Quantitative analyses on the relationship between water erosion rate and underlying surface factors at regional scale

Using remote sensing, the causes of water erosion were studied and the effects of underlying surface factors on water erosion rate were analyzed. The results show that, among the underlying surface factors that affect water erosion in Chifeng region, slope gradient, relative altitude, gully density and vegetation coverage are significantly correlated with water erosion rate (p<0.01). Land use type reach a significant effect on water erosion rate (p<0.05). In the investigated region, Vegetation coverage of <10%, 11%–30%, 31%–50%, 51%–70%, >70% and cropland coverage corresponds to water erosion rate of 4241.2, 2913.7, 2356.6, 1539.5, 888.0 and 1971.4 t/km2/a. Cropland coverage and vegetation coverage from 31 % to 50% have the corresponding effects on soil and water conservation. The water erosion rate of woodland, shrub land, grassland and cultivated land is less than that of bare land by 28.5%, 27.6%, 23.4% and 6.4% respectively. Slope gradient is one of the principal factors on water erosion. There is a critical slope gradient (25°) for the effect of slope gradient on water erosion.