The Effect Of Plant-Microbe Compound Technology On Vegetation And Soil Factors Of Open-Pit Coal Dump In Typical Grassland Area

In the process of open-pit coal mining,the stripped ground surface destroyed the structure of vegetation and soil,and a large area of exposed dump was formed.The restoration of vegetation and soil in the dump is the core issue of ecological restoration in open-pit coal mines.The effect and adaptability of the vegetation restoration technology used in the dump site of the mining area will affect the ecological restoration process and the safety,sustainability and stability of the ecosystem.The Shengli No.1 open-pit coal mine located in the Xilin Gol Grassland formed dumps of different periods and implemented artificial vegetation construction along with its mining.This article took the dump site and the natural grassland outside the mine as the research object,and compared the species structure of the plant community,the diversity of plants and soil microbes,and the changes in soil non-biological factors.Focusing on monitoring the effect of vegetation restoration technology on the plant and soil of the dump site where the different plant configurations and microbial combinations was implemented in 2019,this study aimed to explore the best technical model and optimization plan suitable for the vegetation restoration and ecological restoration of the dump site of the open pit coal mine,and provide basic research data for the vegetation restoration of the dump site of the open pit mine.The main results are as follows:(1)The dominant species in the natural grassland outside Shengli No.1 open-pit mine were Leymus chinensis,Stipa grandis and Cleistogenes caespitosa;the dominant species in the southern dumping site was artificial planting Alfalfa(Medicago sativa),etc.;the dominant species in the northern dumping site was Artemisia sieversiana;the composition and diversity of the plant community in the study area were:coverage 9.03-80.40%,species richness 2.00-7.67 Species/m~3,density 7.20-93.67 plants/m~3,Shannon Wiener index 0.23-1.65,Simpson index0.11-0.71,uniformity index 0.24-0.89.(2)The physical and chemical properties of the soil in the study area were:water content 3.60-25.93%,pH 7.39-9.22,ammonium nitrogen 9.88-130.03 mg/kg,available potassium 1.49-34.02 mg/kg,and available phosphorus 2.53-3.44 mg/kg,Nitrate nitrogen 2.19-73.13 mg/kg,carbon to nitrogen ratio 8.76-42.61.The soil physical and chemical properties of natural grassland and dumping site were significantly different(P<0.05).(3)The enzyme activities in the study area were:acid phosphatase activity2.29-11.79 mg/g,alkaline phosphatase activity 0.07-13.17 mg/g,neutral phosphatase activity 0.39-10.93 mg/g,catalase activity 111.80-113.60?mol/g,urease activity0.33-0.82 mg/g,sucrase activity 19.60-548.377 U/g.The soil enzyme activity of the natural grassland was significantly higher than that of the dump(P<0.05).(4)The number of cultivable bacteria in the study area was 1.33-117.00*10~4CFU/g,the number of cultivable fungi was 1.33-135.67 CFU/g,and the number of cultivable actinomycetes was 3.00-245.33*10~3 CFU/g.The number of soil microorganisms in the natural grassland was significantly higher than that in the dump(P<0.05).(5)A total of 16 species of Arbuscular mycorrhzal fungi belonging to 3 families and 7 genera were isolated and identified from the soil in the study area.Among them2 genera and 5 species belonging to Acaulosporaceae family,1 genus and 2 species belonging to Claroideoglomeraceae family,3 genera and 8 species belonging to Glomeraceae family,and 1 genus and 1 species belonging to Gigasporaceae family,respectively.The dominant species were Glomus reticulatum,G.macrocarpum,Septoglomus deserticola.The AM fungal spore community composition and diversity in the study area were:species richness 2.00-9.33 species/20 g soil sample,spore density 6.00-147.00 per/20 g soil sample,Shannon Wiener index 0.53-1.72,Simpson index 0.29-0.79,The uniformity index is 0.44-0.92.The AMF diversity of the natural grassland was significantly higher than that of the dump(P<0.05).(6)The 16S high-throughput sequencing results showed that the soil bacteria OTU belonging to Actinobacteria,Proteobacteria,Acidobacteria,Chloroflexi,Gemmatimonadetes,etc.,a total of 12 identified phyla.The bacterial genetic diversity indices in the study area were:shannon:5.16-6.56,simpson:0.0042-0.0545,chao:2874.975-3928.816.ITS high-throughput sequencing results showed that the soil fungi OTU belonging to Basidiomycota,Glomeromycota,Chytridiomycota,Olpidiomycota and Mortierellomycota,a total of 8 identified phyla.The fungal genetic diversity indices in the study area were:shannon:1.9478-4.5308,simpson:0.0266-0.3694,chao:168.0667-682.2969.AMF high-throughput sequencing results showed that a total of 19 AM fungi were identified in soil AM fungi,including G.intraradices,G.caledonium,G.mosseae,and G.viscosum.The genetic diversity indices of AM fungi in the study area were:shannon:0.3714-3.3062,simpson:0.0731-0.8334,chao:8.333-124.375.(7)The plant diversity index had a very significant positive correlation with water content,available potassium content,total carbon,and carbon-hydrogen ratio(P<0.01),and a significant positive correlation with phosphatase activity(P<0.05).The number of microorganisms was extremely significantly positively correlated with water content,total nitrogen,total hydrogen,invertase,and phosphatase(P<0.01),and extremely significantly negatively correlated with pH,available phosphorus,carbon-to-nitrogen ratio,and carbon-to-hydrogen ratio(P<0.01).The diversity of AMF spores was significantly positively correlated with water content,available potassium,and neutral phosphatase(P<0.05),was extremely significantly positively correlated with acid phosphatase and alkaline phosphatase(P<0.01),and was significantly negatively correlated with pH Correlation(P<0.05).(8)In the experimental area,the plant coverage and plant diversity of the Caragana korshinskii single-cropping plot were higher than other plots.The soil physical and chemical properties and soil enzyme activity levels of the Astragalus and Alfalfa mixed-cropping plot were higher than other plots,and the number of microorganisms was higher,AMF spores had the highest density,76 per/20 g soil sample.