Elemental Sulfur Effects On Nutrient Availability and Sugarcane Yield On Organic Soil Having Variable Calcium Carbonate Levels.

Organic soil subsidence is lowering the soil depth towards the underlying limestone bedrock in the Everglades Agricultural Area. Incorporation of Ca carbonate into the root zone of soil from the underlying limestone increases pH and reduces availability of phosphorus and micronutrients to crops. Elemental S has been recommended at rate of 448 kg/ha at pH > 6.6 to reduce soil pH and therefore increase nutrient availability to crops. There is a need to determine the effectiveness of elemental S in conditions of high pH and high Ca carbonate levels. The objective of this study was  to determine elemental S effects on nutrient availability and sugarcane yield on organic soil having variable Ca carbonate. Factorial experiment of 4 elemental S rates (0, 90,224, and 448 kg/ha) and 3 organic soil types varying in Ca carbonate (0%, 12.5%, and 50%) was established using a randomized complete block design with four replications at one location. Sulfur application had limited effects on soil pH reduction and therefore failed to enhance the nutrient availability. Sulfur application increased sulfate concentration in soils that could be at risk for export from the field. With increasing the Ca carbonate in soil, soil pH was increased and nutrient availability was decreased except Mn. The expected reason for increased manganese availability was  increased soil moisture and associated reducing conditions due to changes in physical properties of the soil with increased levels of Ca carbonate. High soil pH resulted in Mn and P deficiencies in the plants. Soil pH and Mn were important factors that influenced sugarcane yield.