Soil nutrients drive changes in the structure and functions of soil bacterial communities in a restored forest soil chronosequence

The restoration of plants is effective for restoring ecosystems in eroded areas. Soil bacterial communities play an important role in nutrient cycling. High-throughput sequencing technology was used to determine the changes in soil bacteria in different restored plant communities and years of restoration. The FAPROTAX database and random forest model were also used to analyze the changes in soil bacterial carbon (C), nitrogen (N), and phosphorus (P) metabolic functions and their influencing factors. The results showed that the bacterial community diversity, soil texture, physicochemical properties, and multifunctionality improved substantially with the increments and years of restoration. These changes, in turn, altered the nutrient metabolic functions in soils by increasing the fixation of bacterial C, decreasing the fixation of N, and gradually relieving the limitations on N. However, these changes also increased the limitation of P during the late stage of restoration. The pH values and soil nutrients were crucial and exerted a large influence on the nutrients and metabolic functions of the bacteria. These findings facilitate the restoration of plants in subtropical areas of eroded soil.