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 A gricultural Area (EAA), Work is needed to achieve these reductions while su staining a productive agriculture in the EAA, The objective of this study w as to identify differences in response to P fertilizer among 24 elite genot ypes of sugarcane (interspecific hybrids of Saccharum spp,), Six yield char acteristics were examined on Histosols at four field locations with no adde d P, an often used commercial rate of 24 kg P ha(-1), and 48 kg P ha(-1) fo r 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 ot her groups of eight genotypes each were planted at one of two other locatio ns. Genotype x P fertilizer rate interactions were generally not significan t, Of the eight genotypes tested at two locations, CL 61-620, CP 72-2086, a nd CP 85-1308 were cautiously (P less than or equal to 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 7 3-239 and CP 81-1254 required more than commonly recommended P fertilizer o n 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.