Analysis Of Input-Output And Economic Sustainability Of Different Vegetation Conservation Models In Coal Mining Area

In this study,the vegetation restoration of different conservation models in the northwest arid desert area was taken as the research object.From the perspectives of ecosystem suppliers and consumers,the emergy analysis method and traditional economic value method were used to analyze and compare the emergy input,water saving and tending mode（M₁）,water saving and tending mode（M₂）and conventional mode（M₃）of vegetation restoration In order to provide theoretical support for the selection of cost-effective and efficient vegetation conservation models,the output situation,value input,output situation,system self-organization ability,environmental carrying capacity and sustainable development ability of each conservation model,and the basic structure characteristics of vegetation community were compared and analyzed.The main conclusions are as follows:（1）According to the emergy input and output of different conservation models,the emergy input of three conservation models in Yangchangwan mining area of Lingwu City is4.725E+17 sej·hm^-2-6.398E+17 sej·hm^-2 which is higher than that in Xinxing mining area of Wuhai City(3.788E+17 sej·hm^-2-4.682E+17 sej·hm^-2).The total emergy input of each conservation mode is M₂>M₁>M₃.The structure of emergy input in different conservation models is similar.Purchasing resources is dominant in the total emergy input（more than97%）,and M₂ accounts for the highest proportion.Renewable resources in the conservation modes of Yangchangwan mining area in Lingwu City are the main driving forces for the system operation.The proportion of M₃（62.724%）in total energy input is the same as M1（62.672%）,and both of them are higher than M₂（59.629%）;The non renewable resources in the conservation modes of Xinxing mining area in Wuhai City play an important role in the system operation.The energy output of the same model in each type of area is that of Yangchangwan mining area(2.256E+17 sej·hm^-2-2.725E+17 sej·hm^-2)in Lingwu City is higher than that of Xinxing mining area(1.772E+16 sej·hm^-2-6.652E+16sej·hm^-2),which is the highest in M₁,followed by M₂ and M₃;The energy value output types of each conservation model are mainly support services,mainly organic matter production and forest nutrient accumulation.（2）The results show that the value input and output of different conservation models are M₂>M₁>M₃;In emergy monetary value input,each mode has the same utilization rate of local environmental resources,mainly renewable environmental resources input,and the impact of local environmental resources value input is small.The value output of different conservation models of vegetation reconstruction is M₁,followed by M₂ and M₃.The value output of different conservation modes is mainly supported services（organic matter production,tree nutrient fixation）and carbon fixation and oxygen release in regulating services;From the perspective of direct market value,the value output of vegetation conservation model in different types of areas is mainly carbon fixation and oxygen release in support services and regulatory services;From the perspective of energy value monetary value,the value of support services in vegetation conservation model of each type of area reconstruction is higher than that of regulatory service.Compared with the two different value measurement methods,the input and output of energy value monetary value are less than the direct market value.The input and output of the same conservation model value of vegetation in each type of area are that Yangchangwan mining area in Lingwu City is larger than that of Xinxing mine in Wuhai City.（3）According to the analysis of the sustainability of each conservation model by reconstructing the community structure characteristics,emergy index and economic index,the plant species composition of each model increased in the early stage of vegetation restoration,showing a high species diversity.M₁ had the best effect in species diversity and alien plant species introduction,and had a significant effect in accelerating vegetation restoration.The results show that the input emergy per unit area of each vegetation conservation model in Yangchangwan mining area of Lingwu City is higher,the net emergy output rate,annual output input ratio and profit rate of each model are higher,the economic development degree is higher,the environmental load degree is lower,and the sustainable development ability of the system is strong;The emergy input per unit area of vegetation conservation models in Xinxing mining area of Wuhai City is low,and the self-sufficiency of the system is high.Among the different conservation models,M₁ has higher ratio of production to investment,higher profit rate,higher net emergy output efficiency,lower dependence on purchasing resources and environmental load,stronger self-sufficiency and sustainable development ability,which is the best conservation model for vegetation reconstruction.The emergy input and output efficiency,value input and output,emergy index and economic index of different vegetation restoration models were compared and analyzed.Combined with the basic structure characteristics of vegetation community,it was concluded that the Yangchangwan mining area in Lingwu City was better than the Xinxing mining area in Wuhai City in the same vegetation restoration model in northwest arid desert area;M₁ is the best model among all types of vegetation conservation models.