Effects of antecedent soil water content on infiltration and erosion processes on loessial slopes under simulated rainfall

摘要

Soil texture and antecedent soil water content (ASWC) are primary factors governing hillslope hydrological and erosion processes. We used simulated rainfall to investigate the runoff and erosion processes on sloped plots with three loessial soils and analyzed the effects of soil texture and ASWC on the hydrological processes. The results demonstrated that the average infiltration rate decreased with increasing clay content (i.e.,Ansai (AS) loamy sand > Fuxian (FX) clay loam > Yangling (YL) clay). ASWC had little effect on infiltration processes for the YL clay but exerted a significant influence on infiltration for the FX and AS soils; this implies that infiltration models for loamy soils must consider the effects of ASWC. The Horton model was found to describe infiltration processes in these loessial soils better than the Kostiakov or Philip models. The YL clay yielded much less sediment than the FX and AS soils,and its sediment yield rate gradually decreased with the rainfall duration. There was a negative relationship between clay content and sediment yield under high ASWC,but no clear relation under low ASWC. These erosion differences derived from the splash erosion for the YL clay,and the depressions or rills occurred on the loamy soil plots.