Soil Microoganisms Diversity And Dynamic Changes Of Opencast Mining In Borshil

With the large-scale coal mining activities of opencast mine,the prairie landscape has been destroyed,especially the soil structure and the diversity of plants and microorganisms has been affected seriously.This thesis took the Borshil coal opencast as the research object,did study along the distance gradient from mining area and the time gradient of coal mining disturbance?the opposite direction of the work surface advancing?.The change of physicochemical properties of soils and plant communities structure was measured,and the dynamics of the changes in the quantity and diversity of soil AM fungi and other soil microorganisms were description by morphological and molecular biological methods.We also explained the mechanism of opencast mine on the biodiversity of grassland ecosystem,providing a theoretical basis for ecological security assessment and ecological restoration in mining areas,and the main research results as follows:1.The study area is a typical steppe with Belarus stipa and Lycopersicon.The main dominant species of plant community are Serratula centauroides,Artemisia frigida,Potentilla acauli,and Koeleria macrantha.The Shannon-Wiener index was0.494⁰.776,Simpson index was 1.139¹.580,and evenness index was 0.456⁰.592.Plant diversity decreased with the extension of the time gradient of coal disturbance and the decrease of the distance gradient.2.The physicochemical properties of the soil in the research area were as following:water content was 3.418⁹.827%,pH value was 6.750⁷.612,ammonium nitrogen was 4.400¹4.800 mg/kg,available phosphorus was 3.800¹2.933 mg/kg,available potassium was 11.333¹28.333 mg/kg,total nitrogen was 1.232³.542g/kg,total phosphorus was 0.818².214 g/kg.Mining disturbance reduced the water content,total phosphorus and total nitrogen,and there had a significant effect on the disturbance time?P<0.05?.3.Soil enzyme activities in the research area as following:urease was0.344⁰.880 NH₃-N mg/g,acid phosphatase was 1.456³.529 phenol mg/g,neutral phosphatase was 1.869².874 phenol mg/g,alkaline phosphatase phosphatase was2.141².728 phenol mg/g,sucrase was 0.044⁰.162 glucose g/g,catalase was18.263⁵3.059 H₂O₂?mol/g.Mining disturbance affected the activities of sucrase,catalase and neutral phosphatase,and there was a significant difference on the time gradient?P<0.01?.4.The number of culturable microbial colonies in the study area was as following:bacteria was 1.517-5.750 10⁷ CFU/g,fungi was 0.617-8.383 10³ CFU/g,and actinomycetes was 1.033-3.917 10⁵ CFU/g.Mining disturbances affected the number of fungal and actinomycetic colony,and there was a significant difference on the time gradient?P<0.01?.5.23 species of AM fungi which belong to 9 genera were isolated from the soil in the research area.Among them,6 species belonged to two genera in Acaulosporaceae,1 species belonged to one genus in Ambisporaceae,1 species belonged to one genus in Claroideoglomeraceae,12 species belonged to three genera in Glomeraceae,1 species belonged to one genus in Pacisporaceae,2 species belonged to one genus in Gigasporaceae.The main dominant species were C.etunicatum,G.brohultii,P.scintillans,A.scrobiculata,G.caledomium,of which A.scrobiculata was widely distributed in each plot.6.The spore density of morphological species of AM fungi in the research area was 45.667³01.667 in 20g soil sample;the species richness was 8.667²3.000species in 20g soil sample,the Shannon-Wiener index was 1.856².732,and the Simpson index was 0.721⁰.932;The spore density,species richness Shannon-Wiener index and Simpson index in the topsoil decreased with the extension of the perturbation time gradient and increased with increasing distance gradient.7.Based on 18S rRNA,16S rRNA and ITS high-throughput sequencing,the results showed that the OTU of soil AM fungi belong to Glomus,Diversispora,Paraglomus,Ambispora,Scutellospora;other fungal OTU belong to 13 phylum such as,Ascomycota,Basidiomycota,Zygomycota;the bacterial OTU belongs to Actinobacteria,Proteobacteria,Acidobacteria,Chloroflexi,Verrucomicrobia,Firmicu-tes,Bacteroidetes,Gemmatimonadetes and so on.The diversity of soil bacteria and fungi?including arbuscular mycorrhizal fungi?had a certain trend along with the time gradient of coal mining disturbance,but the variation trend in distance gradient was not obvious.