Determination of field-saturated hydraulic conductivity in unsaturated soil by the pressure infiltrometer method

situ measurements of field-saturated hydraulic conductivity, K-fs, are essential for accurate prediction of water movement in soil. The practical applicability of the pressure Infiltrometer (PI) method to measure K-fs of soil is examined using field and laboratory tests and numerical calculations. Sand and loam soils were selected for the study. Theoretical features of the PI method are explained by the field permeability tests and the numerical calculations. It is shown that the PI method can be an excellent practical in situ permeability test. It is suggested that about 0.06 cm(-1) or some smaller value of alpha* may be more appropriate for sand and loam in calculating K-fs of soil, and that the measurement depth of the PI method can be controlled by combining the radius and insertion depth of the ring, and the constant head imposed on the soil surface within the ring.