「前年に施用した米ぬかは、春先の急激な温度上昇によって急激に分解され、水稲生育、ひいては収量に影響を与えている。」私たちの水田土壌を調査している土壌圏システム学研究室の4年生が、そんな仮説を示唆する解析をしてくれました。そこで本年は、春先、つまり今から田植え直後までの期間、集中的に土壌を採取し短い間隔で土壌養分の状態を調べていきます。本日も1年生が手伝いに来てくれました。

“Rice bran applied in a rice field in the previous year will be rapidly decomposed by the sharp increase in soil temperature during early spring, affecting rice plant growth and hence grain yield.” The forth year student of the Vadose Zone Hydrology Lab who had been investigating soil nutrient status in our rice field presented this hypothesis in his thesis. We therefore have decided to collect soil samples intensively during early spring, that is from now to post-transplanting, to investigate the soil nutrient fluctuation at short intervals. The first year student helped them collect soil samples today too.