Mixed sowing improves plant and soil bacterial community restoration in the degraded alpine meadow

Planting artificial grassland has been widely implemented to restore the extremely degraded alpine meadow. However, the restoration effect of different planting patterns of artificial grassland on the alpine plant and soil is poorly understood.

Three typical native grass species (Elymus nutans, Poa pratensis L. cv. Qinghai, Festuca sinensis) were planted in two patterns: P. pratensis monoculture and mixed sowing containing all three species. The plant, soil physicochemical properties, and soil bacterial community under two different planting patterns in the degraded alpine meadow of Qilian Mountain were evaluated.

The aboveground, belowground biomass, coverage, Shannon-winner, and richness diversity of the mixed sowing grassland was approximately 144%, 111%, 113%, 144%, and 205% higher than that of the monoculture grassland. Furthermore, the mixed sowing grassland significantly increased the soil total nitrogen and water content than monoculture grassland. The soil bacterial Chao1 and ACE diversity in mixed sowing was significantly lower than in monoculture grassland. Soil bacterial species network analysis revealed a higher complexity of the mixed plot than the monoculture. The redundancy analysis (RDA) model suggested that plant characteristics caused more variation in the soil bacterial community than in soil physicochemical characteristics.

The results show that mixed sowing had more positive restoration on plant and soil than monoculture, and could be recommended for the restoration of degraded alpine meadow.