Agricultural use of porous hydrate calcium silicate. I. Evaluation of porous hydrate calcium silicate as a silicate fertilizer

摘要

Laboratory and pot experiments were conducted to evaluate the availability of silica from the industrial wastes of autoclaved light concrete (PS : porous hydrate calcium silicate) to rice cvs Kokoromachi and Satohonami in comparison with seven commercial slag silicate fertilizers (SS). The amounts of water soluble silicon of PS and SS were 0.9 g kg-1 and 0.1-1.2 g kg-1, respectively. The silica concentration of soil solution of the incubated, submerged non-allophanic Andosol treated by PS increased～2.3 times compared to that of non-treated soil, whereas the silica concentration of the same soil treated by SS was only increased 1.0-1.6 times. The silica nutrition of rice plants was measured both at the 9th leaf-stage and harvesting stage. At the 9th leaf-stage, the silica concentration of the rice shoots grown on Andosol treated by PS (150 g kg-1) was～70 g kg-1, which was the highest among the treatments. At the same time, the silica concentration of soil solution with PS treatment was also higher than those with SS treatment. At harvesting time, the silica concentration of leaf blade with PS treatment was 87 g kg-1, 28% higher than that with non-treated soil. However, the silica concentration of leaf blade with soil treated by SS was only 0-16% higher than that with the non-treated soil. In alluvial soil, the effect of PS on the silica nutrition in rice plants was relatively enhanced compared to that in Andosol. It is concluded that porous hydrate calcium silicate is an effective silicate material for improving the silica nutrition of rice.