套种黄精对山核桃林土壤细菌群落的影响OA

[Objective]This study aimed to investigate the effects of intercropping Carya cathayensis Sarg.with Polygonatum cyrtonema Hua on composition,structure,and potential functions of soil bacterial com-munity in C.cathayensis Sarg plantations,thereby providing a microbiological basis for their sustainable management.[Methods]Soil samples from both rhizosphere and bulk were collected from two cultivation systems:C.cathayensis Sarg monoculture(C)and C.cathayensis Sarg-P.cyrtonema Hua intercropping(CP).Bacterial community composition and structure were analyzed using high-throughput sequencing,and functional profiles were inferred through predictive methods.The relationships between bacterial com-munities and soil chemical properties were further explored using redundancy analysis.[Results]Inter-cropping significantly altered the structure and potential functions of soil bacterial communities.Specific-ally,the relative abundance of Acidobacteriota increased by 61.95%in rhizosphere soil and 18.34%in bulk soil,whereas Actinobacteriota decreased by 35.86%and 27.08%,respectively.At the genus level,Bradyrhizobium increased significantly by 26.88%in intercropped rhizosphere soil.Biomarker analysis re-vealed that Flavobacterium was enriched in intercropped soils,while Formylgalactosideaceae was more abundant under monoculture.Non-metric multidimensional scaling(NMDS)demonstrated significant sep-aration of bacterial community structures between the two treatments(p<0.05).Co-occurrence network analysis indicated that intercropping reduced bacterial network complexity.However,functional predic-tions indicated increased abundances of microbial groups associated with nitrogen fixation,anaerobic het-erotrophy,organic matter degradation,and urea decomposition.Furthermore,Methylomirabilota and Ver-rucomicrobiota were significantly correlated with soil alkali-hydrolyzable nitrogen and organic matter,re-spectively.Available phosphorus,available potassium,and organic matter were identified as key drivers of bacterial community variation.[Conclusion]Intercropping with P.cyrtonema modified the soil microenvir-onment in C.cathayensis Sarg plantations,reshaping bacterial community structure,and enhancing micro-bial functions related to nutrient cycling and organic matter decomposition.However,the reduced bacterial network complexity during the early stage of intercropping suggests potential short-term shifts in microbial interactions.Long-term studies are required to elucidate microbial succession dynamics and to optimize understory management strategies for sustainable agroforestry systems.