喀斯特区土壤侵蚀与石漠化协同演变及交互关系

Synergistic Evolution and Interaction of Soil Erosion and Rocky Desertification in Karst Area

为探究喀斯特地区土壤侵蚀、石漠化协同演变规律、驱动因子及主要驱动因子下二者交互关系。采用优化后的RUSLE模型估算贵州省喀斯特地区2005—2015年土壤侵蚀,并利用贵州省全国石漠化普查数据库计算同期石漠化状况,运用地理探测器探究驱动因子以及主要驱动因子下二者交互关系。结果表明:2005—2015年贵州省喀斯特地区土壤侵蚀与石漠化均以中度及以下为主,其中土壤侵蚀中度及以下占比58%以上,而中度及以下石漠化占比达80%以上;时间上二者存在发生时间的异同性,但研究期间,二者均不同程度地趋于好转;中度及以下石漠化中土壤侵蚀发生率较大,中度以上中占比极少,其中无石漠化中土壤侵蚀发生率达70%以上;土壤侵蚀驱动因子解释力大小依次为土地利用>坡度>年降雨量>海拔>岩石裸露率>植被盖度>岩性>土层厚度,石漠化驱动因子解释力大小依次为岩石裸露率>土层厚度>年降雨量>海拔>岩性>土地利用>植被盖度>坡度。因子组合(交互)对土壤流失及石漠化的解释力均较单因子有所增强,其中土壤侵蚀的主导因子为土地利用,石漠化的主导因子为岩石裸露率;主要驱动因子下二者交互关系结果表明,土壤侵蚀与石漠化存在因果关系且土壤侵蚀先于石漠化发生发展,但简单线性关系并不能解释二者关系,而是分阶段呈正相关或负相关的复杂关系。研究结果可为喀斯特地区土壤侵蚀与石漠化防治提供理论参考。

The purpose of this study was to explore the co-evolution of soil erosion and rocky desertification and their interaction under driving factors and main driving factors in the karst region.In this study,Optimized RUSLE model was used to estimate soil erosion from 2005—2015 in the karst area of Guizhou Province,and the national rocky desertification census database was used to calculate the rocky desertification in the same period,and the Geographic detector was used to explore the interaction between the drivers and the main drivers.The results showed that soil erosion and rocky desertification from 2005 to 2015,karst area in Guizhou Province were mainly moderate and below,soil erosion accounted for more than 58%,and moderate and below rocky desertification accounted for more than 80%;In terms of time,there were similarities and differences in the occurrence time of these two,but during the research period,both of them tended to improve in varying degrees.The incidence of soil erosion in moderate and below rocky desertification was large,and the proportion of above moderate rocky desertification was very small,among which the incidence of soil erosion in no rocky desertification was more than 70%.The explanatory force of the soil erosion driver was the land use>slope>yearly precipitation>elevation>rock exposure rate>vegetation cover>lithology>soil thickness;The explanatory force of the rocky desertification driver was the rock exposure rate>soil thickness>yearly precipitation>elevation>lithology>land use>vegetation cover>slope.The explanatory force of factor combination(interaction)on soil loss and rocky desertification was enhanced compared with the single factor,in which the dominant factor of soil erosion was land use,and the dominant factor of rocky desertification was rock exposure rate;The results showed that the causal relationship between soil erosion and rocky desertification exists and soil erosion develops before rocky desertification,but the simple linear relationship cannot explain the two relationships,but a complex relationship with positive or negative correlation exist in stages.The results can provide theoretical reference for soil erosion and rocky desertification control in karst area.