• TABLE OF CONTENTS
HIDE
 Title Page
 Disclaimer
 Acknowledgement
 Vita
 Abstract
 Table of Contents
 List of Tables
 List of appendix tables
 List of Figures
 List of appendix figures
 Introduction
 Literature review
 Crop rotation development
 Results
 Discussion
 Conclusion
 Literature cited
 Appendix






Title: Development of multiple cropping systems for small farmers of El Salvador
CITATION PAGE IMAGE ZOOMABLE PAGE TEXT
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00053947/00001
 Material Information
Title: Development of multiple cropping systems for small farmers of El Salvador
Physical Description: xv, 110 leaves : ill. ; 28 cm.
Language: English
Creator: French, Edwin Charles, 1945-
Publisher: New Mexico State University
Place of Publication: Las Cruces
Publication Date: June, 1975
 Subjects
Subject: Cropping systems -- El Salvador   ( lcsh )
Crop rotation   ( lcsh )
Genre: bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Bibliography: Includes bibliographical references (leaves 94-98).
Statement of Responsibility: by Edwin Charles French, III.
General Note: Reproduced from typewritten copy.
General Note: M.S. thesis--New Mexico State University.
General Note: Vita.
Funding: Electronic resources created as part of a prototype UF Institutional Repository and Faculty Papers project by the University of Florida.
 Record Information
Bibliographic ID: UF00053947
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 01576522

Table of Contents
    Title Page
        Page i
        Page ii
    Disclaimer
        Page iii
    Acknowledgement
        Page iv
    Vita
        Page v
    Abstract
        Page vi
    Table of Contents
        Page vii
        Page viii
    List of Tables
        Page ix
        Page x
    List of appendix tables
        Page xi
    List of Figures
        Page xii
        Page xiii
        Page xiv
    List of appendix figures
        Page xv
    Introduction
        Page 1
        Page 2
        Page 3
    Literature review
        Page 4
        Page 5
        Page 6
        Page 7
        Page 8
        Page 9
        Page 10
        Page 11
        Page 12
    Crop rotation development
        Page 13
        Overview
            Page 13
            Page 14
        Experimental site
            Page 15
        Soil
            Page 16
        Trial Design
            Page 16
        Statistical analysis
            Page 17
        Time of planting
            Page 17
        Field preparation
            Page 18
        Transplants
            Page 18
            Page 19
        Fertilizer
            Page 20
            Page 21
        Observation trial-corn (all rotations)
            Page 22
            Page 23
        Observation trial rotation 1
            Page 24
            Page 25
            Page 26
            Page 27
        Observation trial rotation 2
            Page 28
            Page 29
            Page 30
        Observation trial rotation 3
            Page 31
            Page 32
            Page 33
        Observation trial rotation 4
            Page 34
            Page 35
            Page 36
            Page 37
            Page 38
        Observation trial rotation 5
            Page 39
        Observation trial rotation 6
            Page 39
            Page 40
            Page 41
            Page 42
        Field trial phase I (rotations 1 and 2)
            Page 43
        Field trial rotation 1
            Page 43
            Page 44
            Page 45
            Page 46
            Page 47
            Page 48
        Field trial rotation 2
            Page 49
            Page 50
            Page 51
        Bean cultivar trial
            Page 52
            Page 53
            Page 54
            Page 55
            Page 56
            Page 57
    Results
        Page 58
        Observation trial-corn (all rotations)
            Page 58
        Observation trial rotation 1
            Page 58
            Page 59
            Page 60
        Observation trial rotation 3
            Page 61
        Observation trial rotation 2
            Page 61
        Observation trial rotation 4
            Page 62
            Page 63
            Page 64
        Observation trial rotation 5
            Page 65
        Observation trial rotation 6
            Page 65
        Field trial rotation 1
            Page 66
            Page 67
            Page 68
        Field trial rotation 2
            Page 69
            Page 70
        Bean cultivar trial phase I (corn, beans)
            Page 71
            Page 72
            Page 73
            Page 74
            Page 75
            Page 76
            Page 77
        Bean cultivar trial phase II (corn, beans)
            Page 78
            Page 79
    Discussion
        Page 80
        Page 81
        Page 82
        Page 83
        Page 84
        Page 85
        Page 86
        Page 87
        Page 88
        Page 89
        Page 90
        Page 91
    Conclusion
        Page 92
        Page 93
    Literature cited
        Page 94
        Page 95
        Page 96
        Page 97
        Page 98
    Appendix
        Page 99
        Appendix A: Cultivars and seed sources of crops used in observation trial (OT), field trial (FT), and bean cultivar trial (BCT), 1973-1975
            Page 100
            Page 101
            Page 102
        Appendix B: Field plan for area of investigation (ENA) including plot numbers for observation trial, field trial, and bean cultivar trial, 1973-1975
            Page 103
        Appendix C: Pesticides used in 3 multiple cropping trials (ENA), El Salvador, 1973-1975
            Page 104
            Page 105
        Appendix D: Fertilizer applications for observation trial (OT), field trial (FT), and bean cultivar trial (BCT), 1973-1975
            Page 106
            Page 107
        Appendix E: Analysis of variance (ANOVA) on emergence of beans planted in center and on side of ridge. Bean cultivar trial, May, 1974
            Page 108
            Page 109
            Page 110
Full Text







DEVELOPMENT OF MULTIPLE CROPPING SYSTEMS

FOR SMALL FARMERS OF EL SALVADOR

BY

EDWIN CHARLES FRENCH, III


A Thesis submitted to the Graduate School

in partial fulfillment of the requirements

for the Degree

Master of Science






Major Subject: Horticulture






New Mexico State University

Las Cruces, New Mexico

June, 1975









"Development of Multiple Cropping Systems for Small

Farmers of El Salvador," a thesis prepared by Edwin

Charles French, III in partial fulfillment of the re-

quirements for the degree, Master of Science, has been

approved and accepted by the following:


Deai oY the GradSate-Soho




Chairman of the Examinig Committee





Date


Committee in charge:

Dr. Joe N. Corgan, Chairman

Dr. Donald J. Cotter

Dr. Ricardo E. Gomez

Dr. Boyce C. Williams










DISCLAIMER


The research for this thesis was conducted under

the auspices of United States Peace Corps through the

Ministry of Agriculture and Centro Nacional Tecnologa

Agropecuaria in El Salvador. The work was accomplished

in conjunction with the Agency for International Devel-

opment/University of Florida, and partially funded by a

grant from North Carolina State University. Therefore,

New Mexico State University claims no publication

rights to the contents of the thesis.


iii









ACKNOWLEDGEMENTS


The author wishes to express his gratitude to all

administrators, instructors, technicians, and field

personnel who made the project possible. Special thanks

goes to the Ministry of Agriculture of El Salvador, Ing.

Armando Alas and Centro Nacional de Tecnologia Agrope-

cuaria, Ing. Antonio Cabezas and Ing. Alex Aguiluz and

the National School of Agriculture for their support and

the use of their facilities; Mr. Chico Rodriguez and the

Peace Corps, Adrian Chac6n, M.S. and Ing. Mario Barahona

and the Department of Agriculture Economics/MAG for their

combined efforts to make the project successful; Dr.

Richard Bradfield for his suggestions and ideas; Dr.

Peter E. Hildebrand USAID/University of Florida whose

guidance, support, and cooperation was of inestimable

value; and to Drs. Joe N. Corgan and Donald J. Cotter

whose encouragement, patience, and dedication made this

thesis possible,









VITA


January 2, 1945 Born at New Rochelle, New York

1970 B. S., New Mexico State University, Las Cruces

1970-1971 Teaching Assistant, Horticulture Department,
New Mexico State University, Las Cruces

1972 Research Assistant, Horticulture Department,
New Mexico State University, Las Cruces

1973-1974 U. S. Peace Crops Volunteer to El Salvador

PROFESSIONAL AND HONORARY SOCIETIES

Sociedad Americana de Ciencias Horticolas, Regi6n Tropical

Pi Alpha Xi

American Society for Horticultural Science

PUBLICATIONS

French, Edwin Charles, and Peter E. Hildebrand, "Un
Sistema Salvadoreno de Multicultivos: Su
Potencial y Sus Problemas." Ministerio de
Agriculture y Ganaderia, Centro Nacional de
Tecnologia Agropecuaria, Febrero, 1974

French, Edwin Charles, and Peter E. Hildebrand, "Pro-
ducci6n de Pepinos Utilizando Tallos de
Maiz." Ministerio de Agricultura y Ganaderia,
Centro Nacional de Tecnologia Agropecuaria,
Febrero, 1974

FIELD OF STUDY

Major Field: Horticulture

Vegetable Production
Professors Joe N. Corgan and Donald J. Cotter









ABSTRACT


DEVELOPMENT OF MULTIPLE CROPPING SYSTEMS

FOR SMALL FARMERS OF EL SALVADOR

BY

EDWIN CHARLES FRENCH, III





Master of Science in Horticulture

New Mexico State University

Las Cruces, New Mexico, 1975

Doctor Joe N. Corgan, Chairman





Nine different multiple cropping rotations were

designed and tested for production feasibility in El

Salvador. All rotations were generally successful,

except for specific crops in a few rotations, and all

made good use of family labor. The basic crops were

corn and beans in combination with a number of vegeta-

ble drops. The main feature of the rotations was the

use of corn stalks, after corn harvest, as stakes for

tomatoes, beans, or cucumbers. A bean cultivar test

indicated some variability among cultivars in their

adaptation to a corn-bean multiple cropping rotation.
vi











TABLE OF CONTENTS


LIST OF TABLES . .

LIST OF APPENDIX TABLES .

LIST OF FIGURES . .

LIST OF APPENDIX FIGURES .

INTRODUCTION . .

LITERATURE REVIEW . .

CROP ROTATION DEVELOPMENT

Overview . .

Experimental Site .

Soil . .

Trial Design . .

Statistical Analysis .

Time of Planting .

Field Preparation .

Transplants . .

Fertilizer .

Observation Trial-Corn (All


Observation Trial Rotation 1

Observation Trial Rotation 2

Observation Trial Rotation 3

Observation Trial Rotation 4

Observation Trial Rotation 5

Observation Trial Rotation 6


* .

* *

* *

* *

* *

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* .

* .

* .

. .

* 0

* .

* .

. .

* .

* .

Rota

* *

* *

* 0

* *

* .

* .


Field Trial Phase I (Rotations

vii


1 and 2)


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. 0 0 0 0 0 0

. 0 0


. . 0 *










i o 0 *





. S 0 0 0 0











. 0 0 0 0 0 0 .




tions) 0 .0 .




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* 0 5 0 0 0

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* 0 0 0 0 0 0 0


Page
ix

xi

xii

xv

1

4

13

13

15

16

16

17

17

18

18

20

22

24

28

31

34

39

39









Page

Field Trial Rotation 1 .. .. . .... 43

Field Trial Rotation 2 . . 49

Bean Cultivar Trial . . . 52

RESULTS . . . . 58

Observation Trial-Corn (All Rotations) . 58

Observation Trial Rotation 1 . . 58

Observation Trial Rotation 2 . . 61

Observation Trial Rotation 3 . . 61

Observation Trial Rotation 4 .. . 62

Observation Trial Rotation 5 . 65

Observation Trial Rotation 6 . .. 65

Field Trial Rotation . ... 66

Field Trial Rotation 2 . . .69

Bean Cultivar Trial Phase I (Corn, Beans) 71

Bean Cultivar Trial Phase II (Corn, Beans) 78

DISCUSSION . . . 80

CONCLUSIONS . . .... .. 92

LITERATURE CITED ....... ..... 94

APPENDIX A . 100

APPENDIX B . . . . 103

APPENDIX C . . .... 104

APPENDIX D . . .. . 106

APPENDIX E . . . . 108


viii









LIST OF TABLES


Table rage

1. Soil analysis of a composite sample taken
in the field trial area and analyzed
by the Soils Dept., Centro Nacional
de Tecnologia Agropecuaria (CENTA),
Santa Tecla, El Salvador, 1973 . 16

2. Annual rainfall distribution based on a
30 year average 1944-1974, and minimum
recorded annual rainfall occurring in
1957 for the San Andres experimental
area (ENA) . . . 19

3. Chronological calendar of events for
rotation 1. Observation Trial, 1973 25

4. Chronological calendar of events for
rotation 2. Observation Trial, 1973 . 29

5. Chronological calendar of events for
rotation 3. Observation Trial, 1973 32

6. Chronological calendar of events for
rotation 4. Observation Trial, 1973. 35

7. Chronological calendar of events for
rotation 5. Observation Trial, 1973 . 40

8. Chronological calendar of events for
rotation 6. Observation Trial, 1973 . 42

9. Chronological calendar of events for
rotation 1. Field Trial, 1973-1974. . 44

10. Chronological calendar of events for
rotation 2. Field Trial, 1973-1974. . 45

11. Bean cultivar plots. Planting and har-
vest dates and planting systems, phase
I, Bean Cultivar Trial, May, 1974. . 53

12. Bean cultivar plots. Planting and har-
vest dates, phase II, Bean Cultivar
Trial, August, 1974 .. . . 54

13. Chronological order of development for
the corn cv. H-3. Observation Trial,
1973 . . . . 59








Table Page

14. Yields in M.T./ha and numbers of fruit/ha
of cucumbers grown on 5 different trel-
lising systems, phase II, rotation 4,
Observation Trial, October 8-November
22, 1973 . .. . ... 63

15. Crop yields for phase I, rotation 1,
Field Trial, 1974 . . . 67

16. List of crops and their respective yields
categorized by phase. Rotation 2,
Field Trial, December 10, 1974 . 70

17. Mean number of bean plants emerged 10
days after seeding and their mean yield
of dry beans (M.T./ha) for all cvs., for
2 planting systems. Bean Cultivar Trial,
May, 1974 . . . . 72

18. Mean number of bean plants emerged 10
days after seeding and their mean yield
of dry beans (M.T./ha) for cv. Centa 105
for 2 planting systems. Bean Cultivar
Trial, May, 1974 . . . 72

19. Percentage of bean plant losses from
emergence to harvest for bean cvs. of
phase I, Bean Cultivar Trial, May, 1974 74

20. Days to flowering, days to harvest, and
yield (M.T./ha) for 7 cvs. of Bean
Cultivar Trial, May and August plantings,
1974 . . . . 75

21. The mean bean yields (cv. Centa 105) for the
modified and original planting systems.
Bean Cultivar Trial, May, 1974 . 77

22. Range and average of corn yield of ears
harvested/ha and M.T./ha dry grain (12%
humidity) from 12 plots of corn-bean
rotation, phase 1, Bean Cultivar Trial,
May, 1974 . . . . 77

23. The mean of all bean cv. yields for the May
and August plantings. Bean Cultivar
Trial, 1974 . . . 78









LIST OF APPENDIX TABLES


Table Page

23. Cultivars and seed sources of crops used
in observation (OT), field trial (FT),
and bean cultivar trial (BCT). 1973-
1975 . . . . 100

24. Pesticides used in 3 multiple cropping
trials (ENA) El Salvador, 1973-1975. . 104

25. Fertilizer applications for observation
trial (OT), field trial (FT), and
bean cultivar trial (BCT) 1973-1975. . 106

26. Analysis of variance (ANOVA) on emer-
gence of beans planted in center and
on side of ridge. Bean Cultivar Trial
May, 1974 . . . 108

27. ANOVA on yield of beans planted in center
and on side of ridge. Bean Cultivar
Trial, May, 1974 . . . 108

28. ANOVA on emergence of beans planted in
center and on side of ridge for cv.
Centa 105. Bean Cultivar Trial, May,
1974 . . . . 1. 09

29. ANOVA on yield of beans planted in center
and on side of ridge for cv. Centa 105.
Bean Cultivar Trial, May, 1974 . 109

30. ANOVA on mean yield of beans planted in
May and August. Bean Cultivar Trial,
1974 . . . . 110

31. ANOVA on mean yield of cv. Centa 105 for
modified and original planting systems.
Bean Cultivar Trial, May, 1974 .. 110









LIST OF FIGURES


Figure Page

1. Cross section of fertilizer bands incor-
porated in phases I and II, Observation
Trial and Field Trial, 1973-1974 . 21

2. Cross section of fertilizer bands and
hilling of corn. Observation Trial,
Field Trial, and Bean CuLtivar Trial,
1973-1975 . .. . .. 22

3. Diagram of triangular planting pattern
used for seeding corn. Observation
Trial, 1973 . . 22

4. Cross section of plots seeded with corn,
showing the 4 closely spaced double
corn rows and their spacing. Observa-
tion Trial, 1973 .. . 23

5. Doubled corn stalk with the ear hanging
so that the corn husk sheds the rain.
Observation Trial, Field Trial, and
Bean Cultivar Trial, 1973-1975 . 23

6. Cross section of plots illustrating (a)
mature corn ready for transition to
phase II and (b) phase II vegetable beds
formed and planted. Observation Trial,
1973 . . . . 26

7. Top view of corn rows with tomatoes trans-
planted in phase II. Observation Trial,
1973 .. . .. . . .. .. 26

8. Corn stalks tied to form tripods and the
horizontal support twine tied to the legs
of the tripods and the end posts. Rota-
tions 1, 2, 4, 5, and 6, Observation Trial,
1973 . . . . 27

9. Cross section of plots for rotations 1, 2,
and 5, phase III. (a) Phase III trans-
plants and muskmelon planted beneath
tomato vines. (b) Tomato and tripod
debris placed in the furrows. Observa-
tion Trial, 1973 . . 28


xii











10. Tomatoes interplanted with pole beans.
Rotation 2, Observation Trial, 1973 . 30

LL. Top view of double corn rows with pole
beans seeded in rotation 3. Observa-
tion Trial, 1973 . . 33

12. Cross section of plot illustrating
phase 111, Rotation 3, Observation
Trial, 1973 . . . 33

13. Five trellising methods for cucumbers
in rotation 4, Observation Trial, 1973. 36

14. Two systems of seeding cowpeas with
broccoli. Rotation 4, Observation
Trial, 1973 . . . 37

15. Bed formation and seeding of phase IV.
(a) Overlap period of cowpeas with
carrots and beets and (b) carrots and
beets after removal of cowpeas. Rota-
tion 4, Observation Trial, 1973 . 38

16. Phase I, rotation 5, illustrating the
planting arrangement and row spacings
of corn, squash, and radish. Observa-
tion Trial, 1973 .. . . 41

17. Bush beans seeded beneath tomato vines in
phase III, rotation 6, Observation Trial,
1973 . . . . 41

18. Row and plant spacings for rotations 1 and
2. (a) Single row of beans planted in
rotation 2 and (b) double row of beans
planted in rotation 1, Field Trial, 1973. 47

19. Beds formed and corn stalks de-leaved.
Dotted line represents the row configu-
ration in phase I. Solid line represents
phase II vegetable beds. Field Trial,
1974 . . . 47

20. Phase III, rotation i illustration of (a)
3 rows of cowpeas seeded beneath tomatoes,
and later (b) tomato vines and tripods
placed in the furrow. Field Trial, 1974. 48


xiii


Page


Figure









Figure Page

21. Diagram of phase IV, rotation 1, Field
Trial, 1974 . . . . 49

22. Two rows of cabbage transplanted on the
sides of the cucumber beds. Rotation
2, Field Trial, 1974 .. ..... .. 50

23. Diagram of corn seeding between cabbage
rows. Rotation 2, Field Trial, 1974 . 50

24. Transition of vegetable beds from phase
III to phase IV. (a) Dotted line repre-
sents old cabbage beds. Solid Line repre-
sents newly formed bean and sweet potato
beds. (b) Planting position of pole beans
and sweet potatoes over banded nematocide.
Rotation 2, Field Trial, 1974 . 51

25. Row and plant spacing for original and
modified bean planting systems. (a)
Original system, (b) modified system
and method of planting for south half
of plots, and (c) modified system and
method of planting for north half of
plots. Bean Cultivar Trial, 1974 . 55

26. Transition to phase II illustrating (a)
phase II beans seeded beneath corn and
(b) phase I corn doubled and phase II
corn seeded. Bean Cultivar Trial, 1974. 56


xiv








LIST OF APPENDIX FIGURES

Figure Page

27. Field plan for area of investigation (ENA)
including plot numbers for observation
trial, field trial, and bean cultivar
trial, 1973-1975 .. .. ......... 103









Introduction


A world food shortage places countries which are

not self-sufficient in food production in a very precar-

ious position (16, 19, 30). Dependence of one nation on

another to make up its domestic food production deficit

is risky. The risk can present itself if the donor nation

fails to meet its production goals (19) or if world compe-

tition makes it impossible for the needy nation to afford

needed food products. The balance between the welfare of

nations and disaster is made much more delicate today by

growing populations, agriculture's dependence on petroleum

(21), and unsure climatic conditions. Thus, the need for

individual national self-sufficiency in the production of

basic foods becomes obvious.

Because of its geographical susceptibility to drought

as was experienced in 1972-73, El Salvador is a potential

famine area (45). Coupled with a population growth rate

of 3.8%, and a population density which ranks third high-

est in the world (45), the circumstances for disaster

brought about by a food shortage are real and frightening.

In a recent study by the Sociedad de Ingenieros

Agronomos de El Salvador, an estimated 22,500 sq km of

land, dedicated exclusively to the production of food,

will be required to adequately supply a Salvadorean pop-

ulation now approaching 4 million (2). Combining a







2

high population (approximately 312 persons per sq km) (10)

and limited cultivated land, insufficient land is avail-

able to meet this need under traditional agricultural

systems.

A logical solution for meeting the increasing food

demand is to increase food production on the existing

cultivated land (49). Difficulties range from problems

associated with land tenure (34) to modern day problems

related to a petroleum shortage (21). Methods for in-

creasing food production should include modern technology

and new ideas, as well as a concern for tradition, formu-

lated in such a way as to be acceptable to the farmer

(19), One method, which has the flexibility to comply

with the varied needs of the Salvadorean farmer, would be

multiple cropping or as it has been coined, "multicultivos."

The Salvadorean Ministry of Agriculture (MAG) in 1971

established a 5 year plan (17) directed towards increasing

the production of basic grains. In addition, plans were

made to increase vegetable production through the coordi-

nated efforts of the University of Florida (by contract

with the Agency for International Development), Peace

Corps, and Centro Nacional de Tecnologia Agropecuaria

(a branch of extension and research of MAG). Contributing

within Peace Corps as a volunteer, the author worked as

a multiple cropping specialist. The multiple cropping

program developed was a result of a re-analysis of the






3

countries needs and priorities, focusing on the produc-

tion of basic grains and horticultural crops (26).

The purpose of this thesis is to report the devel-

opment of a multiple cropping system which increased

productivity and was flexible enough to meet the neces-

sities of the small farmer.









Literature Review


Multiple cropping is of much interest in many less

developed areas, but, despite a long history and increas-

ing importance, no comprehensive report on multiple crop-

ping is published. Available studies usually focus on a

technical aspect in the program of one country. The sub-

ject is vast and involved and little solid research ex-

ists in the area (15).

Multicropping, intercropping, interplanting, multi-

crop.sequences, intensive cropping, double cropping,

triple cropping, rotation planting, mixed farming, shift-

ing cultivation, duoculture, polyculture, and relay in-

terplanting are some of the many names given to various

types of multiple cropping (4, 15, 23, 27, 28, 47). How-

ever, the term multiple cropping generally refers to

growing more than one crop on the same piece of land in

one year (14, 23, 27, 28).

According to Dalrymple (15), forms of multiple crop-

ping were in existence before the time of Christ. It was

usually found in densely populated "garden areas" of the

world such as Babylon, Egypt, China, India, and Japan.

Its existence was closely associated with the availability

of water for irrigation, and was usually limited to the

production of two crops per year. The earliest known

reference to multiple cropping is found in a work known

as Taittiriya Samhita written between 3000 and 1000 B.C.
4







5

in India. It distinctly mentions that two crops were

harvested from the same field in the course of one year

(15).

Multiple cropping has long existed in China (37).

In the northern provinces, the systems were designed

around winter wheat as the basic crop while in the south,

multiple cropping of rice was more prevalent. The devel-

opment of an early maturing rice known as Champa around

1012 A.D. made possible the harvesting of two rice crops

in one season. By the Ming period (1368-1644 A.D.),

cold resistant cultivars of rice, which could be planted

in mid-summer, encouraged further practice of multiple

cropping. Fukien Province became very well known for

its double cropping of rice, but the actual area thus

cultivated in not known. Officials of Hunan, in the

north, encouraged the planting of second crops other than

rice during the seventeenth and eighteenth centuries (37).

Multiple cropping was also carried out in Egypt and

India during the 1800's but was limited to the Nile and

Ganges river valleys and in general was not extensive

(15).

The most extensive programs of multiple cropping

today are being conducted by the International Rice Re-

search Institute (IRRI) to improve the welfare of the

southeast Asian rice farmers (22). Within this program,

Bradfield has conducted extensive research on multiple







6

cropping. He developed some very sophisticated systems,

involving the cultivation of five crops per year (15).

These systems have been implemented in the Phillipines,

Java, the lower Mekong Basin, and other tropical areas

(4, 6, 23, 28). It consists primarily of preparing the

soil in an alternation of low beds for rice and high beds

for the other crops. The low beds are 60 cm wide and the

length varies according to topography. Four to 5 rows of

rice can be planted on them. The higher beds are 40 cm

wide and 30-40 cm higher than the low beds which they

separate. One row of corn or 2 rows of soybean, sorghum,

or other crops can be planted on these high beds. An

advantage of this system is that the second crop can be

planted before the harvest of the first paddy crop. The

low beds later serve as irrigation furrows for these

crops. A disadvantage is the large amount of water re-

quired to fill these low beds sufficiently to irrigate

the crops on the higher beds. This system also requires

some specialized mechanization which is for the most part

unavailable to the majority of small farmers. However,

all the data show that with irrigation, this system is

economically feasible (4).

Bradfield (6) has worked with rice in sequence with

sorghum, corn, soybean, mung bean, and sweet potato to

give good distribution of planting and harvesting dates

throughout the year. The frequent harvests, Bradfield







7

states, give the farmer something to market regularly

and can simplify his credit problems (6). IRRI (28)

trials of these patterns have shown that with improved

varieties having approximately the same growth duration

as farmer's varieties, multiple cropping makes better

use of a farmer's land resources.

More land is multiple cropped in Mainland China

than in the rest of the developing world combined (15).

The main forms of multiple cropping in northern China

are winter wheat followed by coarse grains such as mil-

let or corn. Further south, systems of winter wheat

followed by industrial crops such as oilseeds, toabcco,

or cotton and rice followed by a winter crop of barley,

pulses, or rapeseed are found (37). Other more unusual

cropping combinations found in China include cotton

followed by winter wheat, corn followed by rice, corn

followed by soybeans, rice followed by tobacco, and

jute followed by rice (15).

India has the second largest multiple cropped area

in the world (15). Extensive research and implementation

of multiple cropping in India has been provided by the

Ford Foundation (29). A surprisingly large portion of

the multiple cropped areas in India depend on natural

rainfall rather than irrigation (24). Many systems are

used depending on Location and terrain. Some of the

more common sequences used are hybrid corn followed by









wheat, rice followed by wheat, and rice followed by

rice. Other profitable rotations are rice, rice, and

wheat; rice, corn, and wheat; corn, potato, and tobacco;

and corn, potato, and pumpkin (1). Some new 4 crop

sequences now being tested in India include moong (a

legume), corn, wheat, and potato (24). Although yield

data is unavailable, it appears that results are good

based on India's projected doubling of their multiple

cropped area by 1980 (15).

Multiple cropping is being practiced today in many

other Eastern countries but usually on a smaller scale

and less intensively than those discussed.

Although some forms of multiple cropping have long

been practiced in the Americas, little if any information

regarding this has been recorded.

Double cropping rotations of winter wheat or barley

followed by grain sorghums have apparently been practiced

in the southern United States for 40 to 50 years (15).

Other systems found in the United States include soybeans

combined with sorghum, wheat combined with soybeans, and

buckwheat combined with early harvested small grains.

Specialized multiple cropping systems are found in Flo-

rida, Alabama, and California and usually involve vege-

tables (15).

A common rotation found in several Latin American

countries is planting beans in the same field with corn









after the corn has reached the drying stage (2).

A limited amount of corn is double cropped with a

second corn crop in Guatemala (15). Other combinations

now being introduced in Guatemala include vegetables

with grains, grains with grains, and grains with pasture

crops (13, 14).

Montague (33) reported Brazilian farmers to use

some double cropping involving wheat followed by soybeans,

or dry and wet season peanuts, or dry and wet season

beans.

Recently, Latin American agricultural experts de-

clared a need and presented proposals for increasing

the area multiple cropped in all Central America (43).

More than half the population of Central America is in

the rural sector, and the majority of the farmers have

small land holdings. Intensive land use is necessary if

the farm family is to attain satisfactory food supply

and sufficient employment and income to provide a modest

standard of living. In response, the Tropical Agricul-

tural Research and Training Center in Costa Rica is con-

ducting research directed toward developing polycultural

systems which consider the type of crop, growth cycle

duration, degree of affinity and competition between

mixed, overlapping, and crops grown in sequence. Exper-

imental crops include beans, rice, corn, sweet potato,

and cassava, the basic foods of Central American rural

people (44).







10

Ruthenberg (38) states that traditional agricultu-

ral research in the tropics has been directed towards

individual crops and monoculture, resulting in substan-

tial improvement in productivity of certain crops such

as corn, wheat, rice, coffee, cacao, sugar cane, bananas,

and others. However, because monoculture usually requires

fairly large land areas and usually involves some form of

mechanization, this research has benefitted those farmers

with the greatest financial capacity and .has had little

or no impact on the majority of Latin America's rural

population (38, 42).

In the process of developing cropping systems, IRRI

has examined the small farmer's current practices. The

Javanese farmer was found to use labor intensive methods

to grow several field crops in various combinations,

both with rainfall and irrigation, in a low cash-input

situation. The widespread use of these practices by

the small farmer throughout the tropics has encouraged

study as to their efficiency in meeting his needs (27).
There is a positive correlation between the expan-

sion of population and multiple cropping growth (15).

The highest population densities are found in east and

south Asia--multiple cropping is most prevalent in these

regions. The lowest densities are found in Africa,

Latin America, and the near East, and with the exception

of Egypt, multiple cropping in considerably less common









in these areas.

Boserup (5) states that population increases

encourage the adoption of more intensive systems of

agriculture.

Ben-Nun (4) has found that multiple cropping is not

only feasible with irrigation and of great economic impact

in the Mekong Basin, but may also prove to be the chief

factor in the future development of the region in light

of the predicted population growth of 30 million people

in the next 20 years.

Thus, it seems likely, based on very limited data,

that multiple cropping may best fit in land-limiting,

labor-surplus situations. It may also be far more pro-

ductive under situations where management and capital

availability are less than optimum for monoculture (27).

Dalrymple (15) concludes that multiple cropping,

from a social point of view, appears to hold promise of:

improving employment, reducing rural income disparities,

and expanding the quantity and quality of output. Care-

ful mixtures of Legumes, grain crops, and root crops

have exciting potential, not only for high levels of

nutrient production, but also for total productivity

(28). On the other hand, multiple cropping may increase

the demands on scarce human administrative and scientific

skills, and may increase foreign exchange costs for cer-

tain inputs. Still, on balance, multiple cropping appears









to be a most promising use of resources (15).

Forms of multiple cropping have been used for

centuries in various countries of the world. The devel-

opment of early maturing and cold resistant cultivars

and irrigation systems greatly expanded its possibilities.

Multiple cropping appears to be associated with areas of

high population density, limited cultivated land, limited

resources, high unemployment, and low mechanization.

Multiple cropping offers a means of greater employment

(15), greater yield per unit of land area (27), more

efficient utilization of resources (28), and possible

income increase (23).









Crop Rotation Development


Overview

Traditionally farmers of El Salvador plant corn at

the beginning of the rainy season. Beans follow corn

and reach maturity at the beginning of the dry season (9).

The farmer is dependent on these crops for his subsis-

tance, and his needs must be considered in the design of

any multiple cropping program. Those few farmers having

access to irrigation or low humid land often grow vegeta-

bles after corn and beans are harvested.

The following procedures outline the development of

a multiple cropping system that offers farmers without

irrigation or humid land a method to produce their basic

foods (corn, beans) plus high income vegetable crops dur-

ing the rainy season. Those farmers with irrigation can

use the system to grow several vegetable crops and basic

grain crops within a years time.

Vegetables such as tomato and cucumber must be

staked if grown during the rainy season, but staking

material is scarce and expensive. The primary objective

of the preliminary observation trial was to examine the

possibility of growing corn in such a manner that the

stalks could subsequently be used as stakes. A secondary

objective was to formulate techniques for an efficient

crop rotation. Subsequent trials focused on the further









Crop Rotation Development


Overview

Traditionally farmers of El Salvador plant corn at

the beginning of the rainy season. Beans follow corn

and reach maturity at the beginning of the dry season (9).

The farmer is dependent on these crops for his subsis-

tance, and his needs must be considered in the design of

any multiple cropping program. Those few farmers having

access to irrigation or low humid land often grow vegeta-

bles after corn and beans are harvested.

The following procedures outline the development of

a multiple cropping system that offers farmers without

irrigation or humid land a method to produce their basic

foods (corn, beans) plus high income vegetable crops dur-

ing the rainy season. Those farmers with irrigation can

use the system to grow several vegetable crops and basic

grain crops within a years time.

Vegetables such as tomato and cucumber must be

staked if grown during the rainy season, but staking

material is scarce and expensive. The primary objective

of the preliminary observation trial was to examine the

possibility of growing corn in such a manner that the

stalks could subsequently be used as stakes. A secondary

objective was to formulate techniques for an efficient

crop rotation. Subsequent trials focused on the further







14

development and testing of cropping systems on the pro-

duction of basic grains and vegetable crops.

The first experiments were designated 'observation

trial' and consisted of the following crop rotations:


Rotation 1:

Phase I Corn
(fresh)
Phase II Tomato
Phase III Broccoli
Muskmelon


Rotation

Phase

Phase


Phase III


Corn
(fresh)
Tomato
Pole Bean
(fresh)
Cauliflower
Muskmelon


Rotation

Phase

Phase

Phase



Rotation

Phase


3:

I Corn
(dry)
II Pole Bean
(dry)
III Tomato


Phase II


Phase III


Corn
(dry)
Radish
Squash
Tomato
Pole Bean
(dry)
Cabbage
Muskmelon


Rotation

Phase

Phase
Phase

Phase


Rotation

Phase


4:

I

II
III

IV


6:

I


Phase II
Phase III


Corn
(fresh)
Cucumber
Broccoli
Cowpea
Carrot
Beet



Corn
(dry)
Radish
Tomato
Bush Bean
(dry)


Following the observation trial, 2 larger plots,

designated as a 'field trial' were initiated. The rota-

tions in both plots of the field trial began with corn

and beans, the 2 most basic grains of the country. Other

crops were selected on the basis of their market demand







15

plus experience gained in the observation trial. Okra

was selected because of its demand by a freezer process-

ing plant in the area. The field trial was composed of

the following rotations:

Rotation 1: Rotation 2:

Phase I Corn Phase I Corn
(dry) (fresh)
Radish Radish
Bush Bean Bush Bean
(dry) (dry)
Phase II Tomato Phase II Cucumber
Phase III Cowpea Phase III Cabbage
(dry) Corn
Phase IV Okra (dry)
Phase IV Pole Bean
(dry)
Sweet Potato

A third experiment, the 'bean cultivar trial' was

designed to evaluate the cultivar rotation interactions

which might occur in a corn-bean multiple cropping pro-

gram. The following rotation was used for all cultivars:

Phase I Corn
(dry)
Bush Bean
(dry)
Phase II Corn
(dry)
Bush Bean
(dry)

Cultivars and sources of all crops planted are listed

in Appendix A.

Experimental Site

The trials were conducted at the National School of

Agriculture (ENA), located 25 km northwest of San Salvador








at a latitude of 13048' north of the equator.

Soil

A soil analysis indicated high potassium, medium to

high phosphorus, low nitrogen, intermediate calcium,

intermediate magnesium, and pH 5.5 to 6.5 (Table 1). The

soil in the test area was a sandy loam.

Table I. Soil analysis of a composite sample taken in the
field trial area and analyzed by the Soils Dept.,
Centro Nacional de Tecnologia Agropecuaria (CENTA),
Santa Tecla, El Salvador, 1973.



pH P K m.e. Ca/ m.e. Mg/ Texture
(ppm) (ppm) 100 g 100 g

6.4 27 +200 8.57 1.72 Sandy Loam



Trial Design

In each of the 3 trials, land was divided into plots.

A plot is a given area of land upon which a rotation of

crops was grown (Appendix B). A rotation is divided into

phases. A phase is defined as the time span which each

crop or association of crops occupied a plot.

The observation trial was composed of 6 plots, each

49 m long by 4.8 m wide. Each plot had a different rota-

tion (page 14). The plot 4 rotation covered a time span

of 4 phases while the remaining plots covered only 3. The

field trial was composed of 2 plots each 30 s-q_-in The








at a latitude of 13048' north of the equator.

Soil

A soil analysis indicated high potassium, medium to

high phosphorus, low nitrogen, intermediate calcium,

intermediate magnesium, and pH 5.5 to 6.5 (Table 1). The

soil in the test area was a sandy loam.

Table I. Soil analysis of a composite sample taken in the
field trial area and analyzed by the Soils Dept.,
Centro Nacional de Tecnologia Agropecuaria (CENTA),
Santa Tecla, El Salvador, 1973.



pH P K m.e. Ca/ m.e. Mg/ Texture
(ppm) (ppm) 100 g 100 g

6.4 27 +200 8.57 1.72 Sandy Loam



Trial Design

In each of the 3 trials, land was divided into plots.

A plot is a given area of land upon which a rotation of

crops was grown (Appendix B). A rotation is divided into

phases. A phase is defined as the time span which each

crop or association of crops occupied a plot.

The observation trial was composed of 6 plots, each

49 m long by 4.8 m wide. Each plot had a different rota-

tion (page 14). The plot 4 rotation covered a time span

of 4 phases while the remaining plots covered only 3. The

field trial was composed of 2 plots each 30 s-q_-in The









plots had different rotations, each covering 4 phases.

The bean cultivar trial was composed of 14 plots, each

14 m by 6 m wide. Each plot had the same rotation,

which covered 2 phases. All plots are illustrated in

Appendix B.

Statistical Analysis

In the bean cultivar trial, varietal effect was

considered constant among plots and each plot was con-

sidered a replication of the treatment. Data was ana-

lyzed by analysis of variance (41). Correlation was

conducted to determine a possible relationship between

the data set.

Levels of probability for significance were .05

and .01 indicated by and ** respectively in the tables

and significant and highly significant in the text. The

abbreviation N.S. indicates a non-significant difference

between treatments at the .05 level of probability.

Time of Planting

The observation trial was conducted over a time

period of 237 days between June 8, 1973 and January 31,

1974. This trial was initiated 20 days after the begin-

ning of the rainy season. The field trial covered 360

days beginning on December 6, 1973 and terminating on

December 2, 1974. This trial began approximately 2

months after the initiation of the dry season. The bean

cultivar trial covered 220 days commencing on May 30, 1974









plots had different rotations, each covering 4 phases.

The bean cultivar trial was composed of 14 plots, each

14 m by 6 m wide. Each plot had the same rotation,

which covered 2 phases. All plots are illustrated in

Appendix B.

Statistical Analysis

In the bean cultivar trial, varietal effect was

considered constant among plots and each plot was con-

sidered a replication of the treatment. Data was ana-

lyzed by analysis of variance (41). Correlation was

conducted to determine a possible relationship between

the data set.

Levels of probability for significance were .05

and .01 indicated by and ** respectively in the tables

and significant and highly significant in the text. The

abbreviation N.S. indicates a non-significant difference

between treatments at the .05 level of probability.

Time of Planting

The observation trial was conducted over a time

period of 237 days between June 8, 1973 and January 31,

1974. This trial was initiated 20 days after the begin-

ning of the rainy season. The field trial covered 360

days beginning on December 6, 1973 and terminating on

December 2, 1974. This trial began approximately 2

months after the initiation of the dry season. The bean

cultivar trial covered 220 days commencing on May 30, 1974






18

and ending on January 5, 1975. The trial began 1 week

after the initiation of the rainy season.

Although the 30 year average (Table 2) for the San

Andres Station (representative of the experimental area)

indicates measurable rainfall for each month of the year

(32), the period during which these trials were conducted

experienced a dry season with no precipitation from Nov-

ember through the later part of May. The rainfall pattern

of 1957 was typical of the seasonal distribution of rain

during the trials.

Field Preparation

In all the trials the fields were disk-plowed,

disked, then re-disked with a drag. In the observation

trial and field trial, Aldrin (see Appendix C for rates

of all pesticides) was applied over the trial area and

incorporated by the final disking. The bean cultivar

trial was treated in the identical manner except Phoxim

was applied as a pre-plant soil insecticide. In all

trials, except the observation trial, the original rows

were formed with a team of oxen and a wooden plow.

Transplants

Preparation and care of seed beds for transplants

used in the observation and field trial followed the same

procedure. Raised brick beds (10 x 1 x .3 m) were filled

with a mix of a third part each of decomposed manure,

sand, and soil. One kg triple-super-phosphate was






18

and ending on January 5, 1975. The trial began 1 week

after the initiation of the rainy season.

Although the 30 year average (Table 2) for the San

Andres Station (representative of the experimental area)

indicates measurable rainfall for each month of the year

(32), the period during which these trials were conducted

experienced a dry season with no precipitation from Nov-

ember through the later part of May. The rainfall pattern

of 1957 was typical of the seasonal distribution of rain

during the trials.

Field Preparation

In all the trials the fields were disk-plowed,

disked, then re-disked with a drag. In the observation

trial and field trial, Aldrin (see Appendix C for rates

of all pesticides) was applied over the trial area and

incorporated by the final disking. The bean cultivar

trial was treated in the identical manner except Phoxim

was applied as a pre-plant soil insecticide. In all

trials, except the observation trial, the original rows

were formed with a team of oxen and a wooden plow.

Transplants

Preparation and care of seed beds for transplants

used in the observation and field trial followed the same

procedure. Raised brick beds (10 x 1 x .3 m) were filled

with a mix of a third part each of decomposed manure,

sand, and soil. One kg triple-super-phosphate was










Table 2. Annual rainfall distribution based on a 30
year average 1944-1974, and minimum recorded annual
rainfall occurring in 1957 for the San Andres experi-
mental area (ENA).


Month


Rainfall in Millimeters
Average Minimum (1957)


January

February


March

April


May


June


July

August

September

October

November

December


198

259

312

263

299

145


7


71

156

179

164

166


0


Totals


-


- ------ -----


1597


798







20

distributed evenly over the soil surface and incorpo-

rated. The beds were wetted, tilled, and covered with

burlap bags followed by a polyethylene plastic cover

over the entire bed container. A soil sterilant was

applied beneath the plastic cover. Three to 4 days

after fumigation, the beds were uncovered and allowed to

aerate 1 day. The following day the soil was tilled and

leveled. Rows 10 cm apart were planted to the appropriate

crop. The burlap bags were replaced over the seed beds.

When emergence had begun, the bags were removed. One

week after emergence, the plants were thinned leaving

2-3 cm between plants. Ten and 17 days after seeding,

a starter fertilizer solution was applied (see Appendix

D for rates and formulas of all fertilizers). The seed

beds were watered twice daily. Insecticides, nematocides,

and fungicides applied in the seed beds and field followed

recommended practices (39). Each transplant was dipped

in a fungicide solution and then placed in holes 4 cm in

diameter by 10 cm deep that were filled with a starter

fertilizer solution followed by soil.

Fertilizer

The fertilizer programs used during the trials were

based on previous investigation with monocultured crops

(36). Generally the first fertilizer application to any

crop was placed in bands or evenly spaced holes 12 cm







21

deep and 10-15 cm to one or both sides of the plant row.

To avoid root damage and/or root inoculation of disease

causing bacteria, the second fertilization was applied

in bands on the ground surface 15-20 cm to one or both

sides of the plant row and covered with soil pulled from

the furrows (Fig. 1).

Second
Fertilization
of Phase 11
Phase I1
Crop










Second Fertilization Residual First Fertilization
of Phase I Phosphorus of Phase 11
of Phase I

Fig. 1. Cross section of fertilizer bands incorporated
in phases I and II, Observation Trial and Field Trial,
1973-1974.



Hilling soil over the fertilizer and around the base

of the corn stalks helped to prevent lodging and began to

form the vegetable beds beneath the corn upon which the

succeeding crops were planted (Fig. 2).



















t Fertilizer Hilled Second Fe
Band Corn Band


Fig. 2. Cross section of fertilizer bands and hilling
of corn. Observation Trial, Field Trial, and Bean
Cultivar Trial, 1973-1975.



Fertilizer placement near the corn and the vegetable

beds made it possible for succeeding crops to utilize

residual fertilizer of preceding phase.

Observation Trial-Corn (All Rotations)

Since corn was the initial crop in all rotations,

and procedures for corn were similar in all rotations,

procedures for corn are presented separately. The corn

was planted in the triangular pattern illustrated in

Fig. 3.



t--25 cm --P ,e, ----
25 cm 25 cm 21.7 cm
m c-------m ,


Fig. 3. Diagram of triangular planting pattern used
for seeding corn. Observation Trial, 1973.







23

This planting configuration is referred to as a double

corn row (Fig. 4).


25 cm

nr*

120 cm
< --- --
r^ Fft u\


Double
Corn Row
- )-__


Fig. 4. Cross section of plots seeded with corn, show-
ing the 4 closely spaced double corn rows and their
spacing. Observation Trial, 1973.


The day of corn seeding is designated as day 0.

This planting system remained constant for all 6 rotations,

Each of the rotations were seeded with 4 double corn rows.

The corn in rotations 1, 2, and 4 was harvested as

fresh corn while that of rotations 3, 5, and 6 was doubled

and left to dry in the field (Fig. 5).


Fig. 5. Doubled corn stalk with the ear hanging so that
the corn husk sheds the rain. Observation Trial, Field
Trial, and Bean Cultivar Trial, 1973-1975.


_ __









Observation Trial Rotation 1

Refer to Table 3 for a chronological calendar of

events for rotation I. In the observation trial, bed

preparation for transition from phase I to phase II was

done in the same manner for all rotations independent of

the crop. The preparation was carried out in the follow-

ing steps and illustrated in Fig. 6:

1. The corn stalks were stripped of their leaves.

2. ALdrin was applied to the plots.

3. The double corn rows were hilled forming the
vegetable beds.

4. Nematocide was incorporated on the tops of the
beds (excluding rotation 3).

5. The beds were planted.

The tomatoes were transplanted in the center of the

vegetable beds between the corn stalks (Fig.7). After

transplanting, the remainder of the corn leaves and top

section were removed leaving the bare stalks 1.5 m in

height.

The tomato trellising system was initiated by tying

together 3 corn stalks approximately 1.3 m up from the

base of the stalks forming a tripod structure. Then,

4 pairs of horizontal twine supports were tied to the

legs of the tripods. The lower supports began 30 cm

from ground level and the remaining 3 pairs were evenly

spaced to a height of 1.2 m. The horizontal twine

supports were secured to posts located at the ends of









Table 3. Chronological calendar of events for rotation
1. Observation Trial, 1973.



Month Day Procedure


S-----0
June
_-- 12
1 0


July


i---35


---60

Aug. 773
.- 78
---- 81
--- 85
----95
Sept.


Oct.
-132

150
Nov.

177
180

o Dec. 185




,r4
SJan.

0
o4
o --F250
a( Feb.


Corn seeding
Corn thinning and first fertilization


Second corn fertilization


Seed bed planting of phase II tomato
Phase II bed preparation
August fresh corn harvest
Tomato transplant and fertilization
De-leaving and topping of corn stalks
Formation of tomato trellising system




Second tomato fertilization

First tomato harvest, seed bed planting
of phase II broccoli

Phase III bed preparation
Transplant and fertilization of broccoli,
seeding of muskmelon
Final tomato harvest, windrowing of
plant debris


Plot terminated


.


































a. b,


Fig. 6. Cross section of plots illustrating (a) mature
corn ready for transition to phase II and (b) phase
II vegetable beds formed and planted. Observation
Trial, 1973.


Tomato



0 0 0


*


S


* S


Corn Stalk


*


*


* 0


5


50 cm


Fig. 7. Top view of corn rows with tomatoes transplanted
in phase II. Observation Trial, 1973.


o


0


* S


0








the beds (Fig. 8).


Fig. 8. Corn stalks tied to form tripods and the hori-
zontal support twine tied to the legs of the tripods
and the end posts. Rotations 1, 2, 4, 5, and 6,
Observation Trial, 1973.


Transition from phase II to phase III was done in

the same manner for plots 1, 2, and 5 independent of the

crop as follows:

1. Removal of lower tomato leaves.

2. Re-shaping of the sides of the tomato beds.

3. Transplant and seeding of phase III crops.

4. Windrowing of tomato vines and tripods in
furrows after the last tomato harvest.

The phase III broccoli of rotation 1 was transplanted









on the sides of the tomato beds 40 cm between plants.

The muskmelon were seeded between the broccoli trans-

plants (Fig. 9).







A Cauliflower,
Broccoli,
or Cabbage Muskmelon




Muskmelon Plant Debris
a. b. of Phase II


Fig. 9. Cross section of plots for rotations 1, 2, and
5, phase III. (a) Phase III transplants and musk-
melon planted beneath tomato vines. (b) Tomato and
tripod debris placed in the furrows. Observation
Trial, 1973.


The plant debris of the tomatoes and tripods served

as a bed of mulch upon which the muskmelons grew.

Observation Trial Rotation 2

A chronological calendar of events for rotation 2

is presented in Table 4. The transition 'from phase I to

phase II tomatoes followed that of rotation 1. Immedi-

ately following the tomato transplant, pole beans were

seeded between the tomato plants (Fig. 10).

The tomato trellising was done identically to

rotation I (Fig. 8).









Table 4. Chronological calendar of events for rotation 2.
Observation Trial, 1973.



Month Day Procedure


0 Corn seeding

June -- 12 Corn thinning a


---35 Second corn fer
July


-- 60 Seed bed Dlanti
73 Phase II bed pr
. Aug. .-'78 Fresh corn harv
----81 Tomato transpla
___bean fertilizat
85 De-leaving and
'95 Formation of to:
Sept.


--132 Second tomato f
Oct. .--136 First bean harv

---150 First tomato ha
seed bed plant
wer
Nov.
i--177 Phase III bed p
180 Transplant and
N flower, seeding
185 Last tomato har
Dec. plant debris



Jan.


:--250 Plot terminated

Feb.


nd fertilization


utilization



ng of phase II tomato
eparation
est
nt, bean seeding, first
ion
topping of corn stalks
mato trellising system



ertilization
est

rvest, last bean harvest,
ng of phase II cauliflo-


reparation
fertilization of cauli-
of muskmelon
vest, windrowing of


o
.4



I
0

"4
4-4
.,4
,-4
o












Corn Stalk Tomato Pole Bean

O 0 O


50 cm 50 cm




Fig. 10. Tomatoes interplanted with pole beans. Rota-
tion 2, Observation Trial, 1973.







31

The pole beans were harvested as fresh beans. After

the last harvest, the main stems were cut at ground level

and left to dry.

The transition from phase II to phase III was the

same as in rotation 1 except that cauliflower was trans-

planted in place of broccoli.

After the final tomato harvest, the tripods and

vines were cut at the base and placed in the furrow along

with the dried bean plants to serve as mulch for the

muskmelons (Fig. 9).

Observation Trial Rotation 3

A chronological calendar of events for rotation 3 is

summarized in Table 5. The transition from phase I to

phase II was the same as that of rotation 1, substituting

pole beans for tomatoes. The pole beans were planted

(Fig. 11) immediately after the doubling of corn.

Tomato transplant procedure was the same as that

used in rotation 1 except that tomatoes were transplanted

on the sides of the beds (Fig. 12) instead of the center

as in rotation 1.

The dried pole beans and corn were then harvested.

Following harvest, the corn stalks were placed across the

furrows in the manner illustrated for cucumbers in rotation

4. The corn stalks which bridged the furrows between the

tomato plants formed a support bed for the tomato vines.









Table 5. Chronological calendar of events for rotation 3.
Observation Trial, 1973.




Month Day Procedure


0
Ju--n---e
June 12
-~ 2


Corn seeding

Corn thinning, first fertilization


July +--35 Second corn fetilization




Augo

---85 Phase 11 bed preparation
So T--90 Corn doubling, pole bean seeding
o !'-95 Pole bean fertilization
Sept.



O' Oct.

-- 148 Seeding of phase III tomatoes in seed bed
o
Nov.o /168 Phase III nematocide application
-70 Phase III tomato transplant
175 First tomato fertilization, bed of stalks
formed, corn and bean harvest
Dec.
o
(d
0
Jan.
--235 Rotation terminated


Feb.














Corn Stalk

. ^. .


* *


Pole Bean




* *


25 cm


Fig. 11. Top view of double corn rows with pole beans
seeded in rotation 3. Observation Trial, 1973.


Tomatoes Pole Beans


Fig. 12. Cross section of plot illustrating phase III,
Rotation 3, Observation Trial, 1973.


0


r









Observation Trial Rotation 4

A chronological calendar of events for rotation 4

is summarized in Table 6. The transition from phase I

to phase II followed that of rotation 1, substituting

cucumbers for tomatoes (Fig. 7).

Five trellising systems were used for the cucumbers

(Fig. 13). The corn stalks from beds 1 and 2 were bent

at ground level bridging the furrow and forming a bed of

stalks. Corn leaves were evenly distributed over one

half of this bed. One half of the corn stalks of bed

3 and all of bed 4 were formed into tripods. The tripods

on the west half of beds 3 and 4 had one end of a piece

of twine tied at the apex of the tripod and the other

end secured to the base of one leg. The corn stalks on

the east half of bed 3 were left standing, as added sup-

port for the branches (approximately 1.5 m in height)

which were embedded upright every 50 cm between each

group of cucumber plants. -The east half of bed 4 was

trellised in the manner described for tomatoes in Fig. 8.

Cucumber fruit 15 cm and longer were harvested twice

weekly.

The plant spacing and transplant procedure for phase

III was the same as that of the broccoli transplant of

rotation 1 (Fig. 9). Since the corn stalks in unstaked

beds were mulched in the furrow, transplants in these

plots were exposed to full sun.









Table 6. Chronological calendar of events for rotation 4.
Observation Trial, 1973.



Month Day Procedure


--- 0
June
---12


July *:---35



Aug.
---73
78

S85
Sept. 5

\ 95


Oct.


Nov.


Dec.


Jan,


Feb.


_--246
r--247

7' 261
'264


Corn seeding
Corn thinning, first fertilization


Second corn fertilization





Phase 11 bed preparation
Fresh corn harvest
Phase II cucumber seeding
Cucumber thinning and first fertiliza-
tion, upper corn leaves and tassels
removed
Trellising of cucumber
Second cucumber fertilization
First cucumber harvest
First seed bed planting of phase III
broccoli
Second seed bed planting of phase III
broccoli
Broccoli transplant (beds 1 and 2)
Last harvest of untrellised cucumber,
seeding of cowpea
Fertilization of cowpea
Broccoli transplant (beds 3 and 4)
Last harvest of trellised cucumber and
removal, seeding and fertilization of
cowpea
Second fertilization of broccoli (all
beds)
First broccoli harvest

Last broccoli harvest
Bed preparation and seeding of phase IV
carrots and beets
Dry cowpea harvest
Data collection terminated


- -- --1- ---- -- --











West Half of Plot 4


Bed of Corn Vertical Twine
Stalks with Leaves


East Half of Plot 4


/ Bed
No. 1


Bed of Corn
Stalks Without Leaves


Branches Horizontal
Twine


Fig. 13. Five trellising methods for cucumbers in
rotation 4, Observation Trial, 1973.







37

Immediately after the last cucumber harvest of beds

I and 2, the corn stalks and cucumber vines were cut at

ground level and compacted in the furrow between the

beds. A single row of cowpeas was then seeded in the

center of the furrow 15 cm apart.

After the last cucumber harvest of beds 3 and 4,

cowpeas were seeded 15 cm apart in rows on the sides of

the vegetable beds. Immediately following the seeding

of the cowpeas on beds 3 and 4, the tripods and cucumber

vines were cut at ground level and compacted in the

furrow (Fig. 14).





Broccoli
Cowpea C Cowpea

Bed t Bed Bed NSf^Bed
NO* 1 2 No. 3 No. 4

Plant Debris



Fig. 14. Two systems of seeding cowpeas with broccoli.
Rotation 4, Observation Trial, 1973.


The cowpeas of beds I and 2 were harvested as fresh

green beans over a 2 week period. Cowpeas which developed

after this period were left to dry. The 2 rows of cowpeas

between beds 3 and 4 were harvested as dry beans.

Data taking for all rotations was terminated after






38

phase III, but to examine the possibility of continuing

a crop sequence, phase IV was initiated in rotation 4.

After the last broccoli harvest, phase IV began with

the removal of the broccoli plants. The soil on the old

broccoli beds was loosened and spread to form a new lower

and wider bed (Fig. 15). Beds 1 and 2 were seeded with

carrots and beds 3 and 4 with beets (Fig. 15).


Bed
No. 1


Bed
No. 2


Bed
No. 3


Bed
No. 4


Carrots


Fig. 15. Bed formation and seeding of phase IV. (a)
Overlap period of cowpeas with carrots and beets and
(b) carrots and beets after removal of cowpeas.
Rotation 4, Observation Trial, 1973.








Observation Trial Rotation 5

A chronological calendar of events for rotation 5

is summarized in Table 7. Rotation 5 was seeded with

radish and squash in addition to corn in phase I in the

manner illustrated in Fig. 16. The squash were seeded

in the middle of each double corn row at a spacing of

1 m.

The squash were removed before transition from

phase I to phase II began. From this point, rotation 5

followed that of rotation 1 with the exception that

cabbage was transplanted in place of broccoli in phase

III.

Observation Trial Rotation 6

A chronological calendar of events for rotation 6

is summarized in Table 8. In phase I, rotation 6 was

seeded identically to rotation 5 wxcept for the squash

(Fig. 16).

The transition from phase I to phase II tomatoes

was the same as that of rotation 1.

The transition from phase II to phase III was the

same as that of rotation 1, with the exception that bush

beans were planted on the sides of each bed (Fig. 17).

Following the Last tomato harvest, the tripods and

vines were cut at ground level and placed in the furrows

between the beds.








Observation Trial Rotation 5

A chronological calendar of events for rotation 5

is summarized in Table 7. Rotation 5 was seeded with

radish and squash in addition to corn in phase I in the

manner illustrated in Fig. 16. The squash were seeded

in the middle of each double corn row at a spacing of

1 m.

The squash were removed before transition from

phase I to phase II began. From this point, rotation 5

followed that of rotation 1 with the exception that

cabbage was transplanted in place of broccoli in phase

III.

Observation Trial Rotation 6

A chronological calendar of events for rotation 6

is summarized in Table 8. In phase I, rotation 6 was

seeded identically to rotation 5 wxcept for the squash

(Fig. 16).

The transition from phase I to phase II tomatoes

was the same as that of rotation 1.

The transition from phase II to phase III was the

same as that of rotation 1, with the exception that bush

beans were planted on the sides of each bed (Fig. 17).

Following the Last tomato harvest, the tripods and

vines were cut at ground level and placed in the furrows

between the beds.







40


Table 7. Chronological calendar of events for rotation 5.
Observation Trial, 1973.



Month Day Procedure


June -;---3
4-7



---38

(0

-d

OnI






SOct. 30
S--6145

Nov73
85
0 Sept. 9o0

00
E-o
Oct. 130


-1--145
ci Nov.


u

C,
0
-4
oU

&


Corn seeding
Radish seeding
Squash seeding
Corn and radish thinning, first corn
fertilization
First radish harvest
Last radish harvest, second corn
fertilization


Seed bed planting of phase II tomato
Removal of squash, phase II bed prepara-
tion
Tomato transplant, bean seeding, first
fertilization
Corn de-leaving and doubling, phase 11
termination


Dry corn harvest

Seed bed planting of phase III cabbage


----172 Phase III bed prepa
Tl75 Transplant and fert
seeding of muskmelo
Dec.




Jan.



--245 Rotation terminated
Feb.


ration
ilization of cabbage,
n













20 cm 20 cm
rj--^ rl%>


Radish Corn Squash




Fig. 16. Phase 1, rotation 5, illustrating the planting
arrangement and row spacings of corn, squash, and
radish. Observation Trial, 1973.


Phase II Phase III
Tomatoes Bush Beans


Fig. 17. Bush beans seeded beneath tomato vines in
phase III, rotation 6, Observation Trial, 1973.


21.7 cm,
r-k--


1.2 m






42

Table 8. Chronological calendar of events for rotation 6.
Observation Trial, 1973.



Month Day Procedure




June O Corn seeding
: 03 Radish seeding
-12 Corn and radish thinning, first corn
fertilization

SJuly --33 First radish harvest
S--38 Last radish harvest, second corn
fertilization

g 60 Seed bed planting of phase II tomato
Aug.

_.--80 Phase II bed preparation
j- 85 Tomato transplant
87 First tomato fertilization
SSept. 90 Corn de-leaving and doubling
o. "99 Trellising of tomatoes


0 Oct. --130 Second tomato fertilization, dry corn
4 harvest

o
E -1--154 First tomato harvest
Nov.


_1-l84 Bed preparation and seeding of phase
III bush beans
Dec. T 189 Last tomato harvest, windrowing of
__ plant debris, bean fertilization


Jan.


SFeb 25 Bushbeanharvestrotationterminated
Feb. ---254 Bush bean harvest, rotation terminated









Field Trial Phase I (Rotations 1 and 2)

The field trial (Tables 9, 10) differed from the

observation trial in that phase I was planted on raised

beds instead of level land. The planting system used

for corn and radish was the same for both rotations.

The beans were seeded differently for each rotation

(Fig. 18). The beans were seeded 15 cm apart. The

radish spacing was 5 cm. The corn was seeded in the

triangular pattern (Fig. 3). The spacing between the

rows of each double row was increased from 21.7 to 25

cm. The 2 rotations were treated the same through the

transition to phase II except that the corn from rotation

1 was doubled and harvested as dry corn and that of

rotation 2 was harvested as fresh corn.

Field Trial Rotation 1

In the field trial, bed preparation for transition

from phase I to phase II was the same for both rotations.

The preparation was as follows (Fig. 19):

1. Double corn rows were hilled forming vegetable
beds.

2. Corn stalks were stripped of lower leaves.

3. Nematocide was incorporated on tops of beds.

4. Beds were planted.

From this point to the transition to phase III, refer

to observation trial, rotation 1, phase II (page 23).

The transition from phase II to phase III was the









Field Trial Phase I (Rotations 1 and 2)

The field trial (Tables 9, 10) differed from the

observation trial in that phase I was planted on raised

beds instead of level land. The planting system used

for corn and radish was the same for both rotations.

The beans were seeded differently for each rotation

(Fig. 18). The beans were seeded 15 cm apart. The

radish spacing was 5 cm. The corn was seeded in the

triangular pattern (Fig. 3). The spacing between the

rows of each double row was increased from 21.7 to 25

cm. The 2 rotations were treated the same through the

transition to phase II except that the corn from rotation

1 was doubled and harvested as dry corn and that of

rotation 2 was harvested as fresh corn.

Field Trial Rotation 1

In the field trial, bed preparation for transition

from phase I to phase II was the same for both rotations.

The preparation was as follows (Fig. 19):

1. Double corn rows were hilled forming vegetable
beds.

2. Corn stalks were stripped of lower leaves.

3. Nematocide was incorporated on tops of beds.

4. Beds were planted.

From this point to the transition to phase III, refer

to observation trial, rotation 1, phase II (page 23).

The transition from phase II to phase III was the








Table 9. Chronological calendar of events for rotation I.
Field Trial, 1973-1974.



Month Day Procedure


-1

Dec. IL
5
10
10 12
'031
Jan. \- 32
35
7-47

74
a Feb. 778


S" 88
Mar. --797

s---



----- -143
0 1---150

May --- 164


Seeding of radish
Seeding of corn
Seeding of bean
Fertilization of corn
Thinning of corn and radish
Fertilization of bean
Radish harvest
Hilling of corn
Seeding of phase II tomato in seed bed
Second seeding of phase II tomato in
seed bed
Bean harvest
Phase II bed preparation, first fertili-
zation of tomato
Tomato transplant
Upper corn leaves removed, corn doubled
Trellising of tomato





Second tomato fertilization
Harvest of dry corn

First tomato harvest


June
L- ---201 Seeding of cowpea
--206 Final tomato harvest, windrowing of
Svines and tripods
211 Fertilization of cowpea
July



0 Aug.



-Sept. ---287 Cowpea harvest, bed preparation of phase

-- 293 Seeding of Okra
H









Table 10, Chronological calendar of events for rotation 2,
Field Trial, 1973-1974.



Month Day Procedure


S- Radish seeding
:3-0 Corn seeding
Doc. -1 Bush bean seedir
S-10 Radish thinning,
nation
14 Corn thinning
1---35 Radish harvest
Jan. 37 Hilling of corn


-/70 Bush bean harvest
Feb. -73 Bed preparation
cucumber fertiLi
*- 82 Cucumber seeding
S85 Fresh corn harv
Mar. moval of tassel
\96 Trellising of cv


--127 First cucumber
Apr.
---140 Seeding of phas


May
May .169 Phase III cabba
-__ _-174 Last cucumber hi
-i--181 Seeding of phas<

June --191 Fertilization ol



July

S.-239 Cabbage harvest
-'-240 Hilling of corn
Aug.


corn and bean fertili-






>t
for phase II cucumber,
ization

est, de-leaving and re-

icumber


harvest
e III cabbage in seed bed


;e transplant
irvest
e III corn
f cabbage and corn









Table 10. Continued.


Month Day Procedure


Aug. 255
--260
7---265
---2 71
Sept.


Bed preparation for phase IV
Planting of sweet potato
Seeding of pole beans
Doubling of corn


LJ
a Oct.


o ---335 Harvest of pole beans and dry corn
4 Nov.
oi











1.4 m

25 cm 25 cm 47 cm
r~c r


20 cm
r-C-1


Radish Corn Beans
1.4 m


20 cm
r-1-


20 cm


Fig. 18. Row and plant spacings for rotations 1 and 2.
(a) Single row of beans planted in rotation 2 and
(b) double row of beans planted in rotation 1. Field
Trial, 1973.


SPhase II
Phase I Bean Row Vegetable Bed

Fig. 19. Beds formed and corn stalks de-leaved. Dotted
line represents the row configuration in phase I. Solid
line represents phase II vegetable beds. Field Trial,
1974.






48

same as that of the observation trial, rotation 1 except

that 3 rows of cowpeas were seeded on the sides and middle

of the tomato beds (Fig. 20).












a. Tomato Cowpeas







b. Tomato and Tripod Debris



Fig. 20. Phase III, rotation 1 illustration of (a) three
rows of cowpeas seeded beneath tomatoes, and later (b)
tomato vines and tripods placed in the furrow. Field
Trial, 1974.


After the cowpea harvest, the plant debris was wind-

rowed between the beds and the okra seeded over bands of

a nematocide (Fig. 21).











Okra




60 cm 80 cm Banded Plant Debris
Nematocide





Fig. 21. Diagram of phase IV, rotation 1, Field Trial,
1974.


Field Trial Rotation 2

Phase II cucumbers were seeded in the same manner

described in the observation trial (Fig. 7). The cucum-

bers were staked using 3 different systems. One third

of the field was staked with branches and one third with

vertical twine (Fig. 13). The remaining third was the

horizontal twine system (Fig. 8) except that only half

the number of strings were used.

The phase III cabbage was transplanted in 2 rows

50 cm apart on the cucumber beds with 40 cm between

plants (Fig. 22).

After the final cucumber harvest, the tripods and

vines were windrowed between the cabbage beds. Corn was

then planted on each side of the windows. The planting

system was the same as illustrated in Fig. 3, except the

rows were seeded 35 cm apart (Fig. 23),





















50 cm
Cabbage Cucumber
Plant


Fig, 22. Two rows of cabbage transplanted on the sides
of the cucumber beds. Rotation 2, Field Trial, 1974.


140 cm
____A ------
50 cm 35 cm





Plant Cabbage Corn
Debris


Fig. 23. Diagram of corn seeding between cabbage rows.
Rotation 2, Field Trial, 1974.









After the cabbage harvest, soil was hilled around

the base of the phase III corn forming the beds for the

phase IV pole beans and sweet potatoes (Fig. 24).


Plant Debris of Phase II


Sweet Banded
Potatoes Nematocide


Fig. 24. Transition of vegetable beds from phase III to
phase IV. (a) Dotted line represents old cabbage beds.
Solid line represents newly formed bean and sweet potato
beds. (b) Planting position of pole beans and sweet
potatoes over banded nematocide. Rotation 2, Field
Trial, 1974.








Immediately after the bed formation, sweet potato

cuttings were planted. Then the pole beans were seeded.

The corn was then doubled and later harvested as dry corn

along with the dried pole beans, leaving only the sweet

potatoes.

Bean Cultivar Trial

In both phase I and phase II, 7 bean cultivars

(Tables 11, 12) were interplanted with corn. All plots

had 1 m borders left at each end leaving 12 m in which

yield data was collected.

Two systems for planting beans and corn were used.

The original system is described in phase I of the field

trial. A modification of that system is shown in Fig. 25.

The north half of all plots under the modified system

were planted with beans on the tops of the ridges and the

south half had beans planted on the inside of the 2 ridges

between the double corn rows (Fig. 25).

The corn was seeded in the triangular pattern (Fig.

3). There was an increase from 21.7 cm to 30 cm between

corn rows and 1.4 m to 1.5 m from center to center of

the double corn rows (Fig. 25).

The transition to phase II began with the removal of

all lower corn leaves which were windrowed between the

pairs of rows. The phase II beans were then seeded in

rows adjacent to the corn stalks (Fig. 26). The phase







53

Table 11. Bean cultivar plots. Planting and harvest
dates and planting systems, phase I, Bean Cultivar
Trial, May, 1974.



Cultivar Plot Planting Harvest Planting
No. Date Date System


'27-R'


2 5-30-74


'Centa 105'

'Sensuntepeque'

'Centa 105'

'Centa 105'

'S-184'

'Centa 105'

'Centa 105'

'Porrillo 70'

'Centa 105'

'San Fernando'


'Arbolito'

'Centa 105'

'Centa 105'


5-31-74

5-30-74

5-31-74

5-31-74

5-30-74

5-31-74

5-31-74

5-30-74

5-31-74

5-30-74


5-30-74

5-31-74

5-31-74


8-3-74
8-8-74

8-19-74

8-29-74

8-19-74

8-22-74

8-8-74

8-23-74

8-22-74

8-12-74

8-22-74

7-31-74
8-3-74

8-12-74

8-16-74

8-22-74


Modified


Original

Modified

Modified

Original

Modified

Original

Modified

Modified

Original

Modified


Modified

Modified

Modified


---- -- -- -- --









Table 12. Bean cultivar plots. Planting and harvest
dates, phase II, Bean Cultivar Trial, August, 1974.



Cultivar Plot Planting Harvest
No. Date Date


'27-R'

'27-R'

'Sensuntepeque'

'Sensuntepeque'

'Centa 105'

'S-184'

'Centa 105'

'S-184'

'Porrillo 70'

'Porrillo 70'

'San Fernando'

'Arbolito'

'Arbolito'

'San Fernando'


8-26-74

8-26-74

8-26-74

8-26-74

8-26-74

8-27-74

8-27-74

8-27-74

9-3-74

8-27-74

8-29-74

8-27-74

8-27-74

8-29-74


11-4-74

10-30-74

10-28-74

10-29-74

11-18-74

11-6-74

11-7-74

11-7-74

11-11-74

11-18-74

11-7-74

11-14-74

11-18-74

11-8-74


- -- --


















1.5 m 50 cm 30 cm





ae
Corn Beans

1.5 m 50 cm 30 cm 30 cm
--



b. Beans Corn


1.5 m 35 cm 50 cm 30 cm




Co Beans Corn






Fig. 25. Row and plant spacing for original and modified
bean planting systems. (a) Original system, (b)
modified system and method of planting for south half
of plots, and (c) modified system and method of plant-
ing for north half of plots. Bean Cultivar Trial, 1974.































Beans Plant Debris

1.5 m


Plant Debris
of Phase I Corn


Doubled
Corn


Fig. 26. Transition to phase II illustrating (a) phase
II beans seeded beneath corn and (b) phase I corn
doubled and phase II corn seeded. Bean Cultivar
Trial, 1974.







57

II corn was planted immediately after the corn stalks

were topped and doubled (Fig. 26).









Results


Observation Trial-Corn (All Rotations)

The corn from phase I was harvested as fresh corn

in rotations 1, 2, and 4. The data on weight and/or

size of ears was not recorded although they appeared

average as compared to monocultured corn. The corn from

plots 3, 5, and 6 was harvested as dry corn. The average

yield for the 3 plots was 3.6 M.T./ha. This yield was

slightly inferior to the average yield (3.9 M.T./ha) of

monocultured corn grown under experimental conditions by

the Plant Science Department of CENTA.

The corn stalks tended to etiolate, but lodging due

to weak or corn borer (Ostrinia nubilalis Hubner) (7, 8,

20) damaged stalks occurred in less than 1% of the stand,

The observations and physiological data in Table 13

apply to all plots. This table is included because of

its relationship to the timing of events that occurred in

this and following trials.

Observation Trial Rotation 1

Phase I Phase II Phase III

Corn Tomato Broccoli
Muskmelon

The crop sequence of rotation 1 was generally suc-

cessful. The phase II tomatoes and phase III broccoli

had high yields, but muskmelon did not yield any









Results


Observation Trial-Corn (All Rotations)

The corn from phase I was harvested as fresh corn

in rotations 1, 2, and 4. The data on weight and/or

size of ears was not recorded although they appeared

average as compared to monocultured corn. The corn from

plots 3, 5, and 6 was harvested as dry corn. The average

yield for the 3 plots was 3.6 M.T./ha. This yield was

slightly inferior to the average yield (3.9 M.T./ha) of

monocultured corn grown under experimental conditions by

the Plant Science Department of CENTA.

The corn stalks tended to etiolate, but lodging due

to weak or corn borer (Ostrinia nubilalis Hubner) (7, 8,

20) damaged stalks occurred in less than 1% of the stand,

The observations and physiological data in Table 13

apply to all plots. This table is included because of

its relationship to the timing of events that occurred in

this and following trials.

Observation Trial Rotation 1

Phase I Phase II Phase III

Corn Tomato Broccoli
Muskmelon

The crop sequence of rotation 1 was generally suc-

cessful. The phase II tomatoes and phase III broccoli

had high yields, but muskmelon did not yield any









Results


Observation Trial-Corn (All Rotations)

The corn from phase I was harvested as fresh corn

in rotations 1, 2, and 4. The data on weight and/or

size of ears was not recorded although they appeared

average as compared to monocultured corn. The corn from

plots 3, 5, and 6 was harvested as dry corn. The average

yield for the 3 plots was 3.6 M.T./ha. This yield was

slightly inferior to the average yield (3.9 M.T./ha) of

monocultured corn grown under experimental conditions by

the Plant Science Department of CENTA.

The corn stalks tended to etiolate, but lodging due

to weak or corn borer (Ostrinia nubilalis Hubner) (7, 8,

20) damaged stalks occurred in less than 1% of the stand,

The observations and physiological data in Table 13

apply to all plots. This table is included because of

its relationship to the timing of events that occurred in

this and following trials.

Observation Trial Rotation 1

Phase I Phase II Phase III

Corn Tomato Broccoli
Muskmelon

The crop sequence of rotation 1 was generally suc-

cessful. The phase II tomatoes and phase III broccoli

had high yields, but muskmelon did not yield any










Table 13. Chronological order of development for the
corn cv. H-3. Observation Trial, 1973.



Physiological Occurance Number of Days From Seeding


Emergence 5

"Knee High Stage" 30

Tasseling 58

Anthesis 65

Harvest of Fresh Corn 78

Doubling of Stalks for Drying 90

Harvest of Dry Corn 120









marketable fruit. The tripods served very well as a

support for the tomatoes during the entire growing sea-

son.

The tomatoes yielded 51.4 M.T./ha which was much

better than average farm yields (30 M.T./ha). The yield

of broccoli per plant was excellent, but due to a low

planting population, the total yield per unit of area

was lower than that of a planting with normal row spacing.

The broccoli yield was not recorded. The muskmelon were

discarded because of a 100% infection of 'Soft Rot' bac-

teria (Bacterium carotovora L.R. Jones) (18).

During the transition from corn to tomatoes, the

canopy of corn leaves provided shade for the tomato

transplants, which facilitated establishment.

The incidence of Bacterial Spot (Xanthomonas

vesicatoria Gardner and Kendrick) (18), Early Blight

(Alternaria solani E. and M.) (12), and Late Blight

(Phytophthora infestans Mont. DeBary) (12) appeared to

be less in the corn staked tomatoes than in unstaked

tomatoes.

The tomato vines provided shade which was benefi-

cial for the transplants in the transition to phase III.

Muskmelon germination was poor. This appeared to be

due to inadequate lateral water movement across the wide


beds.









Observation Trial Rotation 2

Phase I Phase II Phase III

Corn Tomato CauLiflower
Pole Bean Muskmelon

The crop sequence of rotation 2 was not generally

successful. The tomato-pole bean combination and the

cauliflower-muskmelon combination produced poorly.

The association in rotation 2 of tomatoes and pole

beans resulted in substantial drop in tomato yield

(18.6 M.T./ha) below the average farm production. The

pole beans were a vigorous cv. and quickly surpassed the

tomatoes in height. Due to this shading of the tomato

plants, the yields were low as compared with rotation 1.

The green bean yield (3.8 M.T./ha) and plant development

was good. The beans were seeded at a lower density than

monocultured pole beans, therefore the total yield for

the plot area was lower than average. This was also true

for the cauliflower, which yielded well on a per plant

basis but low per unit of area. The cauliflower yield

was not recorded. The muskmelon yielded no marketable

fruit due to a 100% infection of 'Soft Rot' bacteria

(Bacterium carotovora L.R. Jones) (18).

Observation Trial Rotation 3

Phase I Phase II Phase III

Corn Pole Bean Tomato

In general, rotation 3 worked well. The pole beans

after corn followed the traditional system, and the









Observation Trial Rotation 2

Phase I Phase II Phase III

Corn Tomato CauLiflower
Pole Bean Muskmelon

The crop sequence of rotation 2 was not generally

successful. The tomato-pole bean combination and the

cauliflower-muskmelon combination produced poorly.

The association in rotation 2 of tomatoes and pole

beans resulted in substantial drop in tomato yield

(18.6 M.T./ha) below the average farm production. The

pole beans were a vigorous cv. and quickly surpassed the

tomatoes in height. Due to this shading of the tomato

plants, the yields were low as compared with rotation 1.

The green bean yield (3.8 M.T./ha) and plant development

was good. The beans were seeded at a lower density than

monocultured pole beans, therefore the total yield for

the plot area was lower than average. This was also true

for the cauliflower, which yielded well on a per plant

basis but low per unit of area. The cauliflower yield

was not recorded. The muskmelon yielded no marketable

fruit due to a 100% infection of 'Soft Rot' bacteria

(Bacterium carotovora L.R. Jones) (18).

Observation Trial Rotation 3

Phase I Phase II Phase III

Corn Pole Bean Tomato

In general, rotation 3 worked well. The pole beans

after corn followed the traditional system, and the









tomato vines were supported by the bed of corn stalks.

Although the yield of the pole beans was not recorded,

their growth and development appeared good. The bean

plant population was Lower than that of traditional sys-

tems by approximately one half. Therefore, a lower yield

of dry beans was expected. The pole beans, which were

mature and drying during the transition to phase ll,

gave very little shade to the phase III tomato transplants.

There was a 20% re-transplant of the tomatoes. Due to a

severe mosaic-type viral infection, the plants were re-

moved 60 days after transplant. No fruit was harvested.

Observation Trial Rotation 4

Phase I Phase II Phase III Phase IV

Corn Cucumber Broccoli Carrot
Cowpea Beet

Rotation 4 worked well. The cucumbers and phase

III crops performed well. Phase IV was shown to be

feasible with some modifications to the system. Two

staking systems using tripods and another with branches

worked well as supports for cucumbers and increased

their yield over unstaked vines.

The phase II stand of cucumber seedlings incurred

a 20% loss due to Damping Off (Pythium debaryanum Hesse

and Rhizoctonia solani Kuhn) (12, 50) during the first

4 days after emergence which occurred during a high rain-

fall period. An even stand was established by re-seeding.









Several methods of training cucumber vines were

compared in this rotation (Fig. L3). The staked cucum-

bers had a significant increase in yield and produced

16 days longer than the cucumbers grown on the beds of

corn stalks, with and without leaves (Fig. 13). Yields

were outstanding. The cucumbers grown on the beds of

corn stalks produced over 40% more per ha than tradi-

tional field grown cucumbers which at maximum yield

25 M.T./ha (25). The staked cucumbers produced almost

250% more than traditional methods (Table 14). The

staked cucumbers also provided shade to the phase III

broccoli transplants.


Table 14. Yields in M.T./ha and numbers of fruit/ha of
cucumbers grown on 5 different trellising systems,
phase 11, rotation 4, Observation Trial, October 8-
November 22, 1973.



Trellising Yields
System M.T./ha No. Fruit/ha


Vertical Twine 86.86 404,714

Branches 86.57 399,000

Horizontal Twine 71.70 345,571

Stalks Without Leaves 34.57 149,143

Stalks With Leaves 32.70 150,000









The cucumber fruit on the staked vines were

straighter and had less yellowing than the fruit on the

plants growing on the beds of corn stalks.

The 3 fungal diseases most commonly found in un-

staked cucumbers, Cottony Leak (Pythium debaryanum

Hesse) (12, 46, 47), Downy-Mildew (Pseudoperonospora

cubensis B. and C. Clint) (12, 46, 47, 50), and Angular

Leaf Spot (Pseudomonas lachrymans Sm. and Bryan) (12,46,

47) occurred less frequently and were much easier to con-

trol in the staked cucumbers.

Although yields for the phase III crops were not

recorded, the growth and development of both crops were

very good. Neither crop was planted at a normal mono-

culture population, therefore the yield per crop was

expected to be Low per unit area. Slugs in the plant

debris inflicted extensive damage to the cowpeas during

the seedling stage. The cowpeas, which were in the

maturing and drying stage at the beginning of phase IV,

could not be irrigated. This combined with the wide

vegetable beds is a possible explanation for the sparse

stand of carrots and beets, which lacked sufficient

moisture during germination.

The trial was stopped and no yield data was recorded

for phase IV.









Observation Trial Rotation 5

Phase I Phase II Phase III

Corn Tomato Cabbage
Squash Pole Bean Muskmelon
Radish

The association of corn, radish, and squash in

rotation 5 was unsatisfactory. The tomato stand was

poor, cabbage produced an average yield, and muskmelon

produced nothing.

The radish and squash were severely shaded. The

radish top growth seemed adequate, but only one half the

plants produced marketable roots. The squash produced

only staminate flowers, therefore no fruit were harvested.

Although the yields of the cabbage were not recorded,

the growth and development was average, but because of a

low planting population, the yield per unit was expected

to be below average. As in rotations 1 and 2, all the

muskmelon were discarded.

Observation Trial Rotation 6

Phase I Phase II Phase III

Corn Tomato Bush Bean
Radish

The association of corn and radish in rotation 6

was unsatisfactory. The phase 11 tomatoes staked with

corn tripods and the phase III bush beans both performed

very well. With the exception of radish, the rotation

did exceptionally well.









Observation Trial Rotation 5

Phase I Phase II Phase III

Corn Tomato Cabbage
Squash Pole Bean Muskmelon
Radish

The association of corn, radish, and squash in

rotation 5 was unsatisfactory. The tomato stand was

poor, cabbage produced an average yield, and muskmelon

produced nothing.

The radish and squash were severely shaded. The

radish top growth seemed adequate, but only one half the

plants produced marketable roots. The squash produced

only staminate flowers, therefore no fruit were harvested.

Although the yields of the cabbage were not recorded,

the growth and development was average, but because of a

low planting population, the yield per unit was expected

to be below average. As in rotations 1 and 2, all the

muskmelon were discarded.

Observation Trial Rotation 6

Phase I Phase II Phase III

Corn Tomato Bush Bean
Radish

The association of corn and radish in rotation 6

was unsatisfactory. The phase 11 tomatoes staked with

corn tripods and the phase III bush beans both performed

very well. With the exception of radish, the rotation

did exceptionally well.







66

The growth and development of radish in rotation 6

was similar to rotation 5. A 25% loss of tomato plants

due to Southern Bacterial Wilt (Pseudomonas solanacearum

Smith) (18) was incurred. Presumably, this resulted

from infection through roots wounded during cultivation.

Tomato yield was adjusted on the basis of numbers of

producing plants in rotation 6. The majority of corn

stalk tripods supported the tomato plants during the

entire growing period. A small section of 1 row lodged.

This section was reinforced by placing bamboo stakes

where necessary. The bush beans were harvested as dry

beans. The bush bean yield (2.04 M.T./ha) was considered

good compared to monoculture.

Field Trial Rotation I

Phase I Phase II Phase III Phase IV

Corn Tomato Cowpea Okra
Bush Bean
Radish

The crop sequence for.rotation 1 worked well. The

corn, radish, and beans performed well (Table 15) and

the transition from phase I to phase II was good. The

tomatoes had fair yields, and the tripod supports func-

tioned well throughout the entire growing period.

The transition from phase II to phase III went

smoothly. Phase III did not overlap with phase IV al-

though the old phase 1 tomato beds served as beds for

the okra. The inaccuracy of hand seeding resulted in an











Table 15. Crop yields for phase I, rotation 1, Field
Trial, 1974.



Phase Crop Yield/ha

I Radish 228,570 (No. of roots)

I Bush Beans 0.5 M.T. (dry)

I Corn 3.5 M.T. (dry)







68

average increase of 30 cm between plants and a decrease

in population of 8,889 plants/ha from the projected

53,328 plants/ha.

Thirty days after seeding, the corn, beans, and

radish had formed a completely closed canopy which appeared

to supress weed growth. This marked the point of maximum

competition between the 3 crops. With the harvest of the

radish, additional light was available for the beans.

The date of radish harvest corresponded to the first bean

flowering. The beans had set fruit before the corn com-

pletely shaded them.

The yield of dry corn in rotation 1 was about the

same as that of the dry corn harvested in the observation

trial.

The incidence of Damping Off (Pythium debaryanum

Hesse and Rhizoctonia solani KUhn) (12, 50) of the phase

11 tomato transplants was much less of a problem under

dry season conditions. Approximately 10% of the tomato

plants in rotation 1 were lost to Bacterial Wilt (Pseudo-

monas solanacearum Smith) (18). As the tomato plants

began flowering, symptoms of Curly Top Vi2us (40) ap-

peared. Tomato yield was estimated at half of that

produced in rotation 6 of the observation trial.

The plant debris placed between each set of 3

cowpea rows during phase II (Fig. 20) resulted in prolif-

eration of slugs which caused damage to the young cowpeas.







69

Yield data for phases 11I and IV are not available.

The okra of phase IV was severely damaged by Root Knot

Nematodes (Meloidogyne sp. Berkely) (11, 39).


Field Trial Rotation 2

Phase I Phase II Phase III Phase IV

Corn Cucumber Cabbage Pole Bean
Bush Bean Corn Sweet Potato
Radish

The crop sequence for rotation 2 was satisfactory.

The transition to phase II proceeded smoothly and

the cucumber yield was good. Cabbage yield in phase III

was low although the associated corn performed well.

The transition of sweet potatoes and pole beans into

phase IV worked well. The pole bean production was

average (Table 16) as compared to commercial monoculture.

Cucumber yield was 16% lower than that recorded for

the observation trial (Table 14). A single fertilizer

application, an extensive infection of Angular Leaf Spot

(Pseudomonas Lachrymans Sm. and Bryan) (12, 46, 47), an

infestation of Root Knot Nematodes (Meloidogyne sp.

Berkely) (11, 39), and difference in time of year could

explain the decrease.

There was a 10-15% loss of phase II cabbage within

the first 4 days after transplant due to Damping Off

(Pythium debaryanum Hesse and Rhizoctonia solani Kuhn)

(12, 50). Cabbage was severely shaded by corn and not











Table 16. List of crops and their respective yields
categorized by phase. Rotation 2, Field Trial,
December 10, 1974.



Phase Crop Yield/ha


I Radish 228,570 (No. of roots)

I Bush Bean 0.49 M.T. (dry)

I Corn 36,399 (fresh ears)

II Cucumber 74.347 M.T. (fresh weight)

III Cabbage 480 (No. of heads)

III Corn ---

IV Pole Bean 4.09 M.T. (dry)

IV Sweet Potato ---







71

much marketable yield was obtained. The remainder of the

plants were loose, undeveloped heads. The infestation of

Root Knot Nematodes (Meloidogyne sp. Berkely) (11, 39)

was severe. The phase III corn began to shade the cabbage

approximately 30 days after seeding.

Yield data for the corn is not available, although

its growth and development appeared good.

Four of the 20 beds which were seeded with the phase

IV pole beans were destroyed by slugs. The pole bean

yield is based on the remaining 16 beds. An estimated

80% stand of sweet potatoes was achieved. Yield data

were not obtained.

Records of labor input (man hours) were maintained

throughout the field trial. The labor requirement

necessary to carry out the operations of each rotation

appeared to be high, although no comparison was made of

these crops grown under monoculture.

Bean Cultivar Trial Phase I (Corn, Beans)

Beans planted on the sides of the ridges showed a

highly significant increase in numbers of plants that

emerged but a non-significant increase in bean yield

(Table 17).

Unlike the other bean cvs., Centa 105 was replicated

4 times. Analysis of this cv. showed a non-significant

increase in emergence success and yield between the 2

planting systems (Table 18). However, the averages of









Table 17. Mean number of bean plants emerged 10 days
after seeding and their mean yield of dry beans
(M.T./ha) for all cvs., for 2 planting systems.
Bean Cultivar Trial, May, 1974.


Mean No. of Mean Yield
Treatment Plants Emerged (M.T./ha)


Planted on Center 77,885 .292
of Ridge

Planted on Side 106,124 .375
of Ridge

Significance ** N.S.

**Treatment means were significantly different at the
.01 level of probability.
N.S.--Treatment means were not significantly different
at the .05 level of probability.


Table 18. Mean number of bean plants emerged 10 days
after seeding and their mean yield of dry beans
(M.T./ha) for cv. Centa 105, for 2 planting systems.
Bean Cultivar Trial, May, 1974.


Mean No. of Mean Yield
Treatment Plants Emerged (M.T./ha)


Planted on Center 74,221 .255
of Ridge

Planted on Side 97,715 .333
of Ridge

Significance N.S. N.S.

N.S.--Treatment means were not significantly different
at the .05 level of probability.







73

the cv. Centa 105 followed that of the other cultivars.

Non-significance is probably due to the low f value.

The primary diseases which were encountered in the

May planting were Damping Off (Pythium debaryanum Hesse

and Rhizoctonia solani KUhn) (12, 50), Mustia (Pellicu-

laria filamentosa Pat) (35, 48), and Angular Leaf Spot

(Isariopsis griseola Saccardo) (35, 51).

The cultivars exhibited various degrees of tolerance

to the fungal diseases. An indication of their disease

susceptibility can be seen in the percentage of plants

lost (Table 19) during the time period of 1 week after

emergence until the date of harvest. The cv. Centa 105

had the lowest percentage loss while the cv. S-184 had

the highest percentage loss. However, the percentage

of plant survival (inverse of % figures in Table 19)

was non-significantly correlated with dry bean yield

(r=0.122--N.S.).

Cultivar Porrillo 70 produced 0.29 M.T./ha (dry

beans) more than the next highest producer, cv. 27-R

and yielded twice that of cvs. Centa 105 and 27-R which

had a lower percentage of plant loss (Tables 19, 20),

In those plots in which corn was seeded 5 days after

the seeding of the beans (which excluded cv. S-184 and

cv. Porrillo 70), cv. 27-R flowered 5 days after cv.

Sensuntepeque and still out-yielded it by .08 M.T./ha










Table 19. Percentage of bean plant losses from emergence
to harvest for bean cvs. of phase I, Bean Cultivar
Trial, May, 1974.



Cultivar Percentage of Plants Losta


'27-R' 34%

'Centa 105' (modified) 21%

'Centa 105' (original) 38.2%

'San Fernando' 25.4%

'Sensuntepeque' 27.5%

'S-184' 53%

'Arbolito' 30%

'Porrillo 70' 29%

aNumber of plants lost is based on data collected from
the beans seeded on the sides of the ridges,









Table 20. Days to flowering, days to harvest, and yield (M.T. /ha) for 7 cvs.
of Bean Cultivar Trial, May and August planting, 1974.



Cultivar No. Days to Flowering No. Days to Harvest Yield (M.T./ha)
May Augus t May August May Augus t


'27-R' 33 30 65 65 .47 .55

'Centa 105'a 49 41 83 80 .33 .55

'San Fernando' 30 28 70 70 .30 .68

'Sensuntepeque' 28 28 60 63 .39 .61

'S-184' 32 30 70 71 .35 .91

'Arbolito' 30 30 74 79 .15 .95
'Porrillo 70' 35 35 74 69 .76 1.05


aModified planting system




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