Approach to soil erosion assessment in terms of land-use structure changes

Variations of land-use pattern directly affect both soil conservation and ecological conditions. For regions where soil erosion data are scarce or not available, information on land-use structure changes from various human activities could be used to interpret the soil erosion trends. In this paper, a new approach to soil loss assessment in terms of land-use in Lice changes (SL-LUS) is proposed, using the analytic hierarchy process. The degrees of impact at different levels of land use are determined with the pairwise comparison matrix. A land-use Structure characteristic Index (SI), defined as the sum of products (impacts) between each weighted land-use type and the percentage of the impacted area in the whole test region (composite of various land-use patterns), is developed to reflect the resulting impacts of human factors and serve as an indirect measure of soil erosion variation. Moreover, a new assessment procedure for regional soil erosion is presented, which entails a processes of reference sites selection, classification of reference groups, determination of environmental variables, identification of the matching groups for the test sites, and the comparison of observed and expected results. Application of this approach to a case study in the Zhifanggou Watershed in Ansai, Shaanxi Province, China, indicates that the methods adapted is practical in reasonably describing the processes of soil erosion and in evaluating regional ecological variations.