Extreme rainfall events are occurring more frequently, and research has shown that soil profile can help mitigate the impacts on soil erosion by increasing infiltration and declining surface runoff. Although soil moisture responses to rainfall events are key determinants of soil erosion processes, little study has yet investigated the variations in responses to different rainfall events among landscape positions and depths. Here we have conducted a comprehensive analysis by estimating changes in moisture content, response time, and velocities of peak moisture between soil layers for three rainfall types at 6 locations on two adjacent hillslopes in the Mollisol region of China. The results indicated that soil moisture responses varied widely. In general, the moisture response magnitude declines with increasing soil depths and lowering slope positions but increases with rainfall amount. The response percentage was greatest for heavy rainfall events and at shallow depths (10–20 cm). Notably, we found that Response 0 value represents the simultaneous arrival of response times for different depths. for heavy rainfall events at all slope positions,  The negative response values indicate that the response time for deeper layers reaches its peak earlier compared to the surface at 10cm.

 

Slope positions; Rainfall variations; Soil moisture response; Mollisol region