Effects of vegetation and climate on the changes of soil erosion in the Loess Plateau of China.

Soil erosion is simultaneously driven by multiple factors. Identifying the dominant controlling factors and quantifying the contribution of each factor would be helpful to sustain water and soil resources. China's Loess Plateau was taken as an example area to investigate the above issues since it is the most eroded region in the world, and its soil loss is being controlled by a large-scale revegetation program. We extended the Revised Universal Soil Loss Equation (RUSLE) to large-scale erosion estimation with the aid of GIS for the period of 1986-2015, analyzed the relationship between erosion and controlling factors by correlation and wavelet coherence analysis, and quantified the contribution of each factor to erosion change by the elasticity coefficient method. Results showed that the soil erosion decreased from 1013 t·km-2·a-1 in 1991-1995 to 595 t·km-2·a-1 in 2011-2015, with a downward trend in the whole period. Spatially, most areas had soil erosion of slight intensity, and the areas with high-intensity erosion concentrated in a northeast-southwest strip with hilly-gully landscapes or densely distributed rivers. The changes in surface conditions including vegetation cover and soil conservation measures had dominant effects on the spatial heterogeneity of erosion, their contribution to erosion reduction was 119%. But rainfall erosivity increased soil erosion, and it had a contribution to erosion reduction of -28%. These results are helpful in understanding the mechanism behind the changes in soil erosion and providing information for sustainable soil and water management and vegetation restoration.