水田状態土壌中に於ける燐酸の行動に関する研究(第一報)

概要

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It is generally recognized in Japan that paddy rice plant is a little or not at all responsive to phosphate manuring even in case where barley requires much its application and it is supposed that the above fact may be connected with different behavior of soil phosphate under two conditions. From the above reason, the present author studied the solubility of soil phosphate at various hydrogen ion concentrations under two conditions. And the result will be summarized as follows; 1) The solubility of soil phosphate was very small at pH between 5 and 7 under both conditions. 2) Under the paddy field condition, the solubility at pH smaller than 5 and that. larger than 7,was both remarkably higher than that under dry field condition. 3) From the above different state of the solubility under two soil conditions, it may be concluded that the main part of soil phosphate under dry field condition is ferric phosphate and under paddy field condition, it is changed into ferrous phosphate.
社団法人日本土壌肥料学会の論文
1941-03-25