基于GIS与RUSLE模型的毕节市土壤侵蚀动态变化

Dynamic Variation Analysis on Soil Erosion in Bijie City Based on GIS and RUSLE Models

通过对毕节市2002~2016年的土壤侵蚀进行定量化研究,为研究区土壤侵蚀治理和水土保持工作提供科学依据。利用研究区多年平均月降水数据、土壤类型、土地利用类型、数字高程(DEM)、MODIS-NDVI月合成数据等,结合RUSLE模型对毕节市多年的土壤侵蚀量进行了计算,通过ArcGIS分析研究区土壤侵蚀量时空变化特征,探讨了不同土地利用类型、高程及坡度等因素下土壤侵蚀面积的变化特征。结果表明:研究区2002年到2016年大体上表现为轻度侵蚀,2005~2010年土壤侵蚀程度最为严重。从县域来看,威宁和大方县土壤侵蚀较严重。从土地利用上来看,耕地、林地、草地发生的土壤侵蚀面积大但侵蚀强度等级较低,未利用地发生小面积的剧烈侵蚀。从高程上来看,1000~2000m这个高程发生的土壤侵蚀最为严重。就坡度而言,8°~15°这个坡度等级的土壤侵蚀最为严重。

A rapid and quantitative study has been doneon the soil erosion inBijie city from 2002 to 2016, which pro vides scientific theory and theoretical guidancefor the management of soil erosion and land use decision. With the help of ArcGIS software platform and data on many years the average monthly precipitation, soil type, land use ＂types, DEM, MODIS NDVI data and so on, combined with RUSLE model, the soil erosion amount of Bijie City was calcu lated for many years. The soil in the study area was analyzed by ArcGIS. The temporal and spatial variation charac teristics of soil erosion amount were used to investigate the variation characteristics of soil erosion area under different land use types, elevations and slopes. The spatial and temporal variation characteristics of soil erosion were used to investigate the influences of different land use type, elevation, slope on soil erosion characteristics. From 2002 to 2016, study area is generally characterized by mild erosion. The degree of soil erosion in 2005 2010 is most serious. Concerning the county, soil erosion of Weiningand Da fang countiesis serious. In terms of land use, the erosion area of cultivated land, woodland and grassland is large, but the erosion intensity is low, while a small area of the unused land is severely eroded. From the perspective of elevation, soil erosion is the most serious at 1000 2000m. In terms of the slope, 8°～15° the slope grades of soil erosion are most serious.