Study On Soil Microbial Community Structure And Diversity Of Hippophae Rhamnoides Plantation In Coal Mine Reclamation Land

The ecological restoration and reconstruction of abandoned coal mines has become one of the hot spots in the world.The untreated mine wasteland is one of the important factorscausing environmental pollution and land desertification.In order to study the community structure and diversity of soil microorganism in coal mine wasteland,this study selected the Hippophae rhamnoides forest land reclaimed by Juxinlong coal mine in Dongsheng district of Ordos City as the research area,and selected the Hippophae rhamnoidesand abandoned grassland at the age of 3 a,4 a,5 a,6 a and 7 a as the research objects.Using high-throughput sequencing technology to analyze the changes of soil bacterial community and fungal community structure in different forest ages and different soil depths in the reclamation area.This study focused on the habitat evolution of the ecosystem after land reclamation of mining area,studied and analyzed the soil microorganism and physical and chemical properties of various fields,so as to reveal the relationship between "microbial community and soil environment" in the restoration area.At the same time,the ecological restoration effect of the restoration area is discussed,aiming to provide data support and theoretical basis for the environmental governance in the future land reclamation process of the mining area..The specific research results are as follows:(1)There are 22 phyla,34 classes,40 orders,215 families and 323 genera of bacteria in the soil of Hippophae rhamnoides plantation in different restoration years.At the depth of 0～10 cm and 10～20 cm,actinobacteria and proteobacteria are the main soil bacteria in different forest land,actinobacteria and alpha proteobacteria are the main soil bacteria in different forest land.The number of dominant groups of soil bacteria varies with the age of Hippophae rhamnoides forest and the depth of soil layer.With the increase of the age of Hippophae rhamnoides stands,the diversity of bacterial community first decreased and then increased.At different depths,the species richness and evenness of bacterial community in different age of Hippophae rhamnoides stands in China were different.With the increase of forest age,soil bacterial community structure becomes more complex.At the genus classification level,the dominant genus of each forest age was different..(2)The fungi were 5 phyla,13 classes,27 orders,64 families and 164 genera in the soil of Hippophae rhamnoides plantation in different years.In the depth of 0～10 cm and 10～20 cm,Ascomycota was the main fungi in different forest land,The soil fungi in different forest land are mainly composed of Sordariomycetes,Dothideomycetes,Eurotiomycetes and Leoniomycetes.In different soil depths,with the increase of Hippophae rhamnoides years,the relative abundance of ascomycetes in the dominant group increased first and then decreased,while the relative abundance of Fecocystonales,Chaetomycetes and Acantha varied in different soil depths.With the increase of the age of Hippophae rhamnoides forest,the diversity of Hippophae rhamnoides forest fungi community in soil depth showed differences.The species richness,species evenness and species composition of soil fungi in reclaimed land all affect the diversity of soil fungi community structure,and soil depth and Hippophae rhamnoides forest age are one of the influencing factors.The diversity of soil fungal community structure change with soil depth and forest age.At the taxonomic level of phylum and genus,the depth of soil layer and the age of Hippophae rhamnoides stand have influence on OTUs of each fungus,which determines diversity of fungal species community.Under the genus group,the flora of each forest land was different,showing great species difference.(3)There were significant differences in soil physical and chemical factors in different years of Hippophae rhamnoides plantation in coal mine reclamation land.Under different depth,with the different age of Hippophae rhamnoides plantation,there were significant differences in soil moisture,saturated water content,capillary water holding capacity,total porosity,soil pH,conductivity,soil organic matter,total phosphorus,available phosphorus,available potassium,alkali hydrolyzed nitrogen(P < 0.05),and there was no significant difference in soil bulk density(P>0.05)。The correlation between soil physical and chemical factors and soil bacterial community and fungal community in different rehabilitation years at the mining reclamation area were different.In the correlation analysis of bacterial community and soil physical and chemical factors,7 a Hippophae rhamnoides was significantly different with others;in the correlation analysis of fungal community and soil physical and chemical factors,3 a and 4 a Hippophae rhamnoides forest land had lager difference with others.Soil organic matter and soil available phosphorus had the highest correlation with soil bacterial community and fungal community at 7 a Hippophae rhamnoides forest.