FERTILITY AND MICROBIAL DIVERSITY IN RHIZOSPHERE SOIL OF CAMELLIA OLEIFERA UNDER DIFFERENT INTERCROPPING SYSTEMS

In Guizhou, China, a variety of intercropping systems involving Camellia oleifera have been established, yet comprehensive scientific evaluations of these systems remain scarce. Our study aimed to assess the differences among these systems by examining two key aspects: soil properties and microbial species diversity. We discovered that Ascomycota and Proteobacteria were the prevalent fungal and bacterial groups, respectively, across all Camellia oleifera intercropping systems. In the dual-factor correlation network, encompassing species and soil environmental factors, fungi Satiozyma and bacteria Vicinambicharacters exhibited high Degree Centrality. Urease and Alkaline nitrogen emerged as soil environmental factors strongly associated with these fungi and bacteria. Particularly noteworthy were the Alpha diversity indices (Shannon, PD, and Chao1), which were significantly higher for soil fungi in the Camellia oleifera-Zea mays system and for soil bacteria in the Camellia oleifera-Glycine max system. Furthermore, the Camellia oleifera-Glycine max soil displayed notably elevated levels of Microbial Biomass Phosphorus, Sucrase, Urease, and Catalase. In the Camellia oleifera-Zea mays system, the overall soil fertility was substantially higher, coinciding with a high degree of centrality for fungi Phoma and bacteria SC-I-84 in the correlation network. Additionally, Urease and Available Mn were identified as key environmental factors influencing these fungi and bacteria. Strong correlations were observed between Phoma and TN, and SC-I-84 and TK (r=0.94, 0.99 p<0.01). Also, there was a significant association between fungal Neocosmospora and bacterial AD3 with UE and AMn, respectively (r=0.69, -0.99 p<0.05). Based on our findings, we recommend the Camellia oleifera-Zea mays intercropping system as a particularly promising option, given its advantages in fungal alpha diversity and soil fertility. Concurrently, the Camellia oleifera-Glycine max system demonstrated substantial benefits in terms of microbial biomass phosphorus, bacterial alpha diversity, and soil enzyme activities.