基于地理探测器的土壤侵蚀空间分异关键影响因子分析

Analysis of key affecting factors in soil erosion spatial differentiation based on GeoDetector

为探究地理探测器用于确定县级行政区土壤侵蚀空间分异主导因子的可能性,应用中国土壤流失方程(CSLE)计算重庆市合川区与云阳县土壤侵蚀强度,并用地理探测器探究影响土壤侵蚀空间分异的主导因子。结果表明:因子探测发现,坡度因子和生物措施因子分别是合川区和云阳县土壤侵蚀空间分异的主导因子;交互探测结果表明,任意2因子交互时对土壤侵蚀空间分异的影响都具有增强作用,其中2区(县)地形因子与其他因子交互作用最好。地理探测器可用于识别县级行政区土壤侵蚀空间分异的关键因子,用于辅助水土保持方案的制订。

[Background]Soil erosion is one of the environmental problems worldwide.Chongqing is located in the southwest purple soil area,with severe erosion.Exploring the possibility of using GeoDetector to determine the leading factors of soil erosion spatial differentiation in county-level administrative regions,and mastering the leading factors affecting the spatial heterogeneity of soil erosion in each district and county is the basis for effective soil loss control.[Methods]In this study,China Soil Loss Equation(CSLE)model was used to calculate soil erosion intensity in Hechuan district and Yunyang county of Chongqing,and GeoDetector was used to explore the dominant factors and interaction factors affecting the spatial heterogeneity of soil erosion.The CSLE model is based on the USLE and RUSLE.It is widely used because of its simple structure and easy access to parameters.GeoDetector is a statistical model based on spatial autocorrelation,which detects and analyzes spatial heterogeneity.It has four functions of factor detection,interaction detection,risk detection and ecological detection.This article used factor detection and interaction detection for analysis.Factor detection was used to reveal the influence of each factor on dependent variables.Interaction detection was used to judge the relationship between two different factors acting together on the dependent variable.[Results]1)The slope and biological measure factor were the leading ones for the spatial variability of soil erosion in Hechuan district and Yunyang county,respectively.The affecting factors of the spatial differentiation of soil erosion in Hechuan district were ranked in descending order of explanatory power,namely,slope factor S,slope length factor L,tillage measure factor T,biological measure factor B,engineering measure factor E,soil erodibility factor K,and rainfall erosivity R.The affecting factors of Yunyang county were ranked in descending order of explanatory power,namely,the factor B,L,T,S,E,K,and R factor.2)The interactive detection results showed that the effect of any two factors on the spatial difference of soil erosion was enhanced.The largest interaction q values were terrain factors interacting with other factors in the two counties.The top three interaction types in Hechuan district were L∩B(60.1%),S∩B(56.5%),and L∩S(54.1%).The top three interaction types in Yunyang county were L∩B(78.5%),L∩E(59.0%),and S∩B(56.9%).[Conclusions]These results suggest that GeoDetector can be used to identify key factors in the spatial differentiation of soil erosion in county-level administrative regions.Due to the different geographical environments in different regions,the dominant factors affecting the spatial differentiation of soil erosion were regionally different.The determination of the dominant factors can provide targeted opinions for different districts and counties to control soil erosion.