Response of Paddy Soils to Silicon Fertilization

Silicon (Si) is of nutrient element required very large amounts by rice plant. Thus silicon deficiency can commonly observed in paddling soils. In this study, silicon status and reponse to the silicon fertilizer of Bafra and Terme districts of Samsun for rice cultivation were investigated by means of a pot experiment set up in completely randomised design with three replications. For this purpose, 18 paddy soil samples were taken. Rice plants were grown in a pot filled with 2 kg of oven-dry soil and fertilized with 0-50-100-200 and 400 mg Si kg^-1 as silicic acid (H4SiO2), 75 mg N kg^-1 ammonium sulfate (21%) and 60 mg P2O5 kg-1 tripl superfosfate (42%) before sowing. Initially fifteen germinated seeds of Osmancık 77 rice cultivar, were planted into each pot. Rice grains with husk were harvested after 142 days from planting. The results showed that rice grain yield (1.56 - 45.85%) significantly increased (P 0.01) by silicon fertilization in 83% of the paddy soils in the region. It was found that paddy soils require different doses of Si (50-200 mg kg^-1) and averagely 87 mg kg^-1 of optimum Si dose for the region soils. Also, a critical concentration of 17.11 mg of available Si is required to obtain a relative grain yield of 85% in the experimental soils and below this level silicon deficiency limits grain yield.