Field study of compound microbial agents for soil improvement and microbial community dynamics on rocky slopes in Southwest China.

Engineering construction and mining activities have resulted in numerous exposed rocky slopes, posing significant geological and ecological challenges. To address these issues, this study developed compound microbial agents composed of functional microorganisms and applied them in a field-based ecological restoration project on typical high and steep rocky slopes in Southwest China. The aim was to restore the micro-ecological environment of the slopes by reconstructing the soil conditions. After 240 days of restoration, soil available phosphorus increased from < 2.0 to 6.10 mg/kg, available potassium from 62.80 to 75.00 mg/kg, organic matter from 8.90 to 12.86 g/kg, and organic carbon from 0.70 to 0.73%. Total nitrogen and total phosphorus slightly increased, indicating improved soil fertility. The addition of compound microbial agents enhanced microecological stability while maintaining the overall structure of the indigenous microbial communities. The progressive development of biological soil crusts and rock fissures facilitated the colonization of algae, lichens, mosses, and higher plants. By the 8th month, vegetation coverage exceeded 30% in some areas. This study presents an effective field-based model for the microbial ecological restoration of rocky slopes and offers insights into ecosystem-recovery mechanisms supporting sustainable land management.