Effect Of Biological Agents On Rhizosphere Soil Microbial Community Of Tobacco And Its Correlation Analysis In Liangshan Prefecture

In this paper,high-throughput sequencing was used to study the effects of Bacillus amyloliquefaciens and compound microbial agents on microbial Alpha diversity,community structure and differences of tobacco rhizosphere soil in Ningnan and Huili of Liangshan Prefecture,and to analyze the correlation between microbial community and soil physicochemical properties and flue-cured tobacco quality,so as to provide theoretical basis for the application of soil tobacco biological agents in Liangshan Prefecture.The results are as follows:(1)Compared with conventional fertilization,biological agents changed the rhizosphere soil microbial communities structure of tobacco field.Bacillus amyloliquefaciens and compound microbial agents respectively increased the tobacco bacterial alpha diversity in Huili and Ningnan at rosette and vigorous growing period,while they decreased the soil bacterial alpha diversity in Huili and Ningnan at maturing stage.The single application decreased the soil fungal alpha diversity,but the joint application increased the soil microbial communities alpha diversity at rosette and vigorous growing stage.In rosette,vigorous growing and maturing stage,Bacillus amyloliquefaciens and compound microbial agent increased the relative abundance of Ascomycota in Ningnan and Huili tobacco,and increased the relative abundance of Bacteroidetes,Ascomycota and Massilia in Ningnan tobacco,while decreased the relative abundance of Proteobacteria,Gemmatimonadetes and Ciliophora in Huili tobacco.Co-application increased the relative abundance of Chloroflexi and Frateuria in Ningnan tobacco and Bacteroidetes and Plectosphaerella in Huili tobacco,and increased the relative abundance of Basidiomycota in Ningnan and Huili tobacco.(2)Biological agents application changed the contents of p H,organic matter,alkali-hydrolyzable nitrogen,available phosphorus,available potassium,exchangeable calcium and magnesium,and available iron and manganese in rhizosphere soil of tobacco field,especially increased the content of soil physicochemical properties in vigorous growing and maturing stage.The soil physicochemical properties ware closely related to the microbial communities main bacteria.In the microbial community of Ningnan,soil organic matter,alkali-hydrolyzable nitrogen,available phosphorus and available potassium were significantly positively correlated with Actinobacteria,Firmicutes and Streptomyces,which negatively correlated with Proteobacteria and Acidobacteria.Proteobacteria,Bacteroidetes and Chaetomium were positively correlated with p H and exchangeable magnesium.Ascomycota was positively correlated with available manganese,and Chloroflexi was positively correlated with available iron.In the microbial community of Huili,soil p H,organic matter,exchangeable magnesium were significantly positively correlated Gemmatimonadetes and Sphingomonas.Alkali-hydrolyzable nitrogen and available manganese and iron were significantly positively correlated with Actinobacteria,Firmicutes,Sphingomonas,Frateuria,Mucoromycota,unclassified?f?Chaetomiaceae.Soil p H was significantly positively correlated with Basidiomycota and Plectosphaerella.(3)Compared with conventional fertilization,co-application had significant effects on agronomic characters such as plant height,stem circumference,number of effective leaves,maximum leaf length and leaf width,which increased by 1.14,1.10,1.12,1.08,1.11 times in Ningnan and1.18,1.19,1.11,1.07,1.13 times in Huili tobacco field,respectively.Biological agents improved the economic characters and chemical composition in Ningnan flue-cured tobacco.The quality of flue-cured tobacco was correlated with soil physicochemical properties and microbial community.Available potassium,exchangeable calcium,exchangeable magnesium,Actinobacteria,Firmicutes were significantly positively correlated with total sugar.Chlorofleix was significantly negatively correlated with chlorine.Mucoromycota was significantly positively correlated with reducing sugar,potassium and total nitrogen.Exchangeable calcium and magnesium were positively correlated with yield per mu and output value per mu.All in all,biological agents can change the rhizosphere soil microbial communities structure of tobacco field,and regulate the economic characters and chemical composition of flue-cured tobacco.Biological agents can regulate the quality of flue-cured tobacco by affecting soil microbial community structure and soil physicochemical properties.