Forest type Dominant the soil Bacterial Community Composition Rather than Soil Depth or Slope Position

Soil depth, slope position, and different plantations can influence bacterial community composition in Camellia oleifera forests. However, prior studies have focused on the impacts of different depths, slope positions, and forest types on bacterial diversity independently, without comparing their combined impacts. This study aimed to assess variation in soil bacterial community structures according to soil depth and slope position and different forest types in the same plot. The composition of soil bacterial communities was evaluated using high-throughput sequencing of the 16S rRNA gene. Results indicate that the soil organic carbon, humus, and total organic content increased, and the bacterial composition and structure were significantly altered in response to the G. jasminoides + C. oleifera low-yielding forest in comparison to the other three forest types. The highest soil bacteria numbers, alpha and beta diversity, which improved the soil microecological environment, were associated with the G. jasminoides + C. oleifera forests and not the depth or slope position treatments. The slope position did not have a significant influence on the soil physicochemical and bacterial properties. Structural equation modeling suggested that G. jasminoides + C. oleifera significantly affected the soil bacterial community diversity by mediating the soil pH and NH4+-N. The effects of forest type on soil bacterial diversity were more important than soil depth and slope position. This specific intercropping system was found to be an effective strategy to improve soil health.