水田における浸透性の意義について(第3報) : 水田潅水期日と水稲移植期日との関係

概要

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From the results of our experiments on the amounts of NH_4,leached out from the stagnated paddy soils in the pots with or without growing paddy plant, the following points are discussed. In the early stage of paddy growth, from 25 to 30 days after transplanting, the concentration of NH_4 in the percolating soil solution would be an important factor to govern whether the tillering would be delayed or promoted, and in the case of our experiments it can be said that the concentration of NH_4 should not be less than 10 ppm, at least, during three weeks after transplanting. D pending upon the degree of percolation in paddy field, the begining of irrigation and also the optimum period of transplanting must be determined in reference to keeping the concentration of NH_4 to a above extent. On the other hand, the root of rice plant can utilize NH_4 not only in surface soil but also in subsoil, when elongated. And, in the subsoil, a certain stimulating action of the root to anaerobic bacteria, causing the production of NH_4,is expected. Facility of the root to penetrate into the subsoil must not be neglected, when we reckon the factors for a good growth or a high yield of rice plant, besides the NH_4 concentration and others.
社団法人日本土壌肥料学会の論文
1956-07-05