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 Title Page
 Credits
 Table of Contents
 Introduction
 Materials and methods
 Experimental results
 Discussion
 Application to practice
 Summary
 Literature cited














Group Title: Bulletin - University of Florida. Agricultural Experiment Station ; no. 286
Title: Cutting experiments with bahia grass grown in lysimeters
CITATION THUMBNAILS PAGE IMAGE ZOOMABLE
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00027292/00001
 Material Information
Title: Cutting experiments with bahia grass grown in lysimeters
Series Title: Bulletin University of Florida. Agricultural Experiment Station
Physical Description: 36 p. : ; 23 cm.
Language: English
Creator: Leukel, W. A ( Walter Anthony )
Barnette, R. M
Publisher: University of Florida Agricultural Experiment Station
Place of Publication: Gainesville Fla
Publication Date: 1935
 Subjects
Subject: Grasses -- Florida   ( lcsh )
Lysimeter   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Bibliography: Bibliography: p. 35-36.
Statement of Responsibility: by W.A. Leukel and R.M. Barnette.
General Note: Cover title.
Funding: Bulletin (University of Florida. Agricultural Experiment Station)
 Record Information
Bibliographic ID: UF00027292
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: aleph - 000924364
oclc - 18210065
notis - AEN4982

Table of Contents
    Title Page
        Page 1
    Credits
        Page 2
    Table of Contents
        Page 3
    Introduction
        Page 3
        Page 4
        Page 5
    Materials and methods
        Page 6
        Page 7
    Experimental results
        Page 8
        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
    Discussion
        Page 27
        Page 28
        Page 29
        Page 30
        Page 31
    Application to practice
        Page 32
    Summary
        Page 32
        Page 33
        Page 34
    Literature cited
        Page 35
        Page 36
Full Text


November, 1935


UNIVERSITY OF FLORIDA
AGRICULTURAL EXPERIMENT STATION
GAINESVILLE, FLORIDA
WILMON NEWELL, Director







CUTTING EXPERIMENTS WITH

BAHIA GRASS

GROWN IN LYSIMETERS


By

W. A. LEUKEL and R. M. BARNETTE


TECHNICAL BULLETIN







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


Bulletin 286









EXECUTIVE STAFF

John J. Tigert, M.A., LL.D., President of the
University
Wilmon Newell, D.Sc., Director
H. Harold Hume, M.S., Asst. Dir., Research
Harold Mowry, M.S.A., Asst. Dir., Adm.
J. Francis Cooper, M.S.A., Editor
Jefferson Thomas, Assistant E itor
Clyde Beale, A.B.J., Assistant Editor
Ida Keeling Cresap, Librarian
Ruby Newhall, Administrative Manager
K. H. Graham, Business Manager
Rachel MeQuarrie, Accountant

MAIN STATION, GAINESVILLE

AGRONOMY
W. E. Stokes, M.S., Agronomist**
W. A. Leukel, Ph.D., Agronomist
G. E. Ritchey, M.S.A., Associate*
Fred H. Hull, Ph.D., Associate
W. A. Carver, Ph.D., Associate
John P. Camp, M.S., Assistant
ANIMAL HUSBANDRY
A. L. Shealy, D.V.M., Animal Husbandman**
R. B. Becker, Ph.D., Dairy Husbandman
W. M. Neal, Ph.D., Asso. in An. Nutrition
D. A. Sanders, D.V.M., Veterinarian
M. W. Emmel, D.V.M., Asst. Veterinarian
N. R. Mehrhof, M.Agr., Poultry Husbandman
W. W. Henley. B.S.A., Asst. An. Husbandman
Bradford Knapp, Jr., M.S., Asst. An. Husb.
P. T. Dix Arnold, B.S.A., Assistant Dairy
Husbandman
L. L. Busoff, M.S, Laboratory Assistant
Jeanette Shaw, M.S., Laboratory Technician
CHEMISTRY AND SOILS
R. W. Ruprecht, Ph.D., Chemist**
R. M. Barnette, Ph.D., Chemist
C. E. Bell, Ph.D.. Associate
R. B. French, Ph.D.. Associate
H. W. Winsor, B.S.A., Assistant
ECONOMICS. AGRICULTURAL
C. V. Noble, Ph.D., Agricultural Economist*
Bruce McKinley, A.B., B.S.A., Associate
Zach Savage, M.S.A., Associate
A. H. Spurlock, M.S.A., Assistant
ECONOMICS, HOME
Ouida Davis Abbott, Ph.D., Specialist"
C. F. Ahmann, Ph.D., Physiologist
SPECTROGRAPHIC LABORATORY
L. W. Gaddum, Ph.D., Biochemist
L. H. Rogers, M.A., Spectroscopic Analyst
ENTOMOLOGY
J. R. Watson, A.M., Entomologist*
A. N. Tissot, Ph.D., Associate
H. E. Bratley, M.S.A., Assistant
HORTICULTURE
A. F. Camp, Ph.D., Horticulturist"*
G. H. Blackmon, M.S.A., Horticulturist and
Associate Head of Department
A. L. Stahl, Ph.D., Associate
F. S. Jamison, Ph.D., Truck Horticulturist
R. J. Wilmot, M.S.A., Specialist, Fumigation
Research
R. D. Dickey, B.S.A., Assistant Horticulturist
PLANT PATHOLOGY
W. B. Tisdale, Ph.D., Plant Pathologist*
George F. Weber, Ph.D., Plant Pathologist
R. K. Voorhees, M.S., Assistant***
Erdman West, M.S., Mycologist
Lillian E. Arnold, M.S., Assistant Botanist
Stacy O. Hawkins, M.A., Assistant Plant
Pathologist


BOARD OF CONTROL
Geo. H. Baldwin, Chairman, Jacksonville
A. H. Blanding, Bartow
A. H. Wagg, West Palm Beach
Oliver J. Semmes, Pensacola
Harry C. Duncan, Tavares
J. T. Diamond, Secretary, Tallahassee

BRANCH STATIONS
NORTH FLORIDA STATION, QUINCY
L. O. Gratz, Ph.D., Plant Pathologist in
Charge
R. R. Kincaid, Ph.D., Asso. Plant Pathologist
J. D. Warner, M.S., Agronomist
Jesse Reeves, Farm Superintendent
CITRUS STATION, LAKE ALFRED
A. F. Camp, Ph.D., Horticulturist in Charge
John H. Jefferies, Superintendent
W. A. Kuntz, A.M., Assoc. Plant Pathologist
B. R. Fudge, Ph.D., Associate Chemist
W. L. Thompson, B.S., Asst. Entomologist
EVERGLADES STATION, BELLE GLADE
A. Daane, Ph.D., Agronomist in Charge
R. N. Lobdell, M.S., Entomologist
F. D. Stevens, B.S., Sugarcane Agronomist
Thomas Bregger, Ph.D., SugarcanePhysiologist
G. R. Townsend, Ph.D., Assistant Plant
Pathologist
J. R. Neller, Ph.D., Biochemist
R. W. Kidder, B.S., Assistant Animal
Husbandman
Ross E. Robertson, B.S., Assistant Chemist
B. S. Clayton, B.S.C.E., Drainage Engineer
SUB-TROPICAL STATION, HOMESTEAD
H. S. Wolfe, Ph.D., Horticulturist in Charge
W. M. Fifield, M.S., Asst. Horticulturist
Geo. D. Ruehle, Ph.D., Associate Plant
Pathologist
W. CENTRAL FLA. STA., BROOKSVILLE
W. F. Ward, M.S.A., Asst. An. Husbandman
in Charge*

FIELD STATIONS
Leesburg
M. N. Walker, Ph.D., Plant Pathologist in
Charge
W. B. Shippy, Ph.D,. Asso. Plant Pathologist
K. W. Loucks, M.S., Asat. Plant Pathologist
J. W. Wilson, Ph.D., Associate Entomologist
Plant City
A. N. Brooks, Ph.D., Plant Pathologist
Cocoa
A. S. Rhoads, Ph.D., Plant Pathologist
Hastings
A. H. Eddins. Ph.D., Plant Pathologist
Monticello
G. B. Fairchild, M.S., Asst. Entomologist***
Bradenton
David G. Kelbert, Asst. Plant Pathologist
C. C. Goff, M.S., Assistant Entomologist
Sanford
E. R. Purvis, Ph.D., Assistant Chemist,
Celery Investigations
Lakeland
E. S. Ellison, Ph.D., Meteorologist*
B. H. Moore, A.B., Asst. Meteorologist*
W. O. Johnson, B.A., Asst. Meteorologist*
R. T. Sherouse, Asst. Meteorologist*
M. L. Blanc, Asst. Meteorologist*
In cooperation with U.S.D.A.
** Head of Department.
*** On leave.









CUTTING EXPERIMENTS WITH BAHIA GRASS

GROWN IN LYSIMETERS

By
W. A. LEUKEL and R. M. BARNETTE

CONTENTS
Page Page
Materials and Methods.................................... 6 Composition of Total Plant Materials... 18
Experimental Results................................ 8 Leaching of Water and Plant Nutrient
Growth Behavior ......................................... 8 M aterials....................................... .... .. 18
Top Growth............................................... 9 Discussion ......................... ................ 27
Composition of Top Growth.................... 10 Application to Practice............................. 82
Stolons and Roots........... ....................... 15 Summary...................................... .. 32
Composition of Stolons and Roots........ 16 Literature Cited ....................................... 85

Growth and composition studies on crop plants show that
such plants accumulate the greater percentage and quantity
of nitrogen and some of the essential minerals in their top
growth during their vegetative growth period. Absorption and
utilization of these elements appear to be on the decline during
the more mature stages. One season's combined cutting of
stoloniferous pasture grasses kept vegetative by frequent cut-
ting or grazing often yield nitrogen, phosphorus and potassium
equal to or greater in percentage and quantity than is found
in the top growth of such plants when grown to and harvested
at maturity. Frequent cutting or grazing is known to reduce
the quantity of top growth of plants at any one period during
the season and also results in reduced elaboration of carbohy-
drates in relation to nitrogen. This condition brings about not
only a narrow relation between nitrogen and carbohydrates
associated with a more vegetative growth condition but also a
more balanced ratio in the herbage, essential for feeding pur-
poses. In addition to this change in the composition relation
and quantity of top growth, frequent cutting brings about re-
duced root growth on such plants in comparison to that found
on plants in the more mature growth condition. If these vege-
tative grasses with reduced top and root growth or, in other
words, a smaller plant system, are capable of elaborating an
equal or greater percentage and quantity of nitrogen and some
of the essential minerals in their top cuttings during the season,

Acknowledgments.-The writers acknowledge with appreciation the
timely help of Dr. J. B. Hester and H. W. Jones in collecting and analyzing
the soil percolates at the appropriate periods.









CUTTING EXPERIMENTS WITH BAHIA GRASS

GROWN IN LYSIMETERS

By
W. A. LEUKEL and R. M. BARNETTE

CONTENTS
Page Page
Materials and Methods.................................... 6 Composition of Total Plant Materials... 18
Experimental Results................................ 8 Leaching of Water and Plant Nutrient
Growth Behavior ......................................... 8 M aterials....................................... .... .. 18
Top Growth............................................... 9 Discussion ......................... ................ 27
Composition of Top Growth.................... 10 Application to Practice............................. 82
Stolons and Roots........... ....................... 15 Summary...................................... .. 32
Composition of Stolons and Roots........ 16 Literature Cited ....................................... 85

Growth and composition studies on crop plants show that
such plants accumulate the greater percentage and quantity
of nitrogen and some of the essential minerals in their top
growth during their vegetative growth period. Absorption and
utilization of these elements appear to be on the decline during
the more mature stages. One season's combined cutting of
stoloniferous pasture grasses kept vegetative by frequent cut-
ting or grazing often yield nitrogen, phosphorus and potassium
equal to or greater in percentage and quantity than is found
in the top growth of such plants when grown to and harvested
at maturity. Frequent cutting or grazing is known to reduce
the quantity of top growth of plants at any one period during
the season and also results in reduced elaboration of carbohy-
drates in relation to nitrogen. This condition brings about not
only a narrow relation between nitrogen and carbohydrates
associated with a more vegetative growth condition but also a
more balanced ratio in the herbage, essential for feeding pur-
poses. In addition to this change in the composition relation
and quantity of top growth, frequent cutting brings about re-
duced root growth on such plants in comparison to that found
on plants in the more mature growth condition. If these vege-
tative grasses with reduced top and root growth or, in other
words, a smaller plant system, are capable of elaborating an
equal or greater percentage and quantity of nitrogen and some
of the essential minerals in their top cuttings during the season,

Acknowledgments.-The writers acknowledge with appreciation the
timely help of Dr. J. B. Hester and H. W. Jones in collecting and analyzing
the soil percolates at the appropriate periods.






Florida Agricultural Experiment Station


they apparently must possess a greater capacity for the absorp-
tion and utilization of these elements from the soil while in
this growth condition.
Indications or evidence of the above contention are found in
the literature over a considerable period of time. As early as
1864, Pierre (28)1 working with wheat plants at five different
stages of growth concluded that these plants absorb most of
their nitrogen, silicon, manganese, phosphorus, potassium, cal-
cium and sodium during vegetative growth stages. He noted
little increase in mineral composition during the later growth
stages, although some increase in organic materials was evident.
Similar results are given by Hornberger (13), who analyzed
corn plants at seven-day intervals. He found that the percentage
of all mineral elements as well as nitrogen in the plant decreased
as the plant grew older. He found the percent of ash in the
roots more uniform than in the tops throughout the season.
There was a decrease of all mineral elements except phosphorus
during the maturing of the plants or after a period of rapid
absorption during ear formation. Further work on the corn
plant by Schweitzer (32), Jones and Huston (16) and Ince (14)
indicates a greater absorption of nitrogen and mineral elements
by this plant during the early growth stages. This is further
emphasized by Duly and Miller (8) who concluded that the
second 30-day period or the period before ear formation was
by far the most important in the production of the vegetative
parts of the plant. Smith (31) likewise found the greater share
of the protein of the corn plant in the leaves before ear forma-
tion.
Burd (4) working with barley plants found that the absorp-
tion of potassium and nitrogen by the plant is more nearly pro-
portional to the total growth and water content than to dry
matter, while the reverse was true of calcium, magnesium and
phosphorus. The latter elements increased in proportion to
dry matter up to the eighth or ninth week, after which such
proportional increase ceased. McCall and Richards (22) found
the mineral requirements of the wheat plant for the second
30-day period similar to that of the first, although the require-
ments for magnesium appeared high for the third 30-day period.
Davidson and LeClerc (5, 6, 7) found an increase in the pro-
tein content of wheat, both grain and straw, when nitrate was
applied during the second 30-day period. When applied during
SFigures in parentheses (Italic) refer to Literature cited in the back
of this bulletin.






Cutting Experiments With Bahia Grass


the first 30-day period an increased yield of both grain and
straw was noted.
Janssen and Bartholomew (15) found potassium high in
the vegetative parts of the tomato plant prior to reproduction,
but it was translocated to the more active growing and repro-
ductive plant parts during the later growing period. Further
work by the same investigators (2) showed a luxury consump-
tion of potassium if supplied to the plants in sufficient amounts.
Nightingale, Shermerhorn and Robins (26) likewise found high
potassium in the vegetative parts of the tomato during the early
growth period. High phosphorus was found present in the
growing tissue of the tomato by McGillivary (21). Murneek
(23) showed that tomato plants grown in sand cultures absorbed
the greatest quantities of soil nutrients and synthesized the
largest quantities of organic substances when fertilization
(gametic union) was permitted but fruit not allowed to develop.
A higher percentage and quantity of nitrogen was obtained
by Leukel and Coleman (18) from frequent cuttings of Bahia
grass than from plants grown to maturity. Similar results were
obtained by Leukel, Camp and Coleman (20). These workers
likewise found a higher percentage and total quantity of potas-
sium and phosphorus from frequent cuttings of top growth of
Bahia grass than from plants in the mature growth condition.
Higher percentages of protein were reported in the top growth
of grasses by Enlow and Coleman (10) when such grasses were
treated with nitrogenous fertilizers. Similar results are re-
ported by Grunder (12).
The early spring growth of grasses apparently is correlated
not only with the supply of plant nutrients but also with the
storage of such nutrients or plant compounds formed therefrom
during the slow growing period of the previous season. Results
similar to the above are reported by Leukel (17), Albert (1),
Nelson (25) and Graber, Nelson, Leukel and Albert (11). Remy
(30), working on persistent grasses and clovers, found increased
and earlier spring vegetative growth and vigor from such plants
resulting from storage of nutrient materials in the rootstalks
of the plants during the slow growing period of the previous
season. The principal nutrient materials determined were ni-
trogen, phosphorus, potassium and calcium.
If the higher nitrogen and mineral composition of pasture
grasses during the vegetative growth period is associated with
a more efficient absorption and increased utilization of the vari-
ous nutrient materials, then a study for further information






Florida Agricultural Experiment Station


in regard to this phase of plant growth behavior is essential.
Such study should measure efficiency in the utilization of vari-
ous nutrient materials by plants through a correlation of several
factors. It would include not only a measurement of quantity
and percentage of various nutrient materials in the top growth
of plants but also the total nutrient materials in the entire plant
system. These composition studies of the different parts of the
plant system again should be correlated with the total nutrient
materials made available to the plants and those lost through
leaching. Results from such a study would help towards a more
economical use of fertilizing materials both as to quantity to
be used and best time of application.
To conduct an investigation of this kind would require some
system by which plants could be grown under ordinary field con-
ditions and still provide some means by which nutrient materials
supplied to, utilized by, and not utilized or lost to the plants
could be measured. The nearest approach to a system of this
kind would be plants grown in large lysimeters. Through the
use of lysimeters the nutrient materials available to the plants
can be measured by a proper analysis of the soil at the begin-
ning of the experiment and also by a record of the available
materials supplied to the plants in the form of fertilizing mater-
ials. Nutrient materials utilized by the plants can then be
measured by a correlation of the above with the analysis of the
plants, soils and leachings during and at the termination of the
experiment.
Such an experiment was conducted jointly by the Department
of Agronomy and the Department of Chemistry and Soils. All
plant growth and plant composition studies were made by the
Department of Agronomy, while the soil and leaching studies
were made by the Department of Chemistry and Soils.

MATERIALS AND METHODS
Four 1/2000-acre lysimeters 4 feet deep were installed in the
summer of 1928 and filled with a Norfolk medium fine sand. The
type of lysimeters used in this study has been described by Blair
(3). The soil was placed in the lysimeters by depths 34-45
inches, 22-34 inches, 10-22 inches, and 0-10 inches corresponding
to these depths in an undisturbed soil. The same quantity of
moist soil from the different depths was weighed into each
lysimeter. The soil in the containers was allowed to settle and
leach until January 1929, when the tanks were set uniformly to
Bahia grass plants. These plants became well established by







Cutting Experiments With Bahia Grass


June 1, 1929, when fertilization and cutting treatments were
initiated. These fertilization and cutting treatments were con-
tinued from June 1929 to August 1932.
In the spring of 1929, 1930 and 1931 the plants in each of
the lysimeters were fertilized at the rate per acre of 100 pounds
of superphosphate, 50 pounds of nitrate of soda and 25 pounds
of muriate of potash. During the growing period monthly dress-
ings of 100 pounds nitrate per acre were applied. While these
applications of nitrate of soda are not generally used on grasses,
the desire was to create as favorable conditions as possible for
the growth of the grass and to simplify analyses of the leachings.
For convenient reference, the lysimeters were numbered 9, 10,
11 and 12. Beginning in June 1929, the plants in the different
lysimeters received cutting treatments designated as follows:
"cut frequently", "cut less frequently", "cut in seed stage", and
"cut at end of season". Plants "cut frequently" in lysimeter
9 were cut whenever they attained a height suitable for graz-
ing purposes. Plants in lysimeter 11, "cut less frequently",
were cut about half as often as those in lysimeter 9. Plants in
lysimeter 12 "cut in the seed stage", were cut whenever they
attained the maximum seed stage of growth and again in the
fall at or near the close of the growing season. Plants in
lysimeter 10 "cut at the end of the season" were cut at the end
of the summer season when growth was at its lowest. The
cutting period mentioned in regard to growth and leaching
studies extended from the first cutting of the "cut frequently"
plants in lysimeter 9 to the harvest of the plants "cut at the
end of the season" in lysimeter 10. The pre-cutting period
extended from the transplanting of the Bahia plants in January
1929 to the first cutting of the "cut frequently" plants in June
1929 in lysimeter 9.
PREPARATION OF MATERIALS
Each individual top growth cutting of grass was taken to
the laboratory and the total green weight determined. Moisture
and dry matter determinations were made on separate 30-gram
portions which were dried in an electric oven at 1050C. The re-
mainder of the material was cut into small sections (14 in.) and
dried in a large electrically heated drier through which a cur-
rent of air was blown for rapid removal of moisture. For the
first 20 minutes a 1000C. temperature was maintained, after
which period the temperature was dropped to 75C. When in a
dry brittle condition the plant material was ground in a Wiley







Florida Agricultural Experiment Station


mill and then reduced to a fine stage in a Dreef pestle mill (34)
so as to pass through a 60-mesh sieve. The material was then
preserved in tightly stoppered bottles for later analysis.
The leachings or percolates from the lysimeters were collected
after each leaching rain. Aliquots of each percolate were com-
posited each year of the experiment for later detailed analysis.
A composite soil sample was taken at the beginning of the
experiment from all lysimeters for later analysis.
At the termination of the experiment in August 1932, the
plants and soils were carefully removed from the lysimeters.
The plants were dug at this time to get all possible informa-
tion on them while in an active growth condition. The Bahia
plants from each lysimeter were separated into tops, stolons
and roots and prepared for laboratory analyses as previously
stated. The residual dry and dead plant materials from the
tops and stolons were collected and likewise prepared for analy-
sis. These materials were later included with the total plant
materials in Table 6. Soil samples at previously stated depths
were taken and likewise prepared and preserved for later
analyses.
ANALYTICAL METHODS
Plant Materials.-Total nitrogen determinations were made by
the Kjeldahl method modified to include the nitrogen of nitrates.
Determinations of phosphorus and potassium were made in ac-
cordance with methods for plant materials described in Official
and Tentative Methods of Analysis of the Association of Agri-
cultural Chemists, Third Edition 1930 (27).
Percolates and Soils.-The percolates measured and collected
after each leaching rain were analyzed for their content of ni-
trate nitrogen by the phenoldi-sulphonic acid method given by
Schreiner and Failyer (33). The yearly composite samples of
the percolates were analyzed by the methods of water analyses
given in the Official and Tentative Methods of the Association
of Agricultural Chemists, Third Edition 1930 (27).
EXPERIMENTAL RESULTS
GROWTH BEHAVIOR
Plants subjected to different cutting treatments showed an
apparent difference in their growth behavior throughout the
growing season. Frequently cut plants maintained a more vege-
tative condition than plants cut less frequently. They were
generally of a darker green color and were vigorous in the pro-






Cutting Experiments With Bahia Grass


duction of new leafage and in the extension of vegetative growth
parts. However, under adverse growth conditions at certain
periods during the season, these plants sometimes showed a
less vegetative condition than plants cut less frequently. The
latter appeared to maintain their vegetative growth condition
better under adverse growth conditions. With the seasonal
change in environment in regard to light, temperature and mois-
ture or when such environmental conditions were conducive to
reproduction in plants some reproductive parts were produced
on the plants even when cut frequently. Cutting of the top
growth reverted such plants to the vegetative growth condition.
Under these conditions the frequently cut plants remained more
vegetative as a result of the more frequent removal of top
growth than did plants cut less frequently.
Plants cut in the seed stage were vigorously vegetative dur-
ing the early part of the growing season and produced abundant
leafage during this period. With the advance of the growing
season, these plants became decidedly reproductive and ceased
vegetative growth. Plants cut at the end of the season showed
a growth similar to those cut in the seed stage up to the period
at which the latter were harvested. After this period, these
plants (cut at end of season) developed into an advanced ripened
seed stage of growth that is generally represented by pasture
grasses in the fall of the year when not grazed or mowed. They
were dry and retained practically no vegetative parts when
harvested.
TOP GROWTH
Yield.-There was no very definite correlation between fre-
quency of cutting and yield of green and dry top growth for
the individual years of the experiment as shown in Table 1.
For the total four-year period the yield of green top growth
varied directly with the frequency of cutting. Such variations
in yield of green and dry top growth from differently treated
plants are often brought about by changes in environmental
conditions affecting plant growth. The ability of differently
treated plants to respond to changing conditions, especially in
regard to moisture, temperature and availability of plant nutri-
ent materials, varies. The production of top growth from such
differently treated plants likewise varies with the ability of
the different plants to absorb and utilize plant nutrient mater-
ials under adverse and changing conditions.






Florida Agricultural Experiment Station


TABLE 1.-GREEN AND DRY WEIGHTS AND PERCENTAGES OF DRY MATTER
IN THE TOP GROWTH OF BAHIA GRASS PRODUCED UNDER DIFFERENT
CUTTING TREATMENTS FOR YEARS 1929 TO 1932, INCLUSIVE.
Cutting Lysimeter Cutting Season
.Treatment I No. 1 1929 I 1930 I 1931 | 1932 I Total
Green weight of top growth, grams

Cut frequently ............ 9 3,631 4,024 1,830 2,579 12,064
Cut less frequently .... 11 2,588 4,207 1,459 2,371 10,625
Cut in seed stage ........ 12 3,031 2,535 2,035 2,793 10,394
Cut at end of season.... 10 627 1,240 685 3,780 6,332
Dry weight of top growth, grams

Cut frequently .......... 9 866 994 543 667 3,070
Cut less frequently .... 11 668 1,109 426 644 2,847
Cut in seed stage ........ 12 995 1,042 784 949 3,770
Cut at end of season.... 10 537 892 479 1,182 3,090
Dry matter in top growth, percent

Cut frequently ............ 9 23.9 24.7 29.7 25.9 25.4
Cut less frequently .... 11 25.8 26.4 28.9 27.2 26.8
Cut in seed stage ........ 12 33.0 41.1 38.5 33.9 36.3
Cut at end of season.... 10 85.6 72.0 70.0 31.2 74.81
'The true average percentage for years 1929 to 1931, inclusive.

COMPOSITION OF TOP GROWTH
Dry Matter.-In general, the average percentages of dry mat-
ter in the top growth cuttings from the differently treated
gr asses, as given in Table 1, varied inversely with the frequency
of cutting for each of the four years of the experiment. Like-
wse the true dry matter percentages for the four-year period
varied inversely with the frequency of cutting. For the first
three treatments the true dry matter percentages for the four-
year period are: cut frequently 25.4 percent, cut less frequently
26.8 percent, and cut in the seed stage, 36.3 percent. The plants
cut at the end of the season showed a dry matter percentage
of 74.8 percent for the first three years of the experiment. Dur-
ing the fourth year the top growth of grass cut at the end
of the season was removed before the growing season termin-
ated. Percentage of dry matter in top growth of this grass
was not included in the general four-year average because it was
not representative of the stage of growth at which these plants
were previously harvested.

ITrue percentage in each instance was obtained by dividing the total
weight of nitrogen, phosphorous or potassium for the period designated by
the total dry matter produced during the same period. In case of dry
matter the total weight of dry matter for the period was divided by the
total weight of green material for the same period.
















TABLE 2.-PERCENTAGES AND QUANTITIES OF TOTAL NITROGEN IN THE TOP GROWTH OF BAHIA GRASS SUBJECTED TO DIF-
FERENT CUTTING TREATMENTS FOR YEARS 1929 TO 1932, INCLUSIVE.
All calculations on an oven-dry matter basis.


Cutting Lysimeter) 1929 1 1930 1 1931 | 1932 |Aver. & Total1
Treatment No. I Percent I Grams I Percent I Grams I Percent I Grams I Percent I Grams I Percent I Grams

Cut frequently ................................ 9 1.79 15.50 2.28 22.67 2.15 11.71 2.20 14.71 2.104 64.59
Cut less frequently ........................ 11 1.84 12.34 1.72 19.19 1.37 5.80 1.36 8.81 1.621 46.14
Cut in seed stage ........................... 12 1.12 11.21 1.16 12.12 1.28 10.05 1.28 12.16 1.208 45.54
Cut at end of season ........................ 10 0.96 5.14 0.81 7.21 1.08 5.70 1.06 12.53 0.990 30.58


'True average percentage and total grams for periods specified.


rC
ci.




to






Florida Agricultural Experiment Station


Nitrogen.-True average percentages of nitrogen in dry top
growth of differently treated plants, as given in Table 2, in-
creased progressively with frequency of cutting, with one ex-
ception in 1929. The true percentage of nitrogen in dry top
growth of plants cut less frequently for this year was slightly
higher than that found in similar top growth of plants cut fre-
quently, but for the four-year period it showed positive correla-
tion with frequency of cutting. The true percentage of nitrogen
in the top growth of the frequently cut plants for the period
mentioned was 2.104 percent, cut less frequently 1.621 percent,
and cut in the seed stage 1.208 percent. Plants cut at the end
of the season showed 0.946 percent of nitrogen for a three-
year period, 1929-1931 inclusive. As in the case of dry matter,
these plants were cut in 1932 before the end of the growing
season and therefore were not representative for the stage of
growth at which they were previously harvested and would not
give an accurate true percentage average for a four-year period.
However, a four-year true average for these plants showed a
percentage of 0.990 percent, or lower than the plants subjected
to the other cutting treatments.
On a quantity basis, as shown in Table 2, nitrogen in the top
growth of differently treated plants showed a positive correla-
tion with the frequency of cutting for the first two cutting sea-
sons 1929 and 1930. In 1931 the plants "cut in the seed stage"
contained a greater quantity of nitrogen in their top growth
than did the plants "cut less frequently", while in 1932 the top
growth of plants cut in the seed stage and that of those cut at
the end of the season were approximately equal as to content
of nitrogen and greater than that of plants "cut less frequently".
In all instances, the frequently cut plants contained the great-
est quantity of nitrogen in their top growth for each year of
the experiment.
Total quantities of nitrogen contained in top growth of differ-
ently treated plants for the four-year period were 64.59 grams
for the frequently cut plants, 46.14 grams for plants cut less
frequently, 45.54 grams for plants cut in the seed stage, and
30.58 grams for plants cut at the end of the season. Thus,
the total nitrogen in the top growth of the differently treated
plants for the four-year period on both a percentage and a
quantity basis increased progressively with the frequency of
cutting.
Phosphorus.-True average percentages and quantities of
phosphorus in the dry matter of the top growth of differently





Cutting Experiments With Bahia Grass


treated plants, Table 3, are closely correlated with frequency of
cutting. This element in dry top growth of differently treated
plants increased with frequency of cutting for each year of the
experiment. This relation between percentage of phosphorus
in dry matter of top growth and frequency of cutting also held
true for the four years as shown by the following percentages
of phosphorus for this period:-cut frequently 0.398 percent,
cut less frequently 0.310 percent, and cut in seed stage 0.244
percent. The true percentage of phosphorus for plants cut at
the end of the season for years 1929 to 1931 inclusive was 0.125
percent.
On a quantity basis, as given in Table 3, phosphorus in the
dry top growth of differently treated plants, in general, showed
a positive correlation with frequency of cutting for each year
of the experiment, with the exception of plants cut in the
seed stage for the years 1929, 1931 and 1932. In each of these
instances a slight increase in the total quantity of phosphorus in
the top growth of plants cut in the seed stage occurred over
that of plants "cut less frequently". For the four-year period
the variation in quantity of phosphorus in the dry top growth
of the differently treated plants showed the same trend in rela-
tion to frequency of cutting as that for the individual seasons.
Total quantity of phosphorus in top growth of plants cut at
the end of the season is given for the years 1929, 1930 and
1931. In all instances, on both a percentage and a quantity
basis, phosphorus was highest in the dry top growth of plants
cut frequently.
Potassium.-True average percentages of potassium, Table
4, in the dry top growth increased progressively with frequency
of cutting for the first two years, 1929 and 1930. During 1931
and 1932 this trend was interrupted by plants cut in the seed
stage, which showed the highest true average percentage of this
element. For the entire four-year period the true average per-
centage of potassium in the dry top growth of the differently
treated plants showed a positive correlation with the frequency
of cutting; for plants cut frequently it was 1.439 percent, cut
less frequently 1.087 percent, and cut in the seed stage 0.861
percent. For the three-year period 1929 to 1931, inclusive,
plants cut at the end of the season showed a true average per-
centage of 0.333 which is in accord with the general downward
trend of this element in top growth of plants with the decrease
in frequency of cutting.









TABLE 3.-PERCENTAGES AND QUANTITIES OF PHOSPHORUS IN THE TOP GROWTH OF BAHIA GRASS SUBJECTED TO DIF-
FERENT CUTTING TREATMENTS FOR YEARS 1929 TO 1932, INCLUSIVE.
All calculations on an oven-dry matter basis.
Cutting Lysimeter 1929 I 1930 I 1931 I 1932 IAver. & Total'
Treatment No. Percent I Grams I Percent: Grams I Percent 1 Grams Percent Urans percent rams

Cut frequently ............................... 9 0.343 2.97 0.485 4.82 0.393 2.13 0.347 2.31 0.398 12.23
Cut less frequently ........................ 11 0.301 2.01 0.321 3.56 0.346 1.47 0.276 1.78 0.310 8.82
Cut in seed stage ............................ 12 0.227 2.26 0.249 2.59 0.220 1.72 0.277 2.63 0.244 9.20
Cut at end of season ........................ 10 0.100 0.54 0.113 1.01 0.173 0.83 0.125 2.38

'Total weight and true average for three years (1929 to 1931 inc.)
"True average percentage and total grams for periods specified.



TABLE 4.-PERCENTAGES AND QUANTITIES OF POTASSIUM IN THE TOP GROWTH OF BAHIA GRASS SUBJECTED TO DIF-
FERENT CUTTING TREATMENTS FOR YEARS 1929 TO 1932, INCLUSIVE.
All calculations on an oven-dry matter basis.
Cutting Lysimeter 1929 I 1930 I 1931 I 1932 |Aver. & Total'
Treatment No. Percent l Grams I Percent I Grams I Percent i Grams I Percent Grams I Percent I Grams

Cut frequently ......................... 9 1.751 15.16 1.830 18.19 1.210 6.57 0.870 5.80 1.489 45.72
Cut less frequently ........................ 11 1.530 10.22 1.070 11.87 0.900 3.83 0.780 5.02 1.087 30.94
Cut in seed stage .......................... 12 0.490 4.87 0.840 8.75 1.290 10.11 0.920 8.73 0.861 32.46
Cut at end of season .... ............. 10 0.200 1.07 0.390 3.48 0.380 1.82 0.790' 9.34' 0.508 15.71
0.333" 6.37'

'Cut before end of growing season.
'True average percentage and total grams for periods specified.
'True average percentage and total grams for years 1929 to 1931, inclusive.






Cutting Experiments With Bahia Grass


On a quantity basis, potassium in the dry top growth of the
differently treated plants again increased with the frequency
of cutting for the first two years, 1929 and 1930. In 1931 this
variation of potassium with decrease in cutting frequency was
interrupted by a higher quantity of this element in the dry
top growth of plants cut in the seed stage and of those cut at
the end of the season. The latter plants were cut before the
end of the season and their growth condition approached more
closely the late seed stage. For the four-year period, quantities
of potassium in the dry top growth of the differently treated
grasses decreased with the decrease in frequency of cutting, as
shown by the following weights: cut frequently 45.72 grams,
less frequently, 30.94 grams, and cut in seed stage 32.46 grams.
The total quantity of potassium in the top growth of plants
cut at the end of the season for the three-year period 1929 to
1931, inclusive, was 6.37 grams, and for the four-year period
15.71 grams.
STOLONS AND ROOTS
As in case of top growth, dry weights, percentages and quan-
tities of total nitrogen, phosphorus, and potassium of stolons
and roots, Table 5, in most instances show interesting correla-
tion with frequency of top growth removal.

TABLE 5.-VARIATION IN DRY WEIGHT AND SPECIFIC ANALYSIS OF STOLONS
AND ROOTS OF BAHIA GRASS WHEN SUBJECTED TO DIFFERENT CUTTING
TREATMENTS.
All calculations on an oven-dry matter basis.
T. Nitrogen Phosphorus Potassium
Cutting -
Treatment .n 9
c, 0 to

Stolons

Cut frequently ........ 9 555 0.820 4.55 0.169 0.94 0.216 1.19
Cut less frequently 11 800 0.810 6.48 0.154 1.23 0.323 2.58
Cut in seed stage .... 12 948 0.680 6.45 0.140 1.33 0.174 1.65
Cut at end of season 10 1262 0.680 8.58 0.149 1.88 0.540 6.81

Roots

Cut frequently ........ 9 599 0.780 4.67 0.279 1.67 0.207 1.24
Cut less frequently 11 1119 0.490 5.48 0.148 1.66 0.216 2.42
Cut in seed stage .... 12 1025 0.480 4.92 0.132 1.35 0.207 2.12
Cut at end of season 10 1260 0.640 8.06 0.185 2.33 0.199 2.51






Florida Agricultural Experiment Station


Dry Weights.-Dry weights of stolons and roots of differently
treated plants varied inversely with frequency of cutting, being
highest for plants cut at the end of the season and lowest for
stolons of plants cut frequently. The lowest dry root weight
was obtained from plants cut frequently, while roots of plants
cut at the end of the season showed the greatest root weight.
Roots of plants cut in the seed stage were slightly lower in dry
weight than those cut "less frequently".
COMPOSITION OF STOLONS AND ROOTS
Nitrogen.-The percentage of total nitrogen in dry matter
of stolons was highest for plants cut frequently and less fre-
quently. Percentages of this element in stolons of plants cut
in the seed stage and at the end of the season were similar but
lower. On a quantity basis, total nitrogen in the stolons in-
creased progressively with decreases in frequency of cutting.
Percentage of nitrogen in roots was highest for plants cut fre-
quently, but decreased considerably in the roots of plants cut
less frequently and for those cut in the seed stage. Nitrogen
in the roots of plants cut at the end of the season increased
to a higher percentage level but was slightly lower than that
of plants cut frequently. On a quantity basis, total nitrogen
in the roots, in general, varied inversely with frequency of cut-
ting, being lowest for roots of frequently cut plants and high-
est for the roots of plants cut at the end of the season. Roots
of plants cut less frequently were slightly higher in quantity
of total nitrogen than were roots of plants cut in the seed stage.
Phosphorus.-On a percentage basis, phosphorus in stolons
showed a positive correlation with frequency of cutting, up
to plants cut at the end of the season. Stolons of these plants
showed a slight increase in percentage of this element over
that found in stolons of plants cut in the seed stage. Quantity
of phosphorus in the stolons of differently treated plants varied
inversely with frequency of cutting, being lowest in the stolons
of frequently cut plants and highest in the stolons of plants cut
at the end of the season. In general, variation of percentage and
quantity of phosphorus in the roots of differently treated plants
was similar to that found for the stolons.
Potassium.-Percentage of potassium in the dry matter of
stolons of the differently treated plants, in general, varied in-
verse'y with frequency of cutting of the top growth, with the
exception of stolons of plants cut in the seed stage. The per-
centage of potassium in the dry matter of stolons of these









TABLE 6.-SPECIFIC ANALYSIS OF DIFFERENT PARTS OF BAHIA GRASS PLANTS SUBJECTED TO DIFFERENT CUTTING TREAT-
MENTS FROM 1929 TO 1932, INCLUSIVE.
All calculations on an oven-dry matter basis.
Cutting Lysimeteri Top Growth I Residue Stolons I Roots Aver. & TotaP
Treatment NO. | Percent 1 Grams I Percent I Grams I Percent I Grams I Percent I Grams Percent I Grams
Nitrogen

Cut frequently .................................... 9 2.104 64.59 1.750 1.40 0.820 4.55 0.780 4.67 1.747 75.21
Cut less frequently ......................... 11 1.621 46.14 1.500 1.50 0.810 6.48 0.490 5.48 1.225 59.60
Cut in seed stage ................................ 12 1.208 45.54 1.500 1.24 0.680 6.45 0.480 4.92 0.998 58.15
Cut at end of season ........................ 10 0.990 30.58 1.000 3.12 0.680 8.58 0.640 8.06 0.849 50.34
Phosphorus

Cut frequently ................................... 9 0.398 12.23 0.235 0.19 0.169 0.94 0.279 1.67 0.349 15.03
Cut less frequently ..................... 11 0.310 8.82 0.254 0.25 0.154 1.23 0.148 1.66 0.246 11.96
Cut in seed stage ............................. 12 0.244 9.20 0.248 0.20 0.140 i 1.33 0.132 1.85 0.207 12.08
Cut at end of season ...................... 10 0.125 2.38 0.150 0.47 0.149 1.88 0.185 2.33 0.119 7.06
Potassium

Cut frequently .................................... 9 1.489 45.72 0.190 0.15 0.216 1.19 0.207 1.24 1.122 48.30
Cut less frequently .......................... 11 1.087 30.94 0.200 0.20 0.323 2.58 0.216 2.42 0.743 36.14
Cut in seed stage .................................. 12 0.861 32.46 0.271 0.22 0.174 1.65 0.207 2.12 0.626 36.45
Cut at end of season ........................... 10 0.508 15.71 0.404 0.26 0.540 6.81 0.199 2.51 0.427 25.29
'True average percentage and total grams for periods specified.





Florida Agricultural Experiment Station


plants was slightly lower than from similar stolons of:'plants
cut "less frequently".
On a quantity basis, potassium showed a similar variation in
relation to frequency of cutting.
The percentage of potassium in the dry matter of roots showed
very little variation in relation to frequency of cutting. On
a quantity basis, potassium in the roots of differently treated
plants, in general, varied inversely with frequency of cutting,
or similar to the variation of this element in the stolons.
COMPOSITION OF TOTAL PLANT MATERIALS
The percentages and total quantities of nitrogen, phosphorus
and potassium in top growth, residue, stolons and roots of Bahia
grass subjected to different cutting treatments are given in
Table 6. This table of summaries emphasizes the influence of
different cutting treatments on the nutrient materials absorbed
by the plant. Bahia grass plants cut frequently contained 75.21
grams of total nitrogen, as compared with 59.60 grams absorbed
by plants tut less frequently, 58.15 grams by plants cut in the
seed stage, and 50.34 grams by plants cut at the end of the
season. Likewise phosphorus was absorbed in greater quan-
tities by plants cut frequently than by plants cut less often.
Total plant materials produced by plants cut frequently con-
tained 15.03 grams of phosphorus, those cut less frequently
11.96 grams, those cut in the seed stage 12.08 grams, and those
cut at the end of the season 7.06 grams. Potassium, like nitro-
gen and phosphorus, was found in greater quantities in total
plant materials from plants cut more frequently. Total plant
materials from the: frequently cut grass contained 48.30 grams
of potassium, those cut less frequently 36.14 grams, those cut
in the seed stage 36.45 grams, and those cut at the end of the
season 25.29. grams.
In general, total quantities of nitrogen, phosphorus and potas-
sium found in plant materials from differently treated plants
appeared' to increase progressively with frequency of cutting.
Some of thesee apparent differences in absorption of different
plant nutrient materials are correlated with amounts of nutri-
ents leached from the soil.
LEACHING OF WATER AND PLANT NUTRIENT MATERIALS
Water.-For the purpose of studying the leaching of water
and nitrates, the time covered by !the experiment was divided
into periods. The period of establishment of the grass or the
pre-cuttingi period extended frdm January 7, 1929, to June 5,









TABLE 7.-TABLE SHOWING TOTAL RAINFALL AND PART OF SAME LEACHED FROM DIFFERENTLY TREATED BAHIA GRASS
PLANTS DURING SPECIFIED PERIODS FOR YEARS 1929 TO 1932, INCLUSIVE.


Pre-cutting period Cutting period
Jan. 7, 1929 to June 5, 1929 to
June 5, 1929 Dec. 19, 1929


SRainfall liters 893
Cutting Water leached
Treatment Liters I Percent

Cut frequently.............. 688 77.04
Cut less frequently...... 703 78.72
Cut in seed stage........ 714 79.95
Cut at end of season 664 74.35


I 1,513
I Water leached


I Liters I Percent


781 51.62
845 55.85
746 49.31
792 52.35


t


Resting period I Cutting period IResting period


Dec. 19, 1929 May 29, 1930 to Dec. 8, 1930 C)
o May 29, 1930 Dec. 8, 1930 to July 2, 1931
983 I 1,600 1,131
Water leached Water leached Water leached
Liters | Percent I Liters I Percent Liters I Percent

620 63.07 821 51.31 543 48.01
627 63.78 687 42.94 578 51.10
758 77.11 674 42.12 566 50.04
747 75.99 606 37.87 637 56.32
---- -- ------------


I Cutting period Resting period Cutting period Average
Periods July 2, 1931 to Mar. 4, 1932 to June 9, 1932 to Four cutting Three resting
: | March 4, 1932 June 9, 1932 Aug. 22, 1932 periods periods to
I Rainfall liters 1,146 527 768 | 1,257 880
Lysim- Cutting Water leached I Water leached Water leached I Water leached Water leached "
eter No. Treatment Liters I Percent I Liters I Percent Liters I Percent I Liters I Percent Liters I Percent

9 Cut frequently.............. 312 27.23 48 9.11 100 13.02 504 40.90 403 45.79
11 Cut less frequently...... 292 25.48 57 10.82 135 17.58 489 38.90 421 47.84 co
12 Cut in seed stage........ 260 22.69 48 9.11 169 22.01 462 36.75 457 51.93
10 Cut at end of season 272 23.73 86 16.32 144 18.75 454 36.12 490 55.68


Periods


Lysim-
eter No.

9
11
12
10


I


- ------


.





Florida Agricultural Experiment Station


1929. Subsequent to June 5, 1929, the time was divided into
"cutting periods" and "resting periods". The "cutting periods'
extended from the date of the first harvest of the frequently cut
grass until date' of harvest of the top growth of plants cut at
the end of the season. The "resting periods" intervened.
Total quantities of rainfall expressed in liters, quantity of rain
water which leached through the lysimeters, percentage of rain-
fall which leached for the pre-cutting period and each of the
cutting and resting periods, together with averages are given
in Table 7. During the pre-cutting period there was a variation
of only 5.60 between the lowest and highest percentages of
water leached. This indicates that leaching from the lysimeters
was reasonably uniform before the cutting treatments were
started.
The average data on quantities and percentages of water
leached for the four cutting periods and the three resting per-
iods are instructive. The highest average leaching for the cut-
ting periods was found from the lysimeter growing frequently
cut grass, and average amounts of leaching decreased pro-
gressively with decrease in frequency of cutting. In contrast,
highest amounts of leaching during resting periods were from
lysimeters growing grass cut at the end of the season, and
quantities of leaching decreased progressively with increase in
frequency of cutting. These differences in leaching of water
during the cutting periods and resting periods compensated
each other to give a practically constant total amount of leach-
ing from the lysimeters.
Nitrogen.-Quantities of water leached, amounts of nitrogen
as nitrates leached and found in the cuttings of top growth, to-
gether with averages for the cutting and resting periods, are
given in Table 8. While there are some variations in the order
of leaching of water and nitrogen as nitrates and of the quan-
tity of nitrogen in the cuttings for the lysimeters in which the
grass was subjected to different cutting treatments, the aver-
age results bring out some interesting relationships for the cut-
ting seasons. These average results show that, as a rule, there
were larger quantities of water and smaller quantities of nitro-
gen as nitrates leached from the lysimeters growing the grass
cut frequently than from the other lysimeters. The quantities
of water leached decreased progressively with decrease in fre-
quency of cutting of the grass for the cutting periods. On
the other hand, quantities of nitrogen as nitrates leached from
the lysimeters increased progressively with decrease in fre-








TABLE 8.-TABLE SHOWING THE EFFECT OF DIFFERENT CUTTING TREATMENTS ON BAHIA GRASS IN REGARD TO WATER AND
NITROGEN LEACHED AND NITROGEN RECOVERED IN THE TOP GROWTH.
SPre-cutting Resting per- Resting per-
Treatment i period Jan. 1, Cutting period iod Dec. 19, Cutting period iod Dec. 8,
Period 1929 to June June 5, 1929 to 1929 to May May 29, 1930 to 1930 to July
I 5, 1929 Dec. 19, 1929 29, 1930 Dec. 8, 1930 2, 1931
after Niroen Nitrogen Nitrogen1 Water I Nitrogen Water Nitrogen Nitrogent Water !Nitrogen
Lym-leched leached leachedleached in cut- leached leached leached leached Iin cut- leached leached
Cutting Treatment eter No. I tings I ltings I
SLiters I Grams I Liters Grams Grams Liters I Grams Liters Gramsrams ers rams

Cut frequently.... 9 688 4.40 781 1.10 15.50 620 2.20 821 0.80 22.67 543 0.00
Cut less frequently... 11 703 5.90 845 2.70 12.34 627 3.20 687 0.30 19.19 578 0.00
Cut in seed stage...... 12 714 5.00 746 0.80 11.21 758 4.80 674 2.80 12.12 566 0.10
Cut at end of season 10 664 4.20 792 2.30 5.14 747 9.70 606 6.90 7.21 637 1.10


Resting per- I
Treatment Cutting period iod March 4, Cutting period Average
period July 2, 1931 to 1932 to June June 9, 1932 to Resting
March 4, 1932 9, 1932 August 22, 1932 Cutting periods periods
T WIater Nitro- Nitrogen Water Nitrogen Water Nitro- Nitrogenj Water Nitro- Nitrogen Water Nitrogen
Lys.m- leachedi gen in cu- leached leached leach gen in cut- leache gen in cut- I leached leached
Cutting Treatment eter No. I leachedl tings I I I leachedl tings leached tings I I
| LiterslCGramsl Grams I Liters I Grams I Liters I Grams I Grams I Liters I Grams Grams I Liters I Grams

Cut frequently ....... 9 312 1.50 11.71 48 0.10 100 0.70 ( 14.71 504 1.00 16.15 403 0.70
Cut less frequently... 11 292 0.70 5.80 57 0.00 135 0.50 8.81 489 1.10 11.53 421 1.10
Cut in seed stage ..... 12 260 1.00 10.05 48 0.00 169 0.30 12.16 462 1.20 11.38 457 1.60
Cut at end of season 10 272 0.80 5.70 86 0.60 144 0.50 12.531 454 2.60 7.64 490 3.80

1 Cut before end of season.





Florida Agricultural Experiment Station


quency of cutting the grass. Conversely, the amount of nitrogen
contained in the grass cuttings decreased progressively with de-
crease in frequency of cutting.
During the resting periods the water leached increased pro-
gressively with decrease in frequency of cutting, as did also
the leaching of nitrogen as nitrates.
Total quantities of nitrogen added as sodium nitrate, total
quantities leached, and total quantities in the plant materials
are shown in Table 9. These data permit a study of the relation
between added nitrogen, leached nitrogen and nitrogen in total
plant materials for the years 1929 to 1932, inclusive.
TABLE 9.-TABLE SHOWING QUANTITATIVE RELATIONS BETWEEN ADDED
NITROGEN, LEACHED NITROGEN AND NITROGEN IN TOTAL PLANT MATE-
RIALS FOR YEARS 1929 TO 1932, INCLUSIVE.

p. Added Nitrogen


Cutting z5 M 0
Treatment s g g|
U a-s u P U Cd cs .VS



grams grams grams grams percent percent percent
Cut frequently .............. 9 87.8 10.80 75.21 86.01 12.30 85.66 97.96
Cut less frequently ...... 11 87.8 13.30 59.60 72.90 15.15 67.88 83.03
Cut in seed stage ........ 12 87.8 14.80 58.15 72.95 16.86 66.23 83.09
Cut at end of season .... 10 87.8 26.10 50.34 76.44 29.73 57.33 87.06

With the same quantity of nitrogen added to each of the
different lysimeters, the weight of nitrogen collected in the
leachings varied inversely with frequency of cutting. There
were 10.80 grams from the tank with frequently cut plants and
26.10 grams, or over twice the former amount, from the con-
tainer where the plants were cut at the end of the season. On
the other hand, the total nitrogen recovered in all plant mater-
ials showed a positive variation with frequency of cutting, vary-
ing from 75.21 grams for plants cut frequently to 50.34 grams
for plants cut only at the end of the season. When the total
amounts of nitrogen recovered in the plant materials plus that
collected in the leachings in each instance were compared, the
following relations prevailed in the order of the frequencies of






Cutting Experiments With Bahia Grass


cuttings: cut frequently 86.01 grams, cut less frequently 72.90
grams, cut in seed stage 72.95 grams, and cut at the end of the
season, 76.44 grams.2
In proportion to amount added, nitrogen leached most from
lysimeters growing grasses cut least frequently. Total nitrogen
leached from the lysimeter containing frequently cut plants was
12.30 percent of the added nitrogen, while that from the con-
tainer with plants cut at the end of the season was 29.73
percent.
Total plant materials from plants cut frequently showed a
high percentage of recovery of nitrogen applied as nitrates, in-
dicating better utilization of nitrate fertilizers. The weight of
nitrogen in the frequently cut plants was equivalent to 85.66
percent of the added nitrogen. This percentage decreased to
67.88 percent for plants cut less frequently, 66.23 percent for
those cut in the seed stage, and 57.33 for those cut at the end
of the season.
TABLE 10.-NITROGEN CONTENT OF SOIL IN DIFFERENT LYSIMETERS AT THE
BEGINNING AND TERMINATION OF THE EXPERIMENT.
Soil Depth
Cutting Lysimeter 0-10 I 10-22 23-24 34-45
Treatment No. I nches inches inhe inches
percent percent percent percent
Original soil ............... all 0.050 0.025 0.019 0.016
Cut frequently ............ 9 0.049 0.023 0.024 0.017
Cut less frequently .... 11 0.048 0.028 0.021 0.015
Cut in seed stage ...... 12 0.045 0.023 0.019 0.014
Cut at end of season 10 0.048 0.022 0.023 0.015

The percentages of nitrogen in the soil at the beginning and
at the end of the experiment are given in Table 10. In both
instances the determinations were made on soil screened through
a 2 m.m. round-holed sieve. From these results it may readily
be seen that the nitrogen content of the soil has not been
appreciably affected by growth of the grass nor by the addition
of nitrogen in the form of sodium nitrate.
Only the nitrogen as nitrates was determined on the individ-
ual leachings. The mineral constituents were determined in a
composite of the individual leachings once for each year of the
2The methods of analysis for nitrogen in sandy soils are not sufficiently
exact to account for the small quantities of nitrogen added as sodium
nitrate in all instances.





Florida Agricultural Experiment Station


experiment. The period for compositing the leachings ended
at the middle of April each year.
In contrast to the soluble nitrate, the solubility of the phos-
phorus, potassium, calcium, magnesium, sodium, iron and alum-
inum and silicon compounds in the soil is controlled by numerous
factors. Hence the general relationship between the amounts
leached and absorbed by the plant as noted for nitrates need not
be expected to be so pronounced.
Phosphorus.-The quantities of phosphorus in the cuttings
and leachings from the lysimeters for 1929 to 1931, inclusive, are
given in Table 11. Analyses of the leachings for 1932 could not
be made because of the extremely small quantities of water col-
lected.
TABLE 11.-TOTAL PHOSPHORUS IN TOP CUTTINGS AND LEACHINGS FROM
DIFFERENTLY TREATED BAHIA GRASS PLANTS FOR YEARS 1929 TO 1931,
INCLUSIVE.
~ 1929 I 1930 I 1931
Cutting Lysim- Cut- Leach. Cut- Leach- Cut- I Leach-
Treatment eter tings ings Itings ings tings I ings
No. Grams I Grams I Grams Grams Grams I Grams
Cut at end of season 9 2.97 0.13 4.82 0.07 2.13 0.77
Cut frequently.............. 11 2.01 0.23 3.56 0.14 1.47
Cut less frequently..... 12 2.26 0.16 2.59 0.14 1.72 0.93
Cut in seed stage.......... 10 0.54 0.19 1.01 0.21 0.83 0.65


Drainage waters collected from the four feet of soil contained
very small amounts of phosphorus. However, in general, quan-
tities leached were smallest for the lysimeters growing the
frequently cut grass and largest for the lysimeters growing the
grass cut in the seed stage and at the end of the season.
Potassium.-Total quantities of potassium in the top cuttings
and leachings from the lysimeters for the years 1929 to 1932,
inclusive, and the totals and averages for these seasons are given
in Table 12. Quantities of potassium leached have very little or
no relationship to quantities absorbed in the top growth of the
grass subjected to different cutting treatments.
Leaching of calcium, sodium, magnesium, silicon dioxide and
combined oxides of iron and aluminum.-The total grams of cal-
cium, sodium, magnesium, silicon dioxide and combined oxides
of iron and aluminum leached each year of the experiment are
given in Table 13. No analyses of the Bahia grass for these con-
stituents were made. Only a partial analysis of the leachings


















TABLE 12.-TOTAL POTASSIUM IN TOP CUTTINGS AND LEACHINGS FROM BAHIA GRASS FOR YEAtS 1929 TO 1932, INCLUSIVE.


Cutting
Treatment


Cut frequently............1

Cut less frequently....

Cut in seed stage........

Cut at end of season


Lysim-
eter
No.


1929
Cut- I Leach-
tings I ings
Grams I Grams


15.16

10.22

4.87

1.07


4.08

4.81

5.62

5.53


1930 I 1931 1 932 I Average Total
Cut- Leach- Cut- I Leach- Cut- Leach- Cut-I Leach- I Cut- I Leach-
tings Iings tings ings tings wings tin wings tings ings wings
Grams I Grams 1 Grams I Grams Grams Grams Grams Grams | Grams I Grams

18.19 2.07 6.57 3.49 5.80 0.41 11.43 2.51 45.72 10.05

11.87 2.90 3.83 2.81 5.02 0.40 7.74 2.74 30.94 10.92

8.75 2.62 10.11 2.66 8.73 0.32 8.11 2.80 32.46 11.22

3.48 1.61 1.82 3.38 9.34 0.38 3.93 2.75 15.71 10.90


'


I I






Florida Agricultural Experiment Station


in 1932 was made because of the very small amounts of the com-
posited samples.
TABLE 13.-QUANTITIES OF SPECIFIC ELEMENTS AND COMPOUNDS RECOV-
ERED IN LEACHINGS FROM DIFFERENTLY TREATED BAHIA GRASS PLANTS
FOR PERIODS INDICATED.
Cut Cut lessI Cut in I Cut at end
Treatment frequently frequently seed stage of season
Lysimeter No. 9 I 11 12 I 10
Star ( grams I grams grams grams
Calcium (Ca.)

1928-29 27.14 27.08 31.27 41.01
1929-30 15.07 18.65 29.09
1930-31 7.23 7.66 17.68
1931-32 3.07 -3.57 8.48
Sodium (Na.)

1928-29 11.31 8.61 8.70 8.36
1929-30 18.66 24.74 26.36
1930-31 15.83 19.21 27.78
Magnesium (Mg.)

1928-29 5.06 5.44 4.71 5.56
1929-30 1.79 2.71 2.20 2.93
1930-31 2.79 2.75 2.61 3.09
1931-32 1.02 0.59 0.43 0.93
Silicon dioxide (SiO,)

1928-29 6.07 4.64 6.25 8.19
1929-30 2.66 --4.58 4.36
1930-31 71.88 44.54 26.15
1931-32
Combined iron and aluminum oxides (RO.)

1928-29 2.07 1.55 3.52 2.43
1929-30 4.37 4.90 5.49
1930-31 82.13 59.58 29.83
1931-32

Calcium leached varied with the frequency of cutting of the
grass. The smaller quantities were leached from the lysimeters
growing frequently cut grass where the nitrate was largely ab-
sorbed, and the larger quantities from the lysimeter with the
grass cut at the end of the season, where the nitrate was not
as effectively absorbed: by the plants. How much of this dif-
ference in the leaching of calcium may be attributed to an in-
creased absorption of calcium by the more frequently cut plants
and how much to soil changes due td the growth and absorption
of nitrate by the plant may not be ascertained from the data.






Cutting Experiments With Bahia Grass


For 1928-29 sodium was leached in large quantities from the
lysimeter where the grass was cut frequently. However, for
1929-30 and 1930-31 the leaching of sodium was smallest in the
lysimeter where the grass was cut frequently and increased
progressively with a decrease in the frequency of cutting.
The leaching of magnesium apparently was not influenced
definitely by the cutting treatment of Bahia grass.
Leachings of silicon dioxide and the combined oxides of iron
and aluminum are of interest. During the first two years of
the experiment, small quantities of these soil constituents were
leached from the soil and no correlation between cutting treat-
ments and their leaching could bg detected. However, for the
seasons 1930-31 and 1931-32 the leachings from the lysimeters
with the grass cut frequently were definitely turbid-indicating
a dispersion and movement of colloidal materials in the soil.
The leaching from the lysimeter where the grass was cut in
the seed stage was also turbid but not so turbid as that from
the lysimeter with the frequently cut grass. The leaching from
the lysimeter with the grass cut at the end of the season was
only slightly turbid. Analyses of leachings for 1930-31 show
that large quantities of silicon dioxide and combined oxides of
iron and aluminum were removed from the lysimeter with the
frequently cut grass. Quantities of these soil constituents in
the leachings decreased with a decrease in frequency of cut-
ting. Thus with prolonged use of nitrate and more effective
absorption of nitrate nitrogen from the soils in tanks with the
more frequently cut grass, there had been a dispersion of the
inorganic colloids and a movement of them with the drainage
water.
DISCUSSION
The above results show interesting relations in regard to the
effects of different cutting treatments on Bahia grass in con-
nection with yields, growth behavior, relative composition and
utilization of nutrient materials. The greater total yield of
green top growth produced by the frequently cut plants for the
four-year period is in accord with former results from this Sta-
tion (18) (20). Whenever conditions are favorable for vigorous
vegetative growth, the total green weight of the combined top
cuttings from frequently cut stoloniferous pasture grasses often
will be greater in yield than that produced from such grasses
when cut at the more mature growth stages. On the other
hand, when adverse growth conditions occur, such as low soil
moisture or decrease in the available nitrogen supply, frequently






Florida Agricultural Experiment Station


cut plants are more easily retarded in their growth. Under these
conditions, grasses cut less frequently and having larger and
deeper root systems are more capable of obtaining moisture,
nitrogen and other plant nutrient materials from greater soil
depths and areas. If such plants are not in a reproductive stage
of growth or have their top growth removed before becoming
reproductive, they will produce more green top growth and vege-
tative extension than the more frequently cut plants under
adverse growth conditions. The increased green top growth
produced by the less frequently cut plants in some instances
as given in Table 1, reflect the above mentioned adverse growth
conditions.
Although the frequently cut plants produced the highest
weight of green top growth for the four-year period, more weight
of dry top growth was produced by plants cut in the more
mature growth stages in most instances for the same period.
More frequently cut or vegetative grasses are lower in per-
centage of dry matter, and the nitrogen in their top growth
is high in relation to carbohydrates, i. e., they have a narrow
carbohydrate-nitrogen relation or ratio. This composition rela-
tion is associated with vegetative growth and extension. In-
crease in weight or of top cuttings from such grasses is pro-
duced through increased vegetative material high in moisture
and low in dry matter. Plants in the more mature growth stages,
i. e., at or beyond the reproductive stage, cease vegetative growth
and extension. The plants at this growth period through more
efficient metabolism and an apparent decrease in the absorp-
tion of nutrient materials, especially nitrogen, increase in weight
more through increased elaboration of cellulose and lignin or the
more woody fibrous materials (20) (19). The top growth of
such plants is high in percentage of dry matter and low in per-
centage of nitrogen, showing a wide carbohydrate-nitrogen ratio.
This composition relation is associated with reproduction and
cessation of vegetative growth (18) (20). As a result of these
composition relations and differences in growth behavior be-
tween vegetative and more mature plants, combined cuttings
over a given period from frequently cut plants often may show
a larger yield or weight of green top growth but a smaller yield
of dry matter than plants cut in the more mature growth stages.
Growth and production of the lower plant parts appeared to be
correlated with treatments applied to the aerial parts of the
plants. Frequently cut plants whose top growth was kept in a
more vegetative growth condition showed the lowest weight






Cutting Experiments With Bahia Grass


of roots and stolons when dug, while the greatest weight of
these plant parts was taken from plants cut in the more mature
growth condition, i. e., root and stolon weight varied inversely
with the frequency of top cutting. These correlations indicated
that the frequent removal of top growth maintained plants in
and often reverted them to a vegetative growth condition (24)
which resulted in a lower dry weight of stolons and roots. On
the other hand, plants cut in the more mature growth condition
produced a greater dry weight of stolons and roots with the
gradual cessation of vegetative top growth. This growth be-
havior is in accordance with the work of Reed (29) who showed
that vegetative or high nitrogen plants or cuttings of plants go
mostly to top growth while more mature or low nitrogen plants
or cuttings of plants go mostly to root growth. This greater
dry weight of tops and stolons plus the greater dry weight
of roots from the more mature plants gave a higher production
of total dry plant material from the more mature plants than
from frequently cut or more vegetative plants.
Although more dry weight of plant material was produced by
plants cut in mature growth stages, the percentage and quan-
tity of nitrogen, phosphorus and potassium utilized by the differ-
ently treated plants as measured by the composition of the same
showed a different trend. Nitrogen on both a percentage and
quantity basis in the top growth of the differently treated plants
showed a positive correlation with the frequency of cutting.
The increased percentage of this element in the vegetative top
growth of frequently cut plants brought about a higher recovery
of nitrogen than that found in the top growth of plants cut in
the more mature growth stages, even though the latter did
contain a greater quantity of dry matter. In general, variations
in relative composition of roots and stolons of the differently
treated plants in regard to nitrogen, phosphorus and potassium
were in accord with the growth behavior of these plants when
subjected to different cutting treatments. The greater absorp-
tion and utilization of these elements by the more frequently cut
or vegetative plants is indicated or reflected in the higher per-
centage of nitrogen, phosphorus and potassium in the roots and
stolons. The lower percentages of these elements in the roots
and stolons of plants in the more mature growth stages is in-
dicative of a condition brought about by a slower absorption
of these elements by the roots and by the upward translocation
of the same to the top growth. The general increase in per-
centage of these elements in the stolons and roots of plants cut






Florida Agricultural Experiment Station


at the end of the season is indicative of the downward trans-
location of these elements in the late stages of plant maturity
and to some extent the accumulation of these elements as a
result of their non-utilization by the top growth.
On a quantity basis, nitrogen, phosphorus and potassium
varied directly with frequency of cutting, or in other words,
showed an inverse correlation with increase in the production
of dry matter in the plants. The marked increase in total
amounts of these elements in stolons and roots beyond a pro-
portional increase in dry matter may be attributed likewise
to the above plant growth behavior. These general correlations
of nitrogen, phosphorus and potassium are in accord with the
work of Leukel (17) and Albert (1) on alfalfa and other plants
and also that of Remy (30) on clovers and perennial grasses.
The similar utilization of phosphorus and potassium with that
of nitrogen by the different plant parts indicated that utilization
of the latter may be to some degree dependent upon the absorp-
tion of either one or both of the former elements. Such were
the findings of Eckerson (9), who showed that both phosphorus
and potassium seemed to be necessary for reducase activity.
When either element was deficient there was little or no re-
ducase in the plant and nitrate reduction was retarded.
The greater utilization of nutrient materials was further em-
phasized by means of composition and leaching studies on the
differently treated plants through the use of lysimeters. By
this procedure, better utilization of nutrient materials by vege-
tative grasses was shown through a comparison of the total
amount of materials utilized with those available and the mate-
rials lost through leaching. Results of these comparisons were
more significant for nitrogen applied as sodium nitrate than for
the various mineral elements considered. In sandy soils very
little nitrogen applied as soluble nitrate is combined with the
soil. It is either utilized by the plants or lost through leaching.
Since the content of nitrogen of the soils in the different
lysimeters at the beginning of the experiment was very similar
to that found at the termination of the same, then the nitrogen
recovered in the plants in each of the lysimeters should be a
fair measure of the total quantity of nitrogen utilized by the
plants.
A correlation of the nitrogen added as nitrates, nitrogen in
total plant materials, and leached nitrogen as nitrates for the
four-year period emphatically showed increased utilization of
nitrogen by vegetative plants. In all instances the relation be-






Cutting Experiments With Bahia Grass


tween the nitrogen added as nitrates and that utilized by the
plants was decidedly high for plants cut frequently and decreased
with the frequency of cutting. Conversely, the nitrogen leached
varied inversely with frequency of cutting, being very much
lower for frequently cut plants than for those cut at the end of
the season. This greater utilization of nitrogen by frequently
cut plants was reflected in their continued growth activity.
Although leachings of water from the different lysimeters were
rather uniform in percentage and quantity for the year in each
instance, less water was leached from frequently cut plants
during the rest periods, indicating continued activity of these
plants even during non-growing periods. This greater activity
of frequently cut plants was further shown by the nitrogen
in the leached water from the different lysimeters. In general,
for each year of the experiment and for the four-year period,
the nitrogen leached as nitrates was least for the frequently
cut plants and increased progressively with the decrease in the
frequency of cutting.
Due to the fact that phosphorus and potassium are combined
more or less with the soil, variations in quantities of these ele-
ments leached were not so marked as in case of nitrogen. The
quantity of phosphorus leached was variable but in general was
greater from plants cut at the end of the season. Combined
with the larger quantity of this element in the top growth of
frequently cut plants, this shows an increased utilization of phos-
phorus by vegetative plants similar to that of nitrogen. The potas-
sium leached varied somewhat for each year of the experiment
but the average and total for the four-year period was practically
constant for the differently treated plants. The large amount
of this element in the top growth of frequently cut plants and
likewise the similarity in quantity leached from the differently
treated plants indicate involved factors of availability of this
element in the soil.
Although nitrogen, potassium and phosphorus were the only
elements determined in the plant materials, some of the other
elements showed similar variable results in regard to leaching,
especially the oxides of calcium and sodium. Silica (SiO.) and
the combined oxides of iron and aluminum (R2Oa) leached
approximately the same the first two years from all the tanks,
but in 1931 they increased from tanks growing frequently cut
plants. Increased leaching of these soil constituents may be
attributed to a dispersion of the colloidal SiO2 and R203 and a
movement of these constituents through the soil in the drain-






Florida Agricultural Experiment Station


age water. This movement apparently is associated with more
nearly complete utilization of nitrate nitrogen by the frequently
cut plants. This better utilization of nitrate nitrogen is evi-
denced by a greater absorption of nitrogen by the frequently
cut grass and by a lower leaching of nitrate nitrogen from the
lysimeters growing the frequently cut plants.

APPLICATION TO PRACTICE
The differences in growth behavior, relative composition, and
utilization of nutrient materials by the differently treated grasses
suggest several phases of practical application.
The continued vegetative condition of frequently cut grasses
suggests a herbage more suitable for feeding purposes than in
the others. Such grasses are more palatable, higher in protein
and lower in crude fibrous materials. Their herbage shows a
narrow nutritive ratio, which makes it suitable for feeding
purposes. The higher percentage of some essential minerals
makes such grasses better adapted for building up the bony
framework of the animal body and for aiding in its body metab-
olism. Earlier spring growth of these grasses and their con-
tinued vegetative production until late in the fall provide a long
grazing period and partly curtail the expense of feeding during
the dormant season. Utilization of nutrient materials by these
vegetative grasses brings about more economical returns from
fertilizers used for increased production.
On the other hand, plants harvested in mature growth stages
or permitted to attain such stages of maturity in pastures cease
vegetative growth and are unproductive during a great part of
the growing season. Their lower nitrogen percentage and high
content of crude fibrous materials produce a herbage with a
wide nutritive ratio, unpalatable and unsuitable for feeding or
grazing purposes. Being low in mineral percentage in most in-
stances this herbage is not best for bone building in the animal
or for its metabolism. The poor utilization of nutrient materials
by such grasses produces low returns from fertilizers used
on pastures and does not bring economical returns from the
use of such materials.
SUMMARY
Bahia grass plants were grown in lysimeters, fertilized sim-
ilarly and subjected to the following cutting treatments: "cut
frequently", "cut less frequently", "cut in seed stage" and "cut
at end of season".






Florida Agricultural Experiment Station


age water. This movement apparently is associated with more
nearly complete utilization of nitrate nitrogen by the frequently
cut plants. This better utilization of nitrate nitrogen is evi-
denced by a greater absorption of nitrogen by the frequently
cut grass and by a lower leaching of nitrate nitrogen from the
lysimeters growing the frequently cut plants.

APPLICATION TO PRACTICE
The differences in growth behavior, relative composition, and
utilization of nutrient materials by the differently treated grasses
suggest several phases of practical application.
The continued vegetative condition of frequently cut grasses
suggests a herbage more suitable for feeding purposes than in
the others. Such grasses are more palatable, higher in protein
and lower in crude fibrous materials. Their herbage shows a
narrow nutritive ratio, which makes it suitable for feeding
purposes. The higher percentage of some essential minerals
makes such grasses better adapted for building up the bony
framework of the animal body and for aiding in its body metab-
olism. Earlier spring growth of these grasses and their con-
tinued vegetative production until late in the fall provide a long
grazing period and partly curtail the expense of feeding during
the dormant season. Utilization of nutrient materials by these
vegetative grasses brings about more economical returns from
fertilizers used for increased production.
On the other hand, plants harvested in mature growth stages
or permitted to attain such stages of maturity in pastures cease
vegetative growth and are unproductive during a great part of
the growing season. Their lower nitrogen percentage and high
content of crude fibrous materials produce a herbage with a
wide nutritive ratio, unpalatable and unsuitable for feeding or
grazing purposes. Being low in mineral percentage in most in-
stances this herbage is not best for bone building in the animal
or for its metabolism. The poor utilization of nutrient materials
by such grasses produces low returns from fertilizers used
on pastures and does not bring economical returns from the
use of such materials.
SUMMARY
Bahia grass plants were grown in lysimeters, fertilized sim-
ilarly and subjected to the following cutting treatments: "cut
frequently", "cut less frequently", "cut in seed stage" and "cut
at end of season".






Cutting Experiments With Bahia Grass


Total weight of green top growth produced over a four-year
period was higher for the frequently cut grass and decreased
progressively with decrease in frequency of cutting. Most dry
matter for the same period was produced by plants cut in mature
growth stages. The true average percentage of dry matter
in the top growth from the differently treated plants was lowest
for frequently cut plants and increased progressively with de-
crease in frequency of cutting.
Dry weight of stolons and roots (when dug) was lowest from
frequently cut plants and increased progressively with decrease
in frequency of top growth removal.
The true percentage and quantity of nitrogen in the top growth
of the plants for the four-year period was highest for frequently
cut plants and diminished progressively with each decrease in
frequency of cutting. The percentage of nitrogen in the stolons
of the plants when dug was highest for stolons from plants cut
frequently and lowest for those of plants cut in mature growth
stages. On a quantity basis, nitrogen was highest in stolons
of plants cut at the end of the season. Each increase in fre-
quency of cutting top growth caused a diminution in quantity
of nitrogen in the stolons.
Roots from plants cut frequently and from plants cut at the
end of the season showed the highest percentages of nitrogen.
Plants cut less frequently and those cut in the seed stage gave
similar percentages of nitrogen in their roots. On a quantity
basis, nitrogen in the roots of the differently treated plants
increased with less frequent removal of the top growth.
The true average percentage and quantity of phosphorus in
top growth were highest for frequently cut plants and dimin-
ished progressively with decrease in frequency of cutting.
In the stolons, prosphorus was highest on a percentage basis
for frequently cut plants and in general decreased in the less
frequently cut plants. On a quantity basis the reverse order
prevailed.
The percentage of phosphorus in the roots was highest for
plants cut frequently and for plants cut at the end of the sea-
son, with that of roots of plants cut less frequently and cut in
the seed stage intervening. On a quantity basis, roots of plants
cut at the end of the season contained the highest amount of
phosphorus.
Potassium in the top growth from the differently treated
plants varied directly with the frequency of cutting in both per-
centage and quantity.






Florida Agricultural Experiment Station


In the roots and stolons little variation in percentage of
potassium was noted, except that stolons of plants cut at the
end of the season showed a marked increase of this element.
On a quantity basis, potassium was significantly higher in the
stolons of plants cut at the end of the season.
Leaching of water, during the cutting periods, on an aver-
age, was greatest from the tank with the frequently cut grass,
and decreased with a decrease in frequency of cutting. On
the other hand, leaching of water during the resting periods,
on an average, was less from the tanks with the frequently cut
grass and was progressively higher with each decrease in fre-
quency of cutting. These factors balanced one another to give
practically a constant percentage of percolation of the rainfall
during the course of the experiment.
The amounts of nitrogen as nitrates leiched was lowe-t for
frequently cut plants and highest for plants cut least often.
Little phosphorus was leached from the soil in any instance,
but most came from that in the tank where the grass was cut
at the end of the season.
The average annual amounts of potassium leached showed
very little variation with frequency of cutting of the grass.
Lime was leached in largest quantities from the tank in which
the grass was cut at the end of the season; amounts decreased
progressively with increase in frequency of cutting.
Silicon dioxide and the combined oxides of iron and aluminum
leached practically to the same extent from all tanks during
the first two years, but were greater from the tank with grass
cut frequently during the last two years of the experiment.
The composition of the soil in relation to total nitrogen was
very similar in the different lysimeters at the beginning and
at the termination of the experiment and was not affected to
any measurable extent by the growth of the differently treated
grasses.
The quantity of nitrogen recovered in the total plant materials,
in relation to the added nitrogen, in each instance was greatest
for frequently cut plants and decreased progressively with de-
crease in frequency of cutting.
The proportion of leached nitrogen to added nitrogen in each
instance was lowest for frequently cut plants and increased pro-
gressively with the decrease in the frequency of cutting.







Cutting Experiments With Bahia Grass


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