基于GIS的滇南踏青河源头小流域近20年土壤侵蚀变化

Changes of Soil Erosion in the Small Watershed of the Taqing River in Southern Yunnan Province in Recent 20 Years Based on GIS

基于地理信息系统技术,以小流域2001年、2007年和2016年Quickbird影像数据为基础,利用RUSLE模型计算了2001年、2007年和2016年的土壤侵蚀量,分析了不同土地利用类型下土壤侵蚀变化。结果表明:踏青河左之河流域土壤侵蚀强度以轻度和中度侵蚀为主,占总面积的79. 44%～80. 55%;茶地面积持续增长,分别为137. 92,146. 46,180. 84hm2;林地占小流域面积的60. 04%～67. 17%;茶地和耕地陡坡种植面积逐年增加,不合理开垦,致使流域内土壤侵蚀加剧。2001—2016年间土壤侵蚀量的分别为44 133. 38,46 600. 56,44 856. 95t/a。土壤侵蚀综合指数变化幅度在5%左右。土地利用变化与土壤侵蚀之间为耦合关系,研究区茶地变化对较耕地对流域内土壤侵蚀影响小,需加强流域内耕地相应的水土保持措施。

Based on the geographic information system technology and the 2001,2007 and 2016 QuickBird image data of the small watershed,the RUSLE model was used to calculate the amount of soil erosion in 2001,2007 and 2016.Analysis was done on soil erosion changes under different land use types.The results show that the soil erosion intensity in the left river basin of the Taqing River is mild and moderate,accounting for 79.44%~80.55%of the total area.The area of tea land continued to increase,which was 137.92,146.46,180.84 hm^2 respectively.The forest land accounts for 60.04%~67.17%of the total area.The planting area of tea fields and cultivated land steep slopes has increased year by year and unreasonable reclamation has caused soil erosion in the basin to intensify.The difference in soil erosion between 2001 and 2016 was 44133.38,46 600.56 and 44856.95t/a,respectively.The soil erosion comprehensive index changes by about 5%.There is a coupling relationship between land use change and soil erosion.The change of tea land in the study area has little effect on the soil erosion in the basin.It is necessary to strengthen the corresponding soil and water conservation measures for the cultivated land in the basin.