Soil Erosion Information Entropy: A Comprehensive Measure Index and Simulation Tool for Land Surface Erodibility

摘要

The author put forward the concept for soil erosion information entropy, and expressed by H = -K ∑from i=1 to n of ∑from j=1 to m of ω_(ji) a_(ij) log(ω_(ji) a_(ij)) where K represents unit transform coefficient for information measurement, a_(ij) represents contribution of the jth type corresponding to the ith factor to soil erosion, ω_(ji) represents the weight of the jth type for the ith factor. Soil erosion information entropy, in essence, reflects synthetical information about internal aspect of the ground and also is a comprehensive measure index for erodibility, when related factors of soil erosion are divided into external factor such as precipitation and internal factors such as terrain, physical and chemical properties of soil, land use and land cover, crop, water and soil conservation factors, etc.. Human beings cannot control precipitation process so far, but they do have influences on soil erosion caused by precipitation through change of land surface. Soil erosion information entropy effectively simulates the process of land surface change and manifests its results directly. So it provides a quantative analysis tool for benefit estimation on water and soil conservation. The product of erosion information entropy and precipitation erodibility R(R=EI30), which is αHR (α is unit transform coefficient), can illustrate quantatively the amount of soil erosion and its spatial distribution. This paper also gave a case study at HongShuigou watershed located on tributary of SanChuan river in Shanxi province and gained fairly good results.