| Since 1960 s,the mining of ionic rare earth ore has experienced three technological stages:pool leaching,heap leaching and in-situ leaching.Its special mining technology and characteristics of regional red soil have brought about large-scale land degradation and desertification in mining areas.Therefore,it is very important for ecological management and restoration of rare earth mining areas to construct an effective desertification extraction method and understand the evolution process of land desertification accurately in mining areas.Therefore,in this study,Lingbei mining area in Ganzhou was taken as the study area,Landsat and Google images were taken as the data sources,and the land desertification information in the mining area was extracted by three methods: Albedo-NDVI space,LSMM(Linear Spectral Mixture Model)and RF(Random Forest),and the optimal scheme is selected on the basis of accuracy evaluation and comparative analysis.The influence and interaction of five types of driving factors including terrain,soil,climate,vegetation,and human activities were quantitatively analyzed in the four years before,during,and after reclamation(2000,2005,2010,and 2015)using the geographic probe model.The conclusions are as follows:(1)The results of land desertification inversed by the above three methods showed that the spatial distribution of all kinds of desertified land in rare earth mining areas was basically the same.Severe desertification areas were mainly concentrated in rare earth mines and surrounding bare land,which reflects the influence of rare earth mining on land desertification in mining areas.In quantitative verification and qualitative analysis,the random forest method is the best.(2)From 1986 to 2021,the desertified land area in rare earth mining first increased and then decreased,showing a reverse trend,but it has not recovered to the pre-mining level.It can be divided into four stages: the rapid development stage(1986～1994),the slow development stage(1994～2004),the rapid reversal stage(2004～2011),and the stable reversal stage(2011～2021).During the development period,the main reasons for the intensification of land desertification were rare earth mining,orchard reclamation,and regional urbanization.From2004 to 2021,the land desertification showed a reverse trend and a dynamic decreasing trend,which was mainly related to the national ecological restoration measures.(3)The desertification land disturbed by rare earth mining was the most severely damaged,mainly distributed in the core area of the ore spot,with serious desertification and poor reclamation effect.Moderate desertification and light desertification have not been completely curbed,and the prevention and control of desertification in the later period should focus on the continuous degradation of land caused by cash crop planting.The government should continue to implement ecological restoration projects and desertification control measures for land with serious desertification.(4)Vegetation coverage was the primary factor affecting the distribution of land desertification in rare earth mining areas,followed by land use classification,and other natural factors can not be ignored.In addition,the influence of various detection factors on the distribution of land desertification in rare earth mining areas was weakening in the later stage of reclamation,especially after 2010.The interaction modes of different detection factors were nonlinear enhancement and double-factor enhancement,and the interaction between vegetation coverage factor and other factors was the strongest,reaching more than 50%. |
