Study On The Change And Evaluation Of Land Ecological Quality In Coal Mining Subsidence Area Of Mu Us Sandy Land

In the context of ecological civilization construction,how to effectively coordinate between large-scale mining of coal resources and fragile ecological environmental protection has become an urgent problem to be solved.The transition zone bordering the northern edge of the Loess Plateau and the southern edge of the Mu Us sandy land is where the Shendong mining area was developed and built up.However,the inherent geographical location and the unique resource endowment of the Shendong mining area make it an important position in the field of coal resources in China while becoming a key area for national-level soil erosion management and supervision.Therefore,it is necessary to carry out research on the changes of land ecological quality in coal mining collapse areas,to prevent the deterioration of land ecology and land degradation in coal mining collapse areas,to provide a basis for regulating the rational mining of mining resources and making decisions on ecological management of mining areas,and to provide a reference for the ecological restoration and reconstruction of coal mines in semi-arid northwest China.Based on the summary of relevant theories and research results at home and abroad,this paper analyzes the change characteristics of the land ecological background,structure,stress and benefits of the study area from1990 to 2019,and constructs an evaluation index system consisting of 4criterion layers and 19 indicator layers,and uses hierarchical analysis(AHP)to determine the weights of each evaluation index,so as to make a comprehensive evaluation of the land ecological quality of the study area.A hierarchical analysis(AHP)was used to determine the weights of the evaluation indexes and conduct a comprehensive evaluation of the land ecological quality of the study area;a barrier degree model was constructed to analyze the barrier factors affecting the change of the land ecological quality of the study area and propose targeted ecological restoration proposals for the mine area.The main research findings are as follows:(1)In terms of ecological background quality,the soil fertility index and remote sensing ecological index(RSEI)of the mine area have a significant increasing trend,the net primary productivity(NPP)of plants has increased significantly in 2006,and the precipitation has a trend of decreasing and then increasing,which indicates that the ecological background changes in the study area are developing in a positive direction,and the role of natural conditions such as soil,climate,vegetation and precipitation in ecological regulation of the study area is indelible.(2)From the perspective of ecological structure quality,the results of the calculation of land use index and landscape index in the mine area show that the land use types of different functions in the study area have increased and the distribution of land tends to be balanced.2006 saw a serious fragmentation of the landscape pattern,but overall the ecological structure change in the study area is developing in an orderly direction,and the land use and landscape pattern in the mine area have an important role in enhancing the stability of the land ecosystem.important role in enhancing the stability of land ecosystems.(3)In terms of ecological stress and eco-efficiency quality,the comprehensive soil pollution index in the study area shows a decreasing trend and is lightly polluted overall,and the population density,gross domestic product(GDP)per capita and ecological service value have increased,indicating that the ecological stress changes in the land of the mine area directly restrict the healthy development of the land ecosystem,and the ecological and economic coordination of the mine area is poor,which is a potential crisis area.(4)From 1990 to 2019,the land ecological quality of the mine area of Bulianta coal mine gradually becomes better.The land ecological quality is the most obvious change for the general grade,and its area keeps decreasing;the area of the area with poor land ecological quality decreases,and the area of the area with good quality increases significantly,but in some areas,the land ecological quality keeps decreasing due to human activities and other reasons;in terms of spatial distribution,the land ecological quality grade of the mine area shows the characteristics of low in the east and high in the west.(5)There are some differences in the main obstacle factors of land ecological quality evolution in the study area in different years.The top three evaluation indicators affecting the land ecological quality of the study area are GDP per capita,ecological service value,and NPP,indicating that the evolution of land ecological quality in the study area is closely related to human activities,and accordingly,corresponding land ecological restoration suggestions are proposed to improve the land ecological quality of the mine area in response to the land ecological quality problems in the study area.