Study On The Effect Of Vegetation Reconstruction And Recovery On Open-cast Coal Mine Dump

The open-cast coal mines are mostly concentrated in the ecologically fragile grassland areas in Inner Mongolia.In the process of mining,great damage to the grassland ecology will be caused.The most influential area is the dumping site,in where not only formatted the new bare land,but also caused large-scale pollution surrounding the mine area,even caused the debris flow disaster.Therefore,it's an urgent need to solve the problem of ecological restoration in the dump of open-cast coal mine.The open-cast coal mine in Western One and Two of Shengli coal field in Xilinhaote were selected as research sites in this study.After several years of ecological restoration work,the vegetation community characteristics and soil physical and chemical properties were studied by using the field samples investigation and laboratory analysis.The vegetation reconstruction work began in 2007,and the investigation was carried out in 2016.Recovery measures include bio-fence restoration treatment,sand-protecting barrier restoration treatment and control.The different directions of slopes dump were chosen to be the survey objects including sunny slope,semi-sunny slope,shady slope and semi-shady slope.The following results were obtained:1.56 species plants on the dump of the coal field were observed that including 18 families,and 44 genera among them,Gramineae,Compositae,Leguminosae and Chenopodiaceae plants were the dominant families.Bio-fence restoration treatment had the maximum number of species,then followed by sand-protecting barrier restoration treatment and control.The southern and western slopes had the maximum number of species,then followed by northern and eastern slopes.The life-form of functional group dominant by perennial forbs,and followed by annual or biennial herbs and shrubs or sub-shrubs.The dominant species were composed of drought tolerant and barren tolerant species.It's still in the early stage of community succession,and there were typical steppe species invasion.2.The Shannon Wiener index,Simpson index and Pielou index of bio-fence restoration treatment were lower than other 2 treatments,but Margalef index was higher than other 2 treatments,and had a higher biomass above ground.The biodiversity index of control and sand-protecting barrier restoration treatment were higher,but the weight of biomass above ground were lower than bio-fence restoration treatment.The biodiversity index of southern and western slopes were lower,but Margalef index was higher than eastern and northern slopes,and had a higher biomass above ground.The biodiversity index of eastern and northern slopes were higher,but Margalef index was lower than southern and western slopes,and had a lower biomass above ground.3.The soil organic matter,total phosphorus,total nitrogen content of the bio-fence restoration treatment were higher than other 2 treatments,followed by control and the sand-protecting barrier restoration treatment.The soil total potassium of control was higher than other 2 treatments.Southern slope and western slope increased the soil organic matter,total phosphorus and nitrogen content in soil compared to the other 2 slopes,but soil total potassium content is lower than the other 2 slopes.4.The soil moisture content of bio-fence was higher than other 2 treatments,and esatem slope and southern slope were higher than other 2 slopes.