Study On Succession Pattern Of Reclaimed Soil Microbial Community In High Ground-water Level Mining Area

Due to the dual pressure of arable land protection and food production,ecological restoration in high dive mining areas is mainly based on land reclamation.The quality of reclaimed farmland is often poor due to disturbances from coal mining and reclamation activities,and the problem of low quality reclaimed farmland in eastern high dive mining areas is more serious.Changes in the structure of microbial communities during soil restoration after reclamation can affect the soil formation and soil quality of reclaimed farmland.Strengthening microbial research on reclaimed farmland and examining the spatial and temporal distribution patterns of soil microbial community species composition can help improve reclamation techniques in mining areas and enhance the quality of reclaimed farmland in coal mining collapsed areas.Therefore,it is necessary to take microorganisms as a possible breakthrough in diagnosing and improving reclaimed farmland,collect soil from fields with different reclamation years,and carry out research on microbial community succession patterns in reclaimed farmland in eastern high dive mining areas.In this study,we used laboratory assays and high-throughput sequencing techniques to collect sample sites from reclaimed farmland of different reclamation years,and used a large amount of sample data to analyse and identify the drivers of microbial succession in reclaimed farmland from the perspective of interactions,and to comprehensively analyse the spatial and temporal heterogeneity of microbial community composition in reclaimed farmland.The following key findings were obtained.(1)The reclamation of the land resulted in significant changes in soil physical and chemical properties and enzyme activities.Nitrate-nitrogen,ammonium-nitrogen,fastacting potassium and total nitrogen content showed an overall tendency to increase rapidly with the number of years of reclamation,and were positively correlated with the number of years of reclamation.Effective phosphorus and organic matter were the highest in the control farmland,and their contents tended to decrease first and then increase in the different years of reclamation.The p H,conductivity and oxidizable organic carbon content of the reclaimed fields remained at a relatively stable level and were slightly higher than those of the control fields.Urease,polyphenol oxidase,dehydrogenase,catalase and ?-glucosidase all showed an increasing trend with the increase of reclamation years,and were positively correlated with the length of reclamation years,and their contents were higher than those of the control farmland.(2)The microbial community structure changed significantly after land reclamation.The composition of the microbial community was relatively similar between the reclaimed fields and differed significantly from that of the control fields.At different taxonomic levels,such as phylum,family and genus,Acidobacteria,Chloroflexi,Proteobacteria and Bacteroidetes were the most dominant groups,while Acidobacteria and Chloroflexi were the dominant groups.The dominant groups of Acidobacteria and Chloroflexi were more abundant in the reclaimed fields and showed an overall trend of increasing with the number of years of reclamation,while the dominant groups of Proteobacteria and Bacteroidetes were more abundant in the control fields.The abundance of the dominant groups of Proteobacteria and Bacteroidetes was higher in the control farmland and showed an overall trend of decreasing with the number of years of reclamation.(3)First,Based on the OTU data,the microbial community composition of farmland of different years of reclamation and control farmland are similar to each other,and the patterns are consistent at the taxonomic level,such as phylum,family and genus,and there is intersection between the sampling points of the reclaimed farmland,indicating that the microbial community composition of the reclaimed farmland has some similarity,and there are obvious differences with the sampling points of the control farmland This indicates that the microbial community composition is different from that of the control farmland.Second,Soil environmental factors showed an overall positive correlation between p H,catalase,urease,EC,nitrate-nitrogen,polyphenol oxidase and ?-glucosidase,with p H,catalase and urease significantly positively correlated with EC,nitrate-nitrogen,polyphenol oxidase and ?-glucosidase significantly positively correlated,and overall negatively correlated with effective phosphorus and phosphatase,especially phosphatase and p H,catalase and urease almost in In particular,phosphatase and p H,catalase and urease were almost in a straight line,with significant negative correlations,and the pattern remained consistent at the taxonomic level of phylum,family and genus.Third,The dominant microbial groups show a positive correlation between the dominant group of Acidobacteria and the dominant group of Chloroflexi,the dominant group of Proteobacteria and the dominant group of Bacteroidetes,and the dominant group of Acidobacteria,Chloroflexi and the dominant group of Proteobacteria,Bacteroidetes and Bacteroidetes.The dominant groups of Acidobacteria and Chloroflexi are negatively correlated with the dominant groups of Proteobacteria and Bacteroidetes,and the pattern is consistent at the taxonomic level of phylum,family and genus.Fourth,The overall correlation between microbial dominance and environmental factors showed that p H,catalase,urease,EC,nitrate,polyphenol oxidase and ?-glucosidase were positively correlated with the dominant group of Acidobacteria and Chloroflexi,and negatively correlated with the dominant group of Proteobacteria and Bacteroidetes.The dominant groups of Proteobacteria and Bacteroidetes were negatively correlated.Phosphorus and phosphatase were positively correlated with the dominant groups of Proteobacteria and Bacteroidetes and negatively correlated with the dominant groups of Acidobacteria and Chloroflexi,especially Phosphatase was significantly negatively correlated with the dominant group of Acidobacteria at an angle close to 180 degrees,suggesting that this environmental factor may have a strong inhibitory effect on its abundance,and polyphenol oxidase and ?-glucosidase were significantly positively correlated with the dominant group of Chloroflexi,suggesting that these two environmental factors may have the most The pattern was consistent across the phylum,family and genus levels.Fifth,The dominant groups of Acidobacteria and Chloroflexi were more abundant in the reclaimed fields and positively correlated with environmental factors such as p H,catalase,urease,EC,nitrate nitrogen,polyphenol oxidase and ?-glucosidase.The dominant groups of Proteobacteria and Bacteroidetes were more abundant in the control field and were positively correlated with phosphatase and effective phosphorus.Therefore,the key environmental factors that cause changes in the structure of the reclaimed soil microbial community can be identified,and the driving factors that affect the succession of the reclaimed soil microbial community can be identified,thus providing a theoretical basis for the screening of beneficial microbial communities for land reclamation in high diving coal mine subsidence areas.There are 59 charts,6 tables and 151 references in this thesis.