Sugarcane yield response to calcium silicate on Florida mineral soils

Silicon (Si) is a beneficial nutrient for sugarcane (Saccharum spp.) and yield responses to Si amendment have been determined on soils with low soluble Si. Because a soil test Si calibration has not been published for sugarcane grown on Florida mineral soils, the objectives were to determine sugarcane yield response to silicon soil amendment on two mineral soils (Entisol and Spodosol) and to relate sucrose yield to soil-extractable Si. Calcium silicate application rates were 0, 3.4, and 6.7 Mg ha(-1) (Site 1) and 0, 2.2, 4.5, and 6.7 Mg ha(-1) (Site 2) in small-plot (120 m(2) plot(-1)) experiments, with Si application resulting in significant increases in biomass and sucrose ha(-1). Calcium silicate requirements of 6.7 and 4.3 Mg ha(-1) were determined with initial acetic acid-extractable Si of 21 and 46 g m(-3), respectively. Nonlinear models indicated that Si amendments will be required with acetic acid-extractable Si <105 g m(-3).