Effects Of Returining Of Green Manure-straw Cooperative On Soil Microbial Community And Functional Diversity In Continuous Cropping Cotton Field

In order to clarify the effect of the coordinated return of green manure-straw on the soil micro-ecological environment of continuous cropping cotton fields,this study adopted a two-year field experiment,with no straw return treatment(CK)as a control,and studied green manure(Rape)and straw(Cotton).The effect of cooperative return treatment(T)on soil microbial Community and functional diversity in continuous cropping cotton fields.The main findings are as follows:(1)Metagenomic sequencing found that the cooperative return of green manurestraw to the field significantly increased the number of fungi and bacteria in the soil(P<0.05),and changed the species abundance of soil fungi and bacteria.The dominant phylum of soil fungi is Ascomycota,and the dominant genus is Rhizophagus.The cooperative return of green manure-straw to the field increased the relative abundance of Mucoromycota and Rhizophagus by 9.38% and 10.70%,respectively.However,the abundances of Ascomycota and Aspergillus were reduced,with the reduction rates being13.47% and 0.96%,respectively.The dominant phylum of soil bacteria is Proteobacteria,and the dominant genus is Pseudomonas.The synergistic return of green manure-straw to the field increased the relative abundance of Proteobacteria and Lysobacter by 5.55% and 1.34% respectively.However,the abundance of Actinobacteria and Pseudomonas has decreased,with the reduction rates being 3.75%and 6.93%,respectively.Redundant analysis of soil fungi and bacteria and soil environmental factors shows that the main environmental factors affecting the soil fungal community are available potassium,alkali hydrolyzable nitrogen and p H,and the main environmental factors affecting the soil bacterial community are alkali hydrolyzable nitrogen,available phosphorus and soil.Water content.(3)By comparing the microbial sequence with major functional databases through metagenomic sequencing,it is concluded that the cooperative return of green manurestraw to the field changes the functional abundance of soil microorganisms.Comparing the primary metabolic function pathways of the KEGG PATHWAY database shows that Metabolism is the main function of soil microorganisms.The synergistic return of green manure-straw to the field increased the functional abundance of soil microbial metabolism and environmental information processing,but the functional abundance of four items including genetic information processing decreased.Comparing the KEGG PATHWAY secondary metabolic function pathway,the results show that carbohydrate metabolism is the main function of soil microorganisms.The synergistic return of green manure-straw to the field increased the functional abundance of 9metabolic pathways including amino acid metabolism,but decreased the abundance of10 metabolic functions including carbohydrate metabolism.Comparing with the CAZy database,it is found that glycoside hydrolases(GHs)are the main function of soil microorganisms,and the return of green manure-straw to the field together increase the relative abundance of glycosyltransferases(Gts).However,the abundance of glycoside hydrolases(GHs),glycosyltransferases(Gts)and carbohydrate binding modules(CBMs)has decreased.(4)The coordinated return of green manure-straw to the field changed the abundance of resistance genes in the soil.In this study,a total of 20 soil resistance genes were detected.Compared with CK,the cooperative return of green manure-straw to the field reduced the abundance of 16 resistance genes.In summary,the coordinated return of green manure-straw to the field can provide theoretical basis and technical support for improving the soil micro-ecological environment,regulating the structure and function of soil microbial communities,and rational utilization of agricultural resources.