Temporal dynamics of soil physicochemical properties and bacterial community assembly during 12-year vegetation by planting Paspalum wettsteinii on degraded mountainous
Annotatsiya
Background In the severely eroded red soil regions of southern China, characterized by significant ecological degradation, there is an urgent need for effective vegetation restoration techniques. Method A space-for-time substitution approach was employed, wherein three 20 m × 20 m quadrats were established at each of the Paspalum wettsteinii restoration sites (1-, 6-, and 12-year-old) and a control bare land. Soil samples were collected for physicochemical characterization and 16S rDNA sequencing analysis. Results The result showed that soil structure improved rapidly within the first 6 years, followed by a 357% increase in soil organic matter in the later 6 years. Bacterial α-diversity initially rose and then declined, while the microbial network shifted from loose to tightly reconnected between 6 and 12 years, with Thaumarchaeota emerging as a key stability-indicating taxon. Total nitrogen (TN), organic matter (OM), and available potassium (AK) collectively explained >75% of the community variation, indicating that carbon-nitrogen synergy drives community assembly, with available potassium regulating the secondary axis. Conclusion Vegetation restoration using P. wettsteinii significantly improved soil physicochemical properties and drove bacterial diversity and functional succession, exhibiting a distinct "stage-specific synergistic recovery" pattern in which the 6–12 years period represents a stage for soil bacterial communities, shifting from structural restoration to functional stabilization.