Silicon nutrition to rice alleviates iron, manganese and aluminum toxicity in laterite derived paddy soils

The beneficial role of silicon (Si) in alleviation of abiotic stress is well established. Toxicity of iron, manganese and aluminium are widespread in laterite derived paddy soils of Kerala. Plants undergo severe abiotic stress due to the toxicity of these elements. The aim of our work was to investigate the influence of silicon application to rice on alleviating toxicity of Fe, Mn and Al in laterite derived wet land paddy soils of northern Kerala. A pot culture experiment was laid out in completely randomised design replicated thrice with nine treatments using Aishwarya as the test variety. The results of the study indicated a significant decline in available Fe content (120 mg kg-1) in soil in treatments receiving silicon compared to control (181 mg kg-1). Decline was to the tune of 31% due to the foliar application potassium silicate @ 0.5% spray + borax 0.5%. Similar results were obtained with respect to available Mn and exchangeable Al content in soil. Higher silicon content (44.58 mg kg-1) in soil was obtained with the soil application of calcium silicate @ 4 g kg-1 soil which was superior to foliar application of potassium silicate. The Fe and Mn content in straw and grain were decreased with application of silicon while its uptake in plant alone was significantly increased. Application of potassium silicate @ 0.5 % spray + borax 0.5 % spray thrice recorded maximum plant height (131.6 cm), number of productive tillers plant-1 (23.33), thousand grain weight (27.16 g), grain yield (68.30 g pot-1) and straw yield (88.79 g pot-1).