Hydraulic Properties of Fullerton Cherty Silt Loam

Abstract

AbstractSoil hydraulic properties at eight depths in a Fullerton cherty silt loam (a clayey, kaolinitic, thermic Typic Paleudult) profile were derived from measurements of water content with a calibrated neutron probe and of matric potential with tensiometers during drainage of a flooded 2‐ by 2‐ by 3‐m deep soil plot. Soil cores taken from the field plot were used for laboratory determinations of the retention properties. The field retention data were generally unsatisfactory, indicating significant differences in the response times and spatial resolution of the tensiometers and neutron probe. The tensiometers did not provide reliable hydraulic gradient data during drainage. Hydraulic conductivity was calculated by the instantaneous profile method and by three simple field methods, assuming a unit hydraulic gradient in all methods. There were greater differences in hydraulic characteristics between two profiles 1 m apart than there were between the alternative methods of calculation. Maximum hydraulic conductivity calculated by the instantaneous profile method for the well‐aggregated B horizons had values up to 58 and 177 cm per day at two positions in the soil plot.