• TABLE OF CONTENTS
HIDE
 Title Page
 Introduction
 Materials and methods
 Experimental results
 Discussion
 Application to practice
 Summary
 Literature cited














Group Title: Bulletin University of Florida. Agricultural Experiment Station
Title: Effect of frequent cutting and nitrate fertilization on the growth behavior and relative composition of pasture grasses
CITATION THUMBNAILS PAGE IMAGE ZOOMABLE
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00026833/00001
 Material Information
Title: Effect of frequent cutting and nitrate fertilization on the growth behavior and relative composition of pasture grasses
Series Title: Bulletin University of Florida. Agricultural Experiment Station
Physical Description: 48 p. : charts ; 23 cm.
Language: English
Creator: Leukel, W. A ( Walter Anthony )
Camp, John Perlin
Coleman, J. M ( John Melton )
Publisher: University of Florida Agricultural Experiment Station
Place of Publication: Gainesville Fla
Publication Date: 1934
Copyright Date: 1934
 Subjects
Subject: Plants -- Effect of nitrates on   ( lcsh )
Pastures -- Fertilizers -- Florida   ( lcsh )
Grasses -- Composition   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Bibliography: Includes bibliographical references (p. 46-48).
Statement of Responsibility: by W.A. Leukel, J.P. Camp and J.M. Coleman.
General Note: Cover title.
 Record Information
Bibliographic ID: UF00026833
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: ltuf - AEN4948
oclc - 18207133
alephbibnum - 000924331

Table of Contents
    Title Page
        Page 1
        Page 2
    Introduction
        Page 3
        Page 4
        Page 5
        Page 6
    Materials and methods
        Page 7
        Page 8
    Experimental results
        Page 9
        Page 10
        Page 11
        Page 12
        Page 13
        Page 14
        Page 15
        Page 16
        Page 17
        Page 18
        Page 19
        Page 20
        Page 21
        Page 22
        Page 23
        Page 24
        Page 25
        Page 26
        Page 27
        Page 28
        Page 29
        Page 30
        Page 31
        Page 32
        Page 33
        Page 34
        Page 35
        Page 36
    Discussion
        Page 37
        Page 38
        Page 39
        Page 40
        Page 41
        Page 42
    Application to practice
        Page 43
    Summary
        Page 44
        Page 45
    Literature cited
        Page 46
        Page 47
        Page 48
Full Text



Bulletin 269 July, 1934

UNIVERSITY OF FLORIDA
AGRICULTURAL EXPERIMENT STATION
GAINESVILLE, FLORIDA
Wilmon Newell, Director



EFFECT OF FREQUENT CUTTING AND NITRATE
FERTILIZATION ON THE GROWTH BEHAVIOR
AND RELATIVE COMPOSITION OF
PASTURE GRASSES

By
W. A. LEUKEL, J. P. CAMP and J. M. COLEMAN











40





"Lo \ Mg
N. ^^ Total Nitrogen






S...................... .
.""-. -':. .......... .......".... ........ *




June July August Sept. Oct
Fig. 1.-Diagram showing the percentages of special organic and inorganic compounds
in the top growth of Bahia grass when treated with nitrate of soda and water and cut
frequently. (Outer scale, total hydrolyzable carbohydrates and unhydrolyzed residue; inner
scale, other compounds.)

TECHNICAL BULLETIN

Bulletins will be sent free to Florida residents upon application to
AGRICULTURAL EXPERIMENT STATION
GAINESVILLE, FLORIDA










EXECUTIVE STAFF BOARD OF CONTROL

John J. Tigert, M.A., LL.D., President of the Geo. H. Baldwin, Chairman, Jacksonville
University A. H. Blanding, Bartow
Wilmon Newell, D.Sc., Director A. H. Wagg, West Palm Beach
H. Harold Hume, M.S., Asst. Dir., Research Oliver J. Semmes, Pensacola
Harold Mowry, B.S.A., Asst. Dir., Adm. Harry C. Duncan, Tavares
J. Francis Cooper, M.S.A., Editor J. T. Diamond, Secretary, Tallahassee
R. M. Fulghum, B.S.A., Assistant Editor
Jefferson Thomas, Assistant Editor
Ida Keeling Cresap, Librarian BRANCH STATIONS
Ruby Newhall, Administrative Manager
K. H. Graham, Business Manager NORTH FLORIDA STATION, QUINCY
Rachel McQuarrie, Accountant
Rachel MQuarrie, Accountant L. 0. Gratz, Ph.D., Plant Pathologist in
Charge
MAIN STATION, GAINESVILLE R. R. Kincaid, Ph.D., Asst. Plant Pathologist
J. D. Warner, M.S., Agronomist
R. M. Crown, B.S.A., Asst. Agronomist
AGRONOMY Jesse Reeves, Farm Superintendent
W. E. Stokes, M.S., Agronomist**
W. A. Leukel, Ph.D., Agronomist CITRUS STATION, LAKE ALFRED
G. E. Ritchey, M.S.A., Associate* John H. Jefferies, Superintendent
Fred H. Hull, M.S., Associate Geo. D. Ruehle, Ph.D., Associate Plant
W. A. Carver, Ph.D., Associate Pathologist
John P. Camp, M.S., Assistant W. A. Kuntz, A.M., Assoc. Plant Pathologist
B. R. Fudge, Ph.D., Associate Chemist
ANIMAL HUSBANDRY W. L. Thompson, B.S., Asst. Entomologist
A. L. Shealy, D.V.M., Animal Husbandman"
R. B. Becker, Ph.D., Dairy Husbandman EVERGLADES STATION, BELLE GLADE
W. M. Neal, Ph.D., Associate in Animal A. Daane, Ph.D., Agronomist in Charge
Nutrition R. N. Lobdell, M.S., Entomologist
D. A. Sanders, D.V.M., Veterinarian F. D. Stevens, B.S., Sugarcane Agronomist
M. W. Emmel, D.V.M., Asst. Veterinarian G. R. Townsend, Ph.D., Asst. Plant Patholo-
W. W. Henley, B.S.A., Asst. Animal Hus- gist
bandman B. A. Bourne, Ph.D., Sugarcane Physiologist
P. T. Dix Arnold, B.S.A., Assistant in Dairy J. R. Neller, Ph.D., Biochemist
Investigations R. W. Kidder, B.S., Asst. Animal Husband-
man
CHEMISTRY AND SOILS Ross E. Robertson, B.S., Assistant Chemist
R. W. Rupreeht, Ph.D., Chemist**
R. M. Barnette, Ph.D., Chemist SUB-TROPICAL STATION, HOMESTEAD
C. E. Bell, Ph.D., Associate H. S. Wolfe, Ph.D., Horticulturist in Charge
H. W. Winsor, B.S.A., Assistant W. M. Fifield, M.S., Asst. Horticulturist
H. W. Jones, M.S., Assistant Stacy O. Hawkins, M.A., Assistant Plant
ECONOMICS, AGRICULTURAL Pathologist
C. V. Noble, Ph.D., Agricultural Economist** WEST CENTRAL FLORIDA STATION,
Bruce McKinley, A.B., B.S.A., Associate BROOKSVILLE
Zach Savage, M.S.A., Associate
A. H. Spurloek, M.SA., Assistant W. F. Ward, M.S.A., Asst. Animal Husband-
man in Charge*
ECONOMICS, HOME
Ouida Davis Abbott, Ph.D., Specialist** FIELD STATIONS
L. W. Gaddum, Ph.D., Biochemist
C. F. Ahmann, Ph.D., Physiologist Leesburg
ENTOMOLOGY N. Walker, Ph.D., Plant Pathologist in
ENTOMOLOGY Charge
J. R. Watson, A.M., Entomologist** W. B. Shippy, Ph.D., Asso. Plant Pathologist
A. N. Tissot, Ph.D., Associate K. W. Loucks, M.S., Asst. Plant Pathologist
H. E. Bratley, M.S.A., Assistant J. W. Wilson, Ph.D., Associate Entomologist
J. W. Kea, B.S.A., Assistant C. C. Goff, M.S., Assistant Entomologist
HORTICULTURE, Plant City
HORTICULTUREA. N. Brooks, Ph.D., Plant Pathologist
A. F. Camp, Ph.D., Horticulturist** R. E. Nolen, M.S.A., Asst. Plant Pathologist
A. L. SBahl, Ph.D., Associate
G. H. Blackmon, M.S.A., Pecan Culturist Cocoa
R. J. Wilmot. M.S.A., Specialist, Fumigation A. S. Rhoads, Ph.D., Plant Pathologist
Research
R. D. Dickey, Assistant Horticulturist Hastings
A. H. Eddins, Ph.D., Plant Pathologist
PLANT PATHOLOGY Monticello
W. B. Tisdale, Ph.D., Plant Pathologist** Assistant Entomologist
George F. Weber, Ph.D., Plant Pathologist
R. K. Voorhees, M.S., Assistant Bradenton
Erdman West, M.S.. Mycologist David G. Kelbert, Asst. Plant Pathologist
Lillian E. Arnold,'M.S., Assistant Botanist
Sanford
*In cooperation with U.S.D.A. E. R. Purvis, Ph.D., Assistant Chemist,
"* Head of Department. Celery Investigations










EFFECT OF FREQUENT CUTTING AND NITRATE
FERTILIZATION ON THE GROWTH BEHAVIOR
AND RELATIVE COMPOSITION OF
PASTURE GRASSES

By
W. A. LEUKEL, J. P. CAMP and J. M. COLEMAN

CONTENTS
Page Page
Materials and Methods.................................. 7 Discussion ............... .............---- ....................--- 37
Experimental Results...................................... 9 Application to Practice................................. 43
Growth Behavior.....-..........-........---......... 9 Summary ..................... ........ .....-... -- 44
Yield and Composition of Top Growth... 10 Literature Cited................. ................. ... 46

INTRODUCTION

The value of a pasture grass or forage crop for feeding
purposes is rated from several angles. Such value embodies
succulence or palatability, composition, yield and period of pro-
duction. Regardless of the last three factors, succulence or
palatability stands out as one of the first requirements. Such
a condition in grasses or forage plants is known to exist when
these plants are in the early growth period or before they attain
the more mature growth condition. For example, pasture grasses
are preferable when young and leafy or in vigorous vegetative
growth. Corn silage is generally made when the corn ears are
in the dough stage and the plant as a whole is still in a more or
less leafy condition. Succulence and palatability in other crops
are judged in like manner.
Proper composition of grasses and forage crops not only
necessitates the presence of the different organic and inorganic
food constituents in required quantities, but such materials must
exist in the proper proportions and relations to produce a bal-
anced feed. A certain relation must exist between the carbo-
hydrate and protein compounds in the plant when cut or grazed
to produce as far as possible such a balanced ration. In addition
to this relation between carbohydrate and protein compounds,
a proper quantity of the more essential mineral compounds is
required for the building of the skeleton and to aid in the metabo-
lism of the animal body. To ascertain when or at what growth
stage grasses or forage crops attain the best possible relative
composition, necessitates a knowledge of the relative composition







4 Florida Agricultural Experiment Station

of such plants at their various growth stages throughout the
growing season. If at any growth period a proper relative com-
position is attainable, then the maintenance of the plants in
this growth condition for grazing purposes is a matter of im-
portance. The maintenance of such a growth period in pasture
plants combined with an optimum yield and period of production
must necessarily be correlated with some adequate system of
grazing, top cutting and fertilization.
It is natural to assume that some system as the above must
be employed, since all materials for the production of plant
growth cannot be derived from the soil or be supplied in the
form of fertilizing materials. The major portion of these ma-
terials or foods for plant growth must be elaborated by the
living plant itself. These foods consist of the more complex
and labile organic compounds elaborated through the photo-
synthetic processes of the living plant. Among these foods are
included the sugars, polysaccharides, and the more complex car-
bohydrate compounds-elaborated photosynthetically from the
water taken by the plant from the soil and the carbon dioxide
from the air. By the same process the complex proteins are
elaborated through a combination of the simple carbohydrates
in the plant with the nitrates and some of the minerals from
the soil. Variations in the quantity of these foods elaborated
consequently are dependent to a great extent upon the progres-
sive enlargement or decrease of the photosynthetic area on the
plants. The increase or decrease in the quantity or percentage
of one or the other-i.e., carbohydrates or proteins-not only
varies with the leaf area of the plants but also with the avail-
ability of some of the nutrients supplied from the soil.
With a constant and sufficient supply of soil nitrates available,
a great portion of the synthesized sugars of the plant is utilized
for the production of plant proteins. This increased proportion
of nitrogen or proteins to carbohydrates in the plant is associated
with a vegetative condition resulting in an extension of growing
plant parts. An increase in the elaboration of carbohydrates
over proteins, either through low availability of nitrogen or an
increased elaboration of carbohydrates in the plants themselves
brought about through rapid vegetative extension of the leaf
area, would establish a more mature growth condition or repro-
duction in the plants-i.e., the simple sugars would be trans-
formed into the higher carbohydrate forms and more fibrous
plant materials.







Effect of Cutting, Fertilization on Grasses 5

Assuming the plant can acquire sufficient mineral nutrients
for a proper mineral composition, then the protein and carbo-
hydrate relations in the plant are more or less controlled by
the availability of soil nitrogen and the increase or decrease in
the photosynthetic area of the plant. According to this theory,
a proper system of pasture fertilization combined with a con-
trolled grazing or clipping treatment should keep grasses in a
desired growth condition with the best plant composition. Such
a system of pasture management must naturally be varied, as
the growth and composition of grasses are affected by climatic
factors such as light, temperature and rainfall.
To what extent the composition of grasses can be affected
through fertilization, especially as to increase in percentage of
protein through the application of nitrogen fertilizers, is still
apparently a matter of conjecture. Numerous results reported
show increases in the protein content of grasses by use of ni-
trogenous fertilizers. Such reports appear true in so far as
they report the increase in the amount of protein obtained by
grazing cattle or from cutting yields of plants when such plants
are in the best growth condition for grazing purposes. Whether
such plants are actually higher in percentage of protein for any
particular growth stage or through all growth stages to maturity
is a matter for further investigation.
Pingree reported (30) a slight increase in the protein con-
tent of oats in both grain and straw when fertilized with dried
blood. At the Storrs (Conn.) Experiment Station (39) increases
within certain limits were reported in the protein content of
corn, oat grains and oat straw, stover and grasses in proportions
to the nitrogen added in a mixed fertilizer with uniform pro-
portions of potash and phosphoric acid. From long experience
with fertilizing experiments at the Rothamsted Station, Hall
(10) is led to state that "although the composition and quality
of grain is sometimes affected by the amount of nitrogen sup-
plied to the crop, it is really astonishing to find how small are
the changes brought about by extreme changes in manuring".
Hall states further that "the crop reacts against variations in
the composition of the soil and tends to keep its own composition
constant. Even on the Rothamsted plots where the differences
in the supply of nutrients are extreme and have been accumu-
lating for 50 years, the composition of the grain changes more
Figures in parentheses (Italic) refer to "Literature Cited" in the back
of this bulletin.






6 Florida Agricultural Experiment Station

from one season to another than it does in passing from plat
to plat."
In his experiments with Kubanka wheat Le Clerc (17) dem-
onstrated that "wheat of any one variety from any one source
and absolutely alike in chemical and physical characteristics,
when grown in different localities possessing different climatic
conditions, yields crops of widely different appearance and very
different chemical composition". Similar tri-local experiments
by Shaw and Walters (32) transferring the soil in addition to
the seed yielded results of the same nature. The greater effect
of climate over soil or fertilization was further shown by Le
Clerc (16) with Durum wheat. These workers concluded that
although nitrogenous fertilizers were used, the climatic factor
was the principal one in changing the composition of the plant.
Later experiments by Davidson and Le Clerc (2) (3) (4) showed
a greater yield of wheat through the use of nitrogen fertilizers
in the early growth stages. When applied at the time of heading
it produced the best quality of wheat with reference to yellow
berry and protein content. A higher protein content in the
straw was noted. Early fertilization caused a depression of
phosphoric acid in grain and straw and a further depression
of ash and silica in the straw. Similar results with wheat were
obtained by Geriche (8) and Neidig and Snyder (24).
Increases in the percentage of protein in the top growth of
frequently cut or grazed pasture grasses fertilized with nitrogen
fertilizers are reported by Enlow and Coleman (6) and by Grun-
der (9). Other workers have reported like results. Beneficial
results from fertilized grasses by grazing animals are further
reported by Fink, Mortimer and Truog (7).
The literature on the mineral composition of various crop
plants is extensive. There appears to be a general uniformity
in the results for the trend of the principal mineral compounds
through the different growth stages for various crop plants. A
rather comprehensive review of the results of different workers
in this regard is given by Duley and Miller (5) in connection
with their work "upon the character and composition of the
corn plant at different periods of growth". The general trend
of the results of these workers shows a greater percentage of
mineral compounds in plants during the early growth periods.
Later work by Bartholomew and Janssen (1) on tomato plants
showed a luxury consumption and storage of potassium during
the early growth periods. With decreased availability of potas-






Effect of Cutting, Fertilization on Grasses 7

sium later the same was translocated and re-utilized by the new
growth parts of the plant. Similar results are reported by
Nightingale, Shermerhorn and Robbins (27). MacGillivary (21)
likewise found high phosphorus in the vegetative or most active
growing parts of the tomato plant.
These various mineral compounds appear not only important
from the standpoint of high percentage in plants for forage
purposes but their functions in connection with the elaboration
of various organic compounds are of equal value. A deficiency
of any one mineral element beyond a certain degree affects
apparently the general composition balance of the plant. This
is brought out by Nightingale et al. (26, 27) in regard to calcium
deficiency in one instance and that of sulfur in another. Other
workers (18, 31, 35) have shown the effects of deficiencies of
other mineral elements exerted on general growth and composi-
tion balance of various plants.
It appears that the variation in the protein and mineral com-
position of plants is closely associated with changes in climate
and various cultural practices. How a desired composition or
quality of various pasture or forage plants may be maintained
through different cultural practices such as fertilization, cutting
or grazing appears to be a matter of economic importance. The
following experiments were undertaken in an effort to correlate
different soil and plant treatments with growth behavior and
variation in the relative mineral and organic composition of
four Florida pasture grasses.

MATERIALS AND METHODS
Eight plots of Bahia grass were selected in the spring of 1928
and divided into two series of four plots each. The top growth
from the plants from one series was cut frequently and that
from the other was permitted to grow to maturity and was then
cut in the late seed stage of growth. The following treatments
were applied to different plots in each series: nitrate of soda
and water, nitrate of soda, water, and no treatment.
Six more plots, three of carpet grass and three of centipede
grass, were similarly divided in two series of three plots each
and the following treatments were applied to the different plots
in each series: nitrate of soda and water, water, and no treat-
ment. Each of the fertilized plots in the above two groups was
fertilized with nitrate of soda at the rate of 1,600 pounds per
acre. The fertilizer was proportioned and applied at monthly






8 Florida Agricultural Experiment Station

intervals over a period of nine months during the growing
season.
Four more plots were selected, two of Bahia grass and two
of Sudan grass. Two of these plots, one of Sudan and one of
Bahia, were treated with water and fertilized with nitrate of
soda. The other two plots, likewise one of Sudan grass and
one of Bahia, were treated only with water. The fertilized plot
of Sudan grass received an application of nitrate of soda at the
rate of 2.3 pounds per plot or 400.2 pounds per acre in three
monthly applications. The fertilized plot of Bahia grass received
an application of 2.3 pounds of nitrate of soda per plot or 2,800
pounds per acre in seven monthly applications. The grasses
on all these plots were cut frequently throughout the growing
season or whenever they attained a height suited for grazing
purposes. Green and dry weight records were kept from all
top cuttings in each instance, and moisture determinations were
made on the same. Separate samples were then prepared for
laboratory analysis.
Sufficient water was applied to plants on plots subjected to
treatments termed "nitrate of soda and water", and "water",
at proper intervals so as to make soil nutrients available to the
plants at all times. This treatment kept the plants in a vigorous
growth condition and made for maximum top production. Plants
grown on plots subjected to treatments termed "nitrate of
soda" and "no treatment" received moisture only through the
seasonal rainfall.
PREPARATION OF MATERIAL
The top growth of the grass after being cut was taken to the
laboratory, cut into small sections (1/") and dried in a large
drier through which a current of air was blown for rapid re-
moval of moisture. When the material was in a dry, brittle
state it was ground in a Wiley mill and then reduced to a fine
stage in a Dreef pestle mill (36) so as to pass through a 60
mesh seive. The material was then preserved in tightly stop-
pered bottles for later analysis.
ANALYTICAL METHODS
ORGANIC COMPOUNDS
Carbohydrate and nitrogen analyses were made according to
methods described in previous work from this Station (14, 34).
The carbohydrate compounds were fractionated into sugars,
polysaccharide,. and unhydrolyzed residue. Sugars and poly-






Effect of Cutting, Fertilization on Grasses 9

saccharides were totalled under the term, "total hydrolyzed
carbohydrates". The unhydrolyzed residue mentioned is the
residual material after the removal of the sugars, polysaccharides
and ether extract. This residue consists mostly of lignin and
cellulose or the more woody, fibrous materials. The ether ex-
tract mentioned consists principally of fats, waxes, and resins.
MINERAL COMPOUNDS
The mineral compounds of calcium, potassium, magnesium
and phosphorus were determined according to methods for
analysis of plants described in Tentative and Official Methods
of Analysis of the Association of Official Agricultural Chem-
ists (29).
EXPERIMENTAL RESULTS
GROWTH BEHAVIOR
Plants subjected to frequent cutting treatments and differ-
ently fertilized showed an apparent difference in their growth
behavior throughout the growing season. Such frequently. cut
plants when fertilized with nitrate of soda produced a more
vigorous vegetative top growth when compared with plants not
fertilized. They were of a dark green color indicative of plants
in a very young vegetative growth stage. The chief effect of
nitrate fertilization, however, was reflected in the increased
production of leafage or vegetative growth parts. Plants not
fertilized appeared to be slightly advanced in maturity, i.e., they
were of a lighter green color, appeared less succulent, and did
not produce such an abundance of vegetative parts.
With the change in environment in regard to light, tempera-
ture and moisture, as the summer season approached or when
environmental conditions were conducive to reproduction in
these plants, some reproductive parts were always present when
the plants were cut, although they were more vegetative than
reproductive. Cutting of the top growth caused the plants to
revert to a vegetative growth condition for a time, but soon
reproduction generally took place-before the next cutting
treatment. This repeated reversion to the vegetative condition,
and the maintenance of more leafage than seed stem growth on
the plants as a result of cutting, kept these plants more vegeta-
tive during the entire growing season. Of the three grasses,
Bahia, carpet and centipede, the last became more reproductive
and produced a greater number of seed stems in a shorter period
after cutting than the other two grasses. As reported in former






10 Florida Agricultural Experiment Station

work (15), these frequently cut grasses produced a more hori-
zontal stolon growth which resulted in a better sod formation
for pasture purposes.
Bahia plants not cut during the growing season were some-
what different in their growth behavior from those cut frequent-
ly, except during the early part of the growing season. During
this period the plants in the fertilized areas showed a more vig-
orous vegetative growth condition, in both appearance and top
growth production in comparison with plants not fertilized. As
the summer season approached, the plants from all areas became
reproductive and formed seed stems. Plants from the fertilized
areas showed an earlier and greater production of seed stems
than those from unfertilized areas. In the later part of the
growing season all plants showed a similar growth condition,
although those on the fertilized areas showed a more abundant
growth. Unlike the frequently cut plants, these plants with
nearly all upright growing stolons for the production of seed
stems produced a less dense sod. This condition resulted in the
formation of vacant spaces between the plants which is con-
ducive to weed growth.
The frequently cut carpet and centipede grasses in the second
series of plots showed a similar growth trend, reverting to a
vegetative condition after each cutting. These grasses seed
more readily as the environment changes, and very frequent
cutting is essential to keep them vegetative.
The Bahia and Sudan grasses cut frequently in the third
series of plots presented another picture. As a result of heavier
fertilization, the Bahia grass produced a greater leafage and
appeared to be more succulent when cuttings were made. Sudan
grass is an upright growing plant and shows a marked difference
in its reaction to frequent cutting. Practically all leaf area of
this grass is removed in cutting. Since there is no residual
horizontal leaf area, as in the case of the other grasses, the
reserve foods in the lower organs of the plants are soon depleted
as a result of frequent cutting. After four cuttings this grass
ceased to produce new growth and further work on it was dis-
continued.
YIELD AND COMPOSITION OF TOP GROWTH
Yield:-The yield of green and dry growth of tops from the
frequently cut plots of Bahia grass varied descendingly in the
following order of treatments: nitrate of soda and water, nitrate
of soda, water, and no treatment (Tables 1 and 2). The yield













TABLE 1.-GREEN WEIGHT, PERCENTAGES AND WEIGHTS OF DRY MATTER AND TOTAL NITROGEN IN THE TOP GROWTH OF BAHIA
GRASS CUT FREQUENTLY AND GROWN UNDER DIFFERENT SOIL TREATMENTS.
Calculations on basis of oven-dry, sand-free matter.
Treat-II || -
ment || Irrigation and Nitrate of Soda Irrigation I Nitrae of Soda No Treatment
"Total Total I Total Total Total Total Total Total s,
Datesof Green Dry Dry Nitro-Nitro- Green Dry Dry NitroNitro- Green Dry Dry Nitro- Nitro- Green Dry Dry Nitro- Nitro-
Cutting WWt. t. Matter gen gen Wt. Wt. Matter gen gen Wt. Wt. Matter gen gen Wt. Wt. Matter gen gen 0
1928 Grams Grams % % Grams GGramsGrams % I c Grams Grams Grams % % Grams Grams Grams % % G Grams

May 21 420 142 33.8 1.48 2.10 510 175 34.4 1.26 2.21 420 139 33.0 1.37 1.90 610 201 33.0 1.36 2.74 C'-
June 4 470 150 32.0 1.63 2.45 395 123 31.2 1.59 1.95 365 124 34.0 1.71 2.12 310 105 34.0 1.50 1.58
June 19 2,678 723 27.0 2.31 16.70 1,178 302 25.6 1.59 4.80 1,785 435 24.4 2.25 9.79 984 334 34.0 1.55 5.18
Co
July 9 2,727 962 35.3' 1.64 15.77 1,505 526 34.9 1.87 9.86 2,487 861 34.6 1.69 14.54 1,233 447 36.3 1.60 7.17
July 24 1,511 450 29.8 1.57 7.06 654 199 30.4 1.52 3.03 1,728 524 30.3 1.47 7.70 512 160 31.3 1.54 2.47 ;
N
Aug. 7 1,588 529 33.3 1.75 9.26 851 276 32.4 1.63 4.49 1,368 465 34.0 1.62 7.54 866 288 33.3 1.71 4.94 P4
Aug. 27 1,380 404 29.3 1.87 7.52 905 283 31.3 1.46 4.14 1,651 512 31.0 1.60 8.20 993 321 32.3 1.64 5.25
Sept. 13 2,265 770 34.0 1.56 12.01 1,030 342 33.2 1.37 4.68 1,940 745 38.4 1.25 9.31 520 180 34.6 1.30 2.33 o
Oct. 3 1,437 430 30.0 1.88 8.13 607 192 31.7 1.91 3.68 1,455 448 30.8 1.65 7.39 599 184 30.8 1.64 3.02
Nov. 1 958 320 33.4 1.86 5.95 251 90 35.9 1.46 1.31 881 288 32.1 1.70 4.81 233 96 41.3 1.38 1.82

Totals 15,434 4,880 31.6 1.78 86.95 7,886 2,508 31.8 1.60 40.15 14,080 4,536 32.2 1.62 73.30 6,860 2,316 33.8 1.55 36.00

Plot dimensions, 50' x 5'.



1-'









tO

TABLE 2.-GREEN WEIGHT, PERCENTAGES AND WEIGHTS OF DRY MATTER AND TOTAL NITROGEN, AT DIFFERENT GROWTH
STAGES OF THE TOP GROWTH OF BAHIA GRASS GROWN UNDER DIFFERENT SOIL TREATMENTS.
Calculations on basis of oven-dry, sand-free matter.
Treatment |l Irrigation and Nitrate of Soda IIrrigation
Green Dry Dry Total Total Green Dry Dry Total Total 3.
Dates of Cutting, 1928 Weight Weight Matter Nitrogen Nitrogen Weight Weight Matter Nitrogen Nitrogen
Grams Grams Percent Percent Grams Grams Grams Percent Percent Grams
--- ----------~1 ----__ _--..--_
June 19 ................. .. .. ................... .......- -- ------ -- -- 1.79 .............. .......... ..... .... ....... .............. 1.31 ... .... ...-

July 24 ............................ .. 3,173 1,087 34.2 1.06 11.5 1,650 654 39.6 1.23 8.0

Aug. 28 ......-..................- 14,159 5,187 36.6 1.16 59.0 3,459 1,280 37.0 0.94 12.0

Oct. 3 ................. ................. 16,272 6,332 38.9 1.20 76.3 6,397 2,503 39.2 1.12 27.9


Treatment Nitrate of Soda No Treatment


June 19 .................. .- ........... ................... ....... 1.68 ...... .... ....... ... ............-...... 1.25 .........

July 24 ..............................- 3,322 1,151 34.6 1.02 11.8 1,639 636 38.8 0.99 6.3 t

Aug. 28 ................................ 14,060 4,982 35.4 0.99 49.2 3,450 1,285 37.3 1.00 12.8 .

Oct. 3 -................. ... .... ....- 17,028 6,428 37.7 0.94 60.5 6,167 2,410 39.1 1.12 27.1

Plot dimensions, 50' x 5'.







Effect of Cutting, Fertilization on Grasses 13

of top growth from Bahia plants grown to maturity followed a
similar order with the exception of that from the plot treated
with nitrate of soda. The yield of top growth from this was
slightly higher than that from the plot treated with nitrate of
soda and water.
Carpet and centipede grasses treated with nitrate of soda and
water, water, and no treatment, returned descending yields of
green and dry top growth in the order named. The yield of
top growth from the frequently cut carpet plants compared
favorably with those from similarly treated Bahia plants. For
similar treatments, centipede grass frequently cut was some-
what lower in yields than the yields from Bahia or carpet plants
(Tables 3 and 4).
In the third series of plots of Bahia and Sudan grasses more
marked differences are evident as a result of heavier nitrate
fertilization. The Bahia grass plot fertilized at the rate of 2,800
pounds of nitrate of soda per acre produced 8 times as much
green weight or 5 times as much dry weight of top growth as
was produced by the plot treated with water only. These yields
are about three times as great as those produced from similarly
treated Bahia plants previously mentioned with lighter fertilizer
applications.
Frequently cut Sudan grass fertilized at the rate of 400.2
pounds per acre in three monthly applications produced over
nine times the weight of green top growth anal seven times the
dry weight of top growth produced by the plot treated only with
water. Sudan grass is an upright growing plant and does not
leave the residual horizontal leaf area after cutting that is char-
acteristic of Bahia, centipede and carpet grasses. As a result
of this upright growth habit, its reserve foods for new top
growth are soon depleted after being subjected to several cutting
treatments in the early vegetative growth stage. After four
cuttings this grass ceased to produce further vegetative top
growth and the cutting treatments were discontinued. On the
other hand, Bahia grass on account of its horizontal residual
leaf area produced repeated vegetative top growth throughout
the entire season (Tables 5, 6 and 7).
Dry Matter:-In percentage of dry matter, the top cuttings
from the frequently cut Bahia plants in the first series of plots
show a rather uniform trend throughout the growing season
for each treatment. The top growth from the Bahia plants
grown to maturity and fertilized with nitrate of soda and water











TABLE 3.-GREEN WEIGHTS, PERCENTAGES AND WEIGHTS OF DRY MATTER AND TOTAL NITROGEN IN THE TOP GROWTH OF
CARPET GRASS CUT FREQUENTLY AND GROWN UNDER DIFFERENT SOIL TREATMENTS.
Calculations on basis of oven-dry, sand-free matter.
Treatments I| Irrigation and Nitrate of Soda I Irrigation H No Treatment
Dates of Green Dry Dry Total Total Green Dry Dry Total Total Green Dry Dry Total Total
cutting Weight Weight Matter Nitrogen Nitrogen Weight Weight Matter Nitrogen Nitrogen Weight Weight Matter Nitrogen Nitrogen
1928 Gram Grams Percent Percent Grams Percent Percent Grams Grams Grams Percent Percent Grams

May 21.- I 1,085 304 28.0 1.51 4.59 925 292 31.6 1.45 4.24 820 259 31.6 .......... ............
June 4........ 565 133 23.6 2.03 2.71 554 144 26.0 1.74 2.51 515 134 26.0 ........................
June 19........ 1,718 449 26.1 2.17 9.74 1,386 317 22.8 2.00 6.34 612 167 27.2 1.51 2.52
July 9 ........ 1,799 568 31.6 1.66 9.44 1,533 423 27.6 1.81 7.65 1,301 427 32.9 1.77 7.58
July 24........ 1,412 363 25.7 1.73 6.28 633 169 26.7 1.58 2.67 605 183 28.2 1.62 2.97
Aug. 7.......1,390 415 29.9 1.70 7.06 924 248 26.9 1.70 4.22 644 190 29.5 1.56 2.97
Aug. 27....... 2,293 737 32.1 1.69 12.45 1,202 387 32.2 1.51 5.84 858 295 34.4 1.46 4.31

Sept.13...... 1,180 340 28.8 1.72 5.84 590 177 30.0 1.57 2.78 580 174 30.0 1.54 2.68 C
Oct. 3. 1,289 393 30.4 1.67 6.56 608 190 31.3 1.50 2.86 532 159 29.8 1.55 2.46
Nov. 1........ 1,650 553 33.5 1.82 10.05 750 303 40.4 I 1.15 3.48 605 228 37.7 1.21 2.76 S


Totals ---...14,3811 4,255 29.6 1.75 74.72 9,105 2,650 29.1 1.61 42.59 7,117 2,216 31.1 1.55 28.25








TABLE 4.-GREEN WEIGHTS, PERCENTAGES AND WEIGHTS OF DRY MATTER AND TOTAL NITROGEN IN THE TOP GROWTH OF
CENTIPEDE GRASS CUT FREQUENTLY AND GROWN UNDER DIFFERENT SOIL TREATMENTS.
Calculations on basis of oven-dry, sand free matter.

Treatment I| Irrigation and Nitrate of Soda II Irrigation No Treatment
ates of Green Dry Dry Total Total Green Dry Dry Total Total Green Dry Dry Total Total
Cutting Weight Weight Matter Nitrogen Nitrogen Weight Weight Matter Nitrogen Nitrogen Weight Weight Matter Nitrogen Nitrogen
1928 Grams Grams Percent Percent GrGrams ms Grams Percent Percent Grams Grams Grams Percent Percent Grams

May 21-... ... 925 370 40.0 1.03 3.81 780 312 40.0 0.99 3.09 730 292 40.0............
June 4........ 270 81 30.0 1.5 1.21 236 80 34.0 1.37 1.10 524 178 34.0 .............
June 19........ 1,211 396 32.7 1.61 6.38 1,086 369 34.0 1.53 5.65 810 236 29.1 1.29 3.04
July 9....... 650 273 41.9 1.46 3.98 495 208 42.0 1.25 2.60 534 192 36.0 1.44 2.76
July 24........ 351 111 31.7 1.74 1.94 269 89 33.1 1.31 1.17 227 69 30.3 1.39 0.96 X
Aug. 7........ 665 214 32.2 1.48 3.17 330 107 32.4 1.61 1.72 252 80 31.6 1.51 1.20
Aug. 27........ 2,190 735 33.6 1.48 10.87 937 325 34.7 1.26 4.09 570 184 32.2 1.37 2.52
Sept.13........ 1,800 641 35.6 1.34 8.59 840 323 38.4 1.07 3.45 490 186 38.0 1.14 2.12
Oct. 3......... 1,669 523 31.3 1.51 7.89 603 203 33.6 1.26 2.56 287 100 34.7 1.23 1.22 4
Nov. 1....... 1,080 457 42.3 1.43 6.53 285 123 43.0 1.12 1.37 210 90 43.0 1.02 0.92 c


Totals. 0,811 3,801 35.2 1.43 54.37 5,861 2,139 36.5 1.25 26.80 4,634 1,607 34.7 1.30 14.74

Plot dimensions, 50' x 5'.
Cn











TABLE 5.-GREEN AND DRY WEIGHTS, PERCENTAGE OF DRY MATTER AND PERCENTAGE OF DIFFERENT FORMS OF NITROGEN n
IN THE TOP GROWTH OF BAHIA GRASS, CUT FREQUENTLY, FERTILIZED AND IRRIGATED DURING THE GROWING SEASON OF 1929.
S I j Unex- Coagulable Amino
Date Cut Green Dry Dry Extracted tracted Protein Protein Soluble Acid Nitrate Total ITotal
Weight Weight Matter Nitrogen Nitrogen Nitrogen Nitrogen Nitrogen Nitrogen Nitrogen Nitrogen Nitrogen
Grams Grams Percent Percent Percent Percent Percent Percent Percent Percent Percent Grams

May 24, 1929............ 3,360 907.2 27.0 2.133 0.87 1.06 0.19 1.943 0.268 0.071 3.00 27.21

June 6, 1929............ 4,760 1,251.88 26.3 0.912 0.888 1.54 0.657 0.255 0.0722 0.024 1.80 22.53

June 24, 1929........... 6,800 1,863.2 27.4 0.510 1.79 1.954 0.164 0.346 0.166 0.117 2.30 42.85

July 11, 1929.......... 3,090 719.97 23.3 0.336 2.00 2.013 0.082 0.254 0.169 0.076 2.28 16.41

July 29, 1929.......... 5,970 1,707.42 28.6 0.420 1.69 1.773 0.083 0.337 0.130 0.117 2.11 36.02

Aug. 8, 1929.......... 4,430 1,165.69 26.3 0.305 2.11 2.239 0.129 0.176 0.109 0.061 2.42 28.20

Aug. 19,1929........ 3,675 1,065.75 29.0 0.620 1.75 1.81 0.060 0.560 0.104 0.198 2.37 25.25 (1

Sept. 5, 1929 ........4,648 929.60 20.0 0.580 2.15 2.238 0.088 0.492 0.129 0.160 2.73 25.37

Sept. 19, 1929........... 4,355 1,149.72 26.4 0.580 1.79 1.857 0.067 0.513 0.093 0.134 2.37 27.24 "

Oct. 3, 1929.............. 3,720 978.36 26.3 0.450 2.11 2.177 0.067 0.383 0.147 0.134 2.56 25.04

Oct. 17, 1929.......... 1,265 335.22 26.5 0.540 2.04 2.129 0.089 0.451 0.132 0.066 2.58 8.64

Oct. 31, 1929........... 440 146.52 33.3 0.470 2.10 2.133 0.033 0.437 0.130 0.053 2.57 3.76 *

Nov. 14, 1929 .......... 610 189.10 31.0 0.500 2.59 2.88 0.29 0.210 0.093 0.067 3.09 5.84


Total ............. 47,123 12,409.63 23.33 ..---.. ..--- .......-....------ ..- -...........-.. ...... .............294.36







TABLE 6.-GREEN AND DRY WEIGHTS, PERCENTAGE OF DRY MATTER AND PERCENTAGE OF DIFFERENT FORMS OF NITROGEN
IN THE TOP GROWTH OF BAHIA GRASS CUT FREQUENTLY AND IRRIGATED DURING THE GROWING SEASON OF 1929.
Unex- Coagulable Amino
Date Cut Green Dry Dry Extracted tracted Protein Protein Soluble Acid Nitrate Total Total
Weight Weight Matter Nitrogen Nitrogen Nitrogen Nitrogen Nitrogen Nitrogen Nitrogen Nitrogen Nitrogen
Grams Grams Percent Percent Percent Percent Percent Percent Percent Percent Percent Grams

May 24, 1929 ......... 445 152.63 34.3 0.630 1.070 1.12 0.05 0.625 0.088 0.013 1.60 2.442 ^

June 6, 1929 ......... 390 120.90 31.0 0.451 1.149 1.494 0.345 0.106 0.042 0.058 1.60 1.93

June 24, 1929............ 730 248.20 34.0 0.306 0.844 0.938 0.094 0.212 0.095 0.090 1.15 2.854

July 11, 1929 .......... 790 203.00 25.7 0.376 1.364 1.376 0.012 0.364 0.081 0.025 1.74 3.532
St
July 29, 1929 ........ 850 289.00 34.0 0.180 1.190 1.195 0.005 0.175 0.080 0.050 1.37 3.95 a

Aug. 8, 1929............ 715 243.10 34.0 0.290 1.340 1.481 0.141 0.159 0.103 0.023 1.63 3.96

Aug. 19, 1929 ......... 875 300.125 34.3 0.245 0.055 1.099 0.044 0.201 0.101 0.056 1.30 3.90

Sept. 5, 1929......... 785 243.35 31.0 0.230 1.400 1.436 0.036 0.194 0.062 0.047 1.63 3.93 .

Sept. 19,1929 ....... 1,230 410.82 33.4 0.214 1.486 1.51 0.024 0.190 0.060 0.043 1.60 6.57

Oct. 3, 1929........ 375 124.87 33.3 0.236 1.434 1.458 0.024 0.212 0.085 0.001 1.67 2.08

Oct. 17, 1929........ 430 141.90 33.0 0.240 1.440 1.469 0.029 0.211 0.059 0.019 1.68 2.38

Oct. 31, 1929......... 145 58.00 40.0 0.300 1.750 1.802 0.052 0.248 0.068 0.036 2.05 1.18

Nov. 14, 1929.......... 100 42.00 42.0 0.230 1.700 1.74 0.04 0.226 0.058 0.030 1.93 0.810


Total -------- ...................... 7,860 !2,577.89 32.797 .---- ...... ........... .. ........... .. ................. 39.518
---- --- --- --- ---- --- -- --- ---- --- --- ---- --- -- --- ---- -- ---- --- ---










TABLE 7.-GREEN AND DRY WEIGHTS, PERCENTAGE OF DRY MATTER AND PERCENTAGE OF DIFFERENT FORMS OF NITROGEN 00
IN THE TOP GROWTH OF SUDAN GRASS, CUT FREQUENTLY, FERTILIZED* AND IRRIGATED DURING THE GROWING
SEASON OF 1929.
Unex- Coaculable Amino
Date Cut Green Dry Dry Extracted tracted Protein Protein Soluble Acid Nitrate Total Total
Weight Weight Matter Nitrogen Nitrogen Nitrogen Nitrogen Nitrogen Nitrogen Nitrogen Nitrogen Nitrogen
Grams Grams Percent Percent Percent Percent Percent Percent Percent Percent Percent Grams

May 24, 1929........ 4,255 736.11 17.3 1.78 1.85 2.774 0.924 0.856 0.140 0.527 3.63 26.72 2.

June 6, 1929............ 6,895 1,261.78 18.3 1.20 1.46 2.269 0.804 0.396 0.190 0.12 2.66 33.56 S

June 24, 1929............ 6,105 1,221.00 20.0 0.920 1.81 2.330 0.520 0.400 0.227 0.16 2.73 33.33 Q-

July 11, 1929........... 6,795 1,406.00 20.7 0.485 2.115 2.207 0.092 0.393 0.222 0.100 2.60 36.55


Total ........................ 24,050 4,624.89 19.23 .............. ........................... ............. ....... .....

SAME AS ABOVE BUT ONLY IRRIGATED AND NOT FERTILIZED


May 24, 1929......... 390 94.77 24.3 1.51 0.65 0.998 0.348 1.162 0.086 0.013 2.16 2.047
June 6, 1929-......... 660 165.00 25.0 0.352 1.108 1.317 0.209 0.143 0.048 0.038 1.46 2.407

June 24, 1929 -.......... 595 149.94 25.2 0.660 1.140 1.394 0.254 0.406 0.128 0.14 1.80 2.690

July 11, 1929 .......... 905 232.58 25.7 0.310 1.430 1.523 0.093 0.237 0.136 0.056 1.74 4.046 .


Total ........................ 2,550 642.29 25.18 .............. ........ ...... .... .................... ....................... 11.190

2.3 lbs. of nitrate of soda per plot (5' x 50') in three monthly applications or at the rate of 1,200 lbs. per acre, applied
to parts of plots only.







Effect of Cutting, Fertilization on Grasses 19

in one instance and nitrate of soda in the other showed a higher
percentage of dry matter than was found in the top growth of
the frequently cut plants. A gradual increase in percentage of
dry matter in the top growth of these plants prevailed from the
early vegetative growth stage in spring to the more mature or
late seed stage of growth in autumn. The top growth of plants
grown to maturity and irrigated with water and that from those
receiving no treatment manifested a rather irregular trend in
percentage of dry matter during the season. However, such
plants were much higher in percentage of dry matter in the late
growing season than frequently cut plants.
The frequently cut carpet and centipede grasses in the second
series of plots, like Bahia grass similarly treated, showed a
rather uniform trend in relation to percentage of dry matter
with some variations for the same and different treatments.
In the third series of plots the frequently cut Bahia and Sudan
grasses presented a more marked difference in regard to dry
matter as a result of heavier nitrate fertilizations and frequent
cutting. The top growth from the frequently cut and fertilized
Bahia grass in this case was considerably lower in percentage
of dry matter than that from the grass only irrigated with
water. In case of the Sudan grass, the top growth of the grass
from the nitrated area exhibited a considerably more marked
















June July August ept. Oct.
40







.........::...... .........



June July August Oepl. Oct.
Fig. 2.-Diagram showing the percentage of special organic and inorganic compounds
in top growth of Bahia grass when fertilized with nitrate of soda and cut frequently.
(Outer scale, total hydrolyzable carbohydrates and unhydrolyzed residue; inner scale, other
compounds.)






20 Florida Agricultural Experiment Station

reduction in percentage of dry matter when compared with that
from similar plants only irrigated with water (Tables 1 to 7).
Ether Extract:-The materials extracted with anhydrous
alcohol-free ether consist mostly of fats, waxes, and resins, or
the more dense compounds consisting for the most part of car-
bon, hydrogen and oxygen. A higher and quite uniform per-
centage of these compounds in the top growth of plants cut
frequently was evident throughout the growing season when
compared with the top growth of plants grown to maturity. In
the top growth of the latter plants, the ether extracted sub-
stances were about one-third lower in percentage and somewhat
uniform throughout the growing season.
Carbohydrates:-The various carbohydrate compounds showed
a rather uniform trend on a percentage basis throughout the
growing season in the top growth of the frequently cut grasses,
carpet, Bahia and centipede. Some variations were evident,
depending on the growth stage of the plants when cut. Such
variations are of common occurrence during the summer season
where plants pass into the reproductive stage very readily as
a result of changing environment. When compared with mature
grasses, a somewhat greater variation in hydrolyzable carbohy-
drates was evident from one growth stage to another but no
exceedingly large differences on a percentage basis were found.
The unhydrolyzed residue in the top growth of frequently cut
plants was lower and more uniform in percentage throughout
the growing season than that of plants grown to maturity. In
the top growth of the latter plants, this carbohydrate fraction
gradually increased in percentage as the plants approached the
more mature growth stages. Some irregularities were evident
due to the fact that samples were taken from different parts of
the plots and different growth stages of plants were prevalent
in many such instances (Tables 8 to 12, Figs. 1 to 14).
Nitrogen:-As shown in Table 1, the percentage and weight
of total nitrogen in the top growth of the frequently cut Bahia
grass from the first series of plots varied directly with the fol-
lowing order of treatments: nitrate of soda and water, nitrate
of soda, water, and no treatment. Some variations are shown
in these nitrogen percentages for the top growth from each of
the differently treated Bahia plots on account of the slight dif-
ferences in the growth stages of the plants when cut, but on
the whole such percentages indicate a rather uniform trend
throughout the growing season.













TABLE 8.-SPECIFIC ORGANIC ANALYSIS OF BAHIA GRaSS CUT FREQUENTLY AND GROWN UNDER DIFFERENT
SOIL TRE TMENTS. t
Calculations on basis of oven-dry, sand-free matter. All carbohydrates expressed as glucose. 4

Treatment | Irrigation and Nitrate of Soda I Irrigation
Total I Total ".
Dates of Hydro- Unhydro- Hydro- Unhydro-
Cutting Ether Reducing Total Poly- lyzable lyzed Ether Reducing Total Poly- lyzable lyzed
Extract Sugars Sugars saccharides Carbo- Residue Extract Sugars Sugars saccharides Carbo- Residue
1928 Percent Percent Percent Percent hy rates Percent Percent Percent Percent Percent hydrates Percent
S Percent I Percent _.
--- -_- -_ -- ___ _ 7- - -------------------------- _ _
June 19 ........... 3.64 2.23 2.96 27.56 30.52 40.38 3.03 1.53 3.25 26.01 29.26 40.88

July 9.............. 2.91 1.40 2.80 24.83 27.63 40.21 3.17 0.87 2.52 25.33 27.85 39.12

July 24.......... 2.85 1.42 3.07 30.70 33.77 43.07 2.68 1.46 2.87 29.61 32.48 42.42 !

Aug. 7.............. 2.62 1.29 2.24 24.36 26.60 41.10 3.02 1.53 2.72 23.36 26.08 40.58

Aug. 27........... 3.03 1.87 3.60 24.50 28.10 40.58 2.84 2.11 3.46 25.49 28.95 40.51

Sept. 13......... 2.45 1.49 2.92 22.73 25.65 37.17 2.07 1.49 2.62 21.23 23.85 35.59

Oct. 3............. 2.22 1.33 3.26 24.60 27.86 39.86 2.00 1.18 2.87 26.49 29.36 41.65

Nov. 1.............. 2.32 1.41 3.69 28.40 32.09 38.05 2.33 0.89 2.25 24.58 26.83 42.50
Co




N1













TABLE9.:--SPECIFIC ORGANIC ANALYSIS OF BAHIA GRASS CUT FREQUENTLY AND GROWN UNDER DIFFERENT SOIL TREATMlENTS.
S Calculations on basis of oven-dry, sand-free matter. All carbohydrates expressed as glucose.
Treatment ) Nitrate of Soda II No Treatment
Total Total
.Dates of Hydro- Unhydro- Hydro- Unhydro-
S Ether Reducing Total Poly- lyzable lyzed Ether Reducing Total Poly- lyzable lyzed
tg Extract Sugars Sugars saccharides Carbo- Residue Extract Sugars Sugars saccharides Carbo- Residue
1928 Percent Percent Percent Percent hy 'rates Percent Percent Percent Percent Percent hy-rates Percent
Percent Percent__
June 19............ 3.305 1.15 2.80 25.75 28.55 37.37 I 3.05 1.16 2.79 23.31 26.10 38.84
July 9............. 3.21 1.17 2.83 22.00 24.83 37.21 2.42 1.12 2.82 24.5 27.32 37.55
July 24............ 2.33 1.39 2.57 23.17 25.74 40.90 2.11 1.28 3.16 24.99 28.15 42.68
Aug. 7-........ 2.71 0.78 2.28 21.71 23.99 39.97 2.44 0.98 2.48 22.64 25.12 38.01 M
Aug. 27.......... 3.41 1.39 2.94 26.70 29.64 38.67 2.57 1.30 2.48 25.21 27.69 42.20
Sept. 13............ 3.35 0.96 2.41 23.73 26.14 33.87 1.73 0.76 1.96 23.50 25.46 38.00
Oct. 3............ 1.58 0.73 2.26 21.76 24.02 37.07 2.31 0.86 2.71 22.69 25.40 37.26 .
Nov. 1.........l 2.26 0.81 2.41 23.97 26.38 38.30 2.72 1.04 1.73 24.87 26.60 37.70 '
N ov. 1 .............. I __ S









TABLE 10.-SPECIFIC ORGANIC ANALYSIS OF THE TOP GROWTH OF CARPET GRASS, CUT FREQUENTLY, AND GROWN UNDER
DIFFERENT SOIL TREATMENTS.
Calculations on basis of oven-dry, sand-free matter.

Treatment I Irrigation and Nitrate of Soda |I Irrigation _] No Treatment

w r
Dates of bD S ))
Cutting. 4+ *' 4+) Y4 .)i *4 5 5 )4-) 4. 0* 4) + +.1 5' e>) To
1928 0g s |g* g gg tg ,wg ") E *Vt g w 2.
Jb e 1 9 0b 0 r i 0


Jue 19......... 3.50 0.97 2.66 16.06 18.72 32.52 3.30 0.79 2.42 17.03 19.45 35.98 3.10 0.73 3.01 16.42 19.43 37.56
July 9..... ..... 2.60 0.71 2.87 21.52 24.39 38.53 3.02 1.61 3.20 22.60 25.80 35.89 2.94 1.37 2.95 22.86 25.81 34.38 ..
July 24 ........ 2.65 1.16 2.87 22.48 25.35 39.20 1.85 1.40 2.82 25.83 28.65 42.00 2.61 1.85 2.26 25.39 27.65 35.37 g
Au :. 7............ 3.09 1.55 3.11 23.69 26.80 35.12 2.66 1.35 2.80 23.82 26.62 35.73 2.91 1.71 2.66 26.05 28.71 38.82 '
Auw. 27............. 2.58 1.59 3.61 23.32 26.93 44.50 2.87 1.38 3.23 23.94 27.17 40.02 3.00 1.45 2.66 22.00 24.66 43.44 m
Oct. 3.......... 2.46 1.30 3.33 24.20 27.53 43.35 2.10 1.04 2.80 24.62 27.42 40.58 2.40 0.80 1.65 25.71 27.36 39.88

'i

TABLE 11.-SPECIFIC ORGANIC ANALYSIS OF THE TOP GROWTH OF CENTIPEDE GRASS, CUT FREQUENTLY AND GROWN UNDER c
DIFFERENT SOIL TREATMENTS,
Calculations on basis of oven-dry, sand-free matter. All carbohydrates expressed as glucose.
Treatment jI Irrigation and Nitrate of Soda IL Irrigation II No Treatment
a | S a B ,
s oSs N i' N0s
Dates of 4 &
Cutting 0 4 > t 4)
1928 0 '00 9n 23 0 0 Po o '00

;33 w- 0s 'V cc c'4 ) 5 a!R5
Pq Pk p 5i (S 2. ;Aoi Ula'. ;s s P4i D qPg p- w P'01 I pwpi '014 14 1& 4 mC IS 4 PL

Jure 19............. 3.37 0.782 8.0 23.93 27.23 38.27 3.40 0.76 1.60 24.04 2.641 3 36.31 .64 1.63 1.72 16.62 18.84 86.79
July 9............. 3.24 0.910 2.50 16.55 19.05 33,29 3.21 1.33 2.37 16.43 18.80 35.44 2.96 0.93 1.84 16.20 18.04 29.57
Ju.y 24............. 3.14 2.24 8.68 25.64 29.22 33.82 8.11 0.92 2.89 23.83 26.72 36.86 2.77 0.87 2.75 20.97 23.72 38.42
Aug. 7........ 3.40 0.827 2.76 24.65 27.40 37.41 8.00 1.33 3.09 27.53 30.62 39.21 3.27 1.80 8.05 28.07 31.12 37.98
Au. 27........... 3.23 1.78 2.91 27.78 30.69 31,89 2.43 1.52 2.40 25.90 28.30 87.30 2.46 1.10 2.82 24.04 26.36 86.78
Oct. 3.....--......- 2.73 1.84 8.51 28.17 81.68 87.82 2.35 1.29 4.03 23.83 27.86 40.01 2.33 1.29 3.38 25.84 29.22 38.41
co








tO


TABLE 12.-SPECIFIC ORGANIC ANALYSIS OF BAHIA GRASS AT DIFFERENT STAGES OF GROWTH AND GROWN UNDER
DIFFERENT SOIL TREATMENTS.
Calculations on basis of oven-dry, sand-free matter. All carbohydrates expressed as glucose.
Treatment II Irrigation and Nitrate of Soda I Irrigation
STotal ITotal .
Dates of Hydro- Unhydro- Hydro- Unhydro-
Cutting Ether Reducing Total Poly- lyzable lyzed Ether Reducing Total Poly- lyzable lyzed t
Extract Sugars Sugars saccharides Carbo- Residue Extract Sugars Sugars saccharides Carbo- Residue
1928 Percent Percent Percent Percent hy rates Percent Percent Percent Percent Percent hy-rates Percent
SPercent ____Percent_
Tune 19-............ 2.01 1.18 3.19 20.33 23.52 45.43 2.48 1.18 3.23 22.33 25.56 46.88

July 24.........- 2.37 1.84 3.81 26.08 29.89 42.38 1.89 1.48 2.86 22.83 25.69 43.41
Aug. 28.......... 2.24 1.64 2.78 24.7 27.48 49.0 1.91 1.26 2.68 23.35 26.03 50.19
Oct. 3 ............ .... ..... 1.65 2.23 21.60 23.83 45.56 2.65 1.20 3.05 25.0 28.05 46.04


Treatment I Nitrate of Soda No Treatment


June 19-......... 2.42 1.48 3.19 23.06 26.25 46.74 2.04 0.76 3.13 20.73 23.86 46.83

July 24 ...........1 2.33 1.69 2.93 26.18 29.11 41.08 1.65 1.71 2.86 24.92 27.78 45.42

Aug. 28........... 2.19 1.56 3.10 24.5 27.60 55.20 2.05 1.78 3.51 22.69 26.20 59.91
Oct. 3........... .............. 1.13 2.07 22.8 24.87 46.40 2.00 0.95 2.87 ......... ................









Effect of Cutting, Fertilization on Grasses 25






40 -- -- zed Res due


















"in the top growth of Bahia grass when irrigated and cut frequently. (Outer scale, total
















VLydojy WS., dr Residue
20























u
June July August Sept. Oct.
Fig. 3.-Diagram showing the percentage of special organic and inorganic compounds
in the top growth of Bahia grass when irrigated and cut frequently. (Outer scale, total
hydrolyzable carbohydrates and unhydrolyzed residue; inner scale, other compounds.)























LO ..mo. 'un
^*****' .. .. .... ..> .




U


June July August Sept. Oct.
Fig. 4.-Diagram showing the percentage of special organic and inorganic compounds
in the top growth of Bahia grass when receiving no fertilizing treatment and cut frequently.
(Outer scale, total hydrolyzable carbohydrates and unhydrolyzed residue; inner scale, other
compounds.)








26 Florida Agricultural Experiment Station

30








40








LO





u ****...... ..



June July August Sept.
Fig. 5.-Diagram showing the percentage of special organic and inorganic compounds
in the top growth of Bahia grass at different periods of growth during the growing season
when fertilized with nitrate of soda and water. (Outer scale, total hydrolyzable carbo-
hydrates and the unhydrolyzed residue; inner scale, other compounds.)


60



Ether E tract
Ls

~o








I_0 STotal Nitrogen

0.0



.Os............
........... ........ ................



"June July August Sept.
Fig. 6.--Dagram showing the percentage of special organic and inorganic compounds
in the top growth of Bahia grass at different periods of growth during the growing season
when fertilized with nitrate of soda. (Outer scale, total hydrolyzable carbohydrates and
the unhydrolyzed residue; inner scale, other compounds.)







Effect of Cutting, Fertilization on Grasses 27

60
"Lo




Sotal Hyd rolyzable Carbohydrates






L___t- "___ -_ _-
.o0












June July August Sept.
Fig. 7.--D.agram showing the percentage of special organic and inorganic compounds
in the top growth of Bahia grass at different periods of growth when irrigated with water.
(Outer scale, total hydrolyzable carbohydrates and unhydrolyzed residue; inner scale, other
compounds.)

Similarly, top growth samples of Bahia grass taken at differ-
ent growth stages from the series of plots where such plants
were grown to maturity showed slightly higher percentages of
nitrogen in samples from the fertilized areas and lower in the
unfertilized areas in each instance. The top growth from the
plants from each of these differently treated areas was higher
in percentage of nitrogen in the earlier part of the season when
in a vegetative growth condition. However, whether fertilized
or not, the top growth of these plants for all treatments showed
a gradual decrease in percentage of nitrogen as the more mature
growth stages were approached. In the late seed stage of growth
the top growth from plants for all treatments contained a similar
low nitrogen percentage. The weight of nitrogen in the top
growth of Bahia plants from the series of plots where such
plants were grown to maturity varied directly with the order
of fertilizing treatments previously stated. Although the yield
of top growth from these plants appears to be slightly greater
than that from similar plants cut frequently, the weight of nitro-
gen from the mature top growth was less in each instance than







28 Florida Agricultural Experiment Station

that from the top growth from frequently cut plants (Tables 1
and 2, Figs. 1 to 8).
The frequently cut carpet and centipede grasses from the
second series of differently fertilized plots showed results simi-
lar to those from frequently cut Bahia grass receiving like treat-
ments. In percentage of total nitrogen the top growth from
the fertilized areas of both centipede and carpet grasses was
slightly higher than similar top growth from the unfertilized
plots. The total weight of nitrogen produced in the top growth
from the differently treated plots followed a similar trend. In
comparing the total weight of nitrogen produced by these two
grasses, carpet grass appeared to be superior in this instance,
although this may not hold true under all conditions (Tables 3
and 4, Figs. 9 to 14).
The Bahia and Sudan grasses grown on the third series of
plots and with irrigation and heavier nitrate fertilization showed
marked differences not only in total nitrogen percentages but
also in the different forms of nitrogen. In case of both the
frequently cut Bahia and Sudan grasses, the plants from the
fertilized areas showed a markedly higher total nitrogen per-




40






K2 0


L.0 Total Nitro-en




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


June July August Sept.
Fig. 8.-Diagram showing the percentage of special organic and inorganic compounds
in the top growth of Bahia grass at different periods of growth when not fertilized. (Outer
scale, total hydrolyzable carbohydrates and the unhydrolyzed residue; inner scale, other
compounds.)







Effect of Cutting, Fertilization on Grasses 29





Unhydrolyzed Residue









Lo
30















June July August Sept Oct
Fig. 9.-Diagram showing the percentage of special organic and inorganic compounds
in the top growth of carpet grass when cut frequently and treated with nitrate of soda
and water. (Outer scale, total hydrolyzable carbohydrates and unhydrolyzed residue; inner
scale, other compounds.)
centage and weight of total nitrogen in each instance throughout
the period of the experiment. The total weight of nitrogen
from the top growth of the fertilized Bahia grass was approxi-
mately eight times as great as that produced from the top
growth of similar plants not fertilized but only irrigated with
water. In case of Sudan grass a similar comparison showed a
ratio of 1 to 12 in favor of the plants from the fertilized area.
The different forms of soluble nitrogen such as that of amino
acids and nitrates were somewhat higher in percentage in the
top growth of plants from the more heavily fertilized areas.
The percentage of the other forms of nitrogen followed a similar
trend but the differences in favor of the fertilized plants were
somewhat greater in each instance (Tables 5, 6 and 7).
Mineral Compounds:-In the top growth of the frequently cut
Bahia plants the oxides of calcium, phosphorus, potassium and
magnesium were rather consistent in percentage throughout the
season. Although slightly higher in percentage when plants
were cut in a more vegetative condition, these compounds showed
a rather uniform trend in the top growth cuttings from the
frequently cut plants. These results held true for all three








TABLE 13.-SPECIFIC MINERAL ANALYSIS OF THE TOP GROWTH OF BAHIA GRASS CUT FREQUENTLY AND GROWN UNDER C
DIFFERENT SOIL TREATMENTS.
Calculations on basis of oven-dry, sand free matter.
Treatment I| Nitrate of Soda and Water || Nitrate of Soda
I Total Total
Dates of Cutting, 1928 P05 K20 CaO MgO Nitrogen P=Os KO CaO MgO Nitrogen
_Percent Percent Percent Percent Percent Percent Percent Percent Percent Percent
_____ ___. _V __Q
June 19........... .... ............... 0.869 1.75 0.725 0.773 2.31 0.812 1.930 0.754 0.675 2.25
July 9.............. ..................... 0.901 1.25 0.490 0.668 1.64 0.824 1.45 0.586 0.658 1.69
July 24.................................. 0.612 1.30 0.508 0.670 1.57 0.600 1.44 0.534 0.642 1.47 .
Aug. 7........ ... ......................... 0.690 1.19 0.594 0.856 1.75 0.642 1.63 0.630 0.774 1.62
Aug. 27............. ..................... 0.726 1.76 0.649 0.964 1.87 0.726 1.78 0.632 0.809 1.60
Oct. 3................................... 0.737 1.16 0.545 0.854 1.88 ... .......... ........ ......... ......... .............. 1.65
Nov. 1.............................. 0.783 1.22 0.851 0.968 1.86 0.689 1.28 0.836 0.940 1.70
Treatment Water Ij No Treatment
Total I I Total
Dates of Cutting, 1928 P0:i K20 CaO MgO Nitrogen P206 K.O CaO MgO Nitrogen
Percent Percent Percent Perceercenrcent Percent Percent Percent Percent | Percent
June 19............. .................... 0.838 1.92 1.232 0.832 1.59 0.742 1.50 0.909 0.660 1.55 C"
July 9..........-... ......... 1.00 1.31 0.816 0.708 1.87 I| 1.100 1.40 0.718 0.580 1.60
July 24.......-- .........----- 0.589 1.31 0.789 0.672 1.52 0.472 1.34 ............ ............ 1.54
Aug. 7................................... 0.784 1.40 0.840 0.867 1.63 0.652 1.64 0.844 0.816 1.71
Aug. 27......... ........................ 0.744 1.80 0.678 0.734 1.46 0.744 2.00 0.714 0.750 1.64
Oct. 3.................................... 0.807 1.10 0.638 0.718 1.91 0.976 1.32 0.730 0.766 1.64
Nov. 1................................... 0.690 0.826 1.237 0.990 1.46 0.607 1.25 1.129 0.802 1.38










TABLE 14.-SPECIFIC MINERAL-ANALYSIS OF THE TOP GROWTH OF CARPET GRASS, CUT FREQUENTLY AND GROWN UNDER
DIFFERENT SOIL TREATMENTS. (Calculations on basis of oven-dry, sand free matter.)
Treatment | Irrigation and Nitrate of Soda HI Irrigation I1 No Treatment
"Dates of P..O KO CaO MgO Total P20O K20 CaO MgO Total P0, K.O CaO MgO Total
Cutting Per- Per- Per- Per- Niro- Per- Per- Per- Per- Nitro- Per- Per- Per- Per- Nitro-
gen gen nI g e
1928 cent cent cent cent Percent cent cent cent cent Percent cent cent cent cent Percent
c.
June 19........ 0.722 0.880 1.04 0.67 2.17 0.622 1.72 1.36 0.88 2.00 0.622 1.60 0.90 0.64 1.51
July 9......... 0.603 1.30 0.83 0.56 1.66 0.620 1.64 1.07 0.64 1.81 0.650 1.80 1.04 0.63 1.77
July 24........ 0.650 1.50 0.78 0.60 1.73 0.614 1.36 0.82 0.57 1.58 0.617 1.41 0.99 0.60 1.62
Aug. 7 ..... ..... .... 0.78 0.55 1.70 0.620 1.29 0.88 0.59 1.70 0.620 1.44 0.87 0.54 1.56
Aug. 27.... 0.581 1.21 0.71 0.52 1.69 0.617 1.52 0.85 0.58 1.51 0.605 1.00 0.94 0.57 1.46
Oct. 3.... 0.624 0.832 0.59 0.48 1.67 0.615 1.17 0.62 0.52 1.50 0.570 1.17 0.59 0.48 1.55
N ov. 1.......... ............ ............ ........ .. .......... 1.82 ...- ................... .. ......... 1.15 ............ ............ .......... ............ 1.21 ,
.. ----- -----------------------------------------------------


TABLE 15.-SPECIFIC MINERAL ANALYSIS OF THE TOP GROWTH OF CENTIPEDE GRASS, CUT FREQUENTLY AND GROWN UNDER |
DIFFERENT SOIL TREATMENTS. (Calculations on basis of oven-dry, sand free matter.)
Treatment i Irrigation and Nitrate of Soda | _Irrigation II No Treatment 0
Date of P20. K0 CaO MgO Total P205 K20 CaO MgO Total P0, I K20 CaO MgO Total
Cutting Per- Per- Per- Per- Nr- Per- Per- Per- Per- Per- Per- Per- Per- NP- o
1928 cent cent cent cent Percent cent cent accent ent Percent cent cent cent cent Percent

June 19........ 0.755 1.16 0.570 0.710 1.61 0.652 0.995 0.690 0.775 1.53 0.794 1.11 0.850 0.885 1.29 3
July 9.......... 0.624 0.992 0.782 0.707 1.46 0.645 0.991 0.736 0.586 1.25 0.796 0.834 0.765 0.764 1.44 r
July 24........ 0.463 0.962 0.609 0.594 1.74 0.664 0.931 0.664 0.464 1.31 0.751 0.698 0.696 ............ 1.39
Aug. 7.......... 0.723 0.832 0.768 0.343 1.48 0.643 0.782 0.600 0.460 1.61 ............ ......... ......... 0.531 1.51
Aug. 27........ 0.352 0.723 0.499 ........... 1.48 0.532 1.01 0.540 ............ 1.26 0.693 1.72 0.585 .......... 1.37
Oct. 3.......... 0.433 1.05 0.407 ............ 1.51 0.441 1.18 0.493 ............ 1.26 0.481 1.22 0.709 ............ 1.23
Nov. 1........ .......... ............................. 1.43 .................. ........... . 1.12 ........................ ..... ........ 1.02
---------------------------------I----------- -----------------------------------------------









32 Florida Agricultural Experiment Station














L0
scale, total hydrolyzable carbohydrates and unhydrolyzed residue; inner scale, other com-





Total Nitro en













June July August Sept. Oct.
Fig. 10.-Diagram showing the percentage of special organic and inorganic compounds
in the top growth of carpet grass when cut frequently and irrigated with water. (Outer
scale, total hydrolyzable carbohydrates and unhydrolyzed residue; inner scale, other com-
pounds.)




60



"4 50 -








*A N t n -- "







ag




June July August Sept. Oct.
Fig. 11.-Diagram showing the percentage of special organic and inorganic compounds
in the top growth of carpet grass when cut frequently and not fertilized. (Outer scale,
total hydrolyzable carbohydrates and unhydrolyzed residue ; inner scale, other compounds.)










TABLE 16.-SPECIFIC MINERAL ANALYSIS OF THE TOP GROWTH OF BAHIA GRASS AT DIFFERENT GROWTH STAGES WHEN
GROWN UNDER DIFFERENT SOIL TREATMENTS.
Calculations on basis of oven-dry, sand free matter.
Treatment 1| -Nitrate of Soda and Water I| Water _____
Total Total
Dates of Cutting, 1928 P KO 2 KO CaO MgO Nitrogen PO.. K20 CaO MgO Nitrogen
Percent Percent Percent Percent Percent Percent Percent Percent Percent Percent --.

June 19................................. 0.869 1.75 0.725 0.773 1.79 0.770 ................ 1.232 0.832 1.31
July 24.................................. 0.645 1.68 0.475 0.680 1.06 ------................ 1.80 ................-- ............... 1.23
Aug. 28.................-............. 0.303 1.60 0.564 0.850 1.16 0.300 1.47 0.618 0.790 0.94
Oct. 3......... ----........ --................ 0.240 0.670 0.627 0.796 1.20 0.22 0.700 0.775 0.706 1.12

Treatment | Nitrate of Soda __No Treatment
1 Total Total
Dates of Cutting, 1928 PO0 KO CaO MgO Nitrogen P=Ot KO2 CaO MgO Nitrogen "
Percent Percent Percent Percent Percent Percent Percent Percent Percent Percent

June 19................................. 0.812 1.93 0.754 0.675 1.68 0.708 1.50 0.909 0.660 1.25
July 24.................................. 0.686 1.82 0.564 0.686 1.02 0.444 ................--- 0.516 0.576 0.99
Aug. 28 ..............-- ---......- 0.303 1.05 0.551 0.857 0.99 0.331 1.57 0.592 0.666 1.00
Oct. 3........-------.......................... 0.340 0.514 0.617 0.802 0.94 0.270 0.631 0.886 0.562 1.12



CID








34 Florida Agricultural Experiment Station





Lo
























June July August Sept. Oct.
Fig. 12.-Diagram to show the percentage of special organic and inorganic compounds
in the top growth of centipede grass when cut frequently and fertilized with nitrate of
soda and water. (Outer scale, total hydrolyzable carbohydrates and the unhydrolyzed
residue; inner scale, other compounds.)
405





























I. Tot dl Nitrogen
June July August Sept. Oct:


















Fig. 13.-Diagram showing the percentage of special organic and inorganic compounds
in the top growth of centipede grass when cut frequently and irrigated with water. (Outer
scale, total hydrolyzable carbohydrates and the unhydrolyzed residue; inner scale, other
comr pounds )
40-
















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



June July August Sept. Oct,
Fig. 13.-Diagram showing the percentage of special organic and inorganic compounds
in the top growth of centipede grass when cut frequently and irrigated with water. (Outer
scale, total hydrolyzable carbohydrates and the unhydrolyzed residue; inner scale, other
compounds.)







Effect of Cutting, Fertilization on Grasses 35

grasses, Bahia, carpet and centipede, when cut frequently as
shown in Tables 13, 14 and 15; also Figs. 1 to 4 and 9 to 14.
In the top growth of Bahia grass grown to maturity a down-
ward trend in the percentage of calcium, potassium, phosphorus
and magnesium was evident. This was especially true for phos-
phorus and potassium, both found in high percentage in the
early part of the season when the plants were vegetative but
low as the plants approached the late seed stage of growth.
Regardless of fertilization, phosphorus showed a decrease of
from 60 to 71 percent, while potassium in like manner showed
a decrease of from 60 to 82 percent. The compounds of calcium
and magnesium indicated variations in percentage but not such
a marked' downward trend as in the case of phosphorus and
potassium (Table 16, Figs. 5 to 8).
Composition Relations:-The variation in the growth behavior
of the plants from differently fertilized areas and subjected to
dissimilar treatments was closely correlated with the relation
between the various organic and inorganic compounds in the
plants. In case of the frequently cut plants, when in a vegeta-
tive growth condition, the relation between hydrolyzable carbo-
hydrates and total nitrogen was narrow. Whenever such plants
were cut in a more mature growth stage this relation was wider.
The repeated reversion from the reproductive to a vegetative
growth condition as a result of frequent cutting caused the
carbohydrate-nitrogen ratio to change frequently from wide to
narrow and back again. The unhydrolyzed residue consisting
mostly of lignin and cellulose, the more fibrous woody plant
materials, showed a downward trend whenever plants reverted
to the vegetative stage after cutting and an upward trend when
they approached the more mature stages of growth. In the
top growth of frequently cut plants the variations in the unhy-
drolyzed residue were not so marked. On the whole, this ma-
terial was more uniform in percentage throughout the season
than in plants grown to advanced maturity. The mineral com-
pounds of potassium and phosphorus followed a trend almost
similar to that of total nitrogen in relation to the hydrolyzed
carbohydrates and the unhydrolyzed fibrous residue. The in-
organic compounds of calcium and magnesium showed no con-
sistent relation in percentage with the organic carbohydrate
and nitrogen compounds in the top growth of the frequently
cut plants.
In the case of plants grown to maturity and not cut during







36 Florida Agricultural Experiment Station

the growing season a different trend was apparent in regard to
the relative composition of the differently fertilized plants. In
the early part of the growing season when these plants were in
a vegetative condition the relation between carbohydrates, nitro-
gen and the various mineral compounds was somewhat similar
to that of the frequently cut plants, i.e., rather narrow. There
was a continuous widening of the relation between hydrolyzed
carbohydrates and total nitrogen up to the period of maximum
reproduction. A similar relation was shown between total nitro-
gen and the fibrous unhydrolyzed residue. After this period
there is a continuous widening of the relation between total
nitrogen and the fibrous residue, especially when a decrease in
the percentage of hydrolyzed carbohydrates took place. The
mineral compounds of potassium and phosphorus showed a con-
tinuous widening in their relation to the above named carbohy-
drates and fibrous residue as the plants approached the more
mature growth stages, i.e., they followed the trend of total
nitrogen. The mineral compounds of calcium and magnesium
showed some slight variations in their relation to carbohydrates
but like the frequently cut plants this relation was more uniform
throughout the growing season (Figs. 1 to 14).






O-



S /o Nrtr



S0... .. 9..........



June July August ept. Oct.
Fig. 14.-Diagram showing the percentage of special organic and inorganic compounds
in the top growth of centipede grass when cut frequently and not fertilized. (Outer scale,
total hydrolyzable carbohydrates and the unhydrolyzed residue; inner scale, other compounds.)







Effect of Cutting, Fertilization on Grasses 37

DISCUSSION
The effects of nitrate fertilization on pasture grasses present
some interesting relationships in regard to their growth be-
havior, top production and relative composition. The persistent
after-growth of the prostrate growing pasture grasses resulting
from their residual horizontal leaf area which is capable of
elaborating organic foods for continued vegetative growth, makes
these grasses highly valuable for grazing purposes. Although
some of the upright growing grasses like Sudan grass produce
large yields of top growth from fewer cuttings in a vegetative
growth stage, they finally die as a result of frequent cutting or
grazing, even when fertilized.
The result of nitrate fertilization reflected some marked
changes in growth behavior of the different grasses. Similar
to the results of Stapledon and Beddoros (33), a marked increase
in leafage over seed-stem production resulted where nitrate fer-
tilizer applications were made, indicating a more vegetative
condition of such grasses. This greater vegetative growth con-
dition was not only reflected in increased leafage but also in the
increase of stolon growth both as to extension and number of
stolons produced. In the frequently cut areas, this condition
resulted in a better sod formation due to the fact that these
grasses were cut frequently and repeatedly reverted to a
vegetative growth condition. On the other hand, where plants
were grown to maturity and not cut, vigorous increase in stolon
production and extension took place during the early part of
the growing season. This increased stolon production resulted
subsequently in greater seed stem growth later in the season
when seasonal changes were more conducive to reproduction in
the plants. This caused greater seed production from fertilized
plants even when the ratio of leafage to seed stems is greater
as a result of fertilization.
As noted in Tables 1 to 7, nitrate fertilization increased the
yield of top growth in both frequently cut plants and plants
grown to maturity. Although the yield of forage from the
mature plants was greater, the actual weight of nitrogen or
protein from the frequently cut plants exceeded that of the more
mature plants. This indicates, as shown in Figs. 1 to 8, that
the greater increase in the mature plants was mostly in the form
of the higher carbohydrates or crude fibrous materials. The
low percentage of these crude materials in frequently cut plants
combined with a higher percentage of protein produced a more






38 Florida Agricultural Experiment Station

ideal ratio for feeding purposes. The better mineral content of
frequently cut grasses (Figs. 1 to 4 and 9 to 14) for the building
of the skeleton and for aiding in the metabolism of the animal
body plus their greater succulence and palatability aid in re-
ducing the quantity of supplementary feeds needed for cattle,
as shown by Fink, Mortimer, Truog and others.
Results in general show that the maintenance of a maximum
yield of top growth with an appropriate composition relationship
is closely correlated with the effects of fertilization, top cutting
or grazing and seasonal changes on the growth and composition
variations in the plant. Carbohydrates and other organic com-
pounds cannot be supplied directly to the plant through fertili-
zation but must be elaborated by the plant itself. Since the
quantity of such materials, especially carbohydrates elaborated
by the plant, is dependent upon the extent of its leaf area, the
increase or decrease of such leaf area is an essential factor in
changing the composition relationship of the plant and its re-
sultant growth condition.
Similar to pruning in orchard practices, top cutting and
grazing of pasture grasses are cultural practices used in bal-
ancing the supply of carbohydrate compounds within the plant
with nitrogen to obtain a desired growth condition. This is in
accord with the findings of Kraus and Kraybill (12), who state:
"Pruning is largely effective in promoting or retarding fruitful-
ness by its effects in balancing the carbohydrate supply within
the plant, or the means for its manufacture, with the available
moisture and nitrogen supply." On the other hand, a proper
nitrogen supply within the plant for the above balance with
carbohydrates for a desired growth condition may be procured
through nitrate fertilization.
In this respect, quoting Kraus and Kraybill further, "Fer-
tilizers containing available nitrogen, or that which may be
made available are mainly effective in producing vegetative
response. They may either increase or decrease fruitfulness
according to the relative carbohydrate supply." The more con-
tinuous vegetative condition of the frequently cut pasture grasses
appears to be in accord with the above statements, when com-
pared with similar grasses where the top growth is not fre-
quently removed.
The reduction of carbohydrate accumulation by reducing the
means of its manufacture through removal of top growth results
in a narrower nitrogen to carbohydrate relationship which is






Effect of Cutting, Fertilization on Grasses 39

associated with vegetative growth. This vegetative condition
is further augmented by increasing the supply of available ni-
trogen to the plants through nitrate fertilization. This result
of nitrate fertilization is not only shown by a more vegetative
growth condition within the plant itself, but is reflected in
increased vegetative growth parts or top growth production
(Tables 1 to 7, Figs. 1 to 4 and 9 to 14). On the other hand,
plants grown to maturity with no frequent removal of top growth
show an increased accumulation of carbohydrate material as a
result of increased leaf area for photosynthetic activity. This
increased elaboration of simple carbohydrates and their rapid
transformation into the more fibrous woody materials results
in a wide carbohydrate relation to nitrogen, a condition asso-
ciated with the more mature growth stages (Figs. 4 to 8). Even
where such plants received nitrate fertilizers, increased seed
production occurred as a result of a greater supply of carbo-
hydrates.
Although reproduction and vegetative response are correlated
more or less with the elaboration of carbohydrates and the
available nitrogen supply, environmental factors are likewise
influential in connection with the growth behavior of the plants.
Plant food elaboration may be affected by factors such as length
of the daylight period, temperature, and moisture. These con-
ditions vary the elaboration of carbohydrates on the one hand
and affect the availability of nitrogen from the soil on the other.
Limitation of moisture to plants grown under conditions of
abundant nitrogen may result in accumulation of carbohydrates
and seed production in plants similar to the limiting of the
supply of nitrogen. Again, irrigation or moisture supply to
plants affects vegetative growth or seed formation only in so
far as such moisture is accompanied by an available nitrogen
supply or vice versa (34).
As a result of the effects of these varying environmental con-
ditions during the growing season, frequently cut plants become
partly reproductive. Frequent cutting repeatedly reverts such
plants to a vegetative growth condition with a corresponding
composition relationship (22). (Figs. 1 to 4 and 9 to 14.) If
such plants are cut before seed or fruits are formed a more
vegetative composition in the top growth cutting may still be
obtained. If seeds or fruits are permitted to form, a decrease
in nitrogen occurs and a corresponding increase in the simpler






40 Florida Agricultural Experiment Station

carbohydrates and in the more fibrous woody materials in the
plants.
Stimulation due to sexual reproduction in plants seems to
extend beyond the reproductive organs. As reported by Mur-
neek (23), the greatest quantities of soil nutrients are absorbed
and the larger amounts of organic compounds are formed when
fertilization (gametic union) takes place and fruiting is not
permitted. The highest metabolic efficiency occurs, however,
when normal fruiting takes place. These phases of plant growth
are exhibited by the rapid growth of pasture grasses after re-
production takes place and by the increased accumulation of the
fibrous woody materials in the plant after seed formation occurs
(Figs. 4 to 8). This latter phase of growth may be prevented
in pasture grasses by frequent cutting. The more fibrous ma-
terials in the plant are then prevented from accumulating and
a more vegetative growth condition is maintained (Figs. 1 to 4
and 9 to 14).
The higher percentage of total nitrogen, and especially the
soluble forms of nitrogen, in the top growth of the frequently
cut and more heavily fertilized Bahia and Sudan grasses is in-
dicative of greater vegetative response from fertilization and
frequent cutting. Although similar plots of these grasses were
likewise irrigated, the absence of similar amounts of available
nitrogen failed to produce a similar growth condition both as to
percentage of nitrogen in the top growth and the quantity of
vegetative top growth produced.
This increase in the soluble forms of nitrogen in the more
vegetative top growth is in accord with the work of Leukel (13,
15) who found higher soluble nitrogen in alfalfa plants and
grasses in the early vegetative growth stages than was found
in such plants when in a more mature growth condition.
Although fertilized heavily with sodium nitrate, no large
accumulation of nitrates was found in the top growth of the
plants. The percentage of such was similar to that generally
found in normally growing plants. This indicates that the effect
of heavy nitrate fertilization is reflected more in increased
vegetative growth than in nitrate accumulations in the plant.
It appears that nitrates are rapidly assimilated to the higher
forms of nitrogen compounds. Accumulation of nitrates in
plants may not result from heavy nitrate fertilizations but
rather from a deficiency of other elements or changes in environ-
ment essential for nitrate assimilation. Such were the findings






Effect of Cutting, Fertilization on Grasses 41

of Nightingale (25) and Nightingale et al. (26). In the first
instance, assimilation of nitrates was found to be limited in
salvia, buckwheat, soybean and radish plants by a decrease in
the length of the daylight period. In the second instance, the
investigators found a limitation of nitrate assimilation by a
deficiency in calcium which appeared to be associated with ni-
trate assimilation. Other instances of nitrate accumulation are
found in the literature (38) but such cases appear to be due
more to abnormal growth conditions than to an increased supply
of available nitrogen. Where conditions are favorable for vig-
orous vegetative growth evidence of nitrate accumulation in
pasture plants is very doubtful.
The variation in the percentage of the various mineral com-
pounds, especially those of potassium and phosphorus, appears
to be closely correlated with the growth behavior of the plants.
Potassium, as reported by Bartholomew and Janssen (1), is
taken up at a rapid rate whenever vigorous growth of plants
occurs. This may account for the higher and more constant
percentage of this compound in the frequently cut plants which
were generally in a vegetative growth condition or reverted to
this condition after cutting. Under normal growth conditions
this element is generally stored in the tissues of the plant and
later translocated to the more growing parts (11). Removal of
top growth before such translocation takes place in the more
mature growth stages furnishes a top growth higher in percent-
age of this element, although on a quantity basis the mature
plants may contain an equal weight of potassium. On account
of the more efficient plant metabolism after fruit formation in
the plants with a resultant increase in the formation of lignin
and cellulose or fibrous materials, the percentage or concentra-
tion of potassium in the plant is decidedly decreased. Although
potassium may be taken up by plants at all growth stages if
available, the higher percentage of this element in the frequently
cut plants during the entire season may indicate a more efficient
absorption during the vegetative growth period.
Phosphorus, like potassium, is absorbed and stored in the
tissues of the plant during the early growth period and therefore
the frequently cut top growth contains a higher percentage of
this element. In the top growth of plants grown to maturity,
phosphorus was low in percentage, as was potassium. Phos-
phorus stored in the vegetative stem and leaf tissue during the
early growth stages is translocated to the fruit-forming parts






42 Florida Agricultural Experiment Station

of the plant. This process of translocation combined with the
increased accumulation of woody or fibrous tissue results in a
low percentage of phosphorus in the forage part of the plant.
Calcium and magnesium compounds showed less variation in
percentage between the top growth of frequently cut plants and
that of those grown to maturity. These compounds appear to
be less labile and do not accumulate so greatly in plant tissue for
later translocation as in the case of phosphorus and potassium.
These various mineral elements not only supply materials for
plant growth but they also function in various ways in the gen-
eral metabolism of the plant.
Magnesium has been shown by Willstatter (37) to be a con-
stituent of chlorophyll and a disturbance in the formation of
chlorophyll is noted if this element is lacking. Magnesium is
known to function as a carrier of phosphorus. This element
(phosphorus) enters into the formation of nucleoproteins and
lecithins, two compounds which enter into the formation of
protoplasm. This is substantiated by the fact that phosphorus
is generally high in the tissues of plant parts where rapid growth
occurs. Besides aiding in the formation of nucleoproteins and
lecithins, it is considered by Lyon (19, 20) to aid in respiration
through its catalytic action on certain organic compounds (pyra-
gallol and tannic acid) by atmospheric oxygen. Root crops are
known to develop better when phosphate fertilizers are applied
but whether the proportions of roots to tops in ordinary field
crops are increased by the application of phosphorus has not
been sufficiently proven.
Calcium as calcium pectate is found in the middle lamella of
the cell wall and is essential for the elaboration of this wall
tissue. In addition this element is also essential for combination
with the materials of the protoplasm. Calcium-deficient plants
accumulate carbohydrates in large quantities due to the fact
that nitrate absorption and assimilation is retarded (28). In
general, this element is associated physiologically with the trans-
location of carbohydrates, the composition of plant structures
and with physiological availability of other ions.
The role of potassium in plants as judged from their general
behavior when deprived of this element is associated with vari-
ous phases of plant metabolism. It appears to be essential for
carbon dioxide assimilation since carbohydrates may be low in
potassium-deficient plants. It is also directly or indirectly asso-






Effect of Cutting, Fertilization on Grasses 43

ciated with nitrate reduction, cell division and synthesis of the
proteins of meristematic tissue (5).
Although all the constituents for the elaboration of organic
compounds are not supplied through commercial fertilizers, the
mineral elements in such fertilizers appear to be essential for
their formation (organic compounds) through the general
metabolism of the plant. Although fertilization with nitrogen
fertilizers stimulates vegetative growth, such growth can con-
tinue only when other mineral elements are available in suffi-
cient quantities for a properly balanced plant metabolism.

APPLICATION TO PRACTICE
The growth behavior and relative composition of frequently
cut and fertilized pasture grasses in comparison with grasses
not so treated suggest several phases of practical application.
Frequent cutting tends to keep grasses vegetative or reverts
them to a vegetative growth condition. Grasses in this condi-
tion are more succulent and palatable, higher in protein and
show a narrow relation or ratio between proteins and carbo-
hydrates. Such a ratio is more ideal for feeding purposes and
necessitates smaller quantities of supplementary feeds. The
higher percentage of essential mineral compounds in such
grasses goes far in supplying the needed minerals for building
the skeleton of the animal and to aid in its body metabolism.
The horizontal growth of the stolons of such grasses as a result
of cutting maintains a denser sod which eliminates weed growth
from good pastures. Since nitrate fertilization is reflected in
the production of increased vegetative plant parts, with no
marked accumulation of nitrates in the plant, such fertilization
economically practiced should largely result in the increased
production of a more vegetative herbage high in protein, a longer
growing period and a greater carrying capacity of pastures.
On the other hand, pasture grasses not grazed sufficiently soon
pass into a reproductive growth stage and cease vegetative
growth. Such plants are high in the more fibrous plant ma-
terials, less palatable, and low in protein and mineral constitu-
ents. The wider relation or ratio between proteins and carbo-
hydrates in such herbage results in a poorly balanced ration
and requires more supplementary feed for efficient maintenance.
Although nitrate fertilization increases the vegetative produc-
tion of such plants during the early growth period the benefits
of such increased growth is of short duration if the plants are






44 Florida Agricultural Experiment Station

not properly grazed. The decrease in vegetative growth after
the plants pass into the reproductive or seed stage of growth
greatly shortens the seasonal period for efficient grazing. The
upright growth of stolons in the form of seed stems creates
vacant spaces between the plants. These vacant spaces are soon
covered with weed growth which is detrimental to good pastures.

SUMMARY
A study was made of the growth behavior, yield and relative
composition of four pasture grasses when subjected to different
fertilizer and cutting treatments.
Plants cut frequently maintained a more vegetative growth
condition and a greater horizontal growth of stolons which
resulted in a better sod formation. The yield of green and dry
top growth produced from frequently cut and fertilized plants
varied with the order of treatments given, namely, nitrate of
soda and water, nitrate of soda, water, and no treatment. In-
creased nitrate fertilization resulted in greater yields. Plants
grown to maturity were vegetative during their early growth
period but soon passed into a reproductive growth stage and
ceased vegetative extension. Such plants produced an upright
growth of stolons when reproductive and formed a poor sod.
They produced more vegetative plant parts during the early
growth period but likewise became more reproductive and pro-
duced more seed during the later growth stages. The yield of
green and dry top growth from plants grown to maturity varied
with the following treatments: nitrate of soda, nitrate of soda
and water, water, and no treatment.
The top growth of frequently cut plants showed a more uni-
form trend in percentage of dry matter. Plants grown to ma-
turity showed a gradual increase in percentage of dry matter
as they approached the more mature growth stages.
Frequently cut plants subjected to nitrate fertilization varied
inversely in percentage of dry matter with the rate of such
fertilization. Nitrate fertilization brought about a lower per-
centage of dry matter during the early growth period in the
top growth of plants grown to maturity. Such dry matter
increased in percentage as the plants approached maturity.
In the top growth of plants cut frequently, ether extracted
substances were higher in percentage than they were in the top
growth of plants grown to maturity.
Total hydrolyzable carbohydrates were rather uniform







Effect of Cutting, Fertilization on Grasses 45

throughout the growing season in percentage in the top growth
of plants grown to maturity. More fluctuations occurred in
the percentage of this compound in the tops of frequently-cut
plants during the same period. The unhydrolyzed residue in
the top growth from frequently cut plants was lower and more
uniform in percentage than that from the top growth of plants
grown to maturity. In the latter plants a gradual increase in
the percentage of this substance was found in the top growth
as the plants approached maturity.
In the top growth of frequently cut plants a higher percentage
of nitrogen prevailed from one cutting period to another. Plants
grown to maturity showed a gradual decrease in percentage of
nitrogen in their top growth as they approached the seed stage
of growth.
Frequently cut plants receiving nitrate fertilization were more
vegetative and consequently higher in percentage of nitrogen.
Such fertilization resulted in a higher percentage of nitrogen
in the top growth of plants grown to maturity during the early,
more vegetative growth period but decreased to the same level
as that of unfertilized plants in the later growth stages.
The mineral compounds of phosphorus and potassium were
higher and more uniform in the top growth of frequently cut
plants throughout the growing season than in the top growth
of plants grown to maturity. In the top growth of the latter
plants a gradual decrease in the percentages of these compounds
occurred as the plants approached maturity. The compounds
of calcium and magnesium were more uniform in percentage
in top growth of the differently treated plants.
Frequently cut plants showed a narrow relation between total
hydrolyzable carbohydrates and total nitrogen in their top
growth throughout the season. A similar relation existed
between total nitrogen and the unhydrolyzed residue. The com-
pounds of phosphorus and potassium showed a relation similar
to that of total nitrogen to the above carbohydrate compounds.
This narrow relation in both instances was associated with
greater vegetative growth.
In the top growth of plants grown to maturity the relation
of total nitrogen, phosphorus and potassium to total hydrolyzable
carbohydrates and the unhydrolyzed residue showed a gradual
widening as the plants approached the later growth stages. This
condition was associated with reproduction and seed formation
in the top growth of the plants.







46 Florida Agricultural Experiment Station

Increased nitrate fertilization brought about no marked ac-
cumulation of nitrates in the top growth of pasture plants.
Such fertilization was reflected in increased production of vege-
tative top growth. Increased vegetative top growth of Sudan
grass high in nitrogen was produced over a short period as a
result of frequent cutting and nitrate fertilization. This grass,
on account of its upright growth, succumbed as a result of
frequent cutting.
Some practical applications of the results are suggested.


LITERATURE CITED

1. BARTHOLOMEW, B. P., and JANSSEN, GEO. The rate of absorption of
potassium by plants and its possible effect upon the amount of potas-
sium remaining in soils from applications of potassium fertilizers.
Arkansas Exp. Sta. Bul. No. 265, 1931.
2. DAVIDSON, J., and LECLERC, J. A. Effect of various inorganic nitrogen
compounds, applied at different stages of growth, on the yield, com-
position and quality of wheat. Jour. Agr. Res. 23: 2: 55-69, 1923.
3. DAVIDSON, J., and LECLERc, J. A. Effect of sodium nitrate applied at
different stages of growth on yield, composition and quality of wheat.
Jour. Amer. Soc. Agron. 10: 193-198, 1918.
4. DAVIDSON, J., and LECLERC, J. A. Effect of sodium nitrate applied at
different stages of growth on the yield, composition and quality of
wheat. Jour. Amer. Soc. Agron. 9: 145-154. 1917.
5. DULY, F. L., and MILLER, M. F. The effect of varying supply of
nutrients upon the character and composition of the corn plant. Mo.
Agric. Exper. Sta. Res. Bul. 42. 1921.
6. ENLOW, C. R., and COLEMAN, J. M. Increasing the protein content oJ
pasture grass by frequent light applications of nitrogen. Jour. Amer
Soc. Agron. 21: 845-853. 1929.
7. FINK, D. S., MORTIMER, G. B., and TRUOG, E. Three years' results
with an intensively managed pasture. Jour. Amer. Soc. Agron.
25: 7: 441-453. 1933.
8. GERICKE, W. F. Differences in the protein content of grain by appli-
cation of nitrogen made at different growing periods of the plants.
Soil Science 14: 103-118. 1921.
9. GRUNDER, M. S. Yield and chemical composition of certain pasture
crops, fertilized and unfertilized. Jour. Agr. Res. 46: 375-386. 1933.
10. HART, EDWIN B., and TOTTINGHAM, WILLIAM E. General Agricultural
Chemistry. Madison, Wis.
11. JANSSEN, GEO. The translocation of potassium in tomato plants and
its rela ion to other carbohydrate and nitrogen distribution. Jour.
Agri. Res. 38: 447-465. 1929.








Effect of Cutting, Fertilization on Grasses 47

12. KRAUS, E. J., and KRAYBILL, H. R. Vegetation and reproduction with
special reference to the tomato. Ore. Exp. Sta. Bul. No. 149. 1918.
13. LEUKEL, W. A. Deposition and utilization of reserve foods in alfalfa
plants. Jour. Amer. Soc. Agron. 19: 7: 596-623. 1927.
14. LEUKEL, W. A., BARNETTE, R. M., and HESTER, J. B. Composition and
nitrification studies on Crotalaria striata. Soil Science 28: 5: 347-371.
1929.
15. LEUKEL, W. A., and COLEMAN, J. M. Growth behavior and maintenance
of organic foods in Bahia grass. Fla. Exp. Sta. Tech. Bul. 219, 1930.
16. LECLERC, J. A. The effect of climatic conditions on the composition
of Durum wheat. Yearbook of the U. S. D. A., 199-212. 1906.
17. LECLERC, J. A. Tri-local experiments on the influence of environment
on the composition of wheat. Bureau of Chemistry, U. S. D. A. Bul.
No. 128. 1910.
18. LOEHWING, W. F. Calcium, potassium and iron balance in certain
crop plants in relation to their metabolism. Plant Physiology 3: 261-
275. 1928.
19. LYON, C. J. The role of phosphate in plant respiration. Amer. Jour.
Bot. 14: 274-284. 1927.
20. LYON, C. J. The effect of phosphate on respiration. Jour. Gen.
Physiol. 6: 299-306. 1923.
21. MACGILLIVARY, J. H. Effect of phosphorus on the composition of the
tomato plant. Jour. Agric. Res. 34: 97-127. 1927.
22. MURNEEK, A. E. Effects of fruit on vegetative growth in plants.
Proc. Am. Soc. Hort. Sci., 274-276. 1924.
23. MURNEEK, A. E. Physiology of reproduction in horticultural plants.
I. Reproduction and metabolic efficiency in the tomato. Mo. Agr.
Exp. Sta. Res. Bul. 90. 1926.
24. NEIDIG, R. E., and SNYDER, R. S. The relation of the yield and protein
content of wheat to the nitrogen content of the soil under ten years
of different systems of cropping. Idaho Exp. Sta. Res. Bul. 5. 1926.
25. NIGHTINGALE, G. T. The chemical composition of plants in relation
to photo-periodic changes. Wis. Agr. Exp. Sta. Res. Bul. 74. 1927.
26. NIGHTINGALE, G. T., ADDOMS, R. M., ROBBINS, W. R., and SCHERMER-
HORN, L. G. Effects of calcium deficiency on nitrate absorption and
on metabolism in the tomato. Plant Physiology 6: 4: 605-630. 1931.
27. NIGHTINGALE, G. T., SCHERMERHORN, L. G., and ROBBINs, W. R. Effects
of sulphur deficiency on metabolism in tomato. Plant Physiology 7:
4: 565-595. 1932.
28. NIGHTINGALE, G. T., SCHERMERHORN, L. G., and ROBBINS, W. R. Some
effects of potassium deficiency on the histological structure and ni-
trogenous and carbohydrate constituents of plants. New Jersey Agric.
Exp. Sta. Bul. 499. 1930.
29. Official and tentative methods of analysis of the Association of
Official Agricultural Chemists. 102-114. 1930.







48 Florida Agricultural Experiment Station

30. PENIGREE, M. H. The influence of nitrogenous, phosphatic, and potas-
sic fertilizers upon the percentage of nitrogen and mineral constituents
of the oat plant. Ann. Rept. Penn. State College, 43-45. 1906.
31. REED, H. S. The value of certain nutritive elements in the plant cell.
Ann. Bot. 21: 501-543. 1907.
32. SHAW, G. A., and WALTERS, E. H. A progress report upon soil and
climatic factors affecting the composition of wheat. Cal. Exp. Sta.
Bul. No. 216. 1911.
33. STAPLEDON, R. G., and BEDDOWS, A. R. The quantitative and qualita-
tive response of cocksfoot grass (Dactylis glomerata Lin.) to sodium
nitrate and superphosphate. Welsh Jour. Agr. Fol. H. 1926.
34. STOKES, W. E., LEUKEL, W. A., and BARNETTE, R. M. Effects of irri-
gation with sewage effluent on the yields and establishment of Napier
grass and Japanese cane. Fla. Exp. Sta. Tech. Bul. 215. 1930.
35. TIEDGENS, V. A., and ROBBINS, W. R. The use of ammonia and
nitrate nitrogen by certain crop plants. New Jersey Agr. Exp. Sta.
Bul. 526. 1931.
36. WILEY, H. W. Principles and practice of agricultural analysis, 2nd
Edition. Vol. 20, p. 12. New York Chem. Pub. Co.
37. WILLSTATTER, R. Zur Kenntniss der Zusammensetzung des Chloro-
phylls. Ann. Chem. 350: 48-83. 1906.
38. Woo, M. L. Chemical constituents of Amaranthus retroflexus. Bot.
Gaz. 68: 313-343. 1919.
39. WooD, CHAS. D., and PHELPS, C. S. Special nitrogen experiment on
grass. Conn. (Storrs) Exp. Sta. Bul. No. 8. 1892.





University of Florida Home Page
© 2004 - 2010 University of Florida George A. Smathers Libraries.
All rights reserved.

Acceptable Use, Copyright, and Disclaimer Statement
Last updated October 10, 2010 - - mvs