| Due to the relatively fragile ecosystem in the arid area mining area,coupled with long-term production activities,the ecological environment is extremely vulnerable to damage.At present,it is generally believed that vegetation reconstruction is one of the most effective methods for ecological restoration in mining areas.However,there are large differences in the types of plants suitable for ecological restoration in mining areas in different habitats.Therefore,it is necessary to carry out targeted ecological restoration work for mining areas with different habitats.The No.2Open-pit Coal Mine in the Great South Lake,Hami,Xinjiang Uygur Autonomous Region is located in the extremely arid desert area of Xinjiang.The main limiting factors for ecological restoration are low soil fertility,severe salinization and lack of water.Its vegetation reconstruction is a typical representative of ecological restoration of coal mines in arid areas.In this study,we combined the analysis of environmental characteristics with physical and chemical properties of soil in No.2 Open-pit Coal Mine in the Great South Lake of Hami and preliminarily selected two kinds of herbaceous plants Medicago sativa and Glycyrrhiza Uralensis,and three kinds of suffruticosa plants-Tamarix ramosissima,Lycium chinense,and Haloxylon ammodendron,two arbor plants,Salix hybrid and Elaeagnus angustifolia,as the main plants for ecological restoration in the mining areas,which are used for wind-proof and sand-fixing and soil and improved the physical and chemical properties of soil in the mining area.Based on the monitoring data of changes in soil physical and chemical properties and vegetation growth in the mining area after planting in 2019 and 2020,the effect of ecological restoration was evaluated.On this basis,the TOPSIS model was used to select the optimal planting vegetation,and combined with the evaluation criteria,the ecosystem service function value of the ecological restoration demonstration area was calculated,and suggestions were provided for the next ecological restoration and vegetation restoration work.The results were showed as follows:(1)The average soil bulk density of No.2 coal mine area of the Great South Lake in Hami is1.31 g/cm~3,the average field water holding capacity(Volume)is 33.44%,and the soil has a certain degree of water retention;The study area is desert soil,with the average content of alkali hydrolyzable nitrogen,available phosphorus,available potassium total nitrogen,total phosphorus,total potassium and organic matter are 30.99 mg/kg,1.12 mg/kg,1079.09 mg/kg,0.12 g/kg,0.21g/kg,2.82 g/kg and 21.13 g/kg,respectively.The soil is relatively barren in general.The average surface soil p H is 8.62,accompanied by a certain degree of salinization,in the reconstruction of vegetation,we must choose salt-tolerant,drought-tolerant and barren-tolerant plants.(2)According to the growth status of plants,herbaceous plants can maintain a good growth state in two years of planting,and the plant height and crown width of arbor and shrub vegetation have also increased to a certain extent,so these 7 kinds of plants can be better to adapt to the arid and barren climate and soil environment in the mining area.According to the leaf nitrogen content and chlorophyll content,the most suitable vegetation in the study area is Medicago Sativa,Glycyrrhiza Uralensis,Salix Hybrid and Elaeagnus Angustifolia.In terms of soil physical and chemical properties,the p H value of the soil in the vegetation planting area has shown an increasing trend.Medicago Sativa can significantly increase the content of total nitrogen,available potassium,and alkali-hydrolyzable nitrogen in the soil by 0.11 g/kg,0.51 g/kg and 0.0041 g/kg,respectively.The largest increase in total phosphorus is Salix hybrid,and the increase is 0.15 g/kg.The vegetation that increased the most available phosphorus was Lycium Chinense Mill.,with an increase of 0.27 mg/kg.Most vegetation planting had no significant effect on the available phosphorus in the soil.In general,the vegetation reconstruction in the mining area has played the role of windbreak and sand fixation and soil physical and chemical properties improvement,and has a good effect on the local ecological restoration,but the roles of various plants species are different.(3)Using the TOPSIS model,the best vegetation for soil improvement of 7 plants is Salix hybrid;the best vegetation in terms of ecological benefit is Tamarix ramosissima;Comprehensively all monitoring indicators select the best planting plants to be Salix hybrid,Tamarix ramosissima and Glycyrrhiza uralensis Fisch,but the scores of various plants are relatively close.In the calculation of the ecosystem service function value of the existing planting mode,according to various accounting standards,the total value of the ecosystem service function is 8,8542.5 Yuan. |
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