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Yield and composition of Everglades grass crops in relation to fertilizer treatment

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Yield and composition of Everglades grass crops in relation to fertilizer treatment
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Bulletin - University of Florida Agricultural Experiment Station ; 338
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Neller, J. R.
Daane, A.
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Gainesville, Fla.
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University of Florida Agricultural Experiment Station
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Bulletin 338


October, 1939


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


'ishington Stat rOU ge LibrarY


YIELD AND COMPOSITION OF EVERGLADES GRASS CROPS IN RELATION TO

FERTILIZER TREATMENT

By J. R. NELLER and A. DAANE


Fig. 1.-Devon cattle grazing on a Dallis grass pasture of the Everglades Experiment Station farm.


Single copies free to Florida residents upon request to
AGRICULTURAL EXPERIMENT STATION
GAINESVILLE, FLORIDA









EXECUTIVE STAFF
John J. Tigert, M.A., LL.D., President of
the Universitys
Wilmon Newell, D.Sc., Directors Harold Mowry, M.S.A., Asst. Dir., Research V. V. Bowman, M.5.A., Asst. to the Director J. Francis Cooper, M.S.A., Editor3 Jefferson Thomas, Assistant Editors Clyde Beals, A.B.J., Assistant Editors Ida Keeling Cresap, Librarian Ruby Newhall, Administrative Manager3 K. H. Graham, Business Managers Rachel MeQuarrie, Accountants


MAIN STATION, GAINESVILLE

AGRONOMY
W. E. Stokes, M.S., Agronomist' W. A. Leukel, Ph.D., Agronomists G. E. Ritchey, M.S., Associate2 Fred H. Hull, Ph.D., Associate W. A. Carver, Ph.D., Associate John P. Camp, M.S., Assistant Roy E. Blaser, M.S., Assistant

ANIMAL HUSBANDRY
A. L. Shealy, D.V.M., Animal Husbandman' 8 R. B. Becker, Ph.D., Dairy iustbandman" L. M. Thurston, Ph.D., Dairy Technologist3 W. M. Neal, Ph.D., Asso. in An. Nutrition D. A. Sanders, D.V.M., Veterinarian M. W. Emmel, D.V.M., Veterinarians N. R. Mehrhof, M.Agr., Poultry Husbandman8 W. G. Kirk, Ph.D., Asso. An. Husbandman' R. M. Crown, M.S.A., Asst. in An. Husb.8 P. T. Dix Arnold, M.S.A., Assistant Dairy
Husbandman5
L. L. Rusoff, M.S., Asst. in An. Nutritions
CHEMISTRY AND SOILS
R. V. Allison, Ph.D., Chemist1s F. B. Smith, Ph.D., Microbiologists C. E. Bell, Ph.D., Associate Chemist H. W. Winsor, B.S.A., Assistant Chemist J. Russell Henderson, M.S.A., Associates L. H. Rogers, M.A., Asso. Biochemist Richard A. Carrigan, B.S., Asst. Chemist
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' Ruth Overstreet, R.N., Assistant R. B. French, Ph.D., Associate Chemist
ENTOMOLOGY
J. R. Watson, A.M., Entomologist' A. N. Tissot, Ph.D., Associate H. E. Bratley, M.S.A., Assistant
HORTICULTURE
G. H. Blackmon. M.S.A., Horticulturist' A. L. Stahl, Ph.D., Associate F. S. Jamison, Ph.D., Truck Horticulturist1 R. J. Wilmot, M.S.A., Specialist, Fumigation Research
R. D. Dickey, B.S.A., Assistant Horticulturist J. Carlton Cain, B.S.A., Asst. Horticulturist Victor F. Nettles, M.S.A., Asst. Hart.
PLANT PATHOLOGY
W. B. Tisdale, Ph.D., Plant Pathologist' 8 George F. Weber, Ph.D., Plant Pathologist3 L. 0. Gratz, Ph.D., Plant Pathologist Erdman West, M.S., Mycologist Lillian F. Arnold. M.S. Assistant Botanist


BOARD OF CONTROL
R. P. Terry, Chairman, Miami Thomas W. Bryant, Lakeland W. M. Palmer, Ocala H. P. Adair, Jacksonville Chas. P. Helfenstein, Live Oak J. T, Diamond, Secretary, Tallahassee

BRANCH STATIONS
NORTH FLORIDA STATION, QUINCY J. D. Warner, M.S., Agronomist Acting in
Charge
R. R. Kincaid, Ph.D., Asso. Plant Pathologist Jesse Reeves. Farm Superintendent V. E. Whitehurst, Jr., B.S.A., Asst. An. Husb.
CITRUS STATION, LAKE ALFRED A. F. Camp, Ph.D., Horticulturist in Charge John H. Jefferies. Superintendent Michael Peech, Ph.D., Soils Chemist B. R. Fudge, Ph.D., Associate Chemist W. L. Thompson, B.S., Asso. Entomologist W. W. Lawless, B.S., Asst. Horticulturist R. K. Voorhees, M.S., Asst. Plant Path.
EVERGLADES STATION, BELLE GLADE J. R. Neller, Ph.D., Biochemist in Charge J. W. Wilson, Se.D., Entomologist F. D. Stevens, BS., Sufarcane Agronomist Thomas Bregger, Ph.D., Sugarcane
Physiologist
Frederick Boyd, Ph.D., Asst. Agronomist G. R. Townsend, Ph.D., Plant Pathologist R. W. Kidder, M.S., Asst, An. Husbandman W. T. Forsee, Ph.D., Asso. Chemist B. S. Clayton, B.S.C.E., Drainage Engineer2
SUB-TROPICAL STATION. HOMESTEAD W. M. Fifield, M.S., Horticulturist Acting in
Charge
S. J. Lynch, B.S.A., Asst. Horticulturist Geo. D. Ruehle. Ph.D., Asso. Plant Pathologist
W. CENTRAL FLA. STA., BROOKSVILLE W. F. Ward, M.S., Asst. An. Husbandman
in Charge'

FIELD STATIONS
Leesburg
M. N. Walker, Ph.D. Pant Pathologist in
Charge
K. W. Loucks, M.S., Asst. Plant Pathologist
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
Samuel 0. Hill, B.S., Asst. Entomologist
Bradenton
Jos. R. Beckenbach, Ph.D., Truck Horticulturist in Charge
David G. Kelbert, Asst. Plant Pathologist
Sanford
R. W. Ruprecht, Ph.D., Chemist in Charge, Celery investigations W. B. Shippy, Ph.D., Asso. Plant Pathologist
Lakeland
E. S. Ellison, Meteorologist2 B. H. Moore, A.B., Asst. Meteorologist2
tHead of Department.
2in cooperation with U.S.D.A.
3Cooperative, other divisions. U. of F.
'On leave.








YIELD AND COMPOSITION OF EVERGLADES
GRASS CROPS IN RELATION TO
FERTILIZER TREATMENT

By J. R. SELLER and A. DAANEI CONTENTS
Page
The Saw grass Peat A rea . 4 N e -essary W ater Control . 5 Climatic Factors and Growth of G ss . . . 6 Early Experiments with Grasses . 7 Mineral Composition of Grasses . 8 Influence of Fertilizers upon Yield and Phosphorus Content 9 Protein, Fat and Fiber of Posture Grasses . 13 Fertilizer Requirements for Dallis Grass Hay . . 13 Response to N itrogen . . . 22 Muriate versus Sulfate of Potash . . 23 Greenhouse Experiments with Dallis Gras . 23 Yields of Carpet Grass on Fertilizer Plots . 27 Discussion and Sum m ary . . 27 Literature Cited . . . . . . . 29

Early in its history the Everglades Experiment Station began to investigate the growing of grasses on the organic soils of the Everglades. In general, peat and muck lands are known to be favorable for grass crops, but conditions peculiar to the Everglades precluded the drawing of conclusions from results that have been obtained in other areas of organic soils as to the agricultural possibilities of grasses for either forage or pasture.
The subtropical nature of the climate of the Everglades pointed to the advisability of utilizing grasses indigenous to the tropical and south temperate zones. It was known, however, that frosts may occur here from time to time during the winter months. The high humidity and the occurrence of frequent though brief rains during the summer months indicated that hay making would be limited largely to the possibilities of artificial drying. Experience has shown this to be true and experiments have not yet been conducted to determine whether the artificial drying of hay is practical for the region. But experimentation has progressed far enough to demonstrate that the utilization of grass crops by pasturing has much of promise. Certain of the grasses have an unusually high carrying capacity, especially during the summer months, and considerable grazing can be done throughout the entire year.
This bulletin presents information that has been obtained in relation to fertilizer requirements, yields and nutritive composi'Daane deceased; formerly Agronomist in Charge, Everglades Experiment Station.






Florida Agricultural Experiment 'Station


tion of grasses as fed to cattle in the form of hay and by pasture grazing. As mentioned above it remains to be determined whether the artificial drying of hay may be practical and one phase of that study is embodied herein;-viz., the yield, quality, water control and fertilizer requirements of some of the grasses that have shown themselves to be adapted culturally to the region.
Since the Everglades are composed of organic soils which have a low reserve of certain minerals it is essential to know whether the mineral content of the grasses can be amply maintained by a fertilizer practice that is economical. Special attention is given to the use of phosphates for the reason that a marked response to phosphates develops early in the history of most crops grown on the sawgrass peat soil area where these experiments were conducted. Unless sufficient phosphate fertilizer is used crops of poor feeding value might result because of too low a content of phosphorus.

THE SAWGRASS PEAT AREA
The Everglades of Florida comprise a region of about 3,000,000 acres of organic soils extending in a southeasterly direction from Lake Okeechobee, bordered on the east by marine deposits of sand and calcareous rock and on the west by an expanse known as the Big Cypress Swamp. The area adjacent to the lake is classified as custard apple muck, which is comprised of plastic layers originating from sedimentation and from aquatic plants alternating with deposits from the reed-like plant known as sawgrass, Cladium, effusum. This narrow zone of custard apple muck merges out into a region called sawgrass peat, formed almost entirely from the sawgrass plant.
The inorganic or mineral content of sawgrass peat averages above 10 percent in cultivated areas and somewhat below 10 percent in unplowed soils still covered with a growth of sawgrass. The peat is eight feet or more in depth at points nearest to Lake Okeechobee and gradually becomes thinner at greater distances from the lake. The entire region is underlaid with marl rock, a factor of great importance as the soil waters contain calcium and magnesium in solution (4 ) 2 sufficient to keep the soil in a condition favorable for plant growth without the necessity of liming. In areas under water control the pH of
Italic figures in parentheses refer to "Literature Cited" in the back of this bulletin.






Yield and Composition of Everglades Grass Crops


the surface soil ranges from 5.5 to 6.0 and increases to about
7.0 at lower depths.

NECESSARY WATER CONTROL
The Everglades comprise an extremely fiat expanse with an elevation adjacent to Lake Okeechobee of about 17 feet above mean sea level and a very slight slope east of southward. The water level on the cultivated area is controlled almost entirely with low lift pumps. Water is conducted to and from the pumps by means of a system of field ditches that lead to the larger drainage ditches and canals. Water movement is facilitated by mole drains 30 to 36 inches below the surface soil from 12 to 18 feet apart leading from the field ditches across the fields. These mole drains are quickly and cheaply established by means of a tractor and moving machine and have become an important part of the water control system on all of the better class farms.
A considerable part of the farmed area is in one of the several drainage districts whose pumps supply part of the necessary water control. The remainder comes, from privately owned pumping units. Power for pumping is supplied to a slight extent by electric motors but mostly by engines of the Diesel or semi-Diesel type.
The question of sufficient water control for the protection of crops is one of great importance. For certain crops, especially some of the vegetables, it is essential that too high a water level should be reduced with the minimum of delay. Grass and sugarcane crops are not so sensitive to temporary periods of high water levels. And while the rainfall is not extreme it comes oftentimes in brief heavy downpours that far exceed the removal rate of a practical pumping system. The problem, therefore, is to establish a system with a pumping capacity that is high, enough to offer sufficient protection, but not too expensive to construct and maintain. At the Experiment Station there is a maximum removal capacity of three acre inches per 24 hours. This appears to be about the proper capacity and it has been adopted for several of the successful farms of the region.
This brief summary of water control should not be closed without mentioning that a system of mole lines, ditches and canals should servo not only in the removal of excess water, but also in the conducting of water into the fields during those periods when there is insufficient rain to keep the water level high enough in the soil to provide for good growing conditions.







Florida Agricultural Experiment Station


Practically every year during the dry season, which extends normally from November to May, considerable water has flowed back into the fields on the Station farm from the Hillsborough Canal and on a few occasions it has been necessary to pump it into the field ditches in order to maintain a water level 18 to 22 inches below the soil surface.

CLIMATIC FACTORS AND GROWTH OF GRASS

Except for brief periods of frost, grass and hay crops continue to grow throughout the entire year in the Everglades. Table 1, which records the average monthly temperature, rainfall and evaporation from an open pan at the Everglades Experiment Station for the years 1924-1937, inclusive, shows that the heaviest rainfall occurs during June, July, August and Septem7 ber and the least during November, December and January. These wet and dry seasons roughly parallel changes in length of day and of temperature and the resultant of these climatic

TABLE I.-AVERAGE MONTHLY RAINFALL, MEAN MAXIMUM AND MINIMUM
TEMPERATURES, AND EVAPORATION FROM AN OPEN PAN FOR 1924-37 AT
THE EVERGLADEs EXPERIMENT STATION.


Temperature
Max. Min.
Degrees F. Degrees

76.0 52.6

76.9 52.0

78.1 52.5

82.2 57.3

85.7 62.6

88.1 66.9

90.6 69.2

91.0 70.2

88.6 70.3

84.5 66.1

77.8 58.0

75.6 53.2


Rainfall Inches


1.75 1.75

3.43 3.67

4.63 10.23 6.98 8.62 9.36

4.56 2.80

1.12


58.90


Evaporation
Inches


3.67 4 - .04, 5.73

6.54 7.26

6.14 6.70 6.30

5.44 5.12 3.92

3.40


Month I
-J
January -----February M arch . ------------A pril . M ay . June ------July --------August September October . November . December --Totals w .







Yield and Composition of Everglades Grass Crops


relations is effective in causing the grasses to grow most profusely during spring and early summer, followed by slower vegetative growth and seed forming tendencies in the late summer and fall. These characteristics are shown especially by Dallis grass (Paspalum dilatatum) and to a lesser extent by the carib (Eriochloa sub giabra), carpet (Axonopus compressus) and centipede (Eremochloa ophiuroides) grasses discussed below. It is probable that length of, day and temperature have more effect upon growth than rainfall in a perennial crop such as a grass for the reason that when the water level is maintained in the. soil irrespective of rainfall, as discussed above under water control, a well established root system is supplied with sufficient water from below.

EARLY EXPERIMENTS WITH GRASSES
In the fall of 1929 about two and one-half acres of the Station farm were seeded to a mixture of Dallis, Bahia and carpet grasses. This land was first plowed in 1924 and served for a time as a Para grass pasture until the grass was killed during the winter of 1925 due to a combination of frost and too close grazing. The land was planted to Dallis, Bahia and lespedeza in the early fall of 1928. This stand was killed because of the prolonged period of high water that resulted from the overflow of Lake Okeechobee following a hurricane. Flooding of that nature is no longer likely for the Everglades because of the construction by the Federal Government of a substantial dike around the southern end of the lake.
Previous to the planting of this area in the fall of 1929 it was given a dressing of copper sulfate at the rate of 50 pounds per acre to conform with the requirement that Allison, et al (1) had found to be necessary for sawgrass peat lands. The Dallis and carpet grass seed started well, but Bahia appeared to only a slight extent due to poor germination. The Bahia grass has persisted, however, but the carpet grass was soon smothered out. This area has been used continuously as a pasture and still furnishes good grazing on a firm sod.
This initial success in the establishment of a pasture resulted in the securing of a herd of purebred Devon cattle for the Station in the fall of 1931. To provide additional pasturage for these animals five one-acre areas were planted to carpet, centipede and Dallis on each of three of these acre lots, and of a mixture of Dallis and carpet and of Dallis and centipede on






Florida Agricultural Experiment Station


the fourth and fifth acres, respectively. These pastures are still in use, but the carpet and centipede grasses have been largely smothered out by sedge and by Bermuda grass. The centipede grass also has largely disappeared from the area where it was planted with Dallis grass. Dallis grass only was obtained where it was sown with carpet grass.

MINERAL COMPOSITION OF GRASSES
Before the virgin soil of these five acres was planted to these grasses in the fall of 1931 a fertilizer dressing was disked in; it consisted of 40 pounds of copper sulfate and 150 pounds of sulfate of potash per acre. During the spring and summer of 1934 samples of grass were hand plucked monthly from the carpet, Dallis and centipede acres for the purpose of determining the mineral composition of the grasses as grazed by the cattle. This study was prompted by indications of bone weakness in some of the lactating cows and their calves that were maintained on these and other pastures on the Station farm. Table 2 records the percentages of phosphorus (P2015) that these grasses contained during the months of April, May, June and July. Results are also included from Dallis and carib grass pastures planted in December, 1932. These last two pastures. received a fertilizer dressing before planting of 50 pounds of copper sulfate and 200 pounds of muriate of potash per acre.
TABLE 2.-PHOSPHORUS CONTENT OF GRASSES PLUCKED FRom FivE PASTURES IN 1934.

Percentages of P O,,, on Oven-dry Basis Date Plucked Dallis Dallis' Carib' Centipede Carpet Grass Grass Grass Grass Grass
May 2 . 0.90 0.63 0.87 0.84
June 8 0.98 0.92 1.25 0.73
July 26 0.81 0.89 0.91 0.59 1.16

Average 0.90 0.81 1.01 0.72 1.16

'Th se two pastures were planted in December, 1932, and the other three in September, 1931.

In addition to phosphorus the grasses plucked on May 2 and July 26 were analyzed also for other elements (Table 3). It is to be expected that the calcium and magnesium contents of







Yield and Composition of Everglades Grass Crops


grass in Everglades peat land should be normal to high at all times because of the large amounts of these elements that are present in the soil waters (4) by virtue of the marl substratum that lies next to the organic soil layer. It is to be expected also that the available native phosphorus will soon become deficient in sawgrass peat soil and this hypothesis is verified in the experiments recorded in the following section.

TABLE 3.-MINERAL COMPOSITION OF PLUCKED PASTURE GRASSES.

Given as Percentages of Oven-dry Grass Ingredient Dallis' I Dallis I Carib' Centipede Carpet
Grass Grass Gross Grass Grass
Plucked May 2, 1934

Calcium (CaO) . 1.20 0.94 0.75 0.74
Magnesium (MgO) 1.12 1.27 1.05 1.17
Phosphorus (P20) . 0.90 0.63 0.87 0.84
Iron (FelOe) . 0.027 0.031 0.036 0.026
Silicon (SiO2) . 1.25 0.92 1.07 0.72
Ash .-- . .8.86 5.87 8.93 6.20

Plucked July 26, 1934

Calcium (CaO) ---------- 0.72 0.97 0.48 0.82 0.88
Magnesium (MgO) -- 0.72 0.99 0.42 0.68 0.63
Phosphorus (P205) ---- 0.89 0.81 0.91 0.59 1.16
Iron (Fe,03) . 0.014 0.016 0.016 0.019 0.040 Silicon (SiO2) . 2.25 1.58 2.33 1.93 1.77
Ash . 7.23 1 7.24 9.79 5.97 7.45

'These two pastures were plantel in December, 1932, and the other three in September, 1931.

INFLUENCE OF FERTILIZERS UPON YIELD AND PHOSPHORUS CONTENT

On August 1, 1934, a series of fertilizer plots was laid out in a fenced area of a Dallis grass pasture that had been planted in December, 1932, on virgin sawgrass peat. In preparation for that planting the land received a dressing of 50 pounds of copper sulfate and 200 pounds of muriate of potash per acre.







10 Florida Agricultural Experiment Station

On the fertilizer plots triple phosphate (4417 P205) was used at the rate of 66 pounds per acre and muriate of potash (50% K20) at the rate of 120 pounds per acre (Table 4). The sulfate forms of copper, zinc and manganese were used also in one of the treatments at the rates of 40, 12 and 40 pounds per acre, respectively.

TABLE 4.-TOTAL DRY YIELDS IN POUNDS PER ACRE AND AvERAGE PROTEIN
AND PHOSPHORUS CONTENT OF CLIPPINGS OF GRASS FROM AREAS 1, 2
AND 2A OF A DALLis GRASS PASTURE.


Treatment Area 1. Eight C1


Pe Ac Lb


Yields Phosphorus' I Total Nitrogen'
Rela- Rela- Relar tive to As tive to As tive to
re Potash P20~ Potash Protein Potash s. Only % / Only 1%/1 Only


ippings, August 1,


1934, to September, 6,, 193 ,5


None ._-_._.-- 5,820 50 0.63 109 Potash only.11,548 100 0.58 100

Phosphate and potash 14,548 126 0.71 122

Phosphate, potash
and minor elements' 13,668 118 0.71 122

Area 2. Eight Clippings, November 8, 1935, to Sept.


None. --- 5,228

Potash only.----10,804 Phosphate and potash 12,820 Phosphate, potash
and minor elements' 13,080

Area 2a. Seven Clippings,


None. .

Potash only___----Phosphate and potash Phosphate,' potash and minor elements'


848 5,708 9,176 8,960


14.58 13.97 13.36

14.44


ember 22,


18.23 17.07 17,56 17.47


November 10, 1936, to October 25,


168 100

154

157


17.73

15.46 17.60

18.17


'These were the sulfates


of copper, manganese and zinc.


gThese are simple averages as they represent the concentration o h lmnsbte than weighted averages from the standpoint of pasture condition.


1936

107 j103

102


1937

115

100 114 118


of the elements better






Yield and Composition of Everglades Grass Crops


The plots were in triplicate for each treatment, 1/400 acre in size with three and one-half foot borders and the fertilizer for a given plot was applied to the middle of its borders. Before cuttings: were obtained the borders were removed with a small power mower which cut a swath the exact width of the borders. Since the sickle of the mower is in front of the drive wheels (Fig. 2), the grass in the plots is not run down in the process of cutting out the borders. And where the growth of grass is continuous across plot and border there is less of a border effect than in plots separated from each other by cleanly cultivated strips.




















Fig. 2.-Harvesting equipment in use on the Dallis grass fertility plots. The sickle of the power mower is 31/2 feet wide and the mower is used to cut out borders of that width between the plots.

Table 4 records the total yields per treatment for the eight cuttings of grass that were obtained from these plots of Area 1 from August 1, 1934, to September 6, 1935. The data of Table 4 are based on oven-dry weights which averaged 20% of the green weights. The phosphorus content was considerably higher in the grass of the first cutting from the plots that received phosphate, but it decreased in succeeding cuttings until, in the fifth it was no higher than in the grass from plots that received potash only. A reapplication of fertilizer after the fifth cutting of May 23 caused the phosphorus content of the






Florida Agricultural Experiment Station


next three cuttings to be distinctly higher than those that received potash only. The average effect from the eight cuttings covering a period of 13 months was to increase the phosphorus content of grass from the phosphate treated plots by 22% (Table 4), with a corresponding increase in yield of 26%. The inclusion of the sulfates of copper, manganese and zinc was w without apparent effect. Potash alone more than doubled the yield.
On October 11, 1935, another area of the pasture was fenced off and fertilized as given above for Area 1, Table 4. On December 24, 1934, this pasture received a top-dressing of 50 pounds of triple superphosphate and 100 pounds of muriate of potash per acre. This was the second fertilizer treatment for the pasture, the first having been made when the grass was planted in 1932. Table 4 shows that for the eight clippings obtained from this second set of plots (Area 2) the effect of potash alone and of phosphate with potash was about the same on yields and phosphate content of grass as in Area 1. This demonstrated that the pasture had not received enough phosphorus and potash to render anywhere near its potential yielding capacity and that the higher fertility level also increased the phosphorus content of the greatly increased yields.
A year after it was fertilized Area 2 was given a second treatment on October 1.2, 1936. The seven clippings obtained during the ensuing year (Table 4, Area 2a) demonstrated in the check plots how completely grass fails on this sawgrass peat without additions of potash. It may be observed also that whereasthe use of potash alone will maintain yields for a time the phosphorus content of the grass will decrease sharply, as the average of 0.37% P205 was the lowest that was obtained in these experiments.
This experimental method of studying the fertilizer requirement of a pasture by establishing fertilizer plots on new areas of a pasture from season to season is recognized as not being ideal for the reason that clipping the growth, even though frequently enough to keep it in the grassy or vegetative stage, is not strictly comparable to the removal of the grass by grazing. Ritchey and Henley (6) found this to be true for centipede grass, which is a creeping, prostrate variety. In the more upright grasses such as Bahia and Bermuda, however, they found that the seasonal yields as obtained by clipping were in close agreement with the seasonal gains in steers feeding in






Yield and Composition of Everglades Grass Crops


the pasture. Dallis grass was used in the present experiments and it has a more upright type of growth than either Bahia or Bermuda.
While the experiments recorded above demonstrate the need for the use of both phosphate and potash early in the management of Everglades pastures, they do not determine the best ratio of these two plant food elements. The marked responses in yield (Table 4) indicate that larger amounts of fertilizer might be used with economy. Some indications as to ratios and fertility levels may be obtained from the Dallis grass hay experiments recorded herein.

PROTEIN, FAT AND FIBER OF PASTURE GRASSES
Samples of Dallis, carib, carpet and centipede grasses that were plucked from the various pastures during the summer of 1934 and discussed above as to mineral content (Tables 2 and 3) were analyzed for protein, fat and fiber (Table 5). It may be noted that the protein contents are high, especially of the Dallis grass, even though no nitrogen fertilizer was used. This is to be expected for grasses grown on an organic soil whose reaction and temperature is favorable for the nitrification of the nitrogenous material represented by a soil nitrogen content of 3 to 3.5%. Proteins were also determined in the cuttings of Dallis grass c.'ipped from Areas 1 and 2 (Table 4). It may be observed that fertilizer treatments that affected yield and phosphate content to a marked degree have no significant effect upon protein content. There is apparently no explanation other than that of change of location and season for the somewhat lower amount of protein in the eight clippings from Area 1 than from Area 2 for the two years following. In general the plucked grasses (Table 5) contained about the same percentage of protein as those that were clipped (Table 4). The crude fat and fiber contents of the plucked pasture grasses are about normal for grasses, with little difference between varieties.

FERTILIZER REQUIREMENTS FOR DALLIS GRASS HAY
These experiments are based upon a series of plots 1/400 acre in size and in triplicate for which different fertilizer mixtures were made up and used on the basis of formulas ranging from 6-6-123 to 0-12-24 at 500 pounds per acre. The source materials
'All formulas refer to nitrogen (N), phosphate (1?20 ) and potash (K.0) in the order given.







Florida Agricultural Experiment Station


were ammonium sulfate, sulfate of potash and superphosphate containing 44% P205. Copper sulfate at the rate of 80 pounds per acre was applied to all the plots when fertilizers were added in 1931 and at one-half that rate once a year thereafter.

TABLE 5.-PROmEIN, FAT, FIBER AND NITROGEN-FREE EXTRACT IN DALLIS,
CARIB, CENTIPEDE AND CARPET GRASSES PLUCKED FROM THE PASTURES
IN 1934.


Date Plucked




May 25 ._. June 8 .---July 26 . .



May 25. . June 8 -. July 26 .--Aug.1



May 25. June 8 . July,26 .


Given as Percentages of Oven-dry Weights Protein . 1- -Fat --I- Fiber I N. F. Ext._j___


Dallis Grass Pasture 17.25 3.12 28.50

15.88 2.60 30.89

14.2 ___ 3.20 33.22 Dallis Grass Pasture" 14.13 2.63 29.88

19.19 2.63 26.97

16.37 2.59 30.68

13.96 2.02 31.58

Carib Grass Pasture' 11.19 1.93 27.73

14.69 1.69 26.04

11.25 2.45 29.10
Centipede Grass Pasture


42.27 43.02 42.10



47.49 43.34 43.12 43.92



50.22 45.79

47.41


8.86 7.61 7.23



5.87 7.87

7.24 8.42


8.93 11.79 9.79


May 25 _. 13.81 2.75 29.31 47.93

June 8 . 10.56 2.36 33.14 48.21

July 26.-. 12.63 3.69 28.45 48.56


June8 .


Carpet Grass Pasture

15.81 2.62 26.94 50.24 7.45


'These samples were plucked from pastures planted in 1932. The other three pastures were planted in 1931.


During the period 1931-1937, were removed and each cutting in 'the late bloom or hay stage.


inclusive, 33 cuttings of grass was taken when the grass was 'Moisture determinations from








Yield and Composition of Everglades Grass Crops


Fig. 3.-Growth of Dallis grass just before the cutting of June 29, 1934, on the fertility plots for which the average annual yields are given in Table 6. Treatment 14 wEa an 0-12 24 mixture at 500 pounds per acre; Treatment 7 was an 0-6-12 mixture; Treatment 6 consisted of potash and Treatment 5 of phosphate equal to the amounts used in Treatment 7. Copper sulfate, 40 pounds per acre, was added with all the other treatments, including the check plot, 13. In the first treatment 80 pounds of copper sulfate were used.








TABLE 6.-EFFECT OF PHOSPHATE AND POTASH UPON YIELDS OF DALLIS GRASS HAY FROM FERTILITY PLOTS.
Pound HayPer Acre Per Treatment on Oven-dry Basis
Pons a I 12. Phos- 114. Double Fertilizer No. of
Year I5. Phos- 16. Potash 17. Phos- 1l1. Potashl phate and Iphosphate Applied Cuttings
1. Check' phate Ionly I phate and and double! double and double
only I PotashI phosphate! potash potash

19 31 ---------- -----18,701 18,564 20,660 20,908 18,629 1 20,300 17,778 Feb. 18 I 6
1932 ------ -------- 6,320 6,008 9,806 10,226 9,854 12,266 11,957 May 25 5

1933 -------------------- 5,573 5,207 9,233 10,993 9,090 11,468 12,304 July 14 4
1934 -------------------- 3,085 4,451 6,467 11,880 13,401 13,617 16,466 May 22 5
1935 -----------------.- 2,367 4,662 5,635 10,301 12,017 13,367 17,868 June 10 5

1936 ----------------- -- 2,153 4,059 4,072 9,563 I10,273 11,933 14,814 June 16 5

193 ----- --------------1,253 3,592 5,199 5,4 5,140 9,9 6 0,25 No e

Totals --------- - ----- 39,452 46,543 60,572 79,416 78,404 92,917 101,912 33
Avrg e er------ 5,633 6,649 8,653 .11,345 11,201 13,274 14,559

Yield relative to
potash only treatment i 65 77 100 131 129 ! 153 168

I Copper sulfate at 80 pounds per acre was applied to all treatments including the check plots with first fertilizer application and at 40 pounds per acre with each subsequent application. Phosphate and potash were used on a basis of an 0-6-12 formula at 500 pounds Per acre except where the amounts weie r.oubled.






Yield and Composition of Ever#lades Grass Crops


various cuttings showed that the dry matter content of the fresh cut hay was always close to 2517o. Table 6 shows that the average annual yields of hay from these p'ots varied from 5,633 pounds per acre on the oven-dry basis where no fertilizer was applied (Treatment 1) to 14,559 pounds per acre where an 0-12-24 mixture was used at the rate of 500 pounds per acre (Treatment 14). The photographs of Fig. 3 are of the cutting of June 29, 1934, and illustrate an average type of response to the various fertilizers. Growth differences were still greater at the time of the May 17 cutting, which was just before a reapplication of fertilizer (Table 6). It may be observed that in addition to the usual high response to potash the use of phosphate increased yields to a marked degree over those obtained when potash only was used. Doubling the amount of phosphate resulted in no increase in yields (Fig. 4 and Table 6), whereas doubling the amount of potash caused a considerable increase, showing that potash was the limiting factor. The still greater increase in yields obtained when both phosphate and potash were doubled indicates that phosphate became the limiting factor with an 0-6-24 formula (Treatment 12) and that the fertilizer for Treatment 14 though fairly well balanced was probably not sufficient in quantity for maximum yields.
Table 6 further shows that the omission of fertilizer in 1937 resulted in a marked falling off in yields, which illustrates how quickly the reserves of available plant food can be depleted in this soil of high organic content. The average annual yield of eight tons of hay on a 10% moisture basis from Treatment 14, in which an 0-12-24 fertilizer at 500 pounds per acre per year was used, indicates that the fertilizer elements were well utilized.
This series included plots where treatments were identical with those in Table 6 except that fertilizer applications were omitted in 1932, 1933, 1935 and 1936. The resulting yields are given in Table 7 and are compared with those of Table 6 in Figure 4. This comparison of average annual yields for the seven-year period shows that the omission of phosphate: or potash from plots where these were used singly did nof have much effect, whereas the omission of fertilizer containing both phosphate and potash caused a marked reduction in yields.
From a comparison of the annual yields of comparable treatments such, as No. 14 of Table 6 and No. 10 of Table 7,' as illustrated in Fig. 5, it maybe seen that the fertilizer treatment of May 22, 1934, caused the 1935 yield for Treatment 10








TABLE 7.-EFFECT OF OMISSIONS OF FERTILIZER UPON YIELD OF DALLIS GRASS AS COMPARED WITH YIELDS WHERE FERTILIZER WAS NOT OMITTED (TABLE 6).


Pounds Hay


1931 1932 1933 1934 1935 1936 1937


Totals . Average pc Yields rela
Treatmei


Year


















-r year . tive to nt3 .


1. Check'


18,701 6,320 5,573 3,087 2,367 2,153

1,253


39,454 5,635

77


2. Phosphate only 20,835 5,924 5,823

2,864 2,618 2,432

799


41,295 5,899

80


Per Acre Per Treatment on Oven-dry Basis I F 9. Phos- 10. Double
3. Potash I 4. Phos- 8. Potash lphate and phosphate
only phate and and doubleF double and double
potash phosphateI potash I potash

20,137 19,510 20,744 21,920 20,295

5,931 5,615 5,156 5,734 6,521

5,405 5,601 5,292 6,464 7,150

7,168 8,770 10,700 9,167 9,867

6,751 10,667 12,318 13,450 1 16,467 3,603, 4,113 3,245 3,081 3,273

2,433 2,392 3,252 3,559 3,552


51,428 56,668 65,707 1 63,375 67,125

7,347 8,095 9,387 9,053 9,589

100 110 128 123 131


'Copper sulfate at 80 pounds per acre was applied to all treatments, including the check plots, with first fertilizer application and at 40 pounds per acre with each subsequent application. Phosphate and potash were used on a basis of an 0-6-12 formula at 500 pounds per acre except where the amounts were doubled.


Fertilizer No. of Applied Cuttings



Feb. 18 6

None 5

None 4

May 22 5

None 5

None 5

None 3


33






Yield and Composition of Everglades Grass Crops


to be about equal to that of Treatment 14 in which annual applications of fertilizer had not been omitted. The sharp rise and drop in yields of Treatment 10 (Fig. 5) illustrate again that although these organic soils have a low reserve of phosphate and potash they are apparently able to retain and make available to crops a large part of the amounts that are supplied to them.




lbs. per Fertilized only in 1931 m d 1934
acre oven
dry Fertilized each year except 1937
basis
15,000


10,000


5,000



Treatments 1 2 5 3 6 .4 7 8 11 9 12 10 14
Fig. 4-Average annual yields of Dallis grass hay for the seven-year period 1931-87 =,6). Treatment 1, check; 5, phosphate; 6. potash; 7, phosphate and potash; 11,
te and double Potash; 14, doubJe phosphate and double potash; all applications are based on an 0-6-12 mixture at 500 pounds per acre per year. Treatments 2, 3, 4, 8, 9 and 10 are of the same nature as Treatments 5, 6, 7, 11, 12 and 14 except that applications were omitted in 1932, 1983, 1935 and 1936.

Inasmuch as phosphorus is the nutritive element that is most likely to be deficient in hay grown on Everglades peat land, phosphorus analyses were made, of 12 of the 33 cuttings of Dallis grass hay for which the yields are recorded in Table 6. Table 8 shows that hay from the plots receiving potash only contained the least phosphorus while the highest was in hay from the treatment that received a double application of phosphate (Treatment 11) or an 0-12-12 mixture. The treatment represented by the 0-6-12 formula at 500 pounds per acre produced hay having an intermediate content of phosphorus almost identical with that of hay from Treatment 14, which received an 0-12-24 mixture at 500 pounds per acre.






Florida Agricultural Experiment Station


lbs. per -Treatment 10 acre
oven
dr'y f Treatment 14
basis

20,000


15,000 10,000 5,000


1931 1932 193,3 1934 1935 1936 1937?


Fig. 5.-Comparison of annual yields of Dallis grass as averaged from plots in triplicate where an 0-12-24 mixture was used each year except 1937 for Treatment 14 (Table 6) and in 1981 and 1934 only iar Treatment 10 (Table 7).

Comparing these results with the yield responses (Table 6), it is evident that high yields are associated with a normal phosphorus content which may be increased somewhat by adding phosphate in excess of the amount necessary to balance the potash, as in Treatments 5 and 11. Likewise the use of potash without phosphate produced hay that was lower in phosphorus and it is apparent from Treatment 6, Table 8, that this reduction in the phosphorus content of the hay takes place rather quickly in a soil of this type. This is evident also with respect to the pasture plots that received potash only (Table 4). These effects of phosphates upon, the phosphorus content of grass are of interest in relation to the findings of Blair and Prince (6), with mineral soils, who report that changes in the phosphorus content of plants as influenced by phosphate treatments are relatively small in comparison with the effect of nitrogenous ferti-izer upon nitrogen content. In the organic soils of the Everglades nitrogenous fertilizers have little effect upon the nitrogen content of most crops.





TABLE 8.-PHoSPHoRUs CONTENT OF CUTTINGS OF DALLis GRASS HAY WITH YIELDS RECORDED IN TABLE 6.

Given as Percentage PA0 of Oven-dry Matter for Each Treatment
1 12. Phos- 14. Double
Date of Cutting 5. Phosphate 6. Potash 7. Phosphate I11. Potash phate and Phosphate
1. Check Only Only and Potash and Double Double and Double M
Phosphate Potash Potash
Fertilized February 11, 1931 Z

July 24, 1931 0.64 0.65 0.59 0.66 0.71 0.67 0.66
October 14 ------- 0.66 0.68 0.71 0.70 0.67 0.74 0.70
May 23, 1932 ---- 0.52 I 0.36 0.36 0.42 0.43 0.34 0.45
Fertilized May 25, 1932 i

June 29 --------0.35 0.36 0.63 0.78 0.61 0.67
September 14 --- 0.55 0.86 0.42 0.68 0.71 0.52 0.65 0
May 18, 1934 ---- 0.41 -1 0.23 0.27 0.39 0.25 0.28
Fertilized May 22, 1934

June 29 . 0.37 0.77 0.21 0.39 0.50 0.37 0.51
Fertilized June 10, 1935

July 9, 1935 0.32 0.72 0.29 0.52 0.67 0.46 06
June-,-193 0.40 0.56 0.30 0.41 0.45 ___0.26 0.31
Fertilized June 16, 1936

July 13.0.33 0.75 0.23 0.75 0.8 0. 66 0.75
September 1----- 0.35 0.61 0.27 0.60.77 0.59 0.62
May 13, 1937 ----- 0.37 0.55 I 0.2 0.46 0.67 0.35 0.44

Average . 0.45 0.62 0.35 0.54 0.63 0.49 0.52
'Samp!es were not obtained.







Florida Agricultural' Experiment Station


RESPONSE TO NITROGEN Yields from Treatment 16, Table 9, which received ammonium sulfate as supplied in a 6-6-12 formula at 500 pounds per acre produced no more grass during the seven years of the experi-: ment than Treatment 17 in which the ammonium sulfate wasi, omitted. This study of the possible effect of a nitrogenous fertilizer on grass crops in sawgrass peat may be considered incomplete, however, for the reason that a treatment including nitrogen was not used where a heavier fertilizer application caused heavier yields and the withdrawal of greater quantities ,of nitrogen from the soil as in Treatment 14, Table 6. Data and discussion relating to the nitrogen removed from Treatment 14 may be found in a previous publication (5).

TABLE 9.-EFFECT OF UsE OF NITROGEN AND OF THE MURIATZ INSTEAD OF
THE SULFATE OF POTASH UPON YIELDS OF DALLIS GRASS.

Pounds Per Acre Per Treatment on Oven-dry Basis
Year 16. Nitro- 17. Phos- 25. Phos- No. of Fertilized
gen, Phos- phate phate and Cuttings
phate and and Muriate
Potash' Potash of Potash

1931. 19,562 19,906 19,497 6 Feb. 18,

1932 . . 9,527 8,801 9,242 5 May 25
except,
phosphorus
1~. .859 8,786 9~,591 4 July 14
except
phosphorus
1934. 5,901 6,702 6,517 5 May 22
1935 . 8,420 9,594 '8,822 5 June 10

1936. 4,289 4,817 5,258 5 June 16
except
phosphorus
1937 . 5,084 5,605 4,958 3 None


Totals .61,332 64,211 68,880 33
Av. per year ---- 8,762 9,178 9,126

Yields relative to
Treatment 17 96 100 99

'The sulfates of potash were used in Treatments 16 and 17 and applications were o the basis of a 6-6-12 formula at 50D pounds per acre.






Yield and Composition of Everglades Grass Crops


MURIATE VERSUS SULFATE OF POTASH
Treatment 25 (Table 9) received its potash in the form of muriate with the result that yields were no higher than from Treatment 17 where the sulfate of potash was used. Potash in the form of muriate might be less satisfactory than the sulfate form in treatments involving greater quantities. Thus in the rather large amounts employed in the greenhouse trials discussed below the mixtures containing muriate caused more depression of growth than those containing sulfate of potash. It may be considered quite safe, however, to use muriate in field treatments on grass crops.

GREENHOUSE EXPERIMENTS WITH DALLIS GRASS
Dallis grass was used as one of the index crops in a series of treatments on sawgrass peat soil in glazed six-gallon jars in the greenhouse. This series of 20 treatments in triplicate was designed primarily to study the effect of varying ratios of phosphorus and potassium in the fertilizer mixture. Chemically pure sources of the elements were used except that the phosphorus of Treatments 13 and 14 (Table 10) was derived from superphosphate of 44% P205 grade. Commercial flowers of sulfur was used in Treatments 16, 17 and 20. Rates of application were based upon a 10-10-20 formula at 1,000 pounds per acre. Sulfur was used at the rate of 1,000 pounds per acre in Treatments 16, 17 and 20, while in Treatments 13 and 14 where wood ashes were made the source of potassium, enough extra sulfur was added to take up the alkalinity of the wood ashes on the basis of all of the sulfur changing to sulfate. Sulfur oxidation was active as evidenced by the reduction to pll 5.66 in Treatment 16 from a pff of 6.71 in Treatment 15.
The primary purpose of using Dallis grass in this series of treatments was to ascertain the effect of varying amounts of phosphate upon the phosphorus content of the grass and to correlate these data with those of similar nature in the pasture and hay lands discussAed previously. The cuttings were made in the late bloom stage, and typical growth responses are illustrated in Fig 6. Table 10 shows that hay from Treatment 3, which received no phosphate, and from: Treatment 10, to which a minimum amount of phosphate was added, both contained 0.49 % of phosphorus (P205) - With increasing amounts of phosphate in the soil treatment the phosphorus content of the hay










TABLE 10.-YIELD AND PHOSPHORUS CONTENT OF DALLIS GRASS GROWN IN GREENHOUSE WITH VARIOUS SOIL TREATMENTS TOGETHER WITH THE REACTION OF THE SOIL (SAWGRASS PEAT).


Treatment


No.


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


First

Yield gms.

26.5 31.7 31.5 141.9 111.2 92.1 69.1 85.5
35.4 61.8 104.2 67.0 148.8 104.9
30.4 69.2
134.5 63.8 85.8 128.0


2nd, 3rd, 4th Cuttings
Jan. 18-Aug. 15


Cutting May 21

Phosphate (P O) I_ %

0.64 1.20 0.49 0.61 0.61 0.76 0.70 0.61 0.73 0.49 1.00 1.06 0.94 1.08 0.57 0.79 0.86 0.65
0.63 0.78


Phosphate (P O:


0.67 1.03 0.43 0.62 0.56
0.56 0.55 0.66 0.73 0.48 0.78 0.91 0.77 1.09 0.48 0.67 0.67
0.64 0.58 0.66


Total
Yield

gms.

86.1 76.7 160.3 239.4 254.8 250.8 133.9 159.8
46.2 162.7
232.0 179.3 256.4 260.1 46.0 159.4 287.2 205.0 214.2 315.2


Check --. . 2P .
2K. 2PK ---- - - --.
2 P 2 K -- --- -- -- - -- - -- - -- - -. . . . . . . . . . . . . : . . ---I
2P4K . 2P8K . 2P4K (muriate). 2P8K (muriate) -------------. ------.P4K .
4P4K . 8P 4K . 4P (44% phosphate) -----. 8P (44% phosphate) .----------2P2K plus wocd ashes .
2P2K plus wood ashes plus sulfur 2P4K plus sulfur . 2P4K plus nitrate . I 2P4K plus iron sulfate --.
2P4K plus iron sulfate plus sufur


Soil Reaction

pH

5.42 5.35 5.14 5.34 5.34 5.19 5.29 5.25 5.43 5.29 5.31 5.21
5.16 5.10 6.71 5.66 4.75 5.33 5.24 4.26


Yield gins.

59.6 45.0 128.8 127.5 143.6 158.7 64.8 74.3 10.8 100.8
127.8 112.3 107,6 155.2
15.6 90 2 152.7 141.2 128.4 187.2






Yield and Composition of Everglades Grass Crops


was increased to 1.06% (Treatment 12). Medium amounts of phosphate (Treatments 4-7) produced hay containing an average of 0.62% P205, which is higher than the average of 0.52% P206 of the corresponding field Treatment 14 of Table 8, but lower than the average of 0.85% P205 (Table 2) for Dallis grass plucked from the pastures. These field and greenhouse results indicate that the phosphate-potash ratio of one part of P205 to two of K20 is about as high as the phosphorus content of fertilizer needs to be raised from the standpoint of yield and quality of Everg'ades grass crops.


Fig. 6.-Representative growth of Dallis grass in triplicate greenhouse treatments of the cutting of May 21, 1934 (Table 10). A-Treatment 1 is 2P4K (phosphorus and potash) ; 2 is 2PK; 3 is 4K; 4 is 2P; and 5 is a check. B-No. 1 is 2P2K with wool ashes as the source of. potash; 2 is 2P2K wi h wood ashes plus sulfur; 3 is 2P4K plus sulfur; 4 is 2P4K plus sodium nitrate; 5 is 2P4K plus ferrous sulfate; and 6 is 2P4K plus ferrous sulfate plus sulfur.










TABLE 11.-AERAGE ANNUAL YIELDS OF CARPET GRASS PROM FERTILIZER PLOTS.


Pounds Per Acre Per


Year


1931 -- -- - ----- --

1932 ---- -- -1933 -- ---- -- -- ----

1934 . ----1935 ----------1936 ------- ---

19 3 7 -- - - - - -I- - - - - - -


Totals -- --- --- -Average per year Yields relative to
those from potash


only


Check'

1,804 11,167 8,529

2,439 1,522 1,060

1,746


28,267

4,038

73


Phosphate

1,963

11,301

6,833 2,352 1,638 1,500 1,750


27,3


Treatment on Oven-dry Basis


Pot

2, 12, 11, 3,
2, 2, 3,


~37 '05

70


38,

5,


ash 114 753 663 508 917 059

845


859 ,551 100


and Potash

1,770

18,854 16,118

7,758

5,419 5,945 5,913


61,768

8,824

159


Phosphate' and Potash1,973

18,145 14,776

7,118 4,868 5,100 5,579


57,559
8,223


148


Fertilized


Feb. 11 May 25

July 14 May 22 June 10 June 16 'None


No. of Cuttings


"All -treatments received copper sulfate at the rate of 80 pounds per acre when first fertilized and at the rate of 40 pounds per acre thereafter. Phosphate and potash were used on the basis of an 0-6-12 formula.
-B3asic, sag was used as the source of phosphorus.






Yield and Composition of Everglades Grass Crops


The Dallis grass greenhouse series (Table 10) corroborate those in the field to show that either the muriate or the sulfate form of potash may be used. The highest yields were obtained from Treatments 17 and 20, where the soil reactions were, as a result of sulfofication, reduced to pH values of 4.75 and 4.26, respectively. There was no response to either an iron or a nitrogenous fertilizer.

YIELDS OF CARPET GRASS ON FERTILIZER PLOTS
Although carpet grass is generally considered to be of too prostrate a type to be cut for hay, it is of interest to note that the average annual yield of 8,824 pounds of grass on the dried basis (Table 11) as cut with an ordinary sickle type 'mower (Fig. 2) compares favorably with the annual average yield of 11,345 pounds of Dallis grass hay (Table 6) from plots that received the same amount of phosphate and potash as represented by an 0-6-12 formula, at 500 pounds per acre per year. A similar marked response to both phosphate and potash is shown in Table 11 for carpet grass as in Table 6 for Dallis grass.
It may be inferred that the growth of carpet grass was not limited by any minor element deficiency, as yields were not increased where basic slag was substituted for 447o superphosphate as the source of phosphorus.
Although phosphate analyses were not made of these cuttings of carpet grass it may be assumed that, since carpet grass tends to remain in a more leafy or vegetative state than Dallis, the percent of phosphorus in carpet grass hay would, with the same fertilizer treatment, be fully as high as or higher than is recorded for Dallis grass (Table 8). Carpet grass plucked from a pasture contained 1.165o of phosphorus as P205 (Table 3), which was considerably higher than the phosphorus content of Dallis, carib and centipede plucked on the same date from adjacent, similarly fertilized pastures.

DISCUSSION AND SUMMARY
After the successful establishment of a pasture in 1929 on the sawgrass peat of the Station Farm, a series of experiments was started to determine the influence of fertilizers upon the yield and composition of grass crops.
Climate, soils and necessary water control are discussed in relation to the growing of grass crops in the Everglades.






Florida Agricultural Experiment Station


Since the organic soils of the Everglades are low in reserves of phosphorus, special attention was given to that element, since adequate supplies of it are essential in growth of bone in grazing animals. In a series of samples of Dallis grass plucked from pastures in 1934 the content of phosphorus was found to be 0.63 percent P205 on the dry basis. The phosphorus content of material plucked from pastures of carib and carpet grasses is somewhat higher, while that of centipede grass is slightly lower. In a study of Florida ranges, Becker et al (12) have reported that cattle grazing on grasses that averaged 0.19 percent P205 showed decided symptoms of phosphorus deficiency while those on ranges whose grasses containedan average of
0.31 percent were normal.
The fertility experiments reported herein for Everglades sawgrass peat soil show that sufficient phosphate to insure good grass yields also insures a phosphorus content above that found in the grass of Florida ranges where healthy cattle are raised.
Analyses of the plucked grasses from Everglades pastures indicated that ample amounts of calcium, magnesium and iron are present. The sub-surface waters of these organic soils are well supplied with calcium and magnesium from the underlying marl, and grass crops grown on these soils are well supplied with these elements.
A field plot study of a Dallis grass pasture showed that phosphate and potash equivalent to the amounts contained in an 0-6-12 formula at 500 pounds per acre should be applied at least, once a year to keep the pasture at a moderately high point in its potential productivity as shown by yield records of cuttings from these plots. The carrying capacity of the pasture was very high as may be expected because of its location in a subtropical environment.
Thirty-three cuttings of Dallis grass hay were cut from a series of fertility plots during a period of seven years (1931-37 inclusive). These gave an average annual yield on the dry basis of 5,633 pounds per acre where no fertilizer was applied and 14,559 pounds where phosphate and potash were used in amounts equivalent to an 0-12-24 mixture applied at the rate of 500 pounds per acre per year. With an 0-6-24 mixture the yield was reduced to 13,274 pounds per acre and the phosphorus content of the hay was lower. With an 0-12-12, mixture the yield was reduced to 11,201 pounds per acre and practically the







Yield and Composition of Everglades Grass Crops


same yield was obtained with either an 0-6-12 or a 3-6-12 mixture.
Analyses of cuttings of Dallis grass grown in greenhouse jars corroborated those of field plots in showing that a phosphate (P205) potash (K20) ratio of one to two is about as high as the phosphorus content of a fertilizer needs to be raised, from the standpoint of yield and of phosphorus content of the grass.
In a parallel series of plots using the same fertilizer mixture at the same rate per acre but omitted in 1932, 1933, 1935 and 1936 the average yield was reduced by about one-third. In both series yields were almost identical for 1935 following similar applications of fertilizer to both in 1934, while the 1936 yields on the unfertilized plots dropped to less than half of those from the fertilized plots. This shows how completely the fertilizer was utilized in these sawgrass peat soils.
The average annual yields of Dallis grass hay from plots that received their potash in the form of muriate were practically the same as from plots where the sulfate of potash was used.
In the greenhouse Dallis grass did not respond to soil treatments of iron and nitrogen.
In field fertilizer trials during the seven-year period 19311937, the average annual yield of carpet grass was 8,824 pounds per acre, on the dry basis, where phosphate and potash were used in amounts equivalent to an 0-6-12 formula at 500 pounds per acre. There was a marked response to phosphate as well as to potash.
ACKNOWLEDGMENTS
The authors wish to acknowledge the counsel and advice of Dr. R. V. Allison in connection with some of the earlier experiments. R. W. Kidder took the photograph for the frontispiece and was in charge of the cattle that grazed the pastures discussed in these experiments. Painstaking assistance has been rendered by John Newhouse in obtaining field records, by L. S. Jones and P. M. McIntyre with the laboratory work and by Edward king, Jr., in the taking of weather records.

LITERATURE CITED
1. ALLiSON, R. V., 0. C. BRYAN and J. H. HUNTER. The stimulation of plant response on the raw peat soils of the Florida Everglades through the use of copper sulfate and other chemicals. Fla. Agr.
Exp. Sta. Bul. 190. 1927.






30 Florida Agricultural Experiment Station

2. BECKER, R. B., W. M. NEAL and A. L. SHEALY. Stiffs or sweeny
(phosphorus deficiency) in cattle. Fla. Agr. Exp. Sta. Bul. 264.
1933.
3. BLAIR, A. W., and A. L. PRINCE. The influence of phosphates on the
phosphoric acid content of the plant. Jour. Agr. Research, 44: 579590. 1932.
4. NELLER, J. R. Effect of rainfall and of substrata upon composition and reaction of soil waters of Everglades peat land. Volume B, Transactions of 6th Comm. of International Society of Soil Science,
Zurich 388-393. 1937. Abstract in Volume A, 31-32.
5. NELLER, J. R. The availability to crops of the nitrogen of Everglades peat. Transactions of the Third International Congress of Soil
Science. 1: 421-423. 1935.
6. RITCHEY, GRo. E., and W. W. HENLEY. Pasture value of different grasses alone and in mixture. Fla. Agr. Exp. Sta. Bul. 289. 1936.




Full Text

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(, ~=y1, I .i F G (~ {,. .. . C ' ; L Bulletin 338 October, 1939 UNIVERSITY OF FLORIDA AGRICULTURAL EXPERIMENT STATION GAINESVILLE, FLORIDA WILMON NEWELL, Director Washington Stailt College LibrarY YIELD AND COMPOSITION OF EVERGLADES GRASS CROPS IN RELATION TO FERTILIZER TREATMENT By J. R. NELLER and A. DAANE Fig . 1.-Devon cattle grazing on a Dallis g ra ss p ast ure of the Everglades Expe r iment Station farm. Single copies free to Florida r ' esidents upon request to AGRICULTURAL EXPERIMENT STATION GAINESVILLE, FLORIDA

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EXECUTIVE STAFF John J. Tigeri;, M.A., LL.D., President of the University• Wilmon Newell, D.Sc., Director• Harold Mowry, M.S.A., Asst. Dir;, Research V. V. Bowman, M.l;l,A., Asst. to the Director J. Francis Cooper, M.S.A., Editor• Jefferson Thomas, Assistant Editor• Clyde Beale, A.Il.J., Assistant Editor• Ida Keeling Creaap, Librarian Ruby Newhall, Administrative Manager• K. H. Graham, Business Manager• Rachel McQuarrie, Accountant• MAIN STATION, GAINESVILLE AGRONOMY W. E. Stokes, M.S., Agronomistl W. A. Leukel, Ph.D., Agronomist• G. E. RitChey, M.S., Assoc-iate 2 Fred H. Hull, Ph.D., Associate W. A. Carver, Ph.D., Associate John P. Camp, M.S., Assistan.t Roy E. Blaser, M.S., Assistant ANIMAL HUSBANfiRY A. L. Shealy, D.V.M., Animal Husbandman 1 R. B. Becker, Ph.D .. Daily Husbandman• L. M. Thurston, Ph.D., Dairy Technologist• W. M. Neal, Ph.D., Asso. in An. Nutrition D. A. Sande-rs, D.V.M., Veterinarian M. W. Emmel, D,V.M., Veterinarian• N. R. Mehrhof, M.Agr., Poultry Husbandman• W. G. Kirk, Ph.D., Asso. An. Husbandman• R. M. Crown, M.S.A., Asst: in An. Hush.• P. T. Dix Arnold, M.S.A., Assistant Dairy Husbandman• L. L. Rusoff, M.S., Asst. in An. Nutrition• CHEMISTRY AND SOILS R. V. Allison, Ph.D., Chemist 1 F. B. Smith, Ph.D., Microbiologist• C. E. Bell, Ph.D., Associate Chemist H. W. Winsor, B.S.A., Assistant Chemist J. Russell Henderson, M.S.A., Associate• L. H. Rogers, M.A., Asso. Biochemist Richard A. Carrigan, B.S., Asst. Chemist ECONOMICS, AGRICULTURAL C. V. Noble, Ph.D., Agricultural Econom;st 1 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 1 Ruth Overstreet, R.N., Assistant R. B. French, Ph.D., Associate Chemist ENTOMOLOGY J. R. Watson, A.M., Entomologist' A. N. Tissot, Ph.D., Associate H. E. Bratley, M.S.A .. Assistant HORTICULTURE G. H. Blackmon, M.S.A., Horticulturist 1 A. L. Stahl, Ph.D., Ass.ocfate F. S. Jamison, Ph,D., Truck Horticulturist• R. J. Wilmot, M.S.A., Specialist, Fumigation Research R. D; Dickey, B.S.A., Assistant Horticulturist J. Carlton Cain, B.S.A., Asst. Horticulturist Victor F. Nettles, M.S.A., Asst. Hort. PLANT PATHOLOGY W. B. Tisdale, Ph.D., Plant Pathologist 13 George F. Weber, Ph.D., Plant Pathologist• L. 0. Gratz, Ph.D., Plant Pathologist Erdman West, M.S., Mycologist Li!Jia,n E. Arnolrl. 111.S.. Assistant Botanist BOARD OF CONTROL R. P. Terry, Chairman, Miami Thomas W. Bryant, Lakeland W. M. Palmer, Ocala H. P. Adair, Jacksonville Chas. P. Helfenstein, Live Oak J. T. Diamond, Secretary; Tallahassee BRANCH STATIONS NORTH FLORIDA STATION, QUINCY J. D. Warner, M.S., Agronomist Acting in Charge R. R. Kincaid, Ph.D., Asso. Plant Pathologist JesRe Peeves, F'arm Superintendent V. E. Whitehurst, Jr., B.S.A., Asst. An. Hush. CITRUS STATION, LAKE ALFRED A. F. Camp, Ph.D., Horticulturist in Charge John H. Jefferies. Superintendent Michael Peech, Ph.D., Soils Chemist B; R. Fudge, Ph.D., Associate Chemist W. L. Thompson, B.S., Asso. Entomologist W. W. Lawless, B.S., Asst. Horticulturist R. K. Voorhees, M.S., Asst. Plant Path. EVE.RGLADES STATION, BELLE GLADE J. R. Neller, Ph.D., Biochemist in Charge J. W. Wilson, Sc.D., Entomologist F. D. Stevens, B.S., Su.sarcane Agronomist Thomas Bregger, Ph.D., ,Sugarcane Physiologist Frederick Boyd, Ph.D., Asst. Agronomist G. R. Townsend, Ph.D., Plant Pathologist R. W. Kidder, M.S., Asst, An. Husbandman W. T. Forsee, Ph.D., Asso. Chemist 'B. S. Clayton, B.S.C.E., Drainage Engineer• SUB-TROPICAL STATION, HOMESTEAD W. M. Fifield, M.S., Horticulturist Acting in Charge S. J. Lynch, B.S.A., .i\sst. Horticulturist Geo. D. Ruehle, Ph.D., Asso. Plant Pathologist W. CENTRAL FLA. STA., BROOKSVILLE W. F. Ward, M.S., Asst. An. Husbandman in Charge 2 FIELD STATIONS Leesburg M. N. Walker, Ph.D., Pant Pathologist in Charge K. W. Loucks, M.S., Asst. Plant Pathologist 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 Samuel 0. Hill, B.S., Asst. Entomologist• Bradenton Jos. R. Beckenbach, Ph.D., Truck Horticul turist in Charge David G. Kelbert, Asst. Plant Pathologist Sanford R. W. Ruprecht, Ph.D., Chemist in Charge, Celery Investigations W. B. Shippy, Ph.D., Asso. Plant Pathologist Lakeland E. S. Ellison, Meteorologist• B. H. Moore, A.B., Asst. Meteorologist• t Head of Department. 2 In cooperation with U.S.D.A. 3 Cooperative. other divisions, U. of F. 'On leave-.

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YIELD AND COMPOSITION OF EVERGLADES GRASS CROPS IN RELATION TO FERTILIZER TREATMENT By J. R. NELLER and A. DAANE 1 CONTENTS Page The Sawgrass Peat Area ................................... : ..... ..................... 4 Necessary Water Control .......................................................................... 6 Climatic Factors and Growth of Grass .......... : ..................................... 6 Early Experiments with Grasses ......................... .................................. 7 Mineral Composition of Grasses .............................................................. 8 Influence of Fertilizers upon Yield and Phosphorus Content ........ 9 Protein, Fat and Fiber of Pasture Grasses ...... .................................. 13 Fertilizer Requirements for Dallis Grass Hay .................................... 13 Response to Nitrogen .................................................................................. 22 Muriate versus Sulfate of Potash ............................................................ 23 Greenhouse Experiments with Dallis Grass ......................................... 23 Yields of Carpet Grass on Fertilizer Plots .......................................... 27 Discuss.ion and Summary ................. . ................ 27 Literature Cited ......... . ........... 29 Early in its history the Everglades Experiment Station began to investigate the growing of grasses on the organic soils of the Everglades. In general, peat and muck lands are known to be favorable for grass crops, but conditions peculiar to the Everglades precluded the drawing of conclusions from results that have been obtained in other areas of organic soils as to the agricultural possibilities of grasses for either forage or pasture. The subtropical nature of the climate of the Everglades pointed to the advisability of utilizing grasses indigenous to the tropical and south temperate zones. It was known, however, that frosts may occur here from time to time during the winter months. The high humidity and the occurrence of frequent though brief rains during the summer months indicated that hay making would be limited largely to the possibilities of arti ficial drying. Experience has shown this to be true and experi ments have not yet been conducted to determine whether the artificial drying of hay is practical for the region. But experi mentation has progressed far enough to demonstrate that the utilization of grass crops by pasturing has much of promise. Certain of the grasses have an unusually high carrying capacity, especially during the summer months, and considerable grazing can be done throughout the entire year. This bulletin presents information that has been obtained in relation to fertilizer requirements, yields and nutritive composi1 Daane deceased; formerly Agronomist in Charge, Everglades Experi ment Station.

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4 Florida Agricultural . Experiment Station tion of grasses as fed to cattle in the form of hay and by pasture grazing. As mentioned above it remains to be determined whether the artificial drying of hay may be practical and one phase of that study is embodied herein ;-viz., the yield, quality, water control and fertilizer requirements of some of the grasses that have shown themselves to be adapted culturally to the region. Since the Everglades are composed of organic soils which have a low reserve of certain minerals it is essential to know whether the mineral content of the grasses can be amply main tained by a fertilizer pra.;:tice that is economical. Special atten tion is given to the use of phosphates for the reason that a marked response to phosphates develops early in the history of most crops grown on the sawgrass peat soil area where these experiments were conducted. Unless sufficient phosphate fer tilizer is used crops of poor feeding value might result because of too low a content of phosphorus. THE SAWGRASS PEAT AREA The Everglades of Florida comprise a region of about 3,000,000 acres of organic soils extending in a southeasterly direction from Lake Okeechobee, bordered on the east by marine deposits of sand and calcareous rock and on the west by an expanse known as the Big Cypress Swamp. The area adjacent to the lake is classified as custard apple muck, which is com prised of plastic layers originating from sedimentation and from aquatic plants alternating with deposits from the reed-like plant known as sawgrass, Cladium efJusum. This narrow zone of custard apple muck merges out into a region called sawgrass peat; formed almost entirely from the sawgrass plant. The inorganic or mineral content of sawgrass peat averages above 10 percent in cultivated areas and somewhat below 10 percent in unplowed soils still covered with a growth of saw grass. The peat is eight feet or more in depth at points . nearest to Lake Okeechobee and gradually becomes thinner at greater distances from the lake. The entire region is underlaid with marl rock, a factor of great importance as the soil waters con ta ; n calcium and magnesium in solution (4) 2 sufficient to keep the soil in a condition favorable for plant growth without the necessity of Urning. In areas under water control the pH of ~ Italic figurts in parentheses . refer to "Literature Cited" in the back of this bulietin.

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Yield and Composition of Everglades Grass Crops 5 the surface soil ranges from 5.5 to 6.0 and increases to about 7.0 at lower depths. NECESSARY WATER CONTROL The Everglades comprise an extremely flat expanse with an elevation adjacent to Lake Okeechobee of about 17 feet above mean sea level and a very slight slope east of southward. The water level on the cultivated area is controlled almost entirely with low lift pumps. Water is conducted to and from the pumps by means of a system of field ditches that lead to the larger drainage ditches and canals. Water movement is facilitated ' by mole drains 30 to 36 inches below the surface soil from 12 to 18 feet apart leading from the field ditches across the fields. These mole drains are quickly and cheaply established by means of a tractor and moling machine and have become an important part of the water control system on all of the better class farms. A considerable part of the farmed area is in one of the several drainage districts whose pumps supply part of the necessary water control. The remainder comes from privately owned pumping units. Power for pumping is supplied to a slight extent by electric motors but mostly by engines of the Diesel or semi-Diesel type. The question of sufficient water control for the protection of crops is one of great importance. Fqr certain crops, espe cially some of the vegetabl~s, it is . essential that too high a water level should be reduced with the minimum of delay. Grass and sugarcane crops are not so sensitive to temporary periods of high water levels. And while the rainfall is not extreme it comes oftentimes in brief heavy downpours that far exceed the removal rate of a practical pumping system. The problem, there fore, is to establish a system with a pumping capacity that is high , enough to offer sufficient protection, but not too expensive to construct and maintain. At the Experiment Station there is a maximum removal capacity of three acre inches per 24 hours. This appears to be about the proper capacity and it has been adopted for several of the successful farms of the region. This brief summary of water control should not be closed without mentioning that a system of mole lines, ditches and canals should serve not only in the removal of excess water, but also in the conducting of water into the fields during those periods when there is insufficient rain to keep the water level high enough in the soil to provide for good growing conditions.

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6 Florida Agricultural Experiment Station Practically every year during the dry season, which extends normally from November to May, considerable water has flowed back into the fields on the Station farm from the Hillsborough Canal and on a few occasions it has been necessary to pump it into the field ditches in order to maintain a water level 18 to 22 inches below the soil surface. CLIMATIC FACTORS AND GROWTH OF GRASS Except for brief periods of frost, grass and hay crops con tinue to grow throughout the entire year in the Everglades. Table 1, which records the average monthly temperature, rain fall and evaporation from an open pan at the Everglades Experi ment Station for the years 1924-1937, inclusive, shows that the heaviest rainfall occurs during June, July, August and Septem ber and the least during November, December and January. These wet and dry seasons roughly parallel changes in length of day and of temperature and the resultant of these climatic TABLE 1.-AVERAGE MONTHLY RAINFALL, MEAN MAXIMUM AND MINIMUM TEMPERATURES, AND EVAPORATION FROM AN OPEN PAN FOR 1924-37 AT THE EVERGLADES EXPERIMENT STATION. ----------------------I ~~:fl o,:J-':.1''F::};:; F. i Ev!~~~!!'" January ... :.]Month February March ..... . April ....... . May ................ . June July .... August .... September October ........... . November ....... . December Totals 1.75 1.75 3.43 3.67 4.63 10.23 6.98 8.62 9.36 4.56 2.80 1.12 58.90 76.0 76.9 78.1 82.2 85.7 88;1 90.6 91.0 88.6 84.5 77.8 75.6 52.6 52.0 52.5 57.3 62.6 66.9 69.2 70.2 70.3 66.1 58.0 53.2 3.67 4.Q.l .. 5.73 6.54 7.26 6.14 6.70 6.30 5.44 5.12 3.92 3.40 64.26

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Yield and Composition of F,verglades Grass Crops 7 relations is effective in causing the grasses to grow most pro fusely during spring and early summer, followed by slower vege tative growth and seed forming tendencies in the late summer and fall. These characteristics are shown especially by Dallis grass (Paspalum dilatatum) and to a lesser extent by the carib (Eriochloa subglabra), carpet ( Axonopus compressus) arid cen tipede (Eremochloa ophiuroides) grasses discussed below. It is probable that length of day and temperature have more effect upon growth than rainfall in a . perennial crop such as a grass for the reason that when the water level is maintained in the soil irrespective _ of rainfall, as discussed above under water control, a well established root system is supplied with sufficient water from below. EARLY EXPERIMENTS WITH GRASSES In the fall of 1929 about two and one-half acres of the Sta.:. tion farm were seeded to a mixture of Dallis; Bahia and carpet grasses. This land was first plowed in 1924 and served for a time as a Para grass pasture until the grass was killed during the winter of 1925 due to a combination of frost and too close grazing. The land was planted to Dallis, Bahia and lespedeza in the early fall of 1928. This stand was killed because of the prolonged pe:riod of high water that resulted from the overflow of Lake Okeechobee following a hurricane. Flooding of that nature is no longer likely for the Everglades because of the construction by the Federal Government of a substantial dike around the southern end of the lake. Previous to the planting of this area in the fall of 1929 it was given a dressing of copper sulfate at the rate of 50 pounds per acre to conform with the requirement that Allison, et al (1) had found to be necessary for sawgrass peat lands. The Dallis and carpet grass seed started well, but Bahia appeared to only a slight extent due to poor germination. The Bahia grass has persisted, however, but the carpet grass was soon smothered out. This area has been used continuously as a pasture and still furnishes good grazing on a firm sod. This initial success in the establishment of a pasture resulted in the securing of a herd of purebred Devon cattle for tl;1e Station in the fall of 1931. To provide additional pasturage for these animals five one-acre areas were planted to carpet, centipede and Dallis on each of three of these acre lots, and of a mixture of Dallis and carpet and of Dallis and centipede . on

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8 Florida Agricultural E x periment Statiott the fourth and fifth acres, . respectively. Thes~ pa~t4r:es are still in . use, but the carpet and centipede grasses have been largely smothered out by sedge and by Bermuda grass. The centipede grass also has largely disappeared from the area where it was planted with Dallis grass. Dallis grass only . was obtained where it was sown with carpet grass. MINERAL COMPOSITION OF GRASSES Before the virgin soil of these five acres was planted to these grasses in the fall of 1931 a fertilizer dressing was disked in; it consisted of 40 pounds of copper sulfate and 150 pounds of sulfate of potash per acre. During the spring and summer of 1934 samples of grass were hand plucked monthly from the carpet, Dallis and centipede acres for the purpose of determin ing the mineral composition of the grasses as grazed by the cattle. This study was prompted by indications of bone weak ness in some of the lactating cows and their calves that were maintained on these and other pastures on the Station farm. Table 2 records the percentages of phosphorus (P20~) that these grasses contained during the months of April, May, June and July. Results are also included from Dallis and carib grass pastures planted in December, 1932. These last two pastures received a fertilizer dressing before planting of 50 pounds of copper sulfate and 200 pounds of muriate of potash per acre. TABLE 2.:-PHOSPHORUS CONTENT OF GRASSES PLUCKED FROM FIVE PASTURES IN 1934. Date Plucked May 2 June 8 July 26 •Average I Dalli s Grass 0.90 0.98 0.81 0.90 Percentages of P,O, on Oven-dry Basis Dallis 1 Grass 0.63 0.92 0.89 0.81 Carib 1 Grass . 0.87 1.25 0.91 I Centipede / Carpet Grass Grass 0.84 0.73 0.59 1.16 -0.72 1.16 'Th se two pastures were planted in December, 1932, and the other three in Septem ber, 1931. In addition to phosphorus the grasses plucked on May 2 and July 26 were analyzed also for other elements (Table 3). It is to be expected that the calcium and magnesium contents of

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Yield and Composition of Everglades Grass Crops 9 grass in Everglades peat land should be normal to high at , all times because of the large amounts of these elements that are present in the soil waters (4) by virtue of the marl substratum that lies next to the organic soil layer. It is to be expected also that the available native phosphorus will soon become de ficient in sawgrass peat soil and this hypothesis is verified in the experiments recorded in the following section. TABLE 3.-MINERAL COMPOSITION OF PLUCKED PASTURE GRASSES. Ingredient Calcium (CaO) ---------Magnesium (MgO) -Phosphorus (P,0 , ) .... Iron (Fe,O,) --Silicon (SiO i ) -------Ash o --Calcium (CaO) ---------Magnesium (MgO) .. Phosphorus (P,0 , ) ---Iron (Fe,0,) Silicon (SiO,) . . ......... . Ash #O Given as Percentages of Oven-dry Grass Dallis' I Dallis I Carib' I Centipede I Carpet Grass Grass Grl!ss Grass Grass Plucked May 2, 1934 --------------'"-1.20 0.94 0.75 0.74 1.12 1.27 1.05 1.17 0.90 0.63 0.87 0.84 0.027 0.031 0.036 0.026 ,. 1.25 0.92 1.07 0.72 8.86 5.87 8 .9 3 6.20 Plucked July 26, 1934 -------------0.72 I 0.97 0.48 0.82 0.88 0.72 0.99 0.42 0.68 0.63 0.89 0.81 0.91 0.59 1.16 0.014 0.016 0.016 0.019 0.040 2.25 1.58 2.33 1.93 1.77 7.23 7.24 9.7:) 5.97 7 . 45 1 Tl:ese two pastures were plante :l in December, 1932, and the other three in Septem ber, 1931. INFLUENCE OF FERTILIZERS UPON YIELD AND PHOSPHORUS CONTENT On ~ugust 1, 1934, a series of fertilizer plots was laid out in a fenced area of a Dallis grass pasture that had been plartted in December, 1932, on virgin sawgrass peat. In preparation for that planting the land received a dressing of 50 pounds of copper sulfate and 200 pounds of muriate of potash per a~re.

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10 Florida Agricultural Exp er iment Station On the fertilizer plots triple phosphate (44% P 2 0 5 ) was used at the rate of 66 pounds per acre and muriate of potash (50% K20) at the rate of 120 pounds per . acre (Table 4). The sulfate forms of copper, zinc and manganese were used also in one of the treatments at the rates of 40, 12 and 40 pounds per acre, respectively. TABLE 4.-TOTAL DRY YIELDS IN POUNDS PER ACRE AND AVERAGE PROTEIN AND PHOSPHORUS CONTENT OF CLIPPINGS OF GRASS FROM AREAS l, 2 AND 2A OF . A DALLIS GRASS PASTURE, Yields I I . Phosphorus" I Total Nitrogen• RelaRelaI Rel,
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Yield and Composition of Everglades Grass Crops 11 The plots were in triplicate for each treatment, 1/400 acre tn size with three and one-half foot borders and the fertilizer for a gh r en plot was applied to the middle of its borders. Before o:u.ttings : ; were obtained the borders were removed with a small powerditower which cut a swath the exact width of the borders. Since the sickle of the mower is in front of the drive whe!:)ls (Fig. 2), the grass in the plots is not run down in the process of cutting out the borders. And where the growth of grass is continuous across plot and border there is less of a border effect than in plots separated from each other by cleanly cultivated strips. Fig. 2.-Harvestirig equipment in u s e on the Dallis g r a ss " forfility plots. The sickle of the power mower is 3 feet wide and the mower is used to ct out bord,ers of that width betw e en the plots. Table4 records the total yields per treatment for the eight cuttings of grass that were obtained from these plots of Area 1 from August 1, 1934, to September 6, 1935. The data of Table 4 are based on oven-dry weights which averaged 20 % of the gre!:ln weights. Th!:! phosphorus con.tent was considerably higher in the gra s s of the ,J irst cutting : fro111 the plots that re ceived phnsphate, but it decreased in succeeding cuttings , until in tl).e fi.fth it w~s no higher than in the grass from plots that received potash only. A reapplication of fertilizer after the fifth c1;1tting of May 23 caused the _ phosphorus content of the

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12 Florida Agricult ur al E x periment Stat i on next three cuttings to be distinctly higher than those that re ceived potash only. The average effect from the eight cuttings covering a period of 13 months was to increase the phosphorus content of grass from the phosphate treated plots by 22% (Table 4), with a corresponding increase in yield . of 26%. The inclusion of the sulfates of copper, manganese and zinc was without apparent effect. Potash alone more than doubled the yiel . d. On October 11, 1935, another area of the pasture was fenced off and fertilized as given above for Area 1, Table 4. On De c ember 24, 1934, this p as ture received a top-dressing of 50 pounds of triple superphosphate and 100 pound s of muriate of potash per acre. This was the second fertilizer treatment for the pasture, the first having been made when the grass was planted in 1932. Table 4 shows that for the eight clippings obtained from this second set of plots (Area 2) the effect of potash alone and of phosphate with potash was about the same on yields and phosphate content of grass as in Area 1. This demon s trated that th e pasture had not received enough phos phorus and potash , to render anywhere near its potential yield ing capacity and that the higher fertility level also increased th~ phosphorus content of the greatly increased yields. A year after it was fertilized Area 2 was given a second treatment on October 12, 1936. The seven clippings obtained during the ensuing year (Table 4, Area 2a) demonstrated in the check plots how completely grass fails on this sawgrass peat without additions of potash. It may be observed also that whereas the use of potash alone will maintain yields for a time the phosphorus content of the grass will de c rease sharply, as the average of 0.37 % P 2 0 5 was the lowest that was obtained in these experiments. This experimental method of studying the fertilizer require ment of a pasture by establishing fertilizer plots on new areas of a pasture from season to season is recognized as not being ideal for the reason that clipping the growth, even though fre quently enough to keep it in the grassy or vegetative stage, is not strictly comparable to the removal of the grass by grazing. Ritchey and Henley (6) found this to be true for centipede gra s s, which is a creeping, prostrate variety. In the more upright grasses such as Bahia and Bermuda, however, they found that the seasonal yields as obtained by clipping were in close agreement with the seasona . 1 gains in steers feeding in

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Yield and Composition of Everglades Grass Crops 13 the pasture. Dallis grass was used in the present experiments and it has a more upright type of growth than either Bahia or Bermuda. While the expedments recorded above demonstrate the need for the use of both phosphate and potash early in the manage ment of Everglades pastures, they do not determine the best ratio of these two p!ant food elements. The marked responses in yield (Table 4) indicate that larger amounts of fertilizer might be used with economy. Some indications as to ratios and fertiEty levels may be obtained from the Dallis grass hay experi ments recorded herein. PROTEIN, FAT AND FIBER OF PASTURE GRASSES Samples of Dallis, carib, carpet and centipede grasses that were plucked from the various pastures during the summer of 1934 and discussed above as to mineral content (Tables 2 and 3) were analyzed for protein, fat and fiber (Table 5). It may be noted that the protein contents are high, especially of the Dallis grass, even though no nitrogen fertilizer was used. This is to be expected for grasses grown on an organic soil whose reaction and temperature is favorable for the nitrification of the nitro genous material represented by a soil nitrogen content of 3 to 3.5%. Proteins were also determined in the cuttings of Dallis grass c:ipped from Areas 1 and 2 (Table 4). It may be observed that fertilizer treatments that affected yield and phosphate con tent to a marked degree have no significant effect upon protein content. There is apparently no explanation other than that of change of location and season for the somewhat lower amount of protein in the eight clippings from Area 1 than from Area 2 for the two years following. In general the plucked grasses (Table 5) contained about the same percentage of protein as those that were clipped (Table 4). The crude fat and fiber contents of the plucked pasture grasses are about normal for grasses, with little difference between varieties. FERTILIZER REQUIREMENTS FOR DALLIS GRASS HAY These experiments are based upon a series of plots 1/ 400 acre in size and in triplicate for which different fertilizer mixtures were made up and used on the basis of formulas ranging from 6-6-12 3 to 0-12-24 at 500 pounds per acre. The source materials 3 All formulas refer to nitrogen (N), phosphate (P,0,) and potash (K,O) in the order g:ven.

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14 /?lorida Agricultural Experiment Station were ammonium sulfate, sulfate of potash and superphosphate containing 44% P 205. Copper sulfate at th'e rate of 80 pounds per acre was applied to all the plots when fertilizers were added in 1931 and at one-half that rate once a year thereafter. f TABLE 5.-PROTEIN, FAT, FIBER AND NITROGEN-FREE EXTRACT IN DALLIS, CARIB, CENTIPEDE AND CARPET GRASSES PLUCKED FROM THE P A.STURES . IN 1934. Date Plucked Given as Percentages of Oven-dry W ei_ghts Protein I Fai T -Ii'Tber I N. F. Ext.1 -Ash •~ -------~ ---~---~-~ ~ ---~ May 25 June 8 July _ 26 __ .. : . ::. :.. _ -_ --! Ma Jun July Aug y e 25 8 26 1 M;ar 25 -------------1 Jne 8 --------------1 ~uly 26 : -------------1 '. May 25 Junes July 26 June 8 __ _ , _________ __J 17.25 15.88 14.25 14.13 19.19 16.37 13.96 11.19 14.69 11.25 13.81 10.56 12,63 15.81 Dallis Grass Pasture . 3 .12 28.50 2.60 30.89 3.20 33.22 Dallis Grass Pas:ure 1 2.63 29.88 2.63 26.97 2.59 30.68 2.02 31.58 Carib Grass Pasture' l.93 27.73 1.6 . 9 2.6.04 2.45 29.10 Centipede Grass Pasture 2.75 29.31 2.36 . 33.14 3. _ 69 28.45 Carpet _ Grass Pasture 2.62 I 26.94 42.27 43.02 42.10 47.49 43.34 43.12 43.92 50.22 45.79 47.41 47.93 48.21 48.56 8.86 7.61 7.23 5.87 7.87 7.24 8.42 8.93 11.79 9.79 6.20 5.73 5.97 . . 'These samples were plucked from pastures planted in 1932. The other _ three . pastures ' were planted in 1931. . . -' During the period 1931-1937, inclusive, 33 cuttings of grass w.er.e removed and each cutting was taken when the grass was fo ihe l~te : bl6 .ofn or hay stage. ' Moisture ' d~tenninatfon& from

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Yield and Composition of Everglades Grass Crops 15 Fig. 3.-Growth of Dallis grass just before the cutting of June 29, 1934, on the fertility Plots for which the average annual yields are given in Table 6. Treatment 14 was an 0-12-24 mixture at 600, pounds per acre; Treatment 7 was an 0-6-12 mlxture; Treatment 6 consisted .. of potash and Treatment 6 of phosphate equal to ,the amounts used in Treatment 7, Copper sulfate, 40 pounrls per 'acre, was added with all the other treatments, including the checJi: plot, 13. In the first treatment 80 pounds of coPPer sulfiite ,were used.

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TABLE 6.-EFFECT OF PHOSPHATE AND POTASH UPON YIELDS OF DALLIS GRASS HAY FROM FERTILITY PLOTS. I I Pounds Hay Per Acre Per Treatment on Oven-dry Basis I I 12. Phos1 14. Double Fertilizer No. of Year I 5. Phos6. Potash 7. PhosI 11. Potash phate and phosphate Applied Cuttings I 1. Check 1 phate only phate and l and double double and double : :;;. I only potash I phosphate potash ! _ potash --------1931 -------------__ _\ 18,701 18,564 20,660 20,908 I 18,629 20,300 17,778 Feb. 18 6 1932 i 6,320 6,008 9,306 10,226 9,854 12,266 11,957 May 25 5 ---------------/ I 1933 -----------------------5,573 5,207 9,233 10,993 9;090 11,468 12,304 July 14 4 1934 ..... . . ------------------3,085 4,451 6,467 11,880 13,401 13,617 16,466 May 22 5 1935 ... .. ------------.. 1 2,367 4,662 5,635 10,301 12,017 13,367 17,868 June 10 5 1936 I 2,153 4,059 4,072 9,563 10,273 11 ,933 14,814 June 16 5 ------------------r 1937 -----------------,-/ 1,253 3,592 5,199 5,545 5,140 9,966 10,725 None 3 I Totals --------------------... _ _ _\ 39,452 46,543 60,572 79,416 78,404 92,917 101,912 33 Average per year --------! 5,633 6,649 8,653 .11,345 11,201 13,274 14,559 Yield relative to I I potash only treatment I 65 77 100 131 129 153 168 I 'Copper sulfate at 80 pounds per acre was applied to all treatments including the check plots with first fertilizer application and at 40 pounds per ac r e with each subsequent application. . Phospha;e and patash were used on u basis of an 0-6-12 formula at 500 pounds per acre except where the amounts were C:OubleJ.

PAGE 17

Yield and Composition of Ever.glades Grass Crops 17 various cuttings showed that the dry matter content of the fresh cut hay was always close to 25 % . Table 6 shows that the average annual yields of hay from these plots varied from 5,633 pounds per acre on the oven-dry basis where no fertilizer was applied (Treatment 1) to 14,559 pounds per acre where an 0-12-24 mixture was used at the rate of 500 pounds per acre (Treatment 14). The photographs of Fig. 3 are of the cutting of June 29, 1934, and illustrate an average type of re sponse to the various fertilizers. Growth differences were still greater at the time of the May 17 cutting, which was just before a reapplication of fertilizer (Table 6). It may be observed that in addition to the usual high response to potash the use of phosphate increased yields to a marked degree over those obtained when potash only was used. Doubling the amount of phosphate resulted in no increase in yields (Fig. 4 and Table 6), whereas doubling the amount of potash caused a considerable increase, showing that potash was the limiting factor. The still greater increase in yields obtained when both phosphate and potash were doubled indicates that phosphate became the limiting factor with an 0-6-24 formula (Treatment 12) and that the fertilizer for Treatment 14 though fairly well balanced was probably not sufficient in quantity for maximum yields. Table 6 further shows that the omission of fertilizer in 1937 resulted in a marked falling off in yields, which illustrates how quickly the reserves of available plant food can be depleted in this soil of high organic content. The average annual yield of eight tons of hay on a 10% moisture basis from Treatment 14, in which an 0-12-24 fertilizer at 500 pounds per acre per year was used, indicates that the fertilizer elements were well utilized. This series included plots where treatments were identical with those in Table 6 except that fertilizer applications were omitted in 1932, 1933, 1935 and 1936. The resulting yields are given in Table 7 and are compared with those of Table 6 in Figure 4. This comparison of average annual yields for the seven-year period shows that the omission of phosphate or potash from plots where these were used singly did nof have much effect, whereas the omission of fertilizer containing both phosphate and potash caused a marked reduction in yields. From a comparison of the annual yields of comparable treat ments such. as No. 14 of Table 6 and No. 10 of Table 7, as illustrated in Fig. 5, it may be seen that the fertilizer tr~at ment of May 22l 1934, caused the 1935 yield for Treatment 10

PAGE 18

TABLE 7.-EFFECT OF OMISSIONS OF FERTILIZER UPON YIELD OF DALLIS GRASS AS COMPARED WITH YIELDS WHERE FERTILIZER WAS NOT OMITTED (TABLE 6). p oun d H s ay P A er ere er rea ment P T t on 0 vend ry B as1s 13. Potash I 9. Phos10. Double Fertilizer No. of Year 2. Phos4. Phos8. Potash \phate and phos'phate Applied Cuttings 1. Check' phate I only phate and and double double and double only I potash phosphate I potash potash I I 1931 18,701 20,835 20,137 _ 19,510 20,744 I 21,920 20,295 Feb. 18 6 ---------------------------I I 1932 ----------------------6,320 5,924 5,931 5,615 5,156 I 5,734 6,521 None 5 1933 -------------5,573 5,823 5,405 5,601 5,292 6,464 7,150 None 4 1934 •--------------------------3,087 2,864 7,168 8,770 10,700 9,167 9,867 May 22 5 r 1935 I 2,367 2,618 6,751 10,667 12,318 13,450 16,467 None 5 -----........... , 1936 ------.... . . . -2,153 2,432 3,603 4,113 3,245 3,081 3,273 None 5 1937 ....... -----________ _,, .......... ) 1,253 I 799 I 2,433 2,392 3,252 3,559 3,552 None 3 I I I I Totals .. 39,454 41,295 51,428 56,668 65,707 63,375 67,125 33 Average per year ........ 5,635 5,899 7,347 8,095 9,387 9,053 9,589 Yields relative to i Treatment 3 77 80 I 100 110 128 123 131 I j 'Copper sulfate at 80 :pounds per acre was applied to all treatments, including the check plots, with first fertilizer application and at 40 pounds per acre with each subsequent application. Phosphate and potash were used on a basis of an 0-6-12 formula at 500 pounds per acre except whel'.e the amounts were doubled. .... 00

PAGE 19

Yield and Composition of Everglades Grass Crops 19 to be about equal to that of Treatment 14 in which annual applications of fertilizer had not been omitted. The sharp rise and drop in yields of Treatment 10 (Fig. 5) illustrate again that although these organic soils have a low reserve of phos phate and potash they are apparently able to retain and make available to crops a large part of the amounts that are supplied to them. lbs. per acre oven dry basis 15,000 10,000 5,000 Treatments D Fertilized only in 1931 m d 1934 Fertilized each year except 1937 -1 2 5 3 6 4 7 8 11 9 12 10 14 Fig. 4.-Average annual yields of Dallis grass hay for the seven-year period 1931-37 (Table 6), Treatment 1, check; 5, phosphate; 6, potash; 7, phosphate and potash; 11, phosphate and double potash; 14, double phosphate and double potash; all applications are based on an 0-6-12 mixture at 500 pounds per acre per year. Treatments 2, 3, 4, 8, 9 and 10 are of the same nature as Treatments 5, 6, 7, 11, 12 and 14 except that applications were omitted in 1932, 1U83, 1935 and 1986, Inasmuch as phosphorus is the nutritive element that is most likely to be deficient in hay grown on Everglades peat land, phosphorus analyses were made. of 12 of the 33 cuttings of Dallis grass hay for which the yields are recorded in Table 6. Table 8 shows that hay from the plots receiving potash only contained the least phosphorus while the highest was in hay from the treatment that received a double application of phos phate (Treatment 11) or an 0-12-12 mixture. The treatment represented by the 0-6-12 formula at 500 pounds per acre pro duced hay having an intermediate content of phosphoru$ almost identical with that of hay from Treatment 14, which received an 0-12-24 mixture at 500 pounds per acre.

PAGE 20

20 lbs , per acre oven dry basts 20,000 1 5 , 000 10, 00 0 5,000 Florida Agricult u ral E x periment Station T r e atme n t 10 CJ Treatment 14 .... .... .... --r .... 1931 1 93 2 193 . 3 1934 1935 1 9 36 1937 Fi g . 5 . -Compari s on Of annu a l y i elds of Dallis g rass a s ave r aged from plots in triplicate where an 0-12-24 mixture was use,I ea, h ye a r except 1937 for Treatment 14 (Table 6/ and in 1931 1
PAGE 21

TABLE 8.----,-PHOSPHORUS CONTENT OF CUTTINGS OF DALLIS GRASS HAY WITH YIELDS RECORDED IN TABLE 6. Given as Percentage P,O , of Oven-dry Matter for Each Treatment . I 12. Phos14. Double Date of Cutting 5. Phos ' phate 6. Potash I 7. Phosphate 11. Potash phate and Phosphate 1. Check Only Only and Potash and Doub~e Double and Double Phosphate Potash Potash Fertilized February 11, 1931 July 24, 1931 ........ 0.64 I 0.65 0.59 0.66 0.71 0 . 67 0.66 October 14 ... . .. .. .. . . 0.66 0.68 0.71 0.70 0.67 0.74 0.70 May 23, 1932 ........ 0.52 I 0.36 0.36 0.42 0.43 0.34 0.45 Fertilized May 25, 1932 June 29 ----------_ 1 0.35 0.36 0.63 0.78 0.61 0.67 Septemb3r 14 . .. . .. 0.55 0.86 0.42 0.68 0.71 0 . 52 0.65 May 18, 1934 ...... 0.41 _ 1 0.23 0.27 0.39 0.25 0.28 Fertilized May 22, 1934 June 29 .. .. . . . . ..... , .. ! 0.37 0.77 0.21 0.39 0.50 0.37 0.51 Fertilized June 10, 1935 July 9, 1935 I 0.32 0.72 0.29 0.52 0.67 0.46 0.61 June 4, 1936 . . ...... 0.40 0.56 0.30 0.41 0.45 0.26 0.31 Fertilized June 16, 1936 I I Ju!y 13 ......... .. ...... , 0.33 0.75 0.23 I 0.75 0.80 ) 0.66 0.75 September 1 ... . .... 0.35 0.61 0.27 0.56 0.77 0.59 0.62 May 13, 1937 . . . . .•.. 0.37 0.55 0.25 0.46 0.67 0.35 0.44 0.45 0.62 0.35 0.54 0.63 0.49 0.52 1 Samp!es were not obtainei.

PAGE 22

22 Florida Agricultural Experiment Station RESPONSE TO NITROGEN Yields from Treatment 16, Table 9, which received ammonium sulfate as supplied in a 6-6-12 formula at 500 pounds per acre produced no more grass during the seven years of the experi-" ' ment than Treatment 17 in which the ammonium sulfate w:il,s ;, omitted. This study of the possible effect of a nitrogenous :fertilizer on grass crops in sawgrass peat may be con~Jdered incomplete, however, for the reason that a treatment including nitrogen was not used where a heavier fertilizer application caused heavier yields and the withdrawal of greater quantities of nitrogen from the soil as in Treatment 14, Table 6. Data and discussion relating to the nitrogen removed from Treat ment 14 may be found in a previous publication (5). TABLE 9.-EFFECT OF USE OJ,' NITROGEN AND OF THE MURIATE INSTEAD OF THE SULFATE OF POTASH UPON YIELDS OF DALLIS GRASS. -( Pounds Per Acre Per Treatment on Oven-dry Basis ___ Year 16. Nitro17. Phos25. PhosNo. of Fertilized gen, Phosphate phate and Cuttings phate and and Muriate Potash 1 Potash of Potash ----1931 19,562 19,906 19,497 6 Feb. 18 1932 9,527 8,801 9,242 5 May 25 except phosphorus 1933 8,599 8,786 9,591 4 July 14 except phosphorus 1934 ..... ...... 5,901 6,702 6,517 5 May 22 1935 8,420 9,594 '8,822 5 June 10 1936 4,239 4,817 5,253 5 June 16 except phosphorus 1937 5,084 5,605 4,958 3 None -----'l'otals I 61,332 64,211 63,880 33 Av. per year ...... 8,762 9,173 9,126 Yields relative to Treatment 17 96 100 99 1 T),e sulfates of potash were used in Treatments 16 11,,d 17 and applicatioils were 'on the basis of a 6 0 6-12 formula. at 500 pounds p.er ~ere.

PAGE 23

Yield and Composition of Everglades Grass Crops 23 , MURIATE VERSUS SULFATE OF POTASH Treatment 25 (Table 9) received its potash in the form of muriate with the result that yields were no higher than from Treatment 17 where the sulfate of potash was used. Potash . in the form of muriate might be less satisfactory than the sulfate form in treatments involving greater quantities. Thus in the rather large amounts employed in the greenhouse trials discussed below the mixtures containing muriate caused more depression of growth than those containing sulfate of potash. It may be considered quite safe, however, to use muriate in field treatments on grass crops. GREENHOUSE EXPERIMENTS WITH DALLIS GRASS Dallis grass was used as one of the index crops in a series of treatments on sawgrass peat soil in glazed six-gallon jars in the greenhouse. This series of 20 treatments in triplicate was designed primarily to study the effect of varying ratios of phosphorus and potassium in the fertilizer mixture. Chemically pure sources of the elements were used except that the phos phorus of Treatments 13 and 14 (Table 10) was derived from superphosphate of 44 % P 2 05 grade. Commercial flowers of sulfur was used in Treatments 16 , 17 and 20. Rates of applica tion were based upon a 10-10-20 formula at 1,000 pounds per acre. Sulfur was used at the rate of 1,000 pounds per acre in Treatments 16, 17 and 20, while in Treatments 13 and 14 where wood ashes were made the source of potassium, enough extra sulfur was added to take up the alkalinity of the wood ashes on the basis of all of the sulfur changing to sulfate. Sulfur oxidation was active as evidenced by the reduction to pH 5.66 in Treatment 16 from a pH of 6.71 in Treatient 15. The primary purpose of using Dallis grass in this series of treatments was to ascertain the effect of varying amounts of phosphate upon the phosphorus content of the grass : and to correlate these data with those of similar nature in the pasture and hay lands discussed previously. The cuttings were made in the late bloom stage and typical growth responses are illus trated in Fig 6. Table 10 shows that hay from Treatment 3, which received rio phosphate, and fro:ni Treatment 10, to which a minimum amount of phosphate was added, both contained 0.49 % of phosphorus (P 2 0 6 ). With ipcreasing amounts of phos phate in the soil treatment the phosphorus content of the hay

PAGE 24

TABLE 10.-YIELD AND PHOSPHORUS CONTENT OF DALLIS GRASS GROWN IN GREENHOUSE WITH VARIOUS SOIL TREATMENTS TOGETHER WITH THE REACTION OF THE SOIL (SAWGRASS PEAT). No. Treatment 1 Check . .. . . . ............ . ..... . ......... . , . ........... . 2 2P ....... . ........ .... ...... . . . ... . ......... .. .. ......... . 3 4K ........................... . ........... . .. . ........ . 4 2PK . .. .. .. .. ............ . . . .................... . ... .... . 5 2P2K . . .. : . ............ . . .. . . .... . .......... . . . . ...... .. . 6 2P4K ............ .. ........ . 7 2P8K .................. .. .. .. . ............... . ........ . 8 . 2P4K (muriate) .... , ........... . .. . . ...... ,: .. 9 2P8K (muriate) . . ..................... , ....... . 10 . P4K _ .. ... . ..... .... ... . ..... . ...... ... ........ . . ..... . . g . .. it!~ . ; .: . 13 4P (44% phosphate) ......... . . . ........... . 14 . 8P (44% phosphate) ......... . ... . . . . ...... . 15 .: 2P2K plus wood ashes ..... .. .............. . 16 . 2P.2K plus wood ashes plus sulfur 17 2P4K plus sulfur ............... . ...... , . ...... ! 1& llP4K plus nitrate .............. . . . .......... . ~i . 1 ~~!I El~: Ari:: iii~;~~:a~~ . I First Cutting May 21 \ I Yield Phosphate (P,O,) I gms. % I 26.5 31.7 31.5 141.9 111.2 . 92.1 69.1 -85.5 . 35.4 61.8 104.2 67.0 148.8 104.9 , 30.4 . 69.2 134.5 . 63 .8 . 85.8 128 t Q 0.64 1.20 0.49 0.61 0.61 0.76 0.70 0.61 0.73 0.49 1.00 1.06 0.94 1.08 0.57 0.79 0.86 0.65 0.63 0.78 2nd, 3rd, 4th Cuttings Jan. 18-Aug. 15 Total Soil I Yield Reaction Yield Phosphate (P,O,) I gms. % I gms. pH 59.6 0.67 86.1 5.42 45.0 1.03 76.7 5.35 128.8 0.43 160.3 5.14 127.5 0.62 239.4 5.34 143.6 0.56 254.8 5.34 158.7 0.56 250 .8 5.19 64.8 0.55 133.9 5.29 74;3 0.66 159.8 5.25 10.8 0.73 46.2 5.43 100.8 0.48 162 . 7 5.29 127.8 0.78 232.0 5.31 112 . 3 0.91 179.3 5.21 107.6 0.77 256.4 5.16 155.2 1.09 260.1 5.10 15.6 0.48 46.0 6.71 90 2 0.67 159.4 5.66 152.7 0.67 287.2 4.75 141.2 0.64 205.0 5.33 128.4 I 0.58 214.2 . 187.2 0.66 315.2 . . 5.24 4.26 ;d C "" R, .:. ;:t:.. CC! "" C) ;.:: .,.... .,..,_ ..... t?-j <-< --: "" ;:s .,..,_ ti) .,..,_ _ .,..,_ .... C ;:s

PAGE 25

Yield and Composition of Everglades Grass Crops 25 was increased to 1.06 % (Treatment 12). Medium amounts of phosphate (Treatments 4-7) produced hay containing an average of 0.62% P205, which is higher than the average of 0.52% P20 5 of the corresponding field Treatment 14 of Table 8, but lower than the average of 0.85 % P20 5 (Table 2) for Dallis grass plucked from the pastures. These field and greenhouse results indicate that the phosphate-potash ratio of one part of P20u to two of K20 is about as high as the phosphorus content of fer tilizer needs to be raised from the standpoint of yield and quality of Everg-:ades grass crops. Fig. 6.-Representative growth of Dallis grass in triplicate greenhouse treatments of the cutting of May 21, 1934 (Table 10). A-Treatment 1 is 2P4K (phosphorus and potash) : 2 is 2PK: 3 is 4K; 4 is 2P; and 5 ia a check. B-No. 1 is 2P2K with wool ashes as the source of.'potash; 2 is 2P2K wi'h wood ashes plus sulfur; 3 is 2P4K plus sul:ur; 4 is 2P4K plus sodium nitrate; 6 is 2P4K plus ferrous sulfate; and 6 is 2P4K plus ferrous sulfate plus sulfur.

PAGE 26

TABLE 11.-AVERAGE ANNUAL YIELDS OF CARPET GRASS FROM FERTILIZER PLOTS. -----I _ 1 Pounds Per Acre Per Treatment on Oven-dry Basis I No. of Year I I I I Phosphate \ Phosphate ' I Fertilized Cuttings I Check' Phosphate I Potash and Potash and Potash ____ ,, __ •-------1931 1,804 1,963 2,114 1,770 1,973 Feb. 11 3 1932 . .. . .•... ..•. 11,167 11,301 12,753 18,854 18,145 May 25 5 193 3 8,529 6,833 11,663 16,118 14,776 July 14 4 1934 . 2,439 2,352 3,508 7,758 7,118 May 22 7 1935 1,522 1,638 2,917 5,419 4 ,8 68 June 10 4 1936 ------------1,060 1,500 2,059 5,945 5,100 June 16 5 1937 1,746 1,750 3,845 5,913 5,579 None 4 Totals -----l 28,267 27,337 38,859 61,768 57,559 32 Average per year _ _ I 4,038 3,905 5,551 8,824 8,223 ----! I Yields relative to i those from potash only 73 70 100 159 148 I --'-All treatments received copper sulfate at the rate of 80 p o unds per acre when first fertilized and at the rate of 40 pounds per acre thereafter . Phosphate and potash were used on t!,e basis of an 0-6-12 formula. •Basic s lag was used as the source . of phosphorus. r-:i . 0) "!tj ~ C ;j _ ;i:... ... .... . ..... <:-+... ~ t?:j 'ti ... ~;:s ~ t,_, <:-+. <:-+.... C

PAGE 27

Yield and Composition of Everglades Grass Crops 27 The Dallis grass greenhouse series (Table 10) corroborate those in the field to show that either the muriate or the sul fate form of potash may be used. The highest yields were obtained from Treatments 17 and 20, where the soil reactions were, as a result of sulfofication, reduced to pH values of 4.75 and 4.26, respectively. There was no response to either an iron or a nitrogenous fertilizer. YIELDS OF CARPET GRASS ON FERTILIZER PLOTS Although carpet grass is generally considered to be of too prostrate a type to be cut for hay, it is of interest to note that the average annual yield of 8,824 pounds of grass on the dried basis (Table 11) as cut with an ordinary sickle type mower (Fig. 2) compares favorably with the annual average yield of 11,345 pounds of Dallis grass hay (Table 6) from plots that received the same amount of phosphate and potash as repre sented by an 0-6-12 formula, at 500 pounds per acre per year. A similar marked response to both phosphate and potash is shown in Table 11 for carpet grass as in Table 6 for Dallis grass. It may be inferred that the growth of carpet grass was not limited by any minor element deficiency, as yields were not increased where basic slag was substituted for 44% super phosphate as the source of phosphorus. Although phosphate analyses were not made of these cuttings of carpet grass it may be assumed that, since carpet grass tends to remain in a more leafy or vegetative state than Dallis, the percent of phosphorus in carpet grass hay would, with the same fertilizer treatment, be fully as high as or higher than is re corded for Dallis grass (Table 8). Carpet grass plucked from a pasture contained 1.16% of phosphorus as P205 (Table 3), which was considerably higher than the phosphorus content . of Dallis, carib and centipede plucked on the same date from adjacent, similarly fertilized pastures. DISCUSSION AND SUMMARY After the successful establishment of a pasture in 1929 on the sawgrass peat of the Station Farm, a series of experiments was started to determine the influence of fertilizers upon the yield and composition of grass crops. Climate, soils and necessary water control are discussed in relation to the growing of grass crops in the Everglades.

PAGE 28

28 Florida Ag r icultural Experiment Station Since the organic soils of the Everglades are low in reserves of phosphorus, special attention was g~ven to that element, since adequate supplies of it are es . sential in growth of bone in grazing animals. In a series of samples of Dallis grass plucked from pastures in 1934 the content of phosphorus was found to be 0.63 percent P2O5 on the dry basis. The phosphorus content of material plucked from pastures of carib and carpet grasses is somewhat higher , while that of centipede grass is slightly lower. In a study of Florida ranges, Becker et al (1 2 ) havE) report e d that cattle g razing on grasses that averaged 0.19 per cent P 2 O 0 showed decided symptoms of phosphorus deficiency while tho s e on ranges whose gras s es contained , an average of 0.31 percent were normal. The fertility experiments reported herein for Everglades saw grass peat soil show that sufficient. phosphate to insure good grass yields also insures a phosphorus content above that found in the g ras s of Florida ranges wh e re healthy cattle are raised. Analyses of the plucked grasses from Everglades pasture s indicated that ample amounts of calcium, magnesium and iron are present; The sub-surface waters of these organic soils are well supplied with calcium and magnesium from the under lying marl, and grass crops grown on these soils are well supplied with these elements. A field plot study of a Dallis gras s pasture showed that phos phate and potash equivalent to the amounts contained in an 0-6-12 formula at 500 pounds per acre should be applied at least once a year to keep the pasture at a moderately high point in it s potential productivity as shown by yield records of cut tings from these plots. The carrying capacity of the pasture was very high as may be expected because of its location in a subtropical . environment. Thirty-three cuttings of Dallis grass hay were cut from a s eries of fertility plots during a period of seven years (1931-37 inclusive) . These gave an average annual yield on the dry basis of 5,633 pounds per acre where no fertilizer was applied ahd 14,559 pounds where phosphate and potash were used in amount s equivalent to an 0-12-24 mixture applied at the rate of 500 pounds per acre per year. With an 0-6-24 mixture the yield was reduced to 13,274 pounds per acre and the phosphorus content of the hay was lower. With an 0-12 .. 12 . mixture -' the yielg was reduced to 11,201 pounds per acre and practically the

PAGE 29

Yield and Composition of Everglades Grass Crops 29 same yield was obtained with either an 0-6-12 or a 3-6-12 mixture. Analyses of cuttings of Dallis grass grown in greenhouse jars corroborated those of field plots in showing that a phosphate (P 2 0 5 ) potash (K 2 0) ratio of one to two is about as high as the phosphorus content of a fertilizer needs to be raised, from the standpoint of yield and of phosphorus content of the grass. In a parallel series of plots using the same fertilizer mixture at the same rate per acre but omitted in 1932, 1933, 1935 and 1936 the average yield was reduced by about one-third. In both series yields were almost identical for 1935 fol'.owing similar applications of fertilizer to both in 1934, while the 1936 yields on the unfertilized plots dropped to less than half of those from the fertilized plots. This shows how completely the fertilizer was utilized in these sawgrass peat soils. The average annual yields of Dallis grass hay from plots that received their potash in the form of muriate were prac tically the same as from plots where the sulfate of potash was used. In the greenhouse Dallis grass did not respond to soil treat ments of iron and nitrogen. In field fertilizer trials during the seven-year period 19311937, the average annual yield of carpet grass was 8,824 pounds per acre, on the dry basis, where phosphate and potash were used in amounts equivalent to an 0-6-12 formula at 500 pounds per acre. There was a marked response to phosphate as well as to potash. ACKNOWLEDGMENTS The authors wish to acknowledge the counsel and advice of Dr. R. V. Allison in connection with some of the earlier experiments. R. W. Kidder took the ' photograph for the frontispiece and was in charge of the cattle that grazed the pastures discussed in these experiments. Painstaking assistance has been rendered by John Newhouse in obtaining field records, by L. S. Jones and P. M. McIntyre with the laboratory work and by Edward King, Jr., in the taking of weather . records. LITERATURE CITED 1. ALLISON, R. V., 0. C. BRYAN and J. H. HUNTER. The stimulation of plant response on the raw peat soils of the Florida Everglades through . the use of copper sulfate and other chemicals. Fla. Agr. Exp. Sta. Bui. 190. 1927.

PAGE 30

30 Florida Agricultural Experiment Station 2. ,BECKER, R. B., W. M. NEAL and A. L. SHEALY. Stiffs or sweeny (phosphorus deficiency) in cattle. Fla. Agr. Exp. Sta. Bul. 264. 1933 . . 3, BLAIR, A. W., and A. L. PRINCE. The influence of phosphates on the phosphoric acid content of the plant. Jour. Agr. Research, 44: 579590. 1932. 4. NELLER, J. R. Effe~t of rainfall and of substrata upon composition and reaction of soil waters of Everglades peat land. Vol4me B, ' Transactions of 6th Comm. of International Society of Soil Science, Zurich 388-393. 1937. Abstract in Volume A, 31-32. 5. NELLER, J. R. The availability to crops of the nitrogen of Everglades peat. Transactions of the Third International Congress .. of Soil Science. 1: 421-423. 1935. 6. RITCHEY, GEO. E., a.nd W. W. HENLEY, Pasture value o:f different grasses alone and in mixture. Fla. Agr. Exp. Sta. Bul. 289. 1936.