Intercropping of Tea (Camellia sinensis L.) and Chinese Chestnut: Variation in the Structure of Rhizosphere Bacterial Communities

This study was to determine the composition and diversity of soil microbial communities and evaluate the effect of intercropping on soil fertility in the tea-Chinese chestnut intercropping system. The Illumina platform was used to characterize the rhizosphere bacteria in the intercropping systems. The rhizospheric soil in intercropping systems in fall was enriched in soil organic matter, available phosphorus, and available potassium, and these were positively correlated with several bacterial taxa including Chloroflexi, WPS-2, Bacteroidota, Myxococcota, Bacteroidota, and Patescibacteria. These bacteria permitted the tea plants to obtain sufficient amounts of nutrients from the soil. In spring, the total nitrogen, total phosphorus, and total potassium of the intercropping system of tea and Chinese chestnut planted in the 1980s (80 T) increased, and these nutrients were positively correlated with Myxococcota, Latescibacterota, Bacteroidota, Deinococcota, Bdellovibrionota, SAR324 Clade (Marine Group B), and Patescibacerlai. In addition, several bacteria (Geobacter, Halomonas, Luteolibacter, Adhaeribacter, and Paludibaculum) contained in the 80 T sample in spring and fall were determined to be beneficial for the soil based on previous studies. The effects of intercropping and monocropping on soils were more complex in spring compared to those with fall, and Chinese chestnut tree age had a strong effect on soil. Our results highlight the need to fully consider factors such as tree age and season in the design of intercropping systems as well as collect additional data for scientific applications of intercropping systems.