Agricultural use of porous hydrate calcium silicate. II. Practical use to improve silicon nutrition of rice plants in paddy fields

摘要

The effects of porous hydrate calcium silicate (PS) on the silica nutrition of rice cv. Satohonami were evaluated in a paddy field of Kawatabi Andisol. The growth characteristics of rice and silica concentrations of both soil solution and leaf sheath of rice in the following 5 treatments were determined : control (no silicon application), SC (treated with 150 g m-2 of commercial slag silicate fertilizer) and PS-150, -300 and -500 (treated with 150, 300 and 500 g m-2 of PS, respectively). Plant length, numbers of tillers, leaf colour and total dry weight of rice plants treated by PS were not statistically different to those of non-treated plants. Grain yields of rice plants in the PS plots were almost the same or more than those in the control andSC plots. The silica concentrations of both soil solution and leaf sheath of the rice plants treated by PS were higher than those in the control or SC plots and they tended to increase with the application rate of PS throughout the growth period. The total amount of silicon absorbed by rice plants in the PS plots was 1.2 to 1.5 times higher than that in the control plot. The use efficiencies of silicon by rice plants in the PS-150, -300 and -500 plots calculated by the substraction method were 70, 65 and 60%, respectively. It is concluded that porous hydrate calcium silicate is a very efficient material for improving the silicon nutrition of rice plants without any detrimental influence.