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 Front Cover
 Title Page
 Table of Contents
 Introduction
 Experimental procedure
 Results and discussion
 Summary and conclusions
 Literature cited
 Historic note






Group Title: Bulletin - University of Florida Agricultural Experiment Station ; 811
Title: Fertilization of Roselawn St. Augustinegrass pasture on organic soil
CITATION THUMBNAILS PAGE IMAGE ZOOMABLE
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00027421/00001
 Material Information
Title: Fertilization of Roselawn St. Augustinegrass pasture on organic soil
Series Title: Bulletin University of Florida. Agricultural Experiment Station
Physical Description: 13 p. : ; 23 cm.
Language: English
Creator: Pate, F. M ( Findlay Moye ), 1941-
Allen, R. J
Crockett, J. R ( Joe Richard ), 1926-
Publisher: Agricultural Experiment Stations, Institute of Food and Agricultural Sciences, University of Florida
Place of Publication: Gainesville Fla
Publication Date: 1980
 Subjects
Subject: Pastures -- Fertilizers -- Florida   ( lcsh )
Pastures -- Soils -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Bibliography: Bibliography: p. 13.
Statement of Responsibility: F.M. Pate, R.J. Allen, Jr., and J.R. Crockett.
General Note: Cover title.
 Record Information
Bibliographic ID: UF00027421
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: aleph - 000929896
oclc - 18462607
notis - AEP0707

Table of Contents
    Front Cover
        Front Cover
    Title Page
        Title Page
    Table of Contents
        Table of Contents
    Introduction
        Page 1
    Experimental procedure
        Page 2
        Page 3
    Results and discussion
        Page 4
        Page 5
        Page 6
        Page 7
        Page 8
        Page 9
        Page 10
        Page 11
    Summary and conclusions
        Page 12
    Literature cited
        Page 13
    Historic note
        Page 14
Full Text

RUARY 1980 BULLETIN 811



Fertilization of Roselawn
St.Augustinegrass Pasture
on Organic Soil
F. M. PATE, R. J. ALLEN, Jr., AND J. R. CROCKETT


AAR 211980
1.F.A.S. Univ. of Florida











FERTILIZATION OF ROSELAWN
ST. AUGUSTINEGRASS PASTURE
ON ORGANIC SOIL

F. M. PATE, R. J. ALLEN, JR., AND J. R. CROCKETT


This public document was promulgated at an annual cost of
$1050 or a cost of 420 per copy to provide information on the ef-
fects of various rates of fertilization on quality and growth of
Roselawn St. Augustinegrass pasture on organic soil.


AUTHORS

Dr. Pate is an Associate Professor (Associate Animal Nutritionist), Dr.
Allen is an Assistant Professor (Assistant Agronomist), and Dr. Crockett is
an Associate Professor (Associate Geneticist), Agricultural Research and
Education Center, Belle Glade, Florida 33430.












CONTENTS

Introduction ........................ ............. ..... ........ 1
Experimental Procedure ................... .................. 2
Animal Management Program .............................. 2
Forage Collection and Analysis .................... ............ 3
Soil Analysis ...................... ...................... 4
Statistical Analysis ......................................... 4
Results and Discussion ........................................... 4
Forage Quality ................ ...... ........................ 4
Forage Growth and Intake .................. ............... 8
Animal Performance ....................... ............... 10
Soil Analysis .................... ........................ 11
Summary and Conclusions ....................................... 12
Literature Cited ................... .. .................... 13






METRIC CONVERSION FACTORS

1 pound = 0.454 kilograms 1 inch = 2.54 centimeters
1 ton = 0.907 metric tons 1 foot = 0.30 meters
1 acre = 0.405 hectares

Temperature conversion: 140F = 60C







ACKNOWLEDGMENTS
Appreciation is expressed to J.V. McLeod, W.H. Elliott, Jr., and H.M. Lynn
for the many hours of difficult labor they put into this study to harvest and
analyze forage samples.










INTRODUCTION
Studies to establish the fertilization requirements of organic soil
pastures in south Florida were conducted by Neller and Daane (11)1
in the 1930's. These early studies were limited to Dallis grass (Paspa-
lum dilatatum Poir), a forage plant no longer used in Florida. Results
showed that forages did not respond to N fertilization and that a 1:2
P2,O:KO ratio was the best formulation. Five years of small-plot
harvest data showed that dry matter (DM) yield increased from 1.94
tons/A in unfertilized plots to 5.30 tons/A with 30 lb/A of P20O and 60
lb/A of K20, applied once annually. Dry matter yield was further
increased by 38%, to 7.34 tons, with applications of 60 lb/A of P205
and 120 lb/A of K20.
Neller and Daane (11) also reported on a field study conducted with
harvested plots in a fenced-off area of Dallis grass pasture. Data from
three years compared an unfertilized plot with one receiving 30 lb/A
P205 and 60 lb/A K20. The authors concluded that an annual applica-
tion of 500 lb/A of 0-6-12 was necessary to obtain optimum growth of
well-grazed grass growing in Everglades peat (10, 11). However, they
appeared to ignore the plot experiment which showed that 39% more
DM yield was obtained when P205 and K20 applications were dou-
bled over the rates of 30 and 60 lb/A.
Subsequent recommendations on fertilization of pasture on organ-
ic soil have adhered to an annual application of 30 and 60 lb/A ofP205
and K20, respectively (1, 5). The only deviation was with regard to
virgin land and vegetable land converted to pasture.
A disadvantage of experimental plots for determining pasture fer-
tilizer requirements is that harvested forage is removed, thus remov-
ing nutrients normally recycled in a grazing situation. A harvested
forage containing 0.2% P and 1% K and yielding 10 tons of DM per
acre removes 46 lb of P205 equivalent and 120 lb of K20 equivalent
per acre annually. A cow-calf production system stocked at one cow
per acre removes 12 lb of P205 and 2 lb of K20 equivalent per calf.
Also, 10 lb of P205 equivalent are added to the pasture system bymin-
eral supplementation, and 25 to 30 lb of K20 equivalent are added to
the pasture system by molasses supplementation.
The objective of this study was to measure the effect of gradient
rates of fertilizer applied to Roselawn St. Augustinegrass pasture on
organic soil. Forage growth and quality, and animal performance un-
der a cow-calf production system were measured.

1 Numbers in parentheses refer to literature cited.








EXPERIMENTAL PROCEDURE
This five-year study was conducted on two adjacent 16-acre Rose-
lawn St. Augustinegrass (Stenotaphrum secumdatum (Walt.) Kuntz)
pastures established in 1950. Pastures were fertilized annually as
determined by soil analysis until 1968; then they received 400
pounds per acre annually of 0-10-20 plus trace elements for the three
years preceding the start of this study.
The soil was a Terra Ceia Muck (euic, hyperthermic, Typic Medisa-
pris). This soil type, commonly called sawgrass peat, represents 90%
of the organic soil in the Everglades agricultural area.
Each 16-acre pasture was divided with cross-fencing into four
4-acre quadrants in August 1972. Each quadrant within a pasture
was randomly assigned to one of four fertilization treatments. Fertil-
ization treatments were 200, 400, 600, and 800 pounds of 0-10-20 fer-
tilizer per acre. Fertilizer mixtures were formulated to supply 4
pounds CuO, 4 pounds MnO, 3 pounds ZnO, and 3 pounds B203 per
acre in all treatments. Fertilizer was applied once annually in late
October or November.

Animal Management Program
Forty producing cows and eight two-year-old heifers were random-
ly assigned to the study in September 1972 so that each 4-acre pas-
ture quadrant contained five brood cows and one heifer. Cattle were
Angus x Hereford crosses. The six assigned females were grazed con-
tinuously on each quadrant throughout the five-year study. Cows
were culled for non-conception or unsoundness, and culled cows were
immediately replaced with an unbred two-year-old heifer.
Cows were bred with eight purebred Angus bulls for 65 days begin-
ning on February 15. Four bulls were systematically rotated every 5
days within each replicated pasture group to reduce possible genetic
differences.
From November 15 to February 15, cows were supplemented daily
with 5 pounds per head of millrun blackstrap molasses. Mineral
supplement (EES#2) was available free-choice throughout the year
(4).
Calves were weighed at birth and at weaning during the last two
weeks in September. At weaning, calves were assigned a feeder grade
by two graders. Cows were weighed in September when calves were
weaned and again in February, one to five days prior to the start of
the breeding season.
The stocking rate used (1.5 cows/A) exceeded that normally fol-
lowed (1 cow/A) with St. Augustinegrass pasture on organic soil. The
high stocking rate was used to insure that all experimental pastures








were overstocked and that possible treatment differences would be
expressed in animal performance.

Forage Collection And Analysis
Two 8 x 12-foot wire cages were placed in each 4-acre quadrant to
protect a pasture area from grazing. Once every 28 days, starting on
November 21, 1972, forage was harvested from two 32 x 98-inch
areas (1/2000 acre) inside each cage (ungrazed) and two areas of
pasture immediately outside each cage (grazed). The harvested area
was cut approximately two inches above ground level with a flail-
type plot forage harvester (2). The total harvested sample was
weighed immediately in the field, and a 0.44-lb. subsample was
obtained for determining moisture and for subsequent analysis.
After sampling, cages were moved approximately 100 feet to a
grazed pasture area to allow growth for sampling 28 days later.
Cages were moved so that the two cages were always on opposite sides
of each treatment block, and each cage was moved in such a way that
it was rotated around the pasture quadrant once annually.
Forage samples were dried at 140F for 48 hours in a forced-air
oven. Samples were weighed immediately upon removal from the
oven, and this 1400F DM determination was used to calculate the
quantity of DM harvested in the field. Samples were ground with a
Wiley Mill through a 0.004-inch stainless-steel screen. Subsequent
analyses included crude protein, ash, acid detergent fiber, phospho-
rus, copper and molybdenum (3, 6). These analyses were expressed on
a 100% DM basis using a 212"F DM determination. In vitro organic-
matter digestion values were determined with a modified two-stage
Tilley-Terry procedure (8).
Pastures were mowed periodically during the summer growth pe-
riod to prevent green forage build-up because of undergrazing. To de-
termine the quantity of forage mowed, two 32 x 98 inch areas of
mowed and unmowed pasture in each quadrant were cut with the for-
age harvester. Harvested forage was subsampled for 140'F DM deter-
minations.
Twenty-eight-day forage DM growth and intake (disappearance)
data were calculated using harvested forage weights and 1400F DM
values. Forage growth was determined by subtracting the forage DM
harvested from the grazed area on a sampling date from the forage
DM harvested for the ungrazed (caged) area on the subsequent sam-
pling date. Forage intake was determined by subtracting the forage
DM harvested in the grazed area from the forage DM harvested in the
ungrazed area on the same sampling date. Total annual DM growth
and intake values were determined by adding the values of the 13 re-







spective sampling dates. Dry matter growth also included the mowed
forage.

Soil Analysis
Five soil samples (6 cores per sample) were obtained from each
treatment block in late winter (January-February) and again in late
summer (August-September) of each year. Samples were analyzed for
water-soluble phosphorus and 0.5 N acetic-acid-soluble potassium
(13).

Statistical Analysis
Data were analyzed by analysis of variance of a split-plot design in
time and space (12). Individual degrees of freedom were used to
determine the nature of the response curves as related to fertilization
levels.

RESULTS AND DISCUSSION
Forage Quality
Average analytical values of samples from grazed and ungrazed
(caged) areas by fertilization treatments are presented in Table 1.
With the exception of phosphorus and ash content of ungrazed sam-
ples, fertilization treatment means were not different (P < 0.05), nor
were any trends present to suggest that fertilization influenced for-
age quality. With increasing fertilization levels there was a signifi-
cant (P < 0.01) linear increase in forage phosphorus content. How-
ever, differences did not seem large enough to be of practical impor-
tance from the standpoint of animal nutrition (9).
Average analytical values of forage samples by harvest dates (Ta-
ble 2) showed that forage quality generally followed a summer-
winter cycle, with higher values for crude protein, phosphorus, and
digestibility during the wet-warm months. Crude protein always ex-
ceeded recommended requirements, but phosphorus content during
the winter-spring months was below the 0.22% level recommended
for cows nursing calves (9). Mineral supplementation is recom-
mended year-round (4), but it would be very critical during the
winter-spring period.
Samples from ungrazed (caged) areas were generally superior in
quality to those from grazed areas. They contained more protein and
less fiber, and were more digestible. The poorer quality of samples
from grazed pasture was due to a higher percentage of unpalatable
material (dried grass residue) obtained with the machine-harvested
samples. This difference was very pronounced during the winter-
spring months when there was less green forage available. For exam-








ple, IVOMD for ungrazed samples was 9 to 16 percentage-points
greater than that for samples from grazed pasture areas during the
February-June period.
The analyses of ungrazed forage would possibly be more represen-
tative of forage eaten by cattle, but these analyses probably underes-
timated the true quality of forage consumed by the animal. Animal
digestion trials showed that St. Augustinegrass machine-harvested
from ungrazed plots varied from a 54% total digestible nutrient
(TDN) content in November-December to 65% TDN in April-July
(Ag. Res. Educ. Center, Unpublished Data).


Table 1. Analyses of grazed and ungrazed St. Augustinegrass from organic
soil pastures receiving different rates of 0-10-20 fertilizer; annual
averages of samples taken every 28 days.


Itema
Dry matter, %
Grazed
Ungrazed
Crude protein, %
Grazed
Ungrazed
ADFC, %
Grazed
Ungrazed
IVOMDe, %
Grazed
Ungrazed
Ash, %
Grazed
Ungrazed
Phosphorus, %
Grazed
Ungrazed
Copper, ppm
Grazed
Ungrazed
Molybdenum, ppm
Grazed
Ungrazed


Fertilization Rates Significance of
(lb 0-10-20/A) Treatment
200 400 600 800 Differenceb


37.3 37.8 35.6 35.0
29.4 28.7 28.7 28.0

13.0 12.5 12.6 12.8
14.4 13.9 14.3 14.5

36.7 36.9 36.6 36.3
34.0 34.7 34.1 34.2

47.2 46.5 48.0 48.0
53.6 53.0 54.6 54.6


6.7 7.2
7.8 8.1


0.21 0.24 0.25 0.26
0.22 0.25 0.26 0.27

17.2 17.8 16.9 21.9
16.8 18.5 16.4 16.5


1.6 1.3
1.7 1.6


aDry matter data presented as % of fresh cut sample, other data presented
as % of dry matter; grazed samples were from uncaged areas and ungrazed
samples were from caged areas.
bNS = Non-significant, = P < 0.05 and ** = P < 0.01.
CADF = Acid detergent fiber; IVOMD = in vitro organic matter digestibility.














Table 2. Analyses of grazed and ungrazed St. Augustinegrass from organic soil pastures during different periods of the year;
5 year average.ab


Sampling
Date
November 19
December 17
January 14
February 11
March 11
April 8
May 6
June 3
July 1
July 29
August 26
September 23
October 24
Average


Dry Matter, %
Ungrazed Grazed
26.5 30.3
31.3 37.7
33.4 41.8
43.8 54.4
36.0 60.0
29.8 51.0
28.2 46.5
21.6 29.3
20.6 24.2
22.1 23.6
21.7 23.4
22.5 23.0
25.8 28.4
27.0 34.4


Crude Protein, %
Ungrazed Grazed
13.4 12.1
14.1 12.0
14.2 11.2
14.0 12.0
14.2 11.5
15.7 11.8
15.8 12.8
16.5 14.3
14.5 13.9
13.4 14.0
13.9 13.2
13.3 13.2
13.3 12.5
13.7 12.3


ADF, %
Ungrazed Grazed
34.7 36.3
34.0 36.2
34.2 36.9
34.6 37.7
35.4 39.7
32.2 39.4
33.2 38.6
32.9 35.9
34.5 35.7
35.5 34.5
34.7 35.4
34.5 35.0
34.6 34.6
32.9 34.3


IVOMD, %
Ungrazed Grazed
52.2 46.7
50.8 45.0
49.6 43.0
51.6 42.9
49.3 41.1
57.4 40.9
57.1 41.2
60.9 51.5
57.4 56.8
55.4 55.0
54.5 53.2
52.3 50.0
53.0 49.6
53.9 49.9












Table 2. (continued).


Sampling Ash, %
Date Ungrazed Grazed
November 19 7.9 7.5
December 17 8.0 7.0
January 14 7.1 6.2
February 11 6.5 5.6
March 11 6.4 5.3
April 8 7.7 5.1
May 6 7.1 4.8
June 3 8.4 6.8
July 1 8.5 7.7
July 29 8.3 8.1
August 26 8.2 7.9
September 23 8.2 7.8
October 24 8.0 7.8
Average 7.5 6.5

'bSee respective footnotes, Table 1.


Phosphorus, %
Ungrazed Grazed
0.23 0.22
0.25 0.23
0.22 0.20
0.19 0.16
0.19 0.17
0.23 0.18
0.23 0.18
0.29 0.28
0.32 0.31
0.31 0.31
0.29 0.31
0.29 0.30
0.27 0.28
0.25 0.23


Copper, ppm Molybdenum, ppm
Ungrazed Grazed Ungrazed Grazed
29.0 39.9 1.2 1.1
31.4 34.0 1.7 1.1
42.4 38.4 1.1 1.1
26.7 26.8 1.8 1.7
20.0 19.7 1.9 1.9
15.3 13.4 1.5 1.5
14.0 13.5 1.5 1.5
13.4 15.0 1.4 1.3
9.3 11.9 1.7 1.2
7.0 7.2 2.0 1.8
7.2 6.7 1.7 1.6
6.3 7.9 2.1 1.8
7.9 7.6 1.8 1.6
18.9 20.1 1.6 1.4







Forage Growth and Intake
Annual forage DM growth and intake increased with increased fer-
tilization up to 600 lb/A of 0-10-20 (Table 3). There was not a further
increase in forage DM growth at 800 lb/A of 0-10-20, and forage DM
intake decreased back to that observed at the 400 lb level. The linear
component of the growth and intake curve and the quadratic compo-
nent of the intake curve were significant (P < 0.01).
Plot studies by Neller and Daane (11) showed a 38% increase in DM
yield when P20O and K20 rates were increased from 30 and 60 lb/A to
60 and 120 lb/A. In the present study, DM growth increased only 28%
when P20O and K20 application were tripled from 20 and 40 Ib/A.
This lower response could be explained by the recycling of fertilizer
elements under a grazing system.
Results showed that fertilization rates exceeding 600 lb/A of
0-10-20 were of no benefit with respect to forage growth and were a
disadvantage to forage intake. The reason for the reduced intake
with the higher level of fertilization is difficult to explain.
Forage growth was greatly influenced by season, with low growth
during the cool-dry months and excellent growth during the warm-
wet months (Table 4). This extreme influence of season on forage pro-
duction in south Florida is a major problem in beef production and
has been reported in previous publications (7).
Forage intake followed a pattern similar to that of forage growth
(Table 4). However, intake exceeded forage growth during the cool-
dry months when cattle consumed excess forage carried into the
winter months. During the warm-wet summer months, forage
growth greatly exceeded intake, and pastures were mowed to prevent
accumulation of low-quality forage.
Forage intake on a per-brood-cow basis is also presented in Table 4.
In comparison, the recommended daily DM requirements throughout
the annual management-system cycle are also presented (9). During


Table 3. Total annual forage dry matter growth and intake for different
fertilization treatments.

Fertilization Rates Significance of
(lb 0-10-20/A) Treatment
Item 200 400 600 800 Differencea
Dry matter
growth, ton/Ab 6.06 7.26 7.78 7.76
intake, ton/A 5.66 6.58 7.24 6.63 **
mowed, ton/A 0.49 0.77 0.51 0.97 **
aSignificance at P < 0.05 = *, and P < 0.01 = **
bGrowth data include mowed forage, although mowed data are also shown.








Table 4. Forage dry matter growth, intake and requirements over all treat-
ments by 28-day harvest period.

DM DM DM DM
Growth Intake Intake Required
Time Period lb/A/day lb/A/day lb/cow/day lb/cow/day"
Nov. 19 to Dec. 17 16.4 25.0 16.7(20.7)b 20.0
Dec. 17 to Jan. 14 1.4 16.4 11.0(15.0) 22.5
Jan. 14 to Feb. 11 9.3 18.6 12.3(16.3) 22.5
Feb. 11 to Mar. 11 7.1 20.7 13.8 22.5
Mar. 11 to Apr. 08 20.0 22.9 15.2 22.5
Apr. 08 to May 06 23.6 25.0 16.7 23.5
May 06 to June 03 64.3 47.9 31.9 24.5
June 03 to July 01 84.3 57.1 38.1 25.5
July 01 to July 29 79.3 54.3 36.2 26.5
July 29 to Aug. 26 70.0 56.4 37.6 27.5
Aug. 26 to Sept. 23 68.6 52.9 35.2 28.5
Sept. 23 to Oct. 21 42.9 41.4 27.6 16.5
Oct. 21 to Nov. 18 29.3 29.3 19.5 16.5
aFrom NRC, Nutrient requirements of beef cattle (9).
bFigures in parentheses include the 4 lb of molasses dry matter supplemented
during the winter months.


the warm-wet months from May through September, DM intake
greatly exceeded requirement. After weaning (average date Sep-
tember 25), DM intake dropped substantially, but continued to ex-
ceed the reduced requirement for nonlactating pregnant cows. After
calving in November and December (average date December 6), DM
intake was much lower than requirements for cows nursing calves.
Even with molasses fed at 5 lb/head daily from November 15, total
DM intake fell short of the recommended requirement. After Febru-
ary 15, DM intake was greatly below requirements, considering that
molasses feeding was discontinued.
The preceding data show the critical nutritional periods during the
production cycle. Dry matter intake was below recommended re-
quirements during December-January period, even with molasses
supplementation. Although DM growth was low, excess forage car-
ried into the winter months was available. There were 1600 and 1180
lb/A of DM available on December 17 and January 14, respectively.
Low DM intake during February-May period would be expected, be-
cause both forage growth and available forage were low. There were
540, 440 and 400 lb/A of DM available on March 11, April 8, and May
6, respectively, and much of this was unpalatable dried material.
These data point out the need for supplemental feeding from January
through April, including the breeding season, which is a critical
management period.







Animal Performance
There were no consistent trends in brood-cow performance related
to fertilization level (Table 5). The winter weight loss was lower than
expected in view of the low DM intake estimates presented in Table 4.
This suggests either that recommended energy requirements as ex-
pressed by DM intake were overestimated or that the harvesting pro-
cedure used underestimated DM intake. If anything, the procedure
used may have overestimated DM intake, because it failed to meas-
ure DM losses from trampling.
Calf weaning weight was influenced by fertilization treatments
(P < 0.01). Weaning weights consistently increased from 507 lb/calf
with 200 lb/A of 0-10-20 to 548 lb/calfwith 600 lb/A, then decreased to
512 lb/calf with 800 lb/A, showing a significant quadratic response
(P < 0.01). The correlation coefficient between weaning weight and
annual DM intake was r = 0.71 (n = 20, P < 0.01).
Calf feeder grades followed the same trend as weaning weights
with a significant quadratic response (P < 0.01). Calf birth weights
and survival were not related to fertilization level.
Weaned calf production per acre in this study was a product of
weaning percent and weaning weight. This value represents a unit of

Table 5. Animal performance data for different fertilizer treatments.

Fertilization Rates Significance of
(lb 0-10-20/A) Treatment
Item 200 400 600 800 Differencea
Brood Cow:
February weight, lb 1042 1024 1051 1044 NS
September weight, Ib 1067 1070 1077 1040 NS
Winter
weight change, lbb -14 -23 -10 7 NS
Summer
weight change, lbb 19 36 18 -2 NS
Weaning rate, %c 87.9 87.5 87.9 79.3 *
Calves:
Birth weight, lb 55.3 53.8 56.7 50.9 NS
Weaning weight, lb 507 525 548 512 **
Feeder grade 11.9 12.2 12.7 12.0 **
Weaned calf
weight/A, lb" 669 689 722 605 **

aNS = Non-significant, = P < 0.05, and ** = P < 0.01.
bWeight change between September and February equals winter weight change, and
weight change between February and September equals summer weight change.
CCalves weaned + cows exposed to bull x 100.
dFeeder grades 12, 13, and 14 equal low, medium, and high choice, respectively.
eWeaning rate (%) x stocking rate (1.5 cows/A) x weaning weight (lb).







measurement on which economic inferences can be drawn. Increas-
ing the fertilization level from 200 to 400 lbs of 0-10-20/A increased
calf weight by 20 lb/A. An additional 200 lb/A of 0-10-20 increased
calf weight by another 33 lb/A. It is not within the purpose of this re-
port to present a thorough economic analysis of pasture fertilization;
however, considering only fertilizer cost and calf production per acre,
the following is presented as a guideline: fertilization increments be-
tween 200 and 600 lbs/A of 0-10-20 produced approximately 12.5 lb/A
more weaned calf for each 100 lb/A of additional fertilizer. Using
these values, a $32/cwt selling price for weaned calves would offset
$80/ton fertilizer cost.

Soil Analyses
Significant differences between fertilization treatments were
found for both P20, and K20 levels in soil samples (P < 0.01). The
most pronounced difference was between 200 and 400 lb/A of 0-10-20,
with no consistent trend beyond 400 lb/A (Table 6).
Fertilizer recommendations at AREC Belle Glade have been
made on the assumption that grasses growing on organic soils con-
taining 6 lb of water-soluble P20, and 60 lb of 0.5 N acetic-acid-
soluble K20/A will not respond to additional fertilization with these
elements (5). It was also assumed that 20 lb of P20O and 2 lb of K20/A
would raise soil-test values by 1 lb/A.
Results of the present study do not conform to these guidelines,
particularly with respect to P2 0. Phosphate application in this study
was very high, yet P20, test values (Table 6) remained below the
standard 6 lb/A level, below which PO2 fertilization is recom-
mended. A further complication was that P20O values for one repli-


Table 6. Soil analyses of pastures fertilized with different rates of
0-10-20.
Fertilization Rates Significance of
(lb 0-10-20/A) Treatment
Item 200 400 600 800 Differencea
P205, lb/A
Spring 2.14 4.62 4.49 5.30
Fall 1.35 3.73 3.07 5.09
K20, lb/A
Spring 141 282 218 263
Fall 79 145 119 144

aSignificance at P < 0.01 = **
bSpring samples taken in January-February; fall samples taken in August-
September 6 to 10 weeks prior to fertilization.







cated pasture block were approximately twice those of the other
block. This difference was consistent over all years and fertilization
levels.
SUMMARY AND CONCLUSIONS
A five-year study was conducted to measure the effects of fertiliza-
tion level on quality and growth of Roselawn St. Augustinegrass pas-
ture on organic soil, cow-calf production, and soil analysis. Treat-
ments included 200, 400, 600, and 800 lb/A of 0-10-20 fertilizer ap-
plied annually. The following statements summarize the results and
conclusions.
1. Fertilization treatments in this study had no influence on for-
age quality. Forage phosphorus content was increased
(P < 0.01) with additional fertilizer, but the increase did not
seem of practical significance.
2. Increased fertilization increased annual forage dry matter
(DM) growth from 6.06 tons/A with 200 lb/A of 0-10-20 to 7.78
tons/A with 600 lb/A. No further increase was observed with
800 lb/A of 0-10-20.
3. Annual DM intake by grazing animals increased from 5.66
tons/A with 200 lb/A of 0-10-20 to 7.24 tons/A with 600 lb/A. Dry
matter intake decreased to 6.63 tons/A with 800 lb/A of 0-10-20.
4. Brood-cow weight changes and reproduction were not affected
by fertilization level.
5. Calf weaning weight increased linearly (P < 0.01) from 507 lb
with 200 lb of 0-10-20/A to 548 lb with 600 lb/A. Weaning
weight dropped to 512 lb with 800 lb 0-10-20/A. Weaning
weight was significantly correlated with forage intake
(r = 0.71). Feedergrade was significantly affected by fertiliza-
tion level (P < 0.01), following the same trend as weaning
weight. Birth weight and calf survival were unaffected by fer-
tilization level.
6. Soil analyses showed that P2, and K20 values were influenced
by fertilization level (P < 0.01). Differences were primarily be-
tween the 200 and 400 lb/A treatments. Phosphate and K20
values did not conform to guidelines currently used for making
fertilizer recommendations. These data and differences ob-
served between replicated blocks open to question the value of
soil analyses guidelines currently used for fertilizer recommen-
dations for St. Augustinegrass pasture on organic soil.
7. Production data indicate that for applications between 200 and
600 lb/A of 0-10-20, each additional 100 lb of fertilizer applied to
St. Augustinegrass pasture produces approximately 12.5 lb/A
more weaned calf weight. A $32/cwt selling price for weaned
calves would offset an $80/ton fertilizer cost.








LITERATURE CITED


1. Allen, R.J., Jr. 1967. Recommendations on fertilization and varieties of
pastures for organic soil. Everglades Expt. Sta. Mimeo Rpt. EES67-11.

2. Allen, R.J., Jr., T.W. Casselman, and FH. Thomas. 1968. An improved
forage harvester for experimental plots. Agron. J. 60:584-585.

3. A.O.A.C. 1970. Official Methods of Analysis (11th ed.). Association of
Official Agricultural Chemists, Washington, D.C.

4. Cunha, T.J., R.L. Shirley, H.L. Chapman, Jr., C.B. Ammerman, G.K.
Davis, W.G. Kirk, and J.E Hentges, Jr. 1964. Minerals for beef cattle in
Florida. Fla. Agri. Expt. Sta. Bull. 683. --

5. Forsee, W.T, Jr. 1952. Fertilizer requirements for pastures on peat and
muck soils. Proc. Cattleman's Field Day. Everglades Expt. Sta., Belle
Glade, June 25, 1952. P. 8-10

6 Goering, H.K., and P.J. Van Soest. 1970. Forage fiber analysis. USDA
Agriculture Handbook. No. 379

7. Haines, C.E., H.L. Chapman, Jr., R.J. Allen, Jr., and R.W. Kidder. 1965.
Roselawn St. Augustinegrass as a perennial pasture forage for organic
soils of south Florida. Fla. Agri. Expt. Sta. Bull. 689. ---

8. Moore, J.E., and G.O. Mott. 1974. Recovery of residual organic matter
from in vitro digestion of forages. J. Dairy Sci. 57:1258-1259.

9. National Research Council. 1970. Nutrient Requirements of Domestic
Animals, No. 4. Nutrient requirements of beef cattle. National Research
Council, Washington, D.C.

10. Neiler, J.R. 1944. Factors affecting composition of Everglades grasses
ana legumes with special reference to proteins and minerals. Fla. Agri.
Expt. Sta. Bull. 403.

11. Neller, J.R., and A. Daane. 1939. Yield and composition of Everglades
grass crops in relation to fertilizer treatment. Fla. Agri. Expt. Sta. Bull.
338.

12. Steel, R.G.D., and J.H. Torrie. 1960. Principles and Procedures of Statis-
tics. McGraw-Hill, New York.

13. Thomas, F.A. 1965. Sampling and methods used for analysis of soils in
the soil testing laboratory of the Everglades Experiment Station. Ever-
glades Expt. Sta. Mimeo Rpt. EES65-18.









HISTORIC NOTE


The publications in this collection do
not reflect current scientific knowledge
or recommendations. These texts
represent the historic publishing
record of the Institute for Food and
Agricultural Sciences and should be
used only to trace the historic work of
the Institute and its staff. Current IFAS
research may be found on the
Electronic Data Information Source
(EDIS)

site maintained by the Florida
Cooperative Extension Service.






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