秸秆颗粒还田对黑土不同空间微生境与CAZy功能基因特征影响OA

[Objective]Straw return is an important management practice for improving soil organic carbon levels and enhancing the structure of the plough layer in black soil regions.However,conventional straw return methods generally suffer from slow decomposition rates and low utilization efficiency.Straw pelletized return aims to accelerate straw decomposition by altering its physical form.In this study,four typical black soil regions in eastern Inner Mongolia were selected as research sites.[Method]Four treatments were established:straw return(JG),straw return with microbial inoculant(JJ),straw pellet return(KL),and straw pellet return with microbial inoculant(KJ).Straw decomposition rate,soil physicochemical properties,enzyme activities,and the spatial variation of CAZy functional genes based on metagenomic analysis were investigated.Random forest and redundancy analysis were further applied to reveal the driving mechanisms.[Results]The results showed that straw decomposition rates exhibited significant spatial variation,and spatial effects were stronger than treatment effects.Soil physicochemical properties and enzyme activities were primarily clustered by spatial location,indicating that environmental background conditions played a dominant role in shaping soil microenvironments.Microbial CAZy functional genes differed significantly among regions,with glycoside hydrolases(GH)and glycosyltransferases(GT)being the dominant groups,while key lignocellulose-degrading families showed region-specific enrichment patterns.Driving factor analysis indicated that soil organic carbon,sucrase activity,and soil physicochemical properties were the key factors shaping CAZy functional structures and straw decomposition processes,whereas the direct contribution of individual functional genes was relatively limited.In conclusion,the straw decomposition process is mainly regulated by spatial environmental background,while microbial functional genes undergo adaptive adjustments under given physicochemical conditions.[Conclusion]These findings provide a theoretical basis for the application and optimization of straw return technologies in black soil regions.