Study On Ecological Restoration Effect Of Different Reclamation Modes In Open-pit Mine Dump

In order to explore the ecological restoration effect of different reclamation modes of the Haizhou Open-pit Mine dump in Fuxin,Haizhou open-pit mine dump was taken as the research object in this study.Five reclamation modes,Robinia pseudoacacia forest land,Ulmus pumila forest land,Robinia pseudoacacia-Ulmus pumila mixed forest land(hereinafter referred to as mixed forest land),farmland and grassland in the dump were selected,bare land was used as the control,and the microclimate factors and soil factors in different reclamation modes of the Haizhou Open-pit Mine dump were measured.The microclimate difference,soil nutrient difference and interannual variation of each reclamation mode were analyzed.The results are as follows :(1)The light intensity,atmospheric temperature,relative humidity,average wind speed,soil moisture content and soil temperature in different reclamation modes in the dump were0.06-129.23 klux,9.22-32.88 °C,14.70%-68.22%,0.60-2.15 m/s,0.60%-44.36%,and3.06-32.66 °C respectively.The diurnal variation of light intensity and atmospheric temperature in different reclamation modes increased first and then decreased;The diurnal variation of relative humidity decreased first and then increased;Soil moisture content decreased with the increase of soil depth in May and October,but it was the opposite in July;Soil temperature decreased with the increase of soil depth.The analysis of interannual variation showed that the interannual variation of each microclimate regulation reclamation model tended to be stable.The principal component analysis method was used to evaluate the microclimate of different reclamation modes.The results showed that: Mixed forest land(2.161)> Ulmus pumila forest land(2.015)> Robinia pseudoacacia forest land(1.823)> grassland(-1.749)> farmland(-2.057)> bare land(-2.192),from which can be found mixed forest land has the best effect on microclimate regulation.(2)With the increase of soil depth,the contents of soil organic matter,total nitrogen,total phosphorus,total potassium,alkali-hydrolyzable nitrogen,available phosphorus and available potassium under different reclamation modes of dump decreased,and the contents were4.07-161.65 g/kg,0.03-3.88 g/kg,0.21-1.28 g/kg,10.75-23.35 g/kg,10.48-273.58 mg/kg,1.60-78.66 mg/kg,0.97-43.69 mg/kg.The analysis of interannual variation showed that Robinia pseudoacacia forest land,Ulmus pumila forest land and mixed forest land had remarkable effects on improving soil nutrient content.The principal component analysis method was used to evaluate the soil fertility of different reclamation modes,The results showed that: Mixed forest land(1.743)> Ulmus pumila forest land(0.881)> Robinia pseudoacacia forest land(0.715)>bare land(-0.793)> farmland(-0.793)> grassland(-1.749).It was obvious that the soil fertility of mixed forest land is the best.(3)The principal component analysis method was used to comprehensively evaluate the ecological restoration effect of different reclamation modes.The results showed that: Mixed forest land(2.251)> Ulmus pumila forest land(1.844)> Robinia pseudoacacia forest land(1.451)> farmland(-1.642)> bare land(-1.825)> grassland(-2.079),and the ecological restoration effect of mixed forest land is the best.The dump reclamation in Haizhou Open-pit Mine should be mainly conducted in the Robinia pseudoacacia-Ulmus pumila mixed forest land.