave a good visual fit between sim
ulated and experimental plant growth. Changes were necessary in some
model parameters taken from PENUTZ in order for simulated plant growth
to match that observed in the field. New estimates for these parameters


3
4
5
6
7
8
9
10
11
12
13
14
21
Number of new leaves per branch during the 1978 growing season,
as indicated by weekly plant samples.
Estimated Number of Active
Veg. Growing Points/Plant
4.6
7.8
16.4
26.8
30.1
34.6
28.0
31.3
39.1
17.8
20.7
Estimated Number of New Leaves/
Active Veg. Growing Point
1.6
1.5
1.5
1.4
1.4
1.5
1.6
1.1
1.3
1.2
1.0


Table 3-
Average
weekly
leaf growth
plant samples
for Florunner peanut plants
during the
1978 growing
season, as indicated by
Week
G rowth
of Leaves
During the Preceed
ing Week
Tota 1
F rom
No. New
Wt. New
Specific Leaf
Weight per
Number of
Total Leaf
Weight per
Planting
LA 1 *
Leaves
Leaves, g
Wt., mg/cm2
Leaf, mg
Leaves
Weight, g
Leaf, mq
3
0.04
10.8
0.2
4.66
20.4
10.8
0.2
20.4
4
0.08
7.4
0.2
4.92
28.4
16.8
0.4
25.6
5
0.16
11.8
0.6
5.05
50.0
28.0
0.9
31. r
6
0.73
24.0
2.0
3.66
81.2
60.8
3.3
54.6
7
1.49
36.5
3.6
4.00
99.3
80.7
6.5
80.3
8
2.05
41.8
3.4
3.68
80.4
109.7
8.7
79.3
9
3.62
50.8
5.0
3.73
98.1
164.1
15.0
91.7
10
3.49
30.7
2.6
3.78
84.1
162.7
13.8
85.1
11
4.97
35.5
2.6
3.27
72.1
223.1
17.6
79.0
12
6.55
50.0
3.5
3.09
69.2
277.8
25.0
89.9
13
5.68
20.7
1.5
3.39
71.1
280.3
21.7
77.4
Hi
6.23
20.7
1.6
4.02
76.4
261.5
24.8
94.7
15
6.43
3.0
0.2
3.17
50.0
276.5
24.7
89.3
16
6.09
3.3
0.2
3.51
60.0
229.7
22.8
99.3
17**
6.75
0.3



306.0
26.7
87.2
18
6.24
0.0



286.0
25.4
88.7
20
5.15
0.0



226.7
24.3
107.2
'-Leaf area index.
"Only 3 plants harvested this week.


68
average specific leaf weights for weeks 35, 6-10, and 11-16 (exclud
ing week 14), respectively (Table 3)- These specific leaf weights are
used for defoliated as well as non-defoliated plants.
Division of Day's Net Photosynthate
The amount of carbohydrate allocated to the roots each day for
root growth and nitrogen fixation depends on time in the growing season.
The roots receive 15% of the day's net photosynthate for nitrogen fixa
tion for the first 82 physiological days, and 13% thereafter. The
additional amount allocated for root growth is 28% until week 4, 15%
from week 4 until week 7, and 0% thereafter. The decision to allocate
15% to roots from week 4 until week 7 for root growth rather than the
lower amount indicated in Table 24 was based on balancing top growth
during this time period against photosynthetic supply. Allocating at
least 12% of the net carbohydrate to roots for nitrogen fixation pre
vents any nitrogen shortage from occurring, if 100% efficiency of con
version is assumed.
The remainder of each day's photosynthate is apportioned according
to demand from leaves, stem internodes, seeds, and expanding pods.
Leaf demand for carbohydrate is based on the number of developing
leaves and the amount each leaf can add on a given day. Demands for
the attached petiole and internode are also calculated and included in
the leaf demand variable, WANTLF. Maximum new leaf size is set at 88
mg, the average weight per leaf for new leaves for weeks 6-10 (Table
3). Leaves grow for either 10.8 or 14.4 physiological days, depending
on the point in the season, and thus leaves and petioles only demand
carbohydrate for that length of time. Stem internodes continue to


72
are filled. The model keeps track of potential new growing points each
day and each one is allowed 3 days to be activated. If there is in
sufficient photosynthate to activate it within this time, then it is
relegated to the permanently inactive file of growing points. Once
there are 333 vegetative branches, no new growing points may become
active, except in the event of severe defoliation. Growing point ini
tiation is cut off when ELAI reaches 2.5, even if there are fewer than
333 vegetative branches.
Any carbohydrate left after new branches are initiated goes to
meet stem internode and expanding pod demand. When ELAI is above 2.5,
any shortage in carbohydrate supply is allocated uniformly to leaves,
stems, and expanding pods. Older pods have priority over younger ones,
although PENUTZ and PMINUS are set up so that older pods can be given
from 0 to 100% priority.
PENUTZ was structured so that if a nitrogen shortage occurred, at
any time, the rest of the day's carbohydrate supply would be allocated
to the roots to fix nitrogen. This feature was retained in PMINUS, but
the amount of carbohydrate allocated to roots is set sufficiently high
that a nitrogen shortage never occurs.
Calculation of Increases in Total Dry Weight per Unit of Carbohydrate
The ratio of carbohydrate to nitrogen and the proportion of total
weight which is either carbohydrate or nitrogen are different for
different plant structures. In PENUTZ, Duncan assumed that 12% of
leaf, stem, and shell dry weights was protein, 85% was carbohydrate,
and 3% was other constituents. For nuts he assumed that 25% of total
dry weight was protein, 50% was oil, 20% was carbohydrate, and 5% was


Table 15. The effect of 50% defoliation at week 9 upon plant size at
week 11.
T reatment
Plant Variable
Check
50% Uniform Outer
50% of Canopy
Number of new leaves
52.9b
56.7b
86,8a
Weight of new leaves, g
4. 4b
5.3ab
7.0a
Ratio of stem weight to
length, mg/cm
21.3a
18. lb
18.7b
Number of vegetative
growing points
*9.6b
58.lab
72.2a
Number of new vegetative
growing points
14.4b
14.1 b
25.9a
Number of PI*
19.3b
27.lab
35.1a
Number of P5
19.8a
1 3.9ab
7.7b
P5 weight, g
9.9a
7.0a
4.0b
Kernel weight, g*
6.0a
4.2ab
2.6b
Note: Means in a row followed by the same letter are not significantly
different according to a t-Test (a = 0.05 except for plant variables
marked with an *, in which case a = 0.10).


IF (fDAY( I ).LT.MFTIM2) GO TO l 60
DO 149 J = 1.MERGE
NKE EP .VTLEAFt J, I )/SI 2MIN X INUOIIU, I )
XKEFP = NKEEP
IF ( XKEEP. GT .X INODE ( J I ) ) XKEEP = XlNOUE(J.l)
XOPOP = XI NODE! J, I ) XKEEP
N=NUMUR { J )
IF ( N > 149.149,118
113 DO 149 K = 1,0
IF ( I STFM( J.K ) .NE / ) GO TO 70
IF ( PDA Y ( I ) .LT .T l MEI.F ) GO TO 70
IF ( ICOUNTI J ,K ) .ED.I ) AGRPT5IJ) AGRPTG(J) 1.
7 0 CONT I NOF.
IF ( 1 *',TEM( J K) G.I. 5 ) GO TO 149
IF (PDA Y( 1 ) .LT.TIMELF ) GO TO 10
IF (LCnUNT(J.K) I) 14 9,121.149
1 2 1 MO I SHI-A ( J K)
NODE ( J K ) = NU.)E(J.K) T 1
L = NOOE(J.K)
IF
( L- 3)
14 3, 122.122
1 2 2
GO
TO ( 1
2 3, 1 30, 140, 1 46), MN
1 2 3
IF
( L7 >
126,148,143
126
NUM3R(J)
-- NUMOR(J) f 1
AGHPTS(J) = AGOPTS(J) F 1.
I STEM! J,NOM3H1 J) ) = 3
NODE < J NUMO. ( J ) ) = 1
I COUNT ( J NOM 3R ( J ) ) = NOW
XNLEAF(J,NOW) XNLEAFlJ,NOW) F 1.
XINODE! J .NOW ) = XI NODE( J,NOW) 1.
GO TO 143
130 IF (L-6) 141,12*3,142
12 3 NUMOR(J) = NUMUR(J) F 1
IS T E M(J NOMORJ ) ) = 6
NUDE ( J NON OR ( J) ) = 1
I COUNT ( J.NiMi Jf< ( J ) ) = NOW
OLCOMZ ( J NO V ) = LOOMZ J NOW ) F 1.
IF (KPCGST.EQ.0) KPEG6T = NOW
GO TO 143
141 IF (L-4) 143,143,143
143 IF ((((LH)/2)/2)2 KL4D/.0) 14 4,143,144
14.3 NE JVEG J NOW ) = NLWV EG( J MOW ) F 1
IF ( NOE X 3 G T 0 ) GO TO 14 !3
NU.M\3K(J) = NOM3IUJ) 1
AGR"*I S( J I = AGRPTS(J) FI. ~
I STEM* J ,NUM.3W( J) ) =4 -c-
NODE(J.NOMUR(J)) = 1
NF WVEG ( J Mf'V ) = NEWVEG J NOW ) -
ICOUN I ( J NUN IP ( J ) ) NOW
1


Table 20. Summary of light
interception by plants
defoliated at week 12.
T reatment
Row
LAI Immediately
After Defoliation
% Light
1n te rception
After Defo1 i ation
LAI at
1*4 Weeks
% Light
1 nterception
at 1*4 Weeks
Check
J
*4.8
90.7
5.1
91 .6
K
3.1
85.2
3.3
75.2
L
7.3
92.9
7.5
92.6
M
7.1
92.6
7.3
90.6
50% uniform
J
2.3
69.9
2.5
8*4.9
K
2.2
81.1
2.5
9*.3
L
3.7
87.7
3.9
85.9
M
2.5
72.9
3.0
88.8
Outer 50% of
J
2.8
62.2
3. b
91.1
canopy
K
2.5
86.2
2.8
90.9
L
2.6
68.2
3.3
79.5
M
2.5
76.3
3.1
85.*4


900
800
700
600
500
400
300
200
100
0
S nu
2U t-
simulation
Weeks from Planting
lated and
ay 1978.
experimental growth of fruit filling seeds for Florunner peanuts planted on


Table 17. Summary of light interception by plants defoliated at 9 weeks of age.
T reatment
Row
Estimated LAI
Immediately
After Defoliat ion
% Light Interception
Immedi ate 1y
After Defoiiation
LAI
at 1 1
weeks
% Light
1 nterception
at 11 weeks
Check
F
2.8
82.2
*.o
90. 1
G
A. 7
59.1
6.3
97.2
H


3.3
77.1
50| uniform
F
2.3
56.6
A. 1
91.0
G
1.5
56.8
2.9
96.0
H



71.5
Outer 50% of
F
1.0
56.0
2.7
Sk.k
canopy
G
1.7
kl.2
3.9
96. 1
H


2.9
79.9
-c-


47
Table 16. The effect of
week 15.
501 defoliation at week 9
upon
plant size at
T reatment
Plant Variable
Check
50% Uniform
Outer
50x of Canopy
Number of new leaves'"
105.2b
107.3b
138.8a
Ratio of stem weight to
length, mg/cm
22.8a
20.9b
18.2c
Mainstem length, cm
51.9a
44.6b
44.3b
Average cotyledonary
lateral length, cm
71.3a
61.6b
60.7b
Number of new vegetative
growing points
12.4b
16.8ab
21.8a
Number of PI
4.6b
8.2ab
12.2a
Number of P3*
38.6a
27.2ab
20.0b
Weight of P3, g*
1.0a
0.6ab
0.5b
Number of P5*
47.1a
36.lab
31.6b
Weight of P5, g
44.8a
34.3ab
28.3b
Kernel weight, g
35.0a
27.2ab
22.6b
Note: Means in a row followed by the same letter are not significantly
different according to a t-Test (a = 0.05 except for plant variables
marked with an *, in which case a = 0.10).


3
problems involved with using either of these models for simulation of
Insect and disease damage. PENUTZ, the model developed by Duncan (197^0,
does not Include leaf and stem components explicitly, only as vegetative
top weight. Photosynthesis each day Is based on percent ground cover
which Is calculated by considering the plant canopy as expanding circles
which eventually overlap and achieve 100% ground cover. The rate of
expansion Is determined by temperature (Duncan et al. 1978). Insects
eat leaves and the translation of feeding Into changes In canopy geom
etry would be difficult, If not impossible. Duncan's model therefore
could not be used without modification.
The model developed by Young et al. (1979) does separate leaf from
stem mass and it does store the amount of leaf mass added each day so
that leaf material of a given age can be removed from the system. This
ability to separate plant material by age is important for simulation
of either insect or disease damage. For this reason, the model of Young
and his co-workers would have been used if it had not had one serious
disadvantage. The model requires values for a large number of empirical
parameters. In order to find values for these parameters, Young et al.
fitted data for 9 planting dates each year. In many cases a parameter
value changed radically from one year to the next. There were insuffi
cient data available for determination of realistic values of these
parameters for Florida growing conditions in 1978. Duncan's model was
developed largely from data obtained in Gainesville, Florida, and I
therefore anticipated fewer problems in fitting growth of my non-defoli-
ated plants to his model. Thus a decision was made to modify his model
for this study.


I certify that I have read this study and that in my opinion it
conforms to acceptable standards of scholarly presentation and is fully
adequate, in scope and quality, as a dissertation for the degree of
Doctor of Philosophy.
S. H. Kerr, Chairman
Professor of Entomology and
Nematology
I certify that I have read this study and that in my opinion it
conforms to acceptable standards of scholarly presentation and is fully
adequate, in scope and quality, as a dissertation for the degree of
Doctor of Philosophy.
7trm 7?.
T. R. Ashley
Assistant Professor of Entomology
and Nematology
I certify that I have read this study and that in my opinion it
conforms to acceptable standards of scholarly presentation and is fully
adequate, in scope and quality, as a dissertation for the degree of
Doctor of Philosophy.
few v-
Jone?
/Associate Professor of
Agricultural Engineering
I certify that I have read this study and that in my opinion it
conforms to acceptable standards of scholarly presentation and is fully
adequate, in scope and quality, as a dissertation for the degree of
Doctor of Philosophy.
//
R. C. Littell
Associate Professor of
Stat i stics


3UI3ROUT I Nil EVNTSU X)
COMMON /('.COM 1 / A TR I (3 ( 25 ) JtVNT.Mf AiMFE(ldO) ML L ( l f) 0 ) M3 TOO ,M CUDK N
1 APO, NNAPT NNATR ,NNF II. NNG( 1 00 ) NNTR Y. Mf?M T, OP AR M ( 5 0.4 ) TMOW T T3CG
2 T TCLR. TTF I N ,TTRI O (25 ) TT5ET
COMMON /GCO M2/ ().)( 100), DDL (100), DTFUL DHL) W, I SC t 5 LF L AG ( 50 ) NFL AG,
1 NNFQD, 11 NEOS NNF.OT, 55 ( 1 00) SSL( 1 00 ) TTNEX
COMMON /UCO Ml /NDL'X 1 N )CX2 NO EX 3 NDCX5 NOW O T 3Y N { 7 ) OTS OUT ( 7) ,
1 A 50 G5 T ( 7 ) DA Y INC J, MERGE MOR Oil W
COMMON /UCOM2/HFT1 ME,T 1 MEL F
COMMON /UCOM3/INIT
COMMON /DC )M A/ADOS T M
1
COMMON
1
2
3
COMMON
1
2
COMMON
/UC 0 MS/ I 5 r r. M ( 7,350) NOD h ( 7 33 0 ) XL E AFN ( 7 ) 5 IZ EL F ( 7, 20 0) ,
H TLE AF ( 7,200) W T I NOD ( 7,200) W1 P E T ( 7.2 0 0 ) A RE AL F ( 7 ) ,
GHTLK (7 > *T5t EM( 7 ) XNLEAF ( 7,200) WTROUT 7 ) ICOUNI ( 7,350)
PDAY (200) A G R11T 5 (7 )
/UCO A 21/PODWGT( 7,200) ,MORE,PL UUMZ(7,200) KPEGST ,
PEGNO ( 7.20 0 ) PD PST ( 7 ) OCJDCAO ( 7, 20 0 ) A Gt: MA X( 7, 20 0 ) GRA TEK ,
KOOD5T GRRA TE ,OOPO.) 3(7) PQNUT 5(7 ) POO AGE (200 )
/UC ) M2 ? / HE *VE G( 7,200), ADOLF
COMMON / UCOM24/XNUNOD( 7) NC OU N T ( 2 0 0 ) SURF AC ( 7
VLGNIT VEGNCR. A5VEGF, VEGCI1R PflULF PORPT
COMMON /UCOM31 /ROO IF,SMA INF
COMMON /UCO M 35/N DE X
COMMON /UCOM37/NDEX9
GO TO ( 1,2,3 ) I X
CALL AT TAC
GO TO 3
CALL flE GIN
,200),VEGCRO.
,PORNJ, SL W
GO TO 900
5 IF (LFL AG{ 1 ) ) 1 0 0,100,1 0
10 CONTINUE
IF (N0EXS.EQ.1 ) GO T) 100
NOE XI = 2
NOEX 5 1
NOEX6 = 1
100 IF (LFLAG(2)) 200,200,110
110 SL W = 3.26
5 MAINF = 0,13
ADOLF (10.57 0.97) / (1.0 F VEGNCR)
P()RL F = 6.16 0.9 7
PORI1 T = 2.16 0.9 7
PL) RM i JO = 2.2 5 0.57
XX = T I MELE
I IF T 1 ME = 7.2
TIMELE = 14.4
00 220 I = l.NOW
IF (PDA Y( I ) .LE.0.0) 50 TO 220
rDAY(l) = rlMELF (TIMELF/XXl (XX -
PDAY( I 1 )


vegetative growing points arose toward the exterior of the canopy,
frequently in the axils of defoliated leaves.
The results for plants harvested at week 15 were similar to those
for plants harvested at 11 weeks. By this time, mainstem length and
average cotyledonary lateral length were significantly lower for de-
foliated plants.
There was a significant effect (a=.05) of block (row) on mainstem
length, number of P2 (pegs in ground), number of P5 (fully expanded
pods which did not shrink when dried), P5 weight, kernel weight, and
weight of all pods (P3~P5) at 11 weeks. This was probably due again to
the difference in emergence times of different rows. By week 15, row
had a significant effect only on root weight and the ratio of stem
weight to length.
Light interception by plants harvested at week 11 is summarized in
Table 17- Average light interception immediately following defoliation
by plants defoliated uniformly was 83% of that of the check plants;
average light interception by plants defoliated non-uniformly was 69%
of that of the check plants at the same time. There was no difference
in light interception 2 weeks after treatment between defoliated and
non-defoliated plants.
Third Defoliat ion
The response of plants defoliated at week 12 was similar to that
of plants defoliated at week 9 in that the plants from which leaves
were removed had an equal or greater growth of leaves, as indicated by
number and weight of new leaves per plant, and a reduction in stem
weight to length ratio as compared to the check plants (Tables 18 and
19). More than half of the leaf material by weight was removed in


15 0 CONTINUE
KK = NOW
DO 390 J = 1 MilHGE
I SUM = 0
DO 3 60 I = KK NO W
I SUM = I SUM i NI1WV EG( J I )
NE V.VCGI J,I ) = 0
36 T CONTINUE
IE (ISUV.LF.O) GO TO 390
>0 370 JK 1,1 SUM
NJMMFKJ) = NUMUW(J) 1
1 S T M ( J,NUMT!( J ) ) = 7
MOD-: { J NUMI3R ( J ) ) 1
I COUNT ( J ,NUM 0.9 { J ) ) = MORROW
XNLiTAE ( J MORRO/;) = XNLF.AIT( J, M JlillOW )
ASRPTStJ) = A'iKPTSI J) + 1.
370 CONTINUE
390 CONTINUE
400 CONTINUE
RETURN
E NO
1 .
oo
i


Parameter
Descript¡on
Numerical Value(s)
Source
PNTNCR
Ratio of nitrogen to carbohydrate + oil in seeds
2.80
Duncan (197^
& pers. comm.)
PNTOIL
Percent oil in seed
50.0
Duncan (197^
& pers. comm.)
PNTPRO
Percent protein in seed
25.0
Duncan (197^
& pers. comm.)
PODC
Percent carbohydrate in pod shell
0.85
Duncan (197^
& pers. comm.)
PODMAX
Maximum pod size, mg
1350
ca1ibration,
field results
PODN
Proportion of shell which is nitrogen
0.12
Duncan (197^
& pers. comm.)
PORLF
Maximum amount of weight a growing leaf can
7.96
p. t. <
82
field results
add each physiological day, mg
5.98
p. t. >
82
PORNOD
Maximum amount of weight a growing internode can
2.91
p. t. <
82
field results
add each physiological day, mg
2.18
p. t. >
82
PORPT
Maximum amount of weight a growing petiole can
2.79
p. t. <
82
field results
add each physiological day, mg
2.10
p. t. >
82


23
Leaves continued to add weight for a time after they were con
sidered fully expanded in this study. The specific leaf weight of the
new leaves each week (Experiment 2) is compared in Table 8 with that of
leaves marked during the same week but not harvested until week 16
(Experiment 1).
Pegs were first present on plants harvested at week 7 (Table 5).
Pods first started to swell at week 8 and there were fully expanded
pods (PVs and P5's) present by week 9- The number and weight of pods
in the largest size category (P5's) continued to increase until week
17. The number of aerial pegs (Pi's) decreased after week lA.
The branching pattern of Florunner turned out to be more variable
than the literature indicated for Virginia peanuts (Gregory et al. 1951,
Wynne 1975). According to Gregory et al. (1951), the branching pat
tern should be vegetative in the first node, mostly vegetative in the
second node, then have alternating pairs of reproductive and vegetative
nodes. In a study of the first 2 nodes on the 2 cotyledonary laterals
and the first branches off the mainstem on 20 plants mapped when leaf
and stem growth had essentially stopped, only 72.5% of these branches
were vegetative in the first node, and 29.2% in the second node. For
the most part, however, the cotyledonary laterals and first h branches
off the mainstem had more vegetative nodes than expected. There were
frequently 3 or b vegetative nodes in a row, and sometimes as many as
6. A common pattern was 1 vegetative node, 1 reproductive node, then
3 or vegetative nodes, then alternating pairs of reproductive and
vegetative. Later branches for the most part exhibited the expected
branching pattern. This variation had the effect of making most early


112
pod dry weight if the plants were fed upon randomly, but 6% reduction if
the feeding was on the youngest leaves (Figure 16). When the population
was increased to 20/plant (Figure 17) a much more serious reduction in
yield occurred when the insects entered the field at day 35- Final
pod dry weight was 27% lower than the check for the plants defoliated
randomly and 23% lower for plants on which the youngest leaves were
eaten. There was less of a difference in final yield between types of
feeding damage in this case because LAI was reduced to almost zero by
either type of feeding.


L = KAVG 14-1
5 0 AVC.PTr,(L) = AVGPTS(L-l)
X L M M A Z = AMAX 1 C PTSMEN, POOLM )
IF ( PODLM. G r O. 0) POOL M = XLI-MAZ
DO 110 J = l.MFRGE
if ( lMfinr.c( j ) .Ltz.o ) c,u to iio
IF ( SOL ( il .Lf-.o. 0) r.o TO 15
A = AOCALF(J) / ( SSL ( 3 > 10010. )
GO TO 16
15 A PORK J) / POOP OP(J)
16 CONTINUE
PTSYN(J) ~ i'Tfi A 1 0 00.
XL = PA OF AC XL MO A Z A 1 000.
XN .= PA OF AC PTS A 1 0 00.
IF (A.iru.0.0) GO TO 00
XL IMT { J ) = AMAXl(XL.XM)
IF ( NI1FX3.LT mZ ) XLIMT(J) = XN
00 CONTINUE
PTSOUT(J) = PTSYN(J) SMAINF
PTSYN(J) PTSYNtJ ) PTSOUT( J )
100 ASPGST(J) = ASPGST(J) F ASPGEI(J)
110 CONTINUE
Pf) (NOW ) = PTS
OETUON
r.¡ j d
cr>
ro


Table 32. Comparison of model predictions with field results for plants defoliated at 16 weeks and har
vested at 18 weeks.
Plant Variable
T reatment
Control
50
% Uniform
Outer
50'.? of
Canopy
Field*
Mode 1
Field*
Model
Field*
Mode 1
Original LAI
6.2
(0.8)
6.5
6.9
(0.6)
6.5
5.8
(0.5)
6.5
LAI after defoliation
6.2
6.5
3.1
3.2
0.0
0.0
LAI at harvest
6.2
(0.8)
6.5
3.2
(0.3)
3.2
0.2
(0.1)
0.0
2
Leaf weight at harvest, g/m
241.5
(30.9)
237.3
127.5
(11.8)
121.6
5.7
(1.9)
0.0
2
Weight of new leaves, g/m
0.9
(0.3)
0.0
2.8
(0.7)
0.0
5.5
(1.9)
0.0
2
Stem weight, g/m
309.9
(40.5)
290.0
271.4
(29.7)
244.3
243.1
(27.0)
209.0
2
Gain in stem weight, g/m
-20.9
-5.1
-51.1
-51.0
-90.2
-86.4
2
Number of pods/m
1037.2(129.6)
959.8
874.8
(94.4)
959.8
802.2
959.8
2
Weight of pods, g/m
674.0
(83.6)
653.3
629.9
(57.7)
645.8
492.8
(77.5)
581.1
Number of P4-P5/m^
CO
(95.2)
674.7
665.8
(65.9)
674.7
522.5
(90.9)
674.7
2
Weight of P4-P5, g/m
667.0
(82.5)
637.0
621.4
(57.3)
636.4
484.2
(76.2)
571.6
'Number in parentheses is standard error of the mean.