CALIBRATION OF SUGARCANE RESPONSE TO CALCIUM SILICATE ON FLORIDA HISTOSOLS

Silicon is considered a beneficial nutrient for sugarcane (Saccharum spp.) and yield responses to Si applications on Florida organic soils have been well documented. Growers need calibrated Si recommendations to be able to make cost-effective decisions regarding Si applications. The objective of this study was to develop a soil-test Si calibration based on yield responses to Ca silicate on Everglades Histosols. Twelve paired commercial field comparisons and three small-plot tests of Ca silicate application were conducted. Strong responses in t cane ha^?1 and t sucrose ha^?1 were determined with acetic acid-extractable soil Si <15 g m^?3, with some response to approximately 25 g m^?3. Recommendations were developed over this range with a maximum Ca silicate rate of 6.7 t ha^?1. Optimum leaf Si concentration was determined to be ≥ 6.0 g kg^?1, with 0.95 and 0.80 relative yield at 5.0 and 2.5 g kg^?1, respectively.