Study On The Characteristics Of Soil Bacterial Communities Under Different Vegetation Restoration Methods In Desertified Land Of Poyang Lake

The desertified land formed by the lakeside zone of Poyang Lake is a typical desertified area in the southern region.It has the characteristics of regional uniqueness and regional ecological vulnerability in the soil ecosystem.The changes in natural environment and human activities have led to a series of ecological and environmental problems,such as the decrease of the diversity of sandy land vegetation,loss of soil nutrients,and poor soil in the lakeside zone of Poyang Lake.Improving and restoring the ecological environment of the desertification area of Poyang Lake has always been highly valued by local governments and researchers.Many scholars' research work on the desertified land of Poyang Lake mainly focuses on the formation mechanism of the sandy land,aboveground vegetation,regional microclimate,etc.,and ignores the soil microbial community closely related to soil nutrient cycling and vegetation type diversity.Soil microbes are important participants in nutrient cycling and material transport in soil ecosystems.Understanding the distribution characteristics of soil bacterial communities in Duobao Sandy Land of Poyang Lake has positive significance for the soil degradation ecosystem of sandland.The purpose of this study was to explore the characteristics of soil bacterial communities in sandy land from the effects of different vegetation restoration methods on soil physical and chemical properties,and to explore the correlation between soil environmental factors and soil microbial communities in the desertification control area of Poyang Lake.It shows the enthusiasm of vegetation restoration for sandy land management,and provides basic data and theoretical basis for further sandy soil management by studying the characteristics of sandy soil bacterial communities.Since 2009,the Poyang Lake Desertification Control Team has set up a sand control trial area on the desertification land of Duobao Township,Poyang Lake.By artificially planting wetland pine,vetiver,oleander,lei bamboo and other plants,with the pioneer plants bermudagrass,single leaf Manjing has carried out ecological management and vegetation restoration in desertification areas.In this study,the artificial vegetation restoration test area of the sandy land in Duobao Township,Poyang Lake was selected as the research area.Vine,also set up a bare ground control group(5 treatment methods).The characteristics of soil microbial communities under different vegetation cover in sandy land were systematically studied.In this study,high-throughput sequencing technology was used to investigate the characteristics of the bacterial community composition in sandy soil.The RDA redundancy analysis and Heatmap correlation analysis of soil bacterial communities and environmental factors illustrate the correlation between soil bacterial communities and environmental factors in sandy land.Through the LEfSe statistical tool multi-group comparison strategy,the microbial bacteria in the soil of different vegetation management methods in Poyang Lake sandy land were significantly different.And by using PICRUSt function prediction,the functional species and functional diversity of soil microbial and bacterial communities in the sandy land of Poyang Lake were explored.The test results of this study indicate:(1)The soil bulk density of the desertified land in Poyang Lake is 1.24 g / cm3 ~ 1.51 g / cm3;the soil water content is 2.46% ~ 4.02%;the soil organic matter content is 0.25% ~ 1.78%;the soil total phosphorus content is 0.11 mg / g ?0.39 mg / g;soil available nitrogen content is 11.72 mg / kg?20.63 mg / kg.There are significant differences in soil nutrient content under different vegetation restoration in the desertified land of Poyang Lake,and the soil nutrient content in sandy land is generally barren.(2)The soil bacterial community in the desertified land of Poyang Lake is mainly composed of 36 bacterial phyla,80 bacterial class and 748 bacterial genus.The dominant bacterial phylum of the soil bacterial community in the surface layer(5cm ~ 20cm)of the sandy ground of Poyang Lake is Actinobacteria,Proteobacteria,Acidobacteria,Chloroflexi,Firmicutes,Plantotomycetes,Bacteroidetes,Verrucomicrobia,Cyanobacteria,Unknown Bacteria WPS-2,Patescibacteria,GAL15,etc.Due to the influence of different vegetation types on the soil environment and nutrients,as well as the preference of soil microorganisms for habitat selection,the dominant bacterial communities of soil microorganisms in different vegetation types are different.The dominant soil bacterial community in Pioneer Vegetation is Actinobacteria;the dominant soil bacterial community in bare ground control group is Chloroflexi.The soil bacterial community has significant differences in species diversity and abundance characteristics.By using the LEfSe statistical tool,a group of comparison strategies was used to select 53 bacterial genera with significant differences in soil under different vegetation management methods in the sandy land of Poyang Lake.(3)The diversity and biological characteristics of bacterial communities in the desertified soil of Poyang Lake are affected by the soil physical and chemical properties and vegetation types.Among them,SBD,SOM,TP and AN are the environmental factors that have a greater impact on the soil bacterial community in the sandy land of Poyang Lake.There was no significant relationship between MWC and soil bacterial community in Duobao Sandy Land of Poyang Lake.With the change of surface vegetation types,the types and quantity of surface falling objects,and the differences in root exudates of vegetation,vegetation types have an important impact on the dynamic changes of surface soil microbial communities.The physical and chemical characteristics of the soil and the type of vegetation together shape the changes of the soil bacterial community structure in the sandy land.(4)Nitrogen-fixing microorganisms of soil bacteria in the desertified soil of Poyang Lake mainly have 4 phylums;5 bacteria classes;and 5 bacterial genera.The taxonomic level includes Proteobacteria,Actinobacteria,Planctomycetes and Firmicutes.Phosphobacteria are mainly Bacillus,Pseudomonas,and Bradyrhizobium.By predicting the functional genes of the soil bacterial community in sandy land,the soil bacterial function in sandy land mainly has 6 primary functions and 41 secondary functions.The functional abundance of each functional gene in the soil bacterial community under different vegetation restorations is approximately the same.The functional gene abundance of soil bacteria in Pioneer Vegetation is slightly higher than other treatment groups,indicating that the soil bacterial community of Pioneer Vegetation is highly adaptable in desertified land.Second,the functional gene abundance of soil bacterial community does not change with the change of soil vegetation plots,and the structure of soil microbial community changes due to soil environment,which may indicate that the structure of soil bacterial community precedes the functional gene of soil bacterial community.