Everglades Station Mimeo Report EES64-6 R.ctoberi 1963
SOIL pH AND RESIDUAL PHOSPHORUS EFFECT ON SUGARCANE DS ON
F. le Grand '1/
Several workers (1, 2, 3) have reported the effects of soil phosphorus levels
on sugarcane tonnage. A recent study (4) revealed a decrease of more than twenty
percent in cane tonnage and seven percent brix in juice when 153 pounds of phos-
phorus as superphosphate were applied to the soil.
'7.- number of fields with a high soil phosphorus content have come into cane
production with the recent expansion of the sugar industry. Soils in fields having
grown vegetables for several years often contain 10 to 20 pounds or more of water
soluble phosphorus per acre six inches as a residue from previous heavy applications
to the vegetable crops.
A survey was carried out in commercial fields2/to study the effect of soil
phosphorus level and pH on sugarcane tonnage during the 1961-62 crop season.
In 1960-61 composite soil samples were taken from each 40-acre field in a
total of approximately 3000 acres prior to planting the sugarcane. Analyses for
pH, P and K were conducted in the soil testing laboratory of the Everglades
Experiment Station. The plant crop was harvested for commercial sugar production
and for seed cane. Sugarcane from each field was weighed at the factory scale.
Soil pH and water soluble phosphorus content were compared for their effect
on cane tonnage per acre. For practical purposes the soil pH values were grouped
as follows: 5.4 to 5.7, 5.8 to 6.0 and 6.1 or higher. Similarly, the soil phos-
phorus contents were grouped as 10 or lower, 11 to 20 and 21 or more pounds water
soluble phosphorus per acre six inches. Data are presented in Table 1. The data
included in parentheses in Table 1 are the acreages harvested on which the tons of
cane per acre are based.
Sugarcane tonnage increased as the soil pH increased and was greater at the
lowest soil phosphorus range. At a soil pH below 6.00 the amount of phosphorus
in the soil seemed to have little influence on tonnage. However, with a soil pH
of 6.10 or higher the phosphorus content of 21 or more pounds per acre six inches
in the soil seemed to depress the cane tonnage.
The presently reported yield reductions in sugarcane at high soil phosphorus
levels are in line with previous observations (1, 2, 3). Reductions in sugarcane
yields by superphosphate applications were so consistent during the early days of
sugarcane production in the Everglades that no phosphorus was recommended in the
1/ Assistant Sugarcane AZronomist, Everglades Experiment Station, Belle Glade,
2/ In cooperation with Osceola Farms, Inc., Pahokee, Florida.
sugarcane fertilizer mixtures until more recently (1). Yield reductions at lower
pH may also be associated with phosphorus. Forsee (5) found that lowering the pH
of Everglades peaty muck soils increased the water soluble phosphorus content. Also,
phosphorus content of plant tissue increased as soil pH decreased below 5.80.
Whether or not the effect of pH on cane production is due to influencing the avail-
able phosphorus level is not known, as pH affects other plant nutrients in these
soils, particularly the micronutrients.
Tonnage reduction at higher soil phosphorus levels could also be due to de-
ficiencies induced by phosphorus. Sugarcane growing in fields with a high soil
phosphorus content and a low pH had pale green-colored leaves as well as some
moderate striping on the leaf blades at the spindle. This has previously been
found to be associated with iron deficiency.
1. Bourne, B. A. Physiological effects of soil phosphorus deficiency and excess
on sugarcane on low mineral peat soil. Proc. Intern. Soc. of Sugarcane
Tech.: 233-42. 1950.
2. Neller, J. R. Phosphorus content and buffer capacity of plant sap as related
to the physiological effect of phosphorus in fibrous Low-Moor Peat.
Journal of Agr. Research. 51. 4: 287-300. 1935.
3. Stevens, F. D. Agronomic studies with sugarcane. Fla. Agr. Exp. Sta. Ann.
Rept. 192-3. 1947.
4. le Grand, F. and F. H. Thomas. Influence of phosphorus and sulfur applications
on growth and chemical analysis of sugarcane growing in organic soils.
(Presented at the Puerto Rican Sugarcane Technologists Meeting, 1963).
5. Forsee, W. T., Jr. The place of soil and tissue testing in evaluating fertility
levels under Everglades Conditions. Proc. Soil Sci. Soc. of Am. 15:
NOTATION: This paper will be presented at the annual meeting of the Sugarcane
Technologists Association of Puerto Rico, November, 1963.
Table 1. Influence of soil pH and pounds of water soluble phosphorus on the tonnage of cane harvested in
crop 1961-1962 at Osceola Farms, Inc.
Tons of cane harvested
Water soluble P, lbs. per acre six inches in soil per acre regardless of
Soil H 10 or below 11-20 21 or higher P content in soil
5.4 5.7 37.5 37.6 35.5 37.0
(200)* (600)* (240)* (1040)*
5.8 6.0 43.2 40.4 46.8 42.3
(160)* (640o)* (240)* (104.0)*
6.1 or higher 49.6 48.4 41.6 48.5
(640)* (560)* (80)* (1280)*
Tons of cane harvested per 46.1 41.9 41.2
acre regardless of soil pH (1000)* (1800)* (560)*
* Acreage harvested.