水田の滲透性の意義について(第1報) : 滲透速度と湛水下土壌の Eh の関係

抄録

The influence of degree of percolation velocity on the value of Eh of paddy soils under a stagnant condition in summer was investigated. Two surface soils from paddy field, whose textures were clay loam and sandy loam respectively were mixed; and 13 kg of the mixture was filled in Wagner pots. The velocity of percolation of stagnat water over the surface was controlled to such several rates as 0,l, 2 and 3 cm in depth of water a day. The Eh-values, at center of the soils in pots, were the lower in mV, the larger the velocity of percolation. From this results it was considered that the percolation would increased the decomposition of organic substance in soils under a stagnated condition. The variation of Eh-values were observed every 7〜10 days, especially regularly at the period of about one month after the begining of irrigation. By this observation, we could find there was a tendency that another periodical process of about one month interval where occurred Eh fluctuated in a wide range every month by no explainable reason.