基于形成机理的石漠化敏感性评价:以贵州省黔西县为例

Sensitivity evaluation of Karst rock desertification based on its formation mechanism:A case study of Qianxi County in Guizhou Province

在遥感解译和野外调查基础上,通过分析石漠化的成因与形成机理,找出影响石漠化敏感性的主要自然因素,选取年降雨量、坡度、岩性组合、土壤质地和植被覆盖度5个指标,在GIS的支持下,采用改进的层次分析法,开展了黔西县石漠化敏感性评价。结果表明:黔西县石漠化仍然处于较为敏感状态,中度、高度和极敏感区域的面积合计为1176.39 km^(2),占46.97%,发生石漠化可能性依然存在;中度、高度和极敏感区主要分布于洪水—仁和、定新—重新、五里—沙井和钟山—铁石—素朴等区域,与石漠化土地的分布区域一致;绝大部分石漠化高度敏感区和极敏感区分布在三叠系碳酸盐岩地层中,嘉陵江组是敏感性最高的地层单元;通过综合研究石漠化各相关因素的作用机理和内在联系及继承关系来比较各相关因素的重要性,可以替代专家调查表方法,来降低层次分析法的随意性和主观性。

Based on remote sensing interpretation and field investigation,this paper analyzes the causes and formation mechanisms of rocky desertification,aiming to identify the impact of key natural factors on the sensitivity of Karst rock desertification.The annual rainfall,slope,lithology,soil texture,and vegetation coverage are selected as indicators for evaluating the sensitivity of Karst rock desertification.The sensitivity evaluation of Karst rock desertification is carried out by using improved analytic hierarchy process,with the support of GIS,in Qianxi County,Guizhou Province.The results reveal that Karst rock desertification remains sensitive,with the total area of moderate,strong,and extremely high sensitivity amounting to 1176.39 km2,representing 46.97%of the studied areas,and the possibility of Karst rock desertification still exists.The moderate,strong and extremely sensitive areas are mainly distributed in Hongshui-Renhe,Dingxin-Chongxin,Wuli-Shajing and Zhongshan-Tieshi-Supu,which are consistent with the distribution pattern of rocky desertification land.Most of the strong sensitive and extremely sensitive areas of rocky desertification are distributed in the Triassic carbonate strata,and the Jialingjiang Formation is the most sensitive stratigraphic unit.Through comprehensively studying the mechanism of various related factors of rock desertification and comparing the importance of each related factor based on their internal relationships and inheritance relationships,we can replace expert questionnaire methods to reduce the arbitrariness and subjectivity of the analytic hierarchy process.