Effects of intercropping clover and peanuts on soil bacterial diversity and community structure in tea gardens

To investigate the effects of intercropping clover and peanut on soil bacterial diversity and community structure in tea plantations. Soil samples were selected from 10-20 cm soil layers of tea plantation under tea plantation-peanut, tea plantation-trefoil and tea plantation monoculture, and soil water content, pH, organic matter, total nitrogen, total phosphorus, total potassium and soil peroxidase, acid phosphatase, sucrase and urease were measured. The 16S rDNA high-throughput amplicon sequencing was performed on the soil bacterial communities in the intercropped peanut, clover and tea plantations using Illumina MiSeq sequencing platform. The results showed that intercropping clover and peanut in tea plantations significantly (P<0.05) increased soil nutrient and enzyme activities at flowering and pod stages compared with tea tree monoculture (CK). Intercropping clover at the seedling stage and peanut at the pod stage significantly increased the diversity and abundance of soil bacterial community structure in the tea plantation (P<0.05). The top 10 bacterial phyla Proteobacteria, Acidobacteria, Actinobacteria, and Chloroflexi were the dominant phyla in the soil bacterial community structure during the seedling, flowering, and pod stages. Mantel test correlation distance matrix analysis showed that the distance matrix of dominant bacterial groups was significantly correlated with the distance matrix of physicochemical factors such as water content, total nitrogen, catalase and urease (P<0.05). The predicted metabolic function analysis showed that Carbohydrate metabolism, Amino acid metabolism, Biosynthesis of other secondary metabolites, Cell growth and death were the main metabolic functional pathways of the dominant bacterial community in the intercropping pattern. Compared to tea tree monoculture, clover and peanut intercropping mainly significantly increased the soil's Xenobiotics biodegradation and metabolism, Carbohydrate metabolism, Amino acid metabolism metabolism, Biosynthesis of other secondary metabolite, Metabolism of other amino acids and significantly reduced Cell growth and death function abundance (P<0.05). Therefore, intercropping clover and peanut in tea plantations not only improved soil nutrient and enzyme activities, enhanced soil bacterial microbial structure diversity, but also improved metabolic functions and promoted effective uptake of nutrient elements by the root system, thus providing theoretical basis and technical support for long-term sustainable tea plantations.