间作大豆对木薯根际土壤微生物群落结构的影响OA

[Objective]This study aims to investigate the effects of intercropping with soybean on the microbial community structure in the rhizosphere soil of cassava,and to clarify the regulatory effects of different intercropping row spacings on microbial diversity and composition.[Method]A field experiment was conducted with cassava monoculture(C)and cassava/soybean intercropping at row spacings of 30 cm,40 cm,and 50 cm(denoted as IS30,IS40,and IS50,respectively).Cassava rhizosphere soil samples were collected,and bacterial and fungal communities were analyzed using high-throughput sequencing.[Result]The results showed that intercropping significantly reduced the richness of soil bacterial communities(ACE and Chao1 indices),but had no significant effect on diversity indices(Shannon and Simpson).In contrast,both the richness and diversity of fungal communities were significantly increased under the IS30 treatment.Principal component analysis(PCA)revealed clear separation between intercropping and monoculture treatments in both bacterial and fungal community structures,with the IS40 treatment having the greatest impact on bacteria and IS₃₀ on fungi.At the phylum level,intercropping increased the relative abundance of Proteobacteria and Firmicutes,while decreasing that of Acidobacteriota and Bacteroidota.At the genus level,beneficial taxa such as Burkholderia-Caballeronia-Paraburkholderia and Acidothermus were significantly enriched in intercropped soils.The relative abundance of pathogenic fungi such as Fusarium in the IS₃₀ treatment was 32.69%,significantly lower than the 50.52%observed in monoculture,representing a reduction of 35.29%.[Conclusion]These findings indicate that cassava/soybean intercropping can regulate rhizosphere microbial community structure by enhancing beneficial microorganisms,suppressing pathogens,and optimizing the soil microecological environment,with the 30 cm row spacing being the most effective.This study provides a microbiological ecological basis for optimizing cassava-soybean intercropping systems and promoting sustainable agricultural practices.