Dynamic monitoring of cultivated land changes in loess mining areas based on time series remote sensing:a case of Dafosi Mining AreaNational Natural Science Foundation of China (51674195)

The western loess mining area is an important coal production base in my country. Large-scale coal mining subsidence has a significant destructive effect on its cultivated land resources. However,there is currently a lack of quantitative monitoring and systematic research on the changes in cultivated land caused by such mining. This article takes the Dafosi Coal Mine in the Loess Plateau as the research area,The time series characteristics of the main crops in the mining area were analyzed through time series remote sensing images,and Landsat images and MODIS remote sensing images were combined with the enhanced adaptive reflectance spatio-temporal fusion model to construct a 30 m resolution NDVI time series data set in the study area,and use the S-G filtering method in the TIMESAT program package to smoothly reconstruct it. Combining multi-spectral remote sensing data and digital elevation models,Object-oriented combined with decision tree classification model is used to obtain time series data of farmland changes in the study area. Based on annual remote sensing data,according to the degree of coal mining disturbance,the monitoring area is divided into coal mining area,subsidence area,indirect affected area,and non-mining affected area. By GIS spatial analysis techniques to analysis the temporal and spatial variation characteristics of the reduced farmland area in the different mining-affected areas,the temporal and spatial distribution characteristics of cultivated land area changes in loess mining areas is revealed,and discusses the destruction of cultivated land and related effects of coal mining subsidence. The results show that the change of cultivated land in the study area is closely related to the mining of coal resources. With the advancement of coal mining,the area of cultivated land in the mining area is decreasing year by year,during the study period,with the largest decrease in the initial stage of coal mining. and there are differences in the reduction of cultivated land in the areas affected by different coal mining disturbances,and the reduction gradually decreases as the distance from the Mine-out area is farther. The reduction of cultivated land mainly occurs at the subsidence boundary and topographical changes. In addition,the production capacity of cultivated land and crop conditions in the goaf and subsidence areas have declined compared with before mining. While coal mining,human intervention and protection measures can alleviate the continuous reduction of cultivated land to a certain extent. which provides a reference for the scientific utilization and protection of farmland resources in the coal mining area of the Loess Plateau.