Soil Microbial Composition And Response Of Nitrogen And Phosphorus Soil Enzymes To Habitat In Different Stages Of Karst Vegetation Restoration

In this study,high throughput technology was used to sequence soil microorganisms.Taking limestone soil in Karst Plateau as the research object,The topsoil in different niches under four different vegetation restoration stages of forest,shrubland,brushwood and glassland communities was collected.Combining field experiment with indoor control experiment,The differences of physical and chemical properties of niche soil under different vegetation stages were analyzed.The identification of soil microbial species in different vegetation restoration stages and the correlation between microorganisms,soil nutrients and soil enzyme activities were studied by high-throughput technology.Revealing fungi and bacteria composition in different stages of karst vegetation restoration and clarifying the response of N/P functional microbial activity to different stages of restoration and their niches are of great significance for understanding the role of microorganisms in the process of degraded karst vegetation restoration.The main conclusions are as follows.1.Soil fungi under vegetation in Karst Plateau are mainly composed of Ascomycetes,Basidiomycetes,Zygomycete and unclassified fungi.Bacteria are mainly composed of 12 bacteria,including Proteobacteria,Actinobacteria,Acidobacteria,Chloroflexi,Nitrospitae,Verrucomicrobia,Planctomycetes,Firmicutes,Bacteroidetes,Tectomicrobia,Gemmatimonadetes and Unclassified Bacteria(Others).The difference of fungi and bacterial composition between different stages of vegetation restoration is greater than that between different niches in the same stage.The composition of soil fungi in forest and shrubland stage is similar,mainly consisting of Geminibasidium,Mortierella,Sebacina,Penicillium,Ascomycota and unclassified fungi.Trichoderma,Penicillium,Herpotrichiellaceae,Thelephoraceae,and unclassified fungi are the key dominant fungi groups.The transitional stage of brushwood and grassland community was divided into one type.The transitional stage of brushwood stage included Sebacina,Geminibasidium,Mortierella,etal.among them,Sebacina,Geminibasidium,Capnodiales,Pleosporaleswere the key dominant fungi groups of this type.Unclassified fungi,Fusarium,Mortierella,Archaeorhizomyces and Ascomycota are mainly concentrated in the grassland stage.Fusarium,Archeaorhizomyces,Acremonium,Hypocreales and Ascomycota are the key dominant fungal groups of this type.Similar bacterial composition in forest and shrubland,It is mainly composed of norank Acidobacteria,Nitrospira,norank Xanthobacteraceae,norank Gaiellales and H16,among which Nitrospira is the key group.The bacterial composition of brushwood and grassland community stages was clustered into one group.In addition to the common dominant groups mentioned above,there are also Solirubrobacter and norank Rhodospirillaceae,norank Gaiellales plays a key role.topographic factors such as elevation and slope position have great influence on fungi and bacteria composition;biological factors such as vegetation height,litter,total vegetation coverage,diversity and evenness of herbaceous layer,and soil total phosphorus,total nitrogen and pH value.In the early stage of vegetation restoration,abiotic environmental factors mainly affect microbial communities,and the more mature microbial communities are affected by biological environmental factors.2.Nitrogen and phosphorus-related microorganisms in the study area.There are mainly Sebacina,Tomentella,Exophiala,Acremonium,Periconia,Trichoderma,Fusarium,Penicillium,Talaromyces,Nitrospira,Bradyrhizobiu,Mesorhizobium,Rhodospirillaceae,Bacillus,Desulforibrio,Halomonas,Stenotrophomonas,Azotobacter.3.Soil urease activity decreased gradually with the increase of vegetation restoration,showing brushwood(0.585)>grassland(0.545)> Shrubland(0.378)> forest(0.239);soil protease activity was the largest in forest(0.341)> grassland(0.297)> Shrubland(0.283)> brushwood(0.260).Soil alkaline phosphatase activity was in Shrubland(21.172)> forest(19.172)> grassland(16.323)>brushwood(12.956).Soil urease activity is correlated with fungi and bacterial composition.Geminibasidium,Cylindrocarpon,IIyonectria,Cladophialophora,Oidiodendron,Penicillium,Aspergillusare significantly negatively correlated.Phialophora,Periconia,Bacillus,Solirubrobacter,Steroidobacter are Significant positive correlation.Rubrobacter,norank Nitrosomonadaceae,Sphingomonas are Significant positive correlation.Soil protease is negatively correlated with Sebacina.It is positively correlated withCylindrocarpon.Bacillus and Pedomicrobium are significantly negatively correlated.9.Soil alkaline phosphatase was positively correlated with Cladophialophora and Trichoderma.Significant negative correlation with norank Gaiellales,norank Nitrosomonadaceae and Microlunatus.It was positively correlated with norank Xanthobacteraceae,Mycobacterium,Bradyrhizobium and H16.The main environmental factors affecting soil enzyme activity are SWC,Pd,SOC,TN,TP.4.Actinobacteria were the dominant flora in the control experiment.There was a significant positive correlation between soil urease and Micromonospora and Micrococcaceae.Proteinase had no significant correlation.Soil alkaline phosphatase was positively correlated with Blastococcus,Solirubrobacter.The main environmental factor is the total carbon content.The results are different from field experiments.Soil enzyme activity may not be affected by a single flora.Soil microorganisms and soil enzymes may be affected by many factors at the same time.