基于GIS和USLE模型的巢湖流域土壤侵蚀评价

Estimation of Soil Erosion using USLE and GIS in Chao Lake Basin,Anhui Province,China

土壤侵蚀是全世界都关心的土地资源与环境保护问题。巢湖作为中国第五大淡水湖,近年来由于水体富营养化产生的水华现象引起多方重视,对巢湖流域土壤侵蚀评估对于环境保护战略与土地规划政策具有重要的意义。基于GIS平台,采用通用土壤流失方程(USLE)来评估巢湖流域14县/区2000年到2010年土壤侵蚀空间分布变化趋势。研究表明:(1)巢湖流域土壤侵蚀严重区域主要分布在金安区、舒城县、居巢区以及含山县的丘陵地区,即杭埠河-丰乐河流域、裕溪河流域与柘皋河流域的上游地区;(2)从2000年到2010年,土壤微度侵蚀、强度侵蚀、极强度侵蚀和剧烈侵蚀区域占巢湖流域总面积比例分别减少了0.5%、0.05%、0.21%和0.23%,而轻度侵蚀、中度侵蚀区域所占比例分别增加了0.98%和0.01%,总体呈现土壤强度侵蚀、极强度侵蚀与剧烈侵蚀区域向轻、中度侵蚀转移的趋势。(3)植被覆盖度变化是巢湖流域土壤侵蚀分级发生变化的主要原因,总体上,2000~2010年研究区由于植被覆盖度的波动性增加呈现土壤侵蚀分级波动性降低的趋势。

Soil erosion is the problem for land resources and environmental protection that the whole world is concerned about. Chao Lake is the fifth largest freshwater lake in China,which is located in the eastern part of China,and was draw much attention for its water eutrophication and cyanobacterial bloom. Therefore,assessment of soil erosion in Chao Lake Basin is of great significance for environmental protection strategy and land planning policy. The Chao Lake Basin was taken as a case study area,GIS and USLE model was employed to evaluate the soil erosion in fourteen counties/districts in Chao Lake Basin from 2000 to 2010. The research showed that：（1） soil erosion areas are mainly distributed in Hilly region of Jinan District,Shucheng County,Juchao District,as well as Hanshan County,namely the upstream region of Hangbu-Fengle River watershed,Yuxi River watershed and Zhegao River watershed in Chao Lake Basin;（2） From 2000 to 2010,the ratio of micro erosion,strength erosion,extreme intensity of erosion and severe soil erosion area in Chao Lake basin were reduced by 0. 5%,0. 05%,0. 21% and0. 23%,and the ratio of mild erosion and moderate erosion area were increased by 0. 98% and 0. 01%,generally showing the trend of transfer from micro erosion,strength erosion,extreme intensity of erosion and severe soil erosion area to the light,micro degree erosion;（3） the change of vegetation coverage is the main reason for the change of soil erosion classification,and the fluctuation of vegetation coverage showed a trend of decrease in soil erosion classification in the study area.