基于CSLE模型的珠江流域土壤侵蚀强度评价

Assessment of soil erosion intensity in Pearl River Basin based on CSLE model

为探讨珠江流域土壤侵蚀状况,分析研究区土壤侵蚀的空间格局及主控因子,本文基于中国土壤侵蚀模型(Chinese Soil Loss Equation,CSLE),使用地图代数和空间插值2种方法进行土壤侵蚀制图,并应用地理探测器方法分析土壤侵蚀的主控因子。结果表明:1)研究区土壤侵蚀主要位于研究区内贵州省及云南省、广西中部和广东省沿海区,其中强烈和极强烈侵蚀分布范围较小且位于较零散的坡耕地上;2)地图代数法的制图结果对局地变异表达较好,而空间插值法则对侵蚀速率的宏观格局表达更好,因此空间插值法可作为区域土壤侵蚀制图的首选方法;3)土地利用类型是影响土壤侵蚀的主控因子,其次为植被的影响,其他因素(降雨、地形和土壤等)总体上未表现出控制性影响。因此,调整土地利用结构、优化植被水保功能是今后的主要治理方向,该研究结果可为该区水土流失治理和生态监视提供科学依据。

[Background]Soil erosion has seriously threatened the social and economic development in many regions of the world.The Pearl River Delta is one of the most dynamic economic zones in China and even the world.The Pearl River Basin is located in the south subtropical region,with the disadvantages of heavy precipitation and thin soil.Coupled with the interference of human activities,soil erosion has become more severe.However,it is still insufficient in the current research on the spatial differentiation characteristics and main controlling factors of soil erosion in the Pearl River Basin,which is not suitable for the prosperous economy.Therefore,it is urgent to make use of modern scientific and technological means to systematically study soil erosion in this area.[Methods]In this study,the Pearl River Basin was selected as the study area,and China Water Conservancy Survey(WRI)was used to set up sampling survey units.The Chinese Soil Loss Equation(CSLE)was used,based on the sample survey unit data interpreted by high-resolution remote sensing images and thematic data on soil erosion factors.The map algebra and spatial interpolation were used to calculate the soil erosion rate map in the study area,and to analyze the spatial pattern of soil erosion in the Pearl River Basin.Furthermore,the geo-detector method was used to quantitatively identify the main influencing factors.[Results]1)Among the factors affecting soil erosion rate,R and LS are generally higher,which were the main inducing factors of soil erosion.The B factor value was low,while the E and T factor values were high.The study area had good vegetation coverage and was the main inhibitor of soil erosion.2)The soil erosion in the Pearl River Basin mainly concentrated in Guizhou and Yunnan provinces,central Guangxi and coastal areas of Guangdong province.The areas of intense and extremely intense erosion were relatively small and distributed on relatively scattered sloping farmland.The mean values of soil erosion rate mapped by map algebra and spatial interpolation were 791.78 t/(km^(2)·a)and 615.37 t/(km^(2)·a)respectively.The mean values of the two soil erosion rates were relatively close.The average value of soil erosion rate calculated by map algebra method was higher,which might be related to the difficulty of integrating water conservation measures into the calculation.3)Except for hilly and mountainous area of Zhejiang-Fujian,land use pattern was the main controlling factor of soil erosion,and the influencing factor Q value was above 47%.Secondly,B factor had a great influence on soil erosion rate and its spatial distribution.T factor ranked the third,and K factor and R factor had little influence.That was related to the high vegetation coverage in the study area,which was dominated by forest and grass vegetation.[Conculsions]Two methods of map algebra and spatial interpolation are used to map soil erosion in the Pearl River Basin.Soil erosion is mainly controlled by land use and biological measures.Adjusting land use structure and optimizing the soil conservation function of vegetation are the main direction of future management.This study may provide a reliable scientific basis for ecological environment restoration and soil conservation in this region,and promote the development of soil erosion research in subtropical region.