Phosphorus soil test calibration for sugarcane grown on Everglades Histosols

Abstract

A calibrated phosphorus (P) soil test is an important part of an economically and environmentally sound farming program. During the 1956–1958 period, Bray 2 was selected for use at the United States Sugar Corporation as an organic soil P extractant for sugarcane grown in the Everglades Agricultural Area. The purpose of this study was to evaluate and summarize the results of the numerous sugarcane field experiments that have been conducted relating Bray‐extractable soil P with sugar production. Using only years with significant positive responses in sugar production from P fertilizer experiments on Histosols, categories of Bray‐extractable soil P were determined which indicate the relative need for P fertilizer that will be required for optimum sugar production. A maximum applied P rate of 36 kg P ha^‐1 was found to be sufficient for soils in the very low category of Bray‐extractable P (<14 kg P ha^‐1). At fertilizer P rates ≤36 kg P ha^‐1, Bray‐extractable P in the zone of application (band application) was increased with the plant cane P application (first crop) and was maintained at or near the same level in succeeding ratoon crops with annual P applications. Several experiments had significant positive sugar production responses only in the ratoon crops, demonstrating the importance of maintaining adequate soil P levels in the fertilizer application zone each year.