抄録
By the use of measuring tube with a glass filter plate on its bottom, soil volume in water was measured at various tensions, attained about 90 cm of water in height. Results obtained were as follows : 1. Settling volume of soil in water was decreased when water was percolated through the soil column, and was more decreased by the application of tension. 2. The more the soil had clay, the more the shrinkage of the soil volume was remarkable. 3. High correlation coefficient was found between the clay content and the settling volume in water, but the coefficient turned to be lower by the tension. 4. It was supposed that there produced a negative pressure in the soil column in water, when water was percolated through the soil of having both pores, small and large. 5. The formation of so-called plow pan in paddy soil and also the shrinkage of certain volcanic ash paddy soil, occurs several years after reclamation, were both concluded to be caused to the nagative pressure produced as in 4.
