Effects of rainfall on runoff and sediment yield on yellow soil bare slope in the hilly area of northern Sichuan province

BackgroundBased on the long time series of measured data, exploring the rule of runoff and sediment yield on bare slope under natural rainfall condition, it is important for soil erosion control. MethodsUsing observed data (2014-2022) of runoff and sediment yield on bare slope of yellow soil in hilly area of northern Sichuan,the study analyzed the influence of rainfall factors on runoff and sediment yield on slope by using the method of stepwise regression and path analysis. ResultsThe results showed that 138 erosive rainfall events occurred during the observation period, which distributed from April to October. Average annual soil loss was 1057.63t/km2, average annual runoff depth was 197 mm. Stepwise regression analysis showed that rainfall erosivity, rainfall, I30 and rainfall duration were the main indicators affecting runoff, rainfall erosivity, I30 and rainfall duration were the main indicators affecting soil loss. Path analysis revealed that rainfall erosivity had the strongest direct positive effect(0.692) on runoff depth, which increased the total effect to 0.906 through the synergistic effect with other factors. Although I30 directly inhibited runoff, it showed a significant positive effect (0.501) through strong indirect positive effect (0.7216) with other factors. Soil loss was mainly directly driven by rainfall erosivity ( 0.836 ). Although I30 had direct negative on soil loss, it promoted soil loss through the indirect positive effect with rainfall erosivity. ConclusionsThe study quantifies the influence of rainfall multi-factor interaction on soil erosion, provides theoretical support for the optimization of regional soil erosion model parameters, and provides scientific basis for soil and water conservation measures in the hilly area of northern Sichuan.