Many studies on the permeability of soil have been examined since old times, and nowadays, the saturated flow of soil water is expressed conveniently by Darcy's law. In spite of these researches until now, the unsaturated permeability of soil, especially the measurement of it, is not yet researched sufficiently for practical use. In this paper, at first, we propose a method which calculates the unsaturated permeability with the time-moisture curve obtained from the pF-soil moisture experiment, and compare it with a recent data published by NAKANO et al. Secondly, as a result of application of this method to the field, it is proved that the culculated data almost coincides with the practical comsumptive moisture.

土壌の透水に関する研究は古くから行なわれ, とくに飽和時の水分移動はDarcyの法則によって簡便に表わされるに至っている. しかしながら不飽和時の透水係数に関する検討, 特にその測定については充分な考察がなされていない. 本論文では, まず土壌のpF-水分試験時の時間-水分曲線を利用して不飽和透水係数を求める方法を提案し, それをこれまでのデータと比較した. またこの方法を圃場適用した結果, 実際の水分消費量と良好な一致をみた.