Sugarcane Response to Phosphorus Fertilizer in Relation to Soil Test Recommendations on Everglades Histosols

Abstract

To protect habitat in the Everglades, legislation mandates a reduction of at least 25% in the P content of water discharged from the Everglades Agricultural Area (EAA). Accurate P fertilizer recommendations for sugarcane (interspecific hybrids of Saccharum spp.), the major crop in the EAA, are needed to help achieve this P reduction. The objective of this study was to compare two soil‐tests for basing P fertilizer recommendations for sugarcane grown on Histosols in the EAA. Three yield characteristics were measured at four field locations with no added P (P0), an often‐recommended commercial rate of 24 kg P ha−1 (P1), and 48 kg P ha−1 (P2) for the plant‐cane, first‐ratoon, and, at three locations, the second‐ratoon crop. One group of eight genotypes was planted at two locations, and two other groups of eight genotypes were each planted at one of two other locations. An acetic acid‐extractable P (Pa) soil test predicted yields better than the water‐extractable P (Pw) test. However, unexpected responses in sugar and cane yields occurred for both P extraction procedures. Further knowledge of the effects of soil pH, factors affecting P mineralization, and sugarcane genotype response to P may explain some of the unexpected results.