Study of the Composition of, Water in Soil Structure

Soil properties and water movements in a volcanic deposit (Shirasu) area (VI)

Abstract

This paper considers the composition of water in soil structure.
Some volcanic ash soil samples (Kuroboku, Akahoya, Kuroniga and Shirasu) in different stages of pF (pF=0, 1.0, 2.0, 2.5-3.0, 5.5) were investigated by means of an optical microscope and a scanning electron microscope. Those samples investigated with the scanning electron microscope were used as the freezing state.
The pF values of the soil water kept in a continuous pore were smaller than 2.0. The water covering the surface of soil particles had a pF value of about 3.0 or over.
The experiment clearly showed that the amount of soil water, caused by the energy from pF2.0 to 3.0, was less than the others, and this corresponded to the distribution of pores which were observed in a piece of the soil that was sliced off as a sample.