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111 HUME LIBRARY
Everglades Station Mimeo Report 71-2 JAN 73
SOIL SAMPLING AND FERTILIZER RECOMMENDATIONS SORSUGARCANE
GROWN FOR SUGAR IN SOUTH FLORI .A.S. Univ. of Florida
G. J. Gascho and C. E. Freemanr/
Experiments on sugarcane nutrition at the Everglades Experiment Station date
back to 1928.. Work of this nature has progressed intermittently during the past
50 years. During the period 1943 to 1948 Dr. W. T. Forsee, Jr. developed soil
testing methods which correlate well with crop response on the organic soils of
the Everglades. A continued effort is being made to improve recommendations made
from soil test results. Presently, field experiments are being conducted in several
areas in order to improve our recommendations. A major effort is being made to
consider the various soils and growing conditions as well as yield goals in this
research so that fertilizer recommendations may soon take these two factors into
consideration. A study to determine if there are different nutritional needs for
the various varieties is also in progress.
This Mimeo Report is a supplement to Everglades Station Mimeo Report 65-18
where all crops are.considered and the specific methods used in the laboratory
are given in detail.
II. SAMPLING THE SOIL
Soil test information can never be better than the soil sampling procedure.
Experiments at the Everglades Station and at other stations have shown that sample
taking is nearly always the weakest point in soil testing procedures. This is
particular true for stubble cane soil sampling.
A. Preplanting Samples.
It is recommended that soil sampling take place at least 3 to 4 weeks before
planting. This timetable allows adequate opportunity for drying, screening,
analyses, and return of the recommendations before fertilizers must be ordered.
a soil probe.
should be dug
from the side
may be taken with a round point shovel, or more satisfactorily with
When using a shovel, a small hole which has a nearly vertical side
to a depth of 10 to 12 inches then a narrow slice should be obtained
and about a 1-inch ribbon cut out from the middle of this slice for
An X-pattern should be made on the field. Starting in one corner and
proceeding to the farthest corner, 10 soil samples should be collected to a depth
of 10 to 12 inches, however areas within 200 feet of a lime rock road or a ditch
spoil bank should not be sampled. These areas will be affected by lime incorporation
thus making the pH higher and the phosphorus lower than the bulk of the field.
l/Assistant Professor (Assistant Plant Nutritionist) Everglades Experiment
Station and (Assistant in Agronomy), Cooperative Extension Service, University
Another 10 cores should be collected while walking between the other two corners,
so as to have a minimum of 20 cores per 40-acre block. These cores should be
composite in a clean pail and mixed thoroughly before a pint subsample is
transferred to a clean container of approximately 1-pint volume which is labeled
for grower and field identifications.
B. Stubble Field Samples
Best results will be obtained when samples are collected at least 18 inches
away from row centers to a depth of 10 to 12 inches. Samples taken closer to the
row will be more variable due to the uncertainty of hitting the band of fertilizer
placed at planting. All other details and precautions are the same as those
mentioned under A. Preplanting Samples.
III. SUBMITTING SOIL SAMPLE TO LABORATORY
Bring or mail soil samples to the Everglades Experiment Station located on
Palm Beach Road (State Road No. 80), 2.5 miles east of Belle Glade. When samples
are delivered to the Station, they should be left at the soil testing laboratory
(building no. 54) which is located immediately south of the main office building.
A'laboratory technician is available there to help check in samples. The following
information will be required: Grower's name and mailing address, the name of person
who took samples, the name of the person who delivered or sent samples, location of
fields (include Range, Township, and section if possible or distance from a well
known location), past years' cropping and fertilization history (as much as is
available being sure to note whether recommendation is desired for plant cane or
stubble cane), the analyses desired, and any comments on specific problems which
appear to be nutritional in nature. If samples are to be mailed, forms for giving
this specific information can be obtained from the Experiment Station or your
County Agricultural Agent.
IV. INTERPRETATIONS OF ANALYSES AND THE MAKING OF THE FERTILIZER RECOMMENDATIONS
Results of the soil analysis together with the other information provided by
the grower are the basis on which fertilizer recommendations are made. Tables
provided below are followed fairly closely, however, information provided by grower,
as well as knowledge of special conditions by personnel at the Experiment Station
will be used to make adjustments from Table values in certain instances.
A. Phosphorus, Potassium, and Nitrogen
Amounts of fertilizers recommended at planting and for the first
application on stubble cane are based on the potassium soil test.
Whether or not phosphorus is included in the fertilizer mix depends on
the phosphorus soil test (see Tables 1 and 2). A phosphorus soil test
of 5 pounds per acre and a potassium test of 150 pounds per acre
are considered ideal for sugarcane production on organic soil.
As a rule of thumb, 20 pounds of P205 is required to raise the phosphorus
soil test value 1 pound while 2 pounds of K 20 is required to raise
the potassium soil test 1 pound. If a grower's soil sample for an area
to be planted in sugarcane contained 85 pounds per acre of K and 4 pounds
per acre of P, from Table 1 we would recommend 300 pounds per acre of
0-6-45. This would supply 18 pounds per acre P205 and should increase
soil phosphorus about 1 pound (from 4 to 5). This amount of fertilizer
will also supply 3 x 45 = 135 pounds of K20 which should raise the
potassium soil test 68 pounds (from 85 to 153). Application of more
than 50 lb. of P205 in a season may severely reduce sucrose content.
For sandy soils, 3 to 4 sidedressings with 10-0'-20 are-recommended
(see Table 3). These applications are needed because of the low exchange
capacity (lack of electrical charges) which make nitrogen and potassium
more vulnerable to losses from the soil. It is recommended that the
first fertilization occur about March 15th and subsequent sidedressings
be spaced from 4 to 6 weeks apart. Any application of nitrogen after
August 1st will likely result in a reduction in sucrose content in
Micronutrients (ie. minor elements or trace elements) are roanmmoana
recommended for plant cane on organic soils and for both plant and
stubble cane on sandy soils (Tables 1 and 2). Manganese availability
decreases with increased soil pH, therefore, it is recommended when the
soil pH is greater than 5.65 and not recommended for a pH of 5.65 or
less. When planting cane on newly cleared land, apply broadcast, disc
in, and plow under 300 pounds per acre of 0-0-30 containing 6.0% CuO
and 3.0% ZnO in addition to the normal recommendation for plant cane
grown on "old land".
Due to the high buffering capacity of organic soil, pH alteration
of the whole soil is difficult and costly. Sulfur applied in the
furrow can change the pH of the soil in the fertilizer band thereby
keeping manganese and other micronutrients available. Five hundred
pounds per acre are recommended for furrow application when the soil pH
is 6.5 or greater. When both fertilizer and sulfur are recommended,
the grower should contact his fertilizer dealer to see if a mix of
the two materials can be made, thus allowing fertilization and sulfur
application in one field operation. In event that a mix is obtained,
the rate should be adjusted accordingly so the recommended amounts
D. Comparing Soil Test Results
Caution should be taken in the comparison of soil tests results
from different laboratories as the methods may very likely be different.
For example the Everglades Experiment Station phosphorus test will
usually be considerably lower than those values from other labs where
stronger reagents are used. However, at this laboratory it has been
found that water extractable phosphorus is the soil fraction which best
correlates with plant response on these organic soils.
Table 1: Fertilizer recommendations for pla t and stubble
sugarcane on muck and sandy muck / soils as
affected by soil test results.
Ib/acre soil test
0-6-45 0-0-50 0-0-20
% rmic-routa ient2/
CuO Mn3/ ZnO B203
(plant cane 0-4
above 150) above 4
(stubble cane 0-4
above 150) above 4
No Fertilizer Recommended.
l/Sandy areas may require some sidedressed
and/or early summer.
N during late spring
'/Micronutrients are not recommended for stubble cane
3-No Mn recommended when soil pH is less than 5.7
Table 2: Fertilizer recommendations for plant sugarcane and
first applicationY/ on stubble cane on sand and mucky
sand soils as affected by soil test results.
sand/ mucky sand Imicronutrients
lb/acre Ib/acre Ib-/are Ib/acre
soil test K soil test P 10-6-30 10-0-30 6-6-30 6-0-30 CuO MnOS/ZnO B203
1/First sidedressing on stubble
sugarcane should be about March 15th
--/On sand soils add 2.0% MgO
3-No Mn recommended when soil pH is less than 5.7
Table 3: Sidedress fertilizer recommendations for plant
and stubble sugarcane on sand and mucky sand soils.
I/A fourth application of 200 Ib. of 10-0-20
may be required before August in event of
excessive rain; apply no fertilizers
after August 1.
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