Effects of intercropping Polygonatum kingianum and Zingiber officinale under Illicium verum forests on soil bacterial and fungal communities
In order to study the effects of intercropping Polygonatum kingianum (P. kingianum) and Zingiber officinale under Illicium verum forest on soil bacterial and fungal communities. Soils from three cropping patterns were studied: Illicium verum intercropped with P. kingianum (XZ), Illicium verum intercropped with Zingiber officinale (TZ), and a monoculture Illicium verum forest (CK). High-throughput sequencing was used to analyze the composition and diversity of soil bacterial and fungal communities. The results showed that intercropping different crops under Illicium verum forest led to substantial differences in soil microbial community composition. At the phylum level, the top three bacterial phyla by abundance were Acidobacteriota (19.77%-34.18%), Pseudomonadota (27.49%-29.94%), and Chloroflexota (5.34%-13.11%). The abundance of Acidobacteriota in the XZ soil was significantly lower than that in the TZ and CK, whereas the abundance of Chloroflexota in the XZ soil was significantly higher than that in the TZ and CK. The top three fungal groups were Ascomycota (20.56%-53.55%), Basidiomycota (10.89%-34.05%), and unclassified_k__Fungi (9.37%-27.75%). The abundance of Ascomycota in the XZ soil was significantly higher than that in the TZ and CK, while the abundance of Basidiomycota in the XZ soil was significantly lower than that in the TZ and CK. At the genus level, the bacterial abundance and community structure in the TZ and CK soils were relatively similar, whereas the fungal abundance and community structure differed significantly among the XZ, TZ, and CK. Co-occurrence network analysis revealed that both the bacterial and fungal networks in the XZ and TZ soils had more nodes than those in the CK. Redundancy analysis (RDA) indicated that the soil bacterial and fungal communities under Illicium verum forest were significantly correlated with soil environmental factors (N, P, K, OM, and pH). Specifically, K was the environmental factor that significantly affected both bacterial and fungal community structures in the XZ soil, explaining 98.41% and 92.78% of the variation, respectively; OM and P were the environmental factors that significantly influenced the bacterial community structure in the TZ, explaining 96.43% and 82.79% of the variation, respectively. This study can provide a reference for cultivating economic crops under Illicium verum forests.