基于RUSLE模型的中国土壤水蚀时空规律研究

RUSLE模型是计算土壤水蚀的经典模型,在大尺度研究时参数率定比较困难。基于气候、土地覆盖、地形特征等空间分异特征,对RUSLE模型的降雨侵蚀力(R)、植被覆盖与管理因子(C)、水土保持措施因子(P)进行了率定,估算了2000、2005、2010、2015年的中国的土壤侵蚀量。结果表明:(1)土壤侵蚀强度较大的地区集中在中国长江中下游平原区、云贵高原、黄土高原区、昆仑山山麓区域,占统计总面积的9.65%。(2)土壤侵蚀明显增大的区域面积达10.36×10~4km~2,分布于新疆农田区、四川盆地、云贵高原东南部、长江中下游平原和东北平原。(3)土壤侵蚀显著改善的区域分布于黄土高原南部、秦岭地区和东南沿海地区,面积约13.6×10~4km~2。通过对RUSLE模型参数的率定,阐明了全国尺度土壤水蚀的时空分异规律,可对不同地区制定相应的土壤修复措施提供依据。

Estimation of soil erosion based on the RUSLE model in China

The revised universal soil loss equation (RUSLE) is an empirical model to predict water erosion (soil erosion); however, the model calculation has limitations at large scale. We calibrated the rainfall erosivity factor (R factor) based on climate zones and the cover-management factor (C factor) based on land-cover types and agricultural crops. The support practice factor (P factor) was also revised based on crop types and land slope. Using the RUSLE, we estimated the annual soil erosion reference values in China in 2000, 2005, 2010 and 2015. The results indicate that: (1) in 2015, the hotspots with major erosion rates are predicted to occur in downstream Yangtze River, Yunnan-Guizhou Plateau, Loess Plateau, and the foothill area of Kunlun Mountains, accounting for 9.65% of the statistical area. (2) The hotspots with a rapid increase of erosion during the study period are located in the arable area of Xinjiang, Sichuan Basin, southeastern Yunnan-Guizhou Plateau, Yangtze Plain and Northeast Plain, which cover 10.36×10⁴ km². (3) The erosion areas with a significant decrease are distributed in the southern and eastern Loess Plateau, Qinling Mountains and Southeast coast of China. These regions cover an area of 13.60×10⁴ km². By calibrating the parameters of RUSLE model, this study obtained the spatial and temporal differentiation rules of soil water erosion at a national scale, which could provide a basis for formulating soil restoration measures in different regions.