Soil horizons regulate bacterial community structure and functions in Dabie Mountain of the East China

Soil bacterial communities regulate nutrient cycling and plant growth in forests. Although these bacterial communities vary with soil nutrients and plant traits, the variation and degree with soil horizons in different forest types remain unclear. Here, bacterial communities of 44 soil samples from organic horizon (O horizon) and mineral horizon (M horizon) of three forest types (Cunninghamia, broad-leaved and Pinus forests) in subtropical forests of Dabie Mountain, China were analyzed based on amplicon sequencing. We assessed the effects of soil horizons and forest types on bacterial communities. The results showed that the bacterial richness and diversity were significantly higher in the O horizon than in the M horizon. Furthermore, the bacterial community composition and functions were also remarkably different between the two soil horizons. Furthermore, forest types could affect bacterial community composition but not for diversity and functions. Moreover, soil organic matter, including the total organic carbon, available phosphorus, total organic nitrogen, available potassium, ammonium nitrogen, and pH were main drivers for bacterial community composition. The results propose robust evidence that soil horizons strongly driven bacterial community composition and diversity, and suggest that microhabitat of soil bacterial communities is important to maintain the stability of forest ecosystem.