Soil Erosion Influencing Factors in the Semiarid Area of Northern Shaanxi Province, China

The semiarid loess area in north Shaanxi Province is one of the most serious areas of water erosion of China. Vegetation, rainfall, soil, and topography are the most dominant natural factors affecting soil erosion; and land disturbance/restoration is a significant factor influencing runoff and sediment yield in this area. According to the research, the results showed: (1) the relative impacts of the four factors on runoff were rainfall > soil > topography > vegetation, and the relative impacts of the factors on sediment yield were soil > runoff > rainfall > topography > vegetation; (2) during a period of the preliminary stage after land disturbance, topography was the most critical factor for the runoff, while sediment yield was soil. During a period of land restoration after land disturbance, runoff was primarily affected by vegetation, while sediment yield was rainfall; (3) this study showed Hippophae rhamnoides + Pinus tabulaeformis and Hippophae rhamnoides were the best vegetation type for reducing runoff and sediment yield, especially if the slope is less than 20°. Land disturbance is caused by human activities in semiarid regions, and in order to reduce the runoff and sediment yield quickly and effectively, artificial measures should be taken for rehabilitation of the disturbed lands.