Rates of soil erosion in China: A study based on runoff plot data

Abstract

Soil erosion has been a major environmental issue in China. However, the overall rate and the variability in runoff and soil loss of different regions and land uses in China have not been reported in the literature. In this study, an extensive database of runoff plots in China was compiled. Runoff and soil loss rates of sheet and rill erosion under natural conditions based on plot studies, are reviewed. The history of plot studies in China is briefly introduced, and basic information, such as the geographic distribution of soil erosion monitoring sites, the distribution of slope length and the slope gradient of runoff plots, is described. The runoff and soil loss rates of five water erosion regions in China were analyzed in terms of the main land use types. The soil loss rate was 30.87–107.44tha−1 a−1 on fallow land and 7.65–49.38tha−1 a−1 on farmland under conventional tillage. The land use types with permanent cover experienced the lowest soil loss rates, which were 0–1.89, 0.28–8.06 and 3.98–1.57tha−1 a−1 for forest, shrub and grassland, respectively. In China, the regional differences in the soil loss rate were mainly observed on fallow land and farmland, whereas almost no differences were observed on forest, shrub and grasslands. The soil loss rates of forest, shrub and grasslands showed no significant differences worldwide. However, the soil loss rates of farmland with conventional tillage in northwest and southwest China were much higher than in most other countries. This indicated that farmlands in China are still suffering from a very serious erosion problem that requires additional future attention. This study provided a broad assessment of sheet and rill erosion for prioritizing problems and selecting the appropriate erosion control practices.