Tillage Erosion Effect on Soil Hydrological Properties in a Hilly Landscape

Abstract

Two or more processes of soil erosion simultaneously exist in a hillslope landscape, and those processes can interact with each other. Yet, how one process impacts another remains unresolved. The objective of the study was to determine the relationship between tillage erosion and soil hydrological properties in the hillslope landscape. Five slopes with lengths of 20 to 22 m were selected from hilly areas of the Sichuan Basin, China. Tillage erosion appeared to be most intensive at upper slope positions ranging from 80 to 125 t ha−1 year−1. Drastic differences in total soil depth were observed among different landscape positions, averaging 17, 28, and 39 cm deep for upper, middle, and lower slope positions, respectively. Soil water storage capacity (SWSC) at saturation exhibited remarkable differences among different landscape positions. The lowest steady-state infiltration rates were found in tillage-eroded areas (upper slope) with a mean of 1.21 mm min−1, followed by deposited areas (lower slope) with a mean of 2.32 mm min−1, while the largest steady-state infiltration rates were observed in the balanced areas between soil loss and gain (middle slope) with a mean of 3.34 mm min−1. The thickness of soil profiles and local slope gradients were both associated closely with tillage erosion rates and were found to be two important determinants of soil infiltrability. It is suggested that soil degradation by tillage erosion alters soil hydrological properties, thereby resulting in poor soil infiltrability in the hilly landscape.