近十年来藏东横断山区土壤侵蚀强度变化分析——以烟多镇为例

Analysis of Soil Erosion Change in the Hengduan Mountain Area in Recent 10 Years——Take Yanduo Town as an Example

本文基于研究区2001年和2008年2期的遥感影像数据提取了该区两期土地利用数据、植被盖度数据,并结合该区地形数据,获得了该区两期土壤侵蚀强度数据,对该区土壤侵蚀格局时空变化进行了定量研究。结果显示:1) 研究区土壤侵蚀较轻微。2001年和2008年的结果都表明研究区土壤侵蚀以中度、微度和轻度为主,这三者合计占研究区国土面积的百分比2001年为78.93%,2008年为76.05%;2) 2001年~2008年间,研究区土壤侵蚀明显加重,土壤侵蚀强度结构发生了明显的变化。主要表现在轻度以上土壤侵蚀面积都有所增大,特别是强度以上土壤侵蚀面积增加明显,而微度侵蚀面积明显减少;3) 野外调查结果表明,研究区陡坡开垦和过度采伐林木是导致该区土壤侵蚀加重的主要原因。

The research area’s land use data and vegetation cover data were extracted from the remote sensing imagery, which were acquired in 2001 and 2008. Then combined with topographic data, the soil erosion data of study area in 2001and 2008 were acquired. Final, the spatial and temporal patterns of soil erosion over the study area from 1985 to 2008 were examined and the major changing soil erosion types and their transfer between each other ware explored. Results show that: 1) The soil erosion of study area is slight. The results in 2001 and 2008 all show the slight, light and middle erosion are the primary soil erosion types and their area account for 78.93% in 2001 and 76.05% in 2008. 2) From 2001 to 2008, the soil erosion of study area became more serious and soil erosion structure has changed significantly. The area of light, middle, intense, pole in- tense and severe erosion were all increased, especially the area of intense, pole intense and severe erosion increased markedly. And the slightly eroded area decreased significantly. The result of field survey shows that cultivation on steep slopes and over-harvesting trees are the main reasons which lead to the soil erosion in study area becoming more seriously.