Analysis of Soil Microbial Community Characteristics in the Camellia oleifera-Polygonatum cyrtonema Intercropping System

To investigate the changes in soil microbial communities and their effects on soil nutrient content in the Camellia oleifera-Polygonatum cyrtonema intercropping system, this study employed metagenomic sequencing technology to analyze the microbial community diversity, structure and differences in the rhizosphere soils of C. oleifera （YH）, P. cyrtonema （HJ） and monocropped C. oleifera（CK）, changes in soil nutrient content under the intercropping mode were analyzed concurrently. The results showed that the number of observed species and the Chao1 index in the rhizosphere soil of P. cyrtonema were significantly lower than those in the rhizosphere soil of C. oleifera, the intercropping reduced the species richness of rhizosphere microorganisms in C. oleifera, but had no significant effect on the evenness of species distribution.The microorganisms in the rhizospheres of C. oleifera and P. cyrtonema were primarily composed of bacteria, archaea, eukaryotes, and viruses, in which bacteria were the most abundant, accounting for over 98% of each sample. The number of microorganisms in the phyla Pseudomonadota, Actinomycetota, and Acidobacteriota together accounted for more than 75% of the total number, making them the dominant bacterial groups. Compared to the control, the bacteria abundance of Proteobacteria and Acidobacteria in the rhizosphere soils under the intercropping mode increased by 18.92% and 15.84%, respectively, whereas the abundance of Actinobacteria decreased by 50.71%. Microbial taxa with significant differences were mainly distributed in Acidobacteriota and Pseudomonadota. Under the intercropping mode, Acidobacteriota and its affiliated bacteria were significantly enriched in the rhizosphere soil of C. oleifera, whereas Pseudomonadota and its affiliated groups, including α-proteobacteria, the order Hyphomicrobiales, the genus Bradyrhizobium, and the family Nitrobacteraceae in the rhizosphere soil of P. cyrtonema were significantly enriched. The contents of organic matter, total phosphorus and available phosphorus in the rhizosphere soil of C. oleifera decreased significantly, while the contents of total potassium, available potassium and pH value increased significantly with changes of total nitrogen or alkali-hydrolyzable nitrogen contents unsignificant under the intercropping mode.