Study On Vegetation Restoration Of Wasteland Coal Mine In North Slope Of Tianshan Mountain

Coal occupies a dominant position in China's energy consumption and it plays an important supporting role in development of China's economic and social.However,the large area of wasteland generated in the process of coal mining has seriously damaged the ecological environment of the mining area.It is of great significance to explore the vegetation restoration of wasteland in mining area for improving the ecological environment of mining area and realizing the unity of ecological,social and economic benefits.In this paper,taking Heishan mining area on the north slope of Tianshan Mountain as the research background.Through the measurement,analysis and evaluation of the physical and chemical properties of the surrounding soil in Heishan mining area.Using humic acid,water retaining agent,sheep manure and GGR as additional materials,the L₉(3⁴)orthogonal experiment was designed to improve the soil in the waste dump of the mining area.At the same time,analyzing drought resistance of12 kinds of drought-resistant plants from physiological ecology,photosynthesis,and chlorophyll fluorescence parameters.The comprehensive drought resistance of each plant was evaluated by membership function method and gray correlation analysis.In order to provide technical reference of ecological protection and vegetation restoration in arid areas mining area.The research results are as follows:(1)In the surrounding soil of the mining area,only the content of available phosphorus was high,and other nutrient content was deficient extremely.The Soil was alkaline because its p H value was higher than 7.5.The soil bulk density was tight which exceeds 1.35g cm^-3 in the four sample areas.On the whole,the soil around the mining area was deficient in nutrients,so it was difficult for plants to grow.(2)In the improved soil,the contents of organic matter,total phosphorus,alkali-decomposed nitrogen,and available phosphorus were significantly improved compared to the unmodified soil.The proportion of clay and powder particles was decreased,the soil permeability was increased.The bulk density and p H of soil were decreased,therefore the plant habitat was improved.(3)From the perspective of plant growth,in the improved soil,the indicators of Lolium perenne that seedling length,root length,seedling fresh weight,root fresh weight,seedling dry weight and root dry weight were better than unimproved soil,while the root shoot ratio of the umimproved soil was higher than that of the improved soil.Indicating that the improved soil water and fertilizer conditions were superior to the umimproved soil.(4)The results of the soil quality index show that different materials and levels of addition can change the soil quality index and reflect different improvement effects.The soil quality index(SQI)in experiment No.5 was the highest and the improvement effect was the best.Range analysis results show that the preferred combinations of seedling length,root length,seedling fresh weight,root fresh weight,seedling dry weight,root dry weight and root-to-root ratio were C₃A₂B₂D₂,B₁C₃D₁A₂,C₃D₃B₂A₂,B₂C₃D₃A₃,B₂C₃D₃A₃,C₃A₃D₃B₂,A₂B₃D₃C₃.The best preferred combination selected by comprehensive balance method was A₂B₂C₃D₃,which 100g of humic acid,30g of water retaining agent,300g of sheep manure,and GGR0.02g were added to every 2kg of soil.(5)The results of comprehensive drought resistance index showed that among the7 shrub species,Hippophae rhamnoides had the strongest drought resistance,and the Parthenocissus quinquefolia had the worst drought resistance.Among the 5 herb plants,Elymus nutans had the strongest drought resistance,and the Medicago sativa had the worst drought resistance.In the process of ecological restoration of coal mine wasteland,Hippophae rhamnoides and Elymus nutans can be considered as priority planting species.(6)Through the grey correlation analysis of 12 drought resistance indicators and comprehensive drought resistance,it can be seen that before resumption of water,degree of drought stress in plants reached the highest,and the relationship between chlorophyll fluorescence parameters and comprehensive drought resistance index was the closest.After resumption of water,drought stress was relieved,and the correlation between plant non-chlorophyll fluorescence index and drought resistance was increased,while chlorophyll fluorescence parameters was decreased.