Winter grazing has limited impact on soil erosion compared to rainfall in a typical steppe on the Chinese Loess Plateau
摘要
Soil erosion caused by grazing and rainfall is one of the main problems worldwide. Accurately assessing the long-term dynamics of soil erosion and exploring its drivers is essential to mitigate the risks of soil erosion. So far, there is a lack of information on the combined impacts of rainfall and grazing on soil erosion.
MethodsWe conducted 5-year research to monitor soil erosion during 43 rainfall events and the corresponding runoff and soil loss after winter grazing with three intensities (i.e., 2.7, 5.3, and 8.7 sheep ha−1) in a typical steppe during the growing seasons. We recorded the total runoff and soil loss, as well as vegetation traits, and soil properties at the end of growing seasons.
ResultsRainfall contributed more to vegetation in terms of species richness and biomass than grazing. Runoff and soil loss increased when rainfall increased up to 13.5 mm, after which their increase rates decreased. Grazing had more effects on soil bulk density, and soil fractions, while rainfall had more impacts on soil biocrusts. Increasing stocking rate did not alter the intensities of runoff and soil loss. A stronger vegetation root system and higher cover of biocrusts reduced runoff and soil loss, respectively.
ConclusionWinter grazing has little impacts on soil erosion on Chinese Loess Plateau, and it allows vegetation and soil biocrust recovery during the vegetation growing seasons, which may balance the grazing stress and soil erosion in arid and semiarid areas.