Everglades Station Mimeo Report 62-9
FERTILIZER REQUIREMENTS FOR SUGARCANE GROWING ON MINERAL SOILS
IN SOUTH FLORIDA
Ferdinand le Grand and C. C. Hortenstinel/
Success of growing a satisfactory tonnage of sugarcane on mineral soils
will largely depend on water control. During the growing period a constant
water table of 2-3/4 to 3 feet should be maintained. Large fluctuations in
height of the water table will result in root damage with consequent reduction
of cane growth. A minimum capacity either for drainage or for irrigation of
one and one-half inches per 24 hours is required.
Sugarcane is a deep rooting plant with the main part of its root system
concentrated in the upper two feet of soil. Soil samples should be taken to a
depth of one foot. The number of sample cores to be taken will depend on the
size and uniformity of the fields. A minimum of 15 cores per sample is suggested.
The soil sample should represent a reliable average of soil and field conditions.
For more detailed information on collection and handling of soil samples, the
local County Agricultural Agent should be contacted.
Removal of a heavy crop depletes the soil of considerable amounts of plant
food. Harvesting 45 tons of millable sugarcane per acre will remove from the
soil about 150 pounds N, 40 pounds P and 200 pounds K, assuming that no trash
or tops are returned. Since sugarcane in Florida is burned prior to harvest,
part of the residue is returned to the soil. After harvesting, about 50 pounds
N, 9 pounds P and 17 pounds K are left behind in the underground cane parts and
are available for the next "stubble" crop.
Most mineral soils in the sugarcane producing areas of south Florida are
largely sand mixed with various amounts of either organic matter or marl. Since
these soils are very permeable, most nutrients will leach easily. The rate of
leaching depends on the amount of organic matter or of marl present; a higher
content of either organic matter or of marl will fix the nutrients to some extent
in the soil and prevent them from leaching. Such soils may be classified for
fertilizer recommendations as follows: sand containing 0 to 5 percent, 6 to 15
percent, 16 to 25 percent and 25 percent or more organic matter. The first three
categories of soil may need nitrogen applications in the amounts of 100, 60 and
30 pounds N per acre, respectively. No additional nitrogen is required for soils
having 25 or more percent organic matter. (See Everglades Station Mimeo Report
62-7 for suggestions on fertilizing sugarcane growing on organic soils.) Satis-
factory cane tonnages have been obtained on marl soils with an application of
100 pounds of nitrogen per acre. Higher nitrogen applications to these mineral
soils will not increase the yield. No preference for any one source of nitrogen
fertilizer has been found for growing sugarcane.
Total amounts of nitrogen required for maximum cane growth may vary some-
what depending on weather conditions, height of the water table and cane variety.
An excess of nitrogen may retard the ripening of the cane because it stimulates
1/ Assistant Sugarcane Agronomist and Assistant Soils Chemist, respectively,
University of Florida, Everglades Experiment Station, Belle Glade, Florida.
: C ^ O .' /
November 6, 1961
Analyses. of the leaves are sometimes used to give an indication of the
amount of nutrients taken up by the cane plant from the soil. Applications of
nitrogen to sandy soils that will maintain a nitrogen level of about 2.5 percent
in the dry leaves during the growth period from April through July will give
optimum yields, provided that the water supply is adequate and no deficiency
of other nutrients is limiting the cane growth.
Potassium requirements may vary considerably and the application rate of
this nutrient will depend on the amount of potassium present in the soil before
fertilizing. Sufficient potassium should be added to raise the potassium level
in the soil to about 150 pounds K per acre six inches as determined by the soil
extraction methods used at the Everglades Station. Soils with a low organic
matter or marl content may need an additional application of potassium since
this nutrient may leach. A normal application would be 250 to 300 pounds of
muriate of potash (60 percent K20) per acre.
Split applications of nitrogen and potassium may be of advantage, especially
on sandy soils with a low organic matter or marl content. Half of the amount
should be applied in the furrow at planting while the other half could be applied
as a side dressing prior to the boom growth in the spring.
Phcrphorus moves slowly in the soil. Triple superphosphate applied on
sandy soils did not move from the upper foot of soil even after fields had been
flooded for one week. Since there is little leaching, the required amount of
phosphorus for a crop can be applied in the furrow at planting time.
Sugarcane growing on organic soils has often shown a reduction in cane
tonnage when the available soil phosphorus was high. A soil level of 10 pounds
or more of P per acre six inches, as determined by the soil extraction methods
at the Everglades Station, could be harmful to cane growth; a level of five or
six pounds of P per acre six inches seems to be adequate to produce a satisfac-
Under normal conditions with sugarcane growing on a typical sandy soil with
organic matter percentages of 5 percent or less, a standard fertilizer treatment
Should consist of 500 lbs. 10-10-10 at planting followed by 400 lbs. 10-0-20 as
a side dressed application in April. The amount of nitrogen fertilizer may be
reduced as the organic matter in the soil increases.
Sugarcane has failed to grow without copper on organic soils and a lack of
zinc has retarded the development of the cane plant considerably. Newly develop-
ed areas of mineral soils should receive an application of 10 pounds brown copper
oxide per acre or its equivalent in copper sulfate.
As yet, little is known about the rate of micronutrients needed to maintain
an adequate level in the soil. In order not to limit growth, micronutrients are
added to each furrow-applied fertilizer; about 0.5 percent CuO, lO percent MnO,
0.5 percent ZnO and 0.3 percent B203.
Sometimes small amounts of sulfur may be included in the fertilizer formula,
especially to soils with a pH of 6.00 or higher within which pH range the avail-
ability of manganese to the cane plant may be limited. Sulfur is applied in order
to lower the pH in the vicinity of the fertilizer. At a pH of about 7.00 or
higher the sugarcane plant may suffer severely from lack of manganese.
Foliar applications of manganese sulfate have been successful in eliminat-
ing manganese deficiency in the cane plant.
Major and micronutrient requirements for "ratoon" or "stubble" crops on
mineral soils are generally similar to those of the plant crop. Applications
may be given as a single sidedress after harvest of the previous crop or as
split applications with half the amount as a sidedress after harvest of the
preceding crop and half the amount as a sidedress during spring. The split
application is preferable, espeically on the lighter soil types.