1992-2013年巢湖流域土壤侵蚀动态变化

Dynamic changes of soil erosion in the Chaohu Watershed from 1992 to 2013

基于GIS和RS技术,利用修正的通用土壤流失方程(RUSLE)模型,结合遥感影像、DEM数据、土壤类型数据及相关统计确定了模型中参数因子,计算出巢湖流域1992-2013年土壤侵蚀模数,分析了土壤侵蚀强度的时空动态变化特征。结果表明:巢湖流域土壤侵蚀区域主要呈东北至西南方向分布。微度、轻度、中度、强度、极强和剧烈侵蚀占土壤侵蚀总面积百分比分别是93.46%、6.25%、0.68%、0.19%、0.01%、0.01%。1992-2006年土壤侵蚀模数由510.70 t/(km2·a)减少到129.79 t/(km2·a),降幅为74.59%,同时植被覆盖率由37.0%增至47.80%,土壤侵蚀的面积比例变化明显,轻度、中度、强度、极强和剧烈侵蚀由8.93%、2.33%、1.32%、0.09%、0.05%分别减少为4.74%、1.39%、0.28%、0.02%、0.01%,微度侵蚀由87.88%增加到94.16%。但2013年土壤微度侵蚀又减少为93.46%,土壤微度侵蚀有向高一级转换趋势。2006-2013年土壤侵蚀模数也由129.79 t/(km2·a)增加到149.44 t/(km2·a),增幅为15.14%。

With the help of GIS and RS technology, and based on remote sensing image data, DEM data, soil type data and relevant statistical data, we use the modified universal soil loss equation （RUSLE） as the evaluation model to determine the relevant parameters of the model, to calculate the soil erosion modulus in Chaohu Watershed from 1992 to 2013, and to analyze the spatial and temporal dynamic changes of soil erosion intensity in this region. The soil erosion area in Chaohu basin is mainly distributed in the NE-SW direction. Slight, mild, moderate, intense, strong and severe erosion accounted for 93.46%, 6.25%, 0.68%, 0.19%, 0.01% and 0.01% of the total watershed area respectively. The largest erosion area was paddy field, accounting for 64.42% of the total watershed, followed by woodland （20.98%） and urban and industrial land （10.36%）, which was based on micro erosion and mild erosion mentioned above. From 1992 to 2006, the soil erosion modulus decreased from 510.70 t/（km^2·a） to 129.79 t/（km^2·a）, falling by 74.59%, while the vegetation cover increased from 37% to 47.80%. The change of soil erosion area was obvious： mild （8.93%）, moderate （2.33%）, intense （1.32%）, extreme （0.09%） and severe erosion （0.05%） were reduced to 4.74%, 1.39%, 0.28%, 0.02% and 0.01%, respectively, while slight erosion increased from 87.88% to 94.16%. However, the slight erosion reduced to 93.46%, and the slight erosion had a worsening trend in 2013. From 1992 to 2013, the soil erosion modulus increased from 129.79 t/（km^2·a） to 149.44 t/（km^2·a）, an increase of 15.14%, meanwhile the vegetation cover rate decreased from 47.80% to 45.15%.