Estimating soil water characteristic curves of water repellent volcanic ash soils by time domain reflectometry coil probe measurements
2004
Kawamoto, K. (Saitama Univ. (Japan)) | Banyar, A. | Per, M. | Komatsu, T. | Oda, M.
Soil water repellency is closely related to soil hydrological problems such as the acceleration of soil erosion and the occurrence of fingering flow in an unsaturated soil. In order to estimate water retention of water-repellent aggregated volcanic ash soils, we obtained soil water characteristic curves (SWCCs) by using an experimental apparatus composed of a tune domain reflectometry coil probe and a tensiometer. Prior to measurements of SWCCs, we investigated the dielectric property of our soil materials and results show (hat the dielectric property of the materials reflected the soil aggregated structure. In water-repellent materials, there was a sharp increase in water content from initial water content to full saturation with a slight increase of water pressure on the wetting processes of SWCCs. Based on the scanning curves from redrying and resetting processes of SWCCs, it was revealed that water was firstly absorbed in intraaggregate pores rather than interaggregate pores irrespective of the degree of soil water repellency of materials. In water-repellent materials, however, water absorption in intraaggregate pores was restrained in comparison to non water-repellent materials.
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