鄂渝喀斯特山区土壤侵蚀特征及主影响因子识别分析

Identification and analysis of soil erosion characteristics and main influencing factors in the karst mountainous areas of Hubei and Chongqing

鄂渝喀斯特山区属于水土流失敏感地带,生态脆弱,对这一典型区域进行水土流失的空间差异性研究及其主影响因子识别分析,能为中微观尺度上开展针对性的水土流失治理提供重要指导作用.为此,在GIS和RS等多种技术手段的支持下,对地处鄂渝喀斯特山区的8个县市,基于修正的通用水土流失模型(revised universal soil loss equation,RUSLE)进行土壤侵蚀模数的测度,并采用耦合灰色关联度的改进型层次分析法逐一确定各地水土流失的主影响因子,结果表明:鹤峰县的土壤侵蚀模数最大,宣恩县次之,其余各县市从大到小依次为彭水、酉阳、咸丰、黔江、利川和来凤;研究区内水土流失呈现出这一明显空间差异性的原因,主要源于各县市水土流失的主影响因子不尽相同,其中在鹤峰县,各影响因子对当地土壤侵蚀强度的贡献度是地形坡度(LS)>植被覆盖(C)>水土保持措施(P)>降雨(R),而彭水县是R>LS>C>P,其他县市则为LS>C>R>P.

The karst mountainous area in southwest China is a sensitive area of soil erosion,and the ecology is fragile.The spatial difference of soil erosion in this typical area,and the identification and analysis of its main influencing factors can provide targeted soil erosion control at the medium and micro scale.To this end,in the support of GIS and RS,and other technical means,the soil erosion status is measured based on the revised universal soil loss equation(RUSLE)in eight counties and cities in Hubei and Chongqing karst mountainous area.And the improved analytic hierarchy process with coupled grey correlation degree is used to determine the main influencing factors of soil erosion in each place.The results showed that He Feng had the largest soil erosion modulus.Secondly,it was followed by Xuan En,Peng Shui,You Yang,Xian Feng,Qian Jiang,Li Chuan and Lai Feng.The reasons for the significant spatial difference in soil erosion in the study area were mainly related to slope length factor(LS).In addition,the main factors of soil erosion were different among counties and cities.Among them,the weights of Peng Shui were from R to LS,C,and P,and the weights of He Feng influence factors were sorted from large to small,that was:LS,C,P,R.The weighting of each impact factor in other counties and cities was consistent with the ranking of LS,C,R,and P in the whole region.