Sugarcane Genotype Response to Phosphorus Fertilizer in the Everglades

To protect the natural Everglades, federal legislation mandates a reduction of at least 25% in the P content of water discharged from the Everglades Agricultural Area (EAA). Work is needed to achieve these reductions while sustaining a productive agriculture in the EAA. The objective of this study was to identify differences in response to P fertilizer among 24 elite genotypes of sugarcane (interspecific hybrids of Saccharum spp.). Six yield characteristics were examined on Histosols at four field locations with no added P, an often used commercial rate of 24 kg P ha -1 , and 48 kg P ha -1 for the plant-cane, first-ratoon, and, in three locations, the second-ratoon crop. One group of eight genotypes was planted at two locations, and two other groups of eight genotypes each were planted at one of two other locations. Genotype x P fertilizer rate interactions were generally not significant. Of the eight genotypes tested at two locations, CL 61-620, CP 72-2086, and CP 85-1308 were cautiously (P ≤ 0.15) identified at both locations as more sensitive than other genotypes to changes in P rates. Reduced P rates were recommended for CP 85-1308 on soils with low P. CL 73-239 and CP 81-1254 required more than commonly recommended P fertilizer on low-P soils. Identification of sugarcane genotypes that respond favorably to varying rates of P may evolve into a cost-effective strategy to reduce P content of EAA drainage water.