基于GIS的大宁河流域土壤侵蚀评价及其空间特征研究

EVALUATION OF SOIL EROSION AND SPATIAL ANALYSIS BASED ON GIS IN DANING RIVER WATERSHED

以大宁河流域为研究区域,采用修正的通用土壤流失方程（RUSLE）为评价模型,以地理信息系统（GIS）软件Arcview 3.3为分析平台,通过数字高程模型（DEM）、土地利用类型和土壤类型等空间数据与属性数据,获取基于栅格数据的小流域土壤侵蚀量和侵蚀强度,对大宁河流域的土壤流失量进行了定量化分析.采用土壤侵蚀综合指数法评价研究区域的土地利用状况、坡度及土壤类型对土壤流失的影响,对水土流失的空间特征进行了研究,并提出了相应的治理措施.结果表明：大宁河流域大部分地区土壤侵蚀模数小于101.73 t·km^-2·a^-1,总体上水土保持良好;不同用地类型上,旱地的土壤侵蚀较草地严重,而草地又较水田的严重;不同坡度等级中,15°-25°上土壤侵蚀强度最强,3°-8°上土壤侵蚀强度最弱;各种土壤类型中,黄褐土的侵蚀强度最重,山地草甸土最轻.

Based on the platform of Arcview 3. 3, soil erosion in the watershed of Daning river watershed is evaluated by using RUSLE. The factors related to soil erosion are inputted to Arcview in vector which include DEM, landuse types and soil types. Then cell based on soil loss and erosion intensity is calculated by using RUSLE based on map algebra. Finally, the measures to gather soil erosion are given. The results indicate that： a） Soil loss in most area is less than 101.73 t·km^2·a^-1·b） The order of the descending degrees of soil erosion in different landuse types is steep dryland, mountainous dryland, middle coverage grassland etc. In general, erosion on dryland is more serious than that on grassland, and grassland is more serious than wetland, c） In the case of different slope gradients, soil erosion at 15-25 degree is the strongest while at 3-8 degress is the weakest., d） Among various soil types, erosion on yellow-brown is the strongest while hill county meadow is the weakest.