延河流域退耕前后土壤侵蚀强度的变化

 根据修正通用土壤流失方程,在ArcGIS软件平台下,以黄土高原延河流域为例,在合理选用和计算修正通用土壤流失方程中各因子参数的基础上,计算并分析陕北黄土高原延河流域退耕前后土壤侵蚀量的变化及其动态分布。结果表明:1)延河流域退耕后,土壤侵蚀明显减少,与1986—1997年相比,退耕后至2000年土壤侵蚀量平均减少34%;2)坡耕地对土壤侵蚀影响明显,尤其是陡坡耕地退耕至关重要;3)在修正通用土壤流失方程各因子中,短期内影响土壤侵蚀动态变化的主控因子是植被覆盖管理因子,所以调整土地利用结构是减少土壤侵蚀的有效方法。

Changes of soil erosion intensity due to conversion of farmland to forest and grassland in Yanhe River Basin

Based on the revised universal soil loss equation(RUSLE),the variables for RUSLE were selected carefully and calculated and the dynamic changes of soil erosion were analyzed due to the conversion of slope farmland to forest and grassland in Yanhe River Basin using ArcGIS techniques.The results showed that: 1) after the conversion of slope farmland to forest and grassland,soil erosion decreased greatly.Compared with soil erosion in period from 1986 to 1997,soil erosion amount had been reduced averagely by 30.6% by 2000;2) Of different land uses,slope farmland had the greatest impact on soil erosion,and the conversion of slope farmland to forest and grassland was the main driving force for the reduction of soil erosion;3) In short term,soil erosion was mainly controlled by C-factor,implying that the adjustment of land use structure might be an effective approach to reduce soil erosion.