泾河流域土壤侵蚀风险时空演化分析

Spatial-temporal evolution of soil erosion risk is defined as a time changing relationship of soil erosion risk within a certain spatial extent, which is a dynamic evolution process of soil erosion possibility. It is important to evaluate the rationality and benefit of soil and water conservation measures with the notion of evolution risk of soil erosion under different temporal and spatial scales. The study took the Jinghe River Basin located in the center of the Chinese Loess Plateau as an example. Three space data of land use in 1986, 1995 and 2000 were considered. A notion of evolution risk factor and its calculation formula were presented to analyze the evolution risks of soil erosion over 1986-2000 period in the Jinghe River Basin based on GIS technique, information theory and the Universal Soil Loss Equation. Results demonstrate that the soil erosion risk of the watershed decreases and the soil and water conservation measures for over twenty years are effective in general, which offers a new tool to analyze regional soil erosion risk.