Soil erosion characteristics on grassland slope under light grazing and closed grazing in Xiazangtan landslide

The giant landslide distribution area in the upper reaches of the Yellow River faces severe ecological and environmental challenges, including grassland degradation and slope soil erosion. Quantitative evaluation of soil erosion on grassland slope under different conditions in this region is therefore essential for addressing these issues. In this study, the effects of vegetation coverage (50% and 80%) and rainfall intensity (0.42 mm/min and 0.83 mm/min) on runoff and sediment yield process and its characteristics on slopes with light grazing and closed grazing grassland were investigated through simulated rainfall experiments in Xiazangtan landslide in Jianzha County, upper Yellow River. Results show that increasing vegetation coverage can effectively delay the initial runoff-yielding time and reduce both runoff yield and sediment yield rates on the slope. When vegetation coverage increased from 50% to 80%, the initial runoff-yielding time of light grazing grassland under 0.42 mm/min rainfall was delayed by 234.61%, while average runoff yield rate and sediment yield rate decreased by 29.46% and 55.47%, respectively. Higher rainfall intensity significantly accelerates the initial runoff-yielding time and increases both runoff yield and sediment yield rates. When the rainfall intensity increases from 0.42 mm/min to 0.83 mm/min, the initial runoff-yielding time of light grazing grassland with 50% vegetation coverage was 40.91% earlier, and the average runoff yield rate and sediment yield rate increase by 49.33% and 28.86%, respectively. Grassland grazing prohibition can delay the initial runoff -yielding time on the slope, and reduce the runoff yield rate and sediment yield rate. Under 0.42 mm/min rainfall, the initial runoff-yielding time of the closed grazing grassland with 50% vegetation coverage was delayed by 18.18% compared with the light grazing grassland, while the average runoff yield rate and sediment yield rate were reduced by 10.39% and 21.39% respectively. This study provides scientific basis and guidance for soil erosion evaluation and control of grassland slope in the upper reaches of the Yellow River.