北京郊区近13年来水土流失变化监测分析——以房山区为例

Monitoring and Analyzing the Soil Erosion Changes in Beijing Suburb During the Latest Thirteen Years——A Case Study of Fangshan County of Beijing Suburb

以Land-sat TM5在1992年、2001年、2004年的三期遥感影像为数据源,采用美国农业部通用土壤流失方程RUSLE计算和分析了北京郊区房山区1990年以来的水土流失量和水土流失面积变化,并在此基础上利用主成分分析法进一步分析比较了土地利用变化对水土流失的影响。分析结果认为,研究区三年间均以轻度水土流失为主,但三年间总体水土流失以2004年最严重,2001年最轻。不同的土地利用类型对三年的水土流失影响不同,未利用地水土流失严重程度2004年>1992年>2001年,农田1992年>2004年>2001年,草地2001年>1992年>2004年,林地2004年>1992年>2001年。研究区历年总体水土流失变化与林地的水土流失变化一致,反映了林地的水土流失对研究区内的水土流失起主导作用,揭示了保护和绿化好林地,降低林地的水土流失程度对减缓和降低研究区的水土流失具有重要作用。

Based on three times RS images of Landsat TM5 in 1992,2001 and 2004, the area and quantity changes of soil erosion in Fangshan county , which was selected as one case of soil erosion area in Beijing suburb, were derived using RUSLE equation from USDA. And the effect on soil erosion from LUCC since 1990s was researched and compared using principle component analyses. As the result showed, the research results by using the different parameters of soil erosion quantity and soil erosion area, were consistent. During the three years, light level of soil erosion was always dominant on the whole area erosion. The soil erosion in 2004 was the most severe, just the opposite, the soil erosion in 2001 was the most light. The effect of different LUCC types on soil erosion was also different. On naked land, the soil erosions were severe by the following sequence that one of 2004 〉 one of 1992 〉 one of 2001. Otherwise on field land, it was the sequence of one of 1992 〉one of 2004 〉one of 2001, and on the grassland, it was one of 2001 〉one of 1992 〉one of 2004, while on forestry land, it was one of 2004 〉 one of 1992 〉one of 2001. Based on the consistent changes of soil erosion in different years and that on forestry land in different years, it is showed out that the soil erosion on forestry land is dominant on that of the research area. So it is very important to relieve the soil erosion by protecting and foresting the forestry land in the research area.