Objective The aim was to clarify the role of artificial inoculation of moss crusts in improving the degraded habitats of grassland coal mines, in order to provide a scientific basis for the restoration of degraded habitats in grassland mining areas, and meanwhile to enrich the theory and technology of ecological restoration in mining areas.

Method The treatments included: Moss crust + grass mixed planting (TC), moss crust (TT), and sole sowing of grass (CC), natural restoration (CK) as a control, to analyze the changes in above-ground plant diversity, soil physical and chemical properties, soil enzyme activities, and soil microbial communities after artificial inoculation of moss crusts.

Results Artificial inoculation of moss crusts could increase above-ground plant biodiversity and surface vegetation coverage, with a vegetation coverage up to 91% after the TC restoration treatment. TC and TT treatments significantly reduced soil pH and the erodibility K factor. Compared to the CC treatment, the TC treatment significantly increased the contents of total carbon, total nitrogen, organic carbon and available phosphorus in the soil (P < 0.05), with the highest nutrient levels observed in the TT treatment. Soil enzyme activities in the TC, TT and CC treatment groups were significantly higher than in the CK treatment, and all three restoration treatments could enhance the soil enzyme activities of degraded soils in mining areas; notably, the activities of catalase, β-glucosidase, urease and alkaline phosphatase were significantly improved under the TC treatment, while the activities of catalase and urease were significantly improved under the TT treatment (P < 0.05). All three restoration treatments significantly increased the α diversity of the soil bacterial community compared to the CK treatment (P < 0.05), showing the trend TC > TT > CC.

Conclusion The structural equation model research indicates that artificial inoculation of moss crusts has a direct impact on above-ground plant diversity, soil physical and chemical properties, and enzyme activity, which directly affects the α diversity of the soil bacterial community through interactions and indirectly impacts the α diversity of the soil fungal community.