Tilled Soil Subsidence During Repeated Wetting

ABSTRACT A total of 15.2 cm of water was applied without raindrop impact energy to six replicates of four freshly tilled soils to determine its effect on subsidence, random roughness, bulk density, and hydraulic conductivity. Texture of the soils ranged from sandy loam to clay loam. Random roughness degraded to a relatively constant value about 0.5 cm below initial values for all soils except one which was degraded to 1.3 cm below the initial value. Bulk density increased about 0.1 g/cm3 for three soils while the fourth increased 0.2 g/cm3. Regression equations were developed to predict these changes. Coefficients of determination ranged from 0.84 to 0.97 for both random roughness and bulk density. Hydraulic conductivity also decreased with added water. Maximum decreases ranged from 3.0 cm/h to 8.9 cm/h...