抄録
Experiment with rice plants was made for 30days in greenhouse under the scheme, shown in Table 1,combining several factors in different ways. The amounts of NH_3-N and iron found in drainages were discussed with a special reference to the redox condition of soil (Fig. 1). In the plot, cdC, the amount of water stable aggregates larger than 1.0mm in diameter, remained constant during the experimental period, but, in other plots decreased clearly. The most important factor for the growth of roots in these periods might not be the redox condition of soil but the amount of NH_3-N in the soil. (Fig. 2& 3) Analytical data on the ferruginous films formed around roots were discussed. (Fig. 4 & Table 3)
