Dynamic Assessment of Soil Water Erosion in the Three-North Shelter Forest Region of China from 1980 to 2015

Resumo

To evaluate the risk and dynamic change trends of water erosion status and intensity spatial distribution in the Three-North Shelter Forest Project (TNSFP) region from 1980 to 2015, the revised universal soil loss equation (RUSLE), after integrating precipitation, soil characteristics, vegetative cover, topography, land use, and a cover management factor weighted with rainfall during flood seasons, was employed. The results illustrated that soil conservation improved and the average water erosion rate decreased from 530 to 230 t/ (km² a) following vegetation restoration and land use changes. The water erosion area decreased by 17% in the study area, and 78% of the area tended to be stable. However, a deteriorated region of 14.87 million km² area was determined to be an erosional risk region, mainly distributed on the Qinghai-Tibet Plateau region and the southwestern Sandstorm region, which should be a priority for conservation measures. The new approach to calculate C-factor values, fully considering rainfall intensity as an appropriate weight, provided a rational and reliable estimate of the C-factor on a pixel-by-pixel basis. Further, it was found that the effectiveness of forest land use in reducing water erosion is a significant priority. These results will be useful for soil conservation management and the planning of TNSFP in the future.