Pinhole Multistep Centrifuge Outflow Method for Estimating Unsaturated Hydraulic Properties with Small Volume Soil Samples

If soil hydraulic conductivity or water holding capacity could be measured with a small volume of samples, it would benefit international fields where researchers can only carry limited amount soils out particular regions. We performed pinhole multistep centrifuge outflow method on three types soil, which included granite decomposed (Masa soil), volcanic ash (Andisol and alluvial clayey (paddy soil). The experiment was conducted using 2 mL 15 tubes in pinholes were created the top bottom for air intrusion outflow, respectively. Water content at 5, 15, 30 min after applying to examine equilibrium time. results showed that drainage worked well sufficient obtain data each step. Compared data, retention curve successfully optimized. Although shape similar, unsaturated conductivities deviated largely, implied Ks caused convergence issues. When set as constant, properties converged gave excellent results. This provide regions sampling is lacks data.