Potential of Silicon Fertilization in Sugarcane Production in Louisiana.

Many studies have documented the benefits of silicon (Si) fertilization particularly to Si accumulator plants such as sugarcane. Sugarcane is grown on the alluvial plain of Louisiana along the lower Mississippi River consisting of highly diverse soils. This study was conducted to document the potential benefits of Si fertilization to sugarcane grown on alluvial soils in south Louisiana. Three rates of calcium silicate slag (CaSiO₃; 2, 4, and 8 MT ha^-1), including a control, were superimposed to three 1.8 m-row x 12 m-long plots prior to planting of three cane varieties (LCP 85-384, HoCP 96-540, and L01-283) in 2009. The treatments were arranged in a randomized complete block design with four replications established on Sharkey clay and Commerce silt loam soils in St. Gabriel, Louisiana. The effect of CaSiO₃ application was consistent across cane varieties. Sugarcane grown on Commerce silt loam had the highest sugar yield both in 2010 and 2011 with 2 MT CaSiO₃ ha^-1 application rate. In 2010, an application of 4 MT ha^-1 of CaSiO₃ raised % Si in stalk from 0.40 to 0.43% while Si removed by cane was increased by 48 kg ha^-1 (P<0.05). Acetic acid-extractable (CH₃COOH) Si was generally higher in Sharkey clay than in Commerce silt loam. There was a general pattern of increasing CH₃COOH-extractable Si with increasing CaSiO₃ application rates but these increases declined with cropping year. All measured parameters in 2010 and 2011 were pooled; cane tonnage, sugar yield and Si removal rate were significantly increased (P<0.05) by CaSiO₃ fertilization for sugarcane grown on Commerce silt loam but not on Sharkey clay soil. Due to the nature of soils in the alluvial plain of Louisiana being highly diverse, some areas under sugarcane production may benefit from Si fertilization thus future research should focus on establishing the method for quantifying plant-available Si.