基于GIS技术的贵州省土壤侵蚀危险性评价

Assessment of Erosion Risk in Guizhou Province Based onGeological Information System(GIS)Technology

针对目前喀斯特区土壤侵蚀潜在危险度研究相对薄弱的现状,以典型喀斯特区贵州省为研究对象,获取研究区土地利用类型、岩性、基岩裸露率等专题因子。基于地理信息系统(GIS)技术,在非喀斯特区和喀斯特区分别采用《土壤侵蚀分类分级标准》和《岩溶地区水土流失综合治理技术标准》解译出研究区土壤侵蚀强度等级分布图。并根据土壤允许流失量和土壤抗蚀年限,利用土壤侵蚀潜在危险度指数(SEPDI)对贵州省土壤侵蚀潜在危险度进行评价,为喀斯特区土壤侵蚀防治提供参考。结果显示:贵州省水土流失面积为47831.73 km^2,以轻度侵蚀为主,侵蚀模数为341 t/(km^2•a),SEPDI为2.52,潜在危险等级较高。贵州25.3%行政村的SEPDI位于2-3之间,其中六盘水、黔西南市和毕节市危险度最高,建议将水土流失防治工作纳入SEPDI指标而非单从水土流失强弱等级进行治理,特别加强对SEPDI高但水土流失等级弱的区域的关注。

Research on the potential danger of soil erosion in karst area is weak at present.We interpreted the soil erosion intensity in Guizhou Province,a typical karst region,with land use,lithology,and base rock coverage as semantic factors by Geological Information System(GIS)according to Standards for classification and gradation of soil erosion and Techniques standard for comprehensive control of soil erosion and water loss in karst region.Furthermore,we assessed the potential danger of soil erosion in Guizhou by using the soil erosion potential danger index(SEPDI)based on the allowable soil loss value and the soil anti-erosion life.Results suggest that the area of soil and water loss in Guizhou has amounted to 47831.73 km 2,dominated by light erosion,with an erosion modulus of 341 t/(km^2•a)and a SEPDI of 2.52,indicating high level of potential danger.The SEPDI of 25.3%of villages in Guizhou ranges between 2 and 3,among which Liupanshui,Qianxinan,and Bijie feature the highest risk.We recommend that prevention work should be incorporated into SEPDI rather than merely soil erosion degree,and special attention needs to be given to areas with high SEPDI but weak soil erosion levels.