Abstract: Opencast coal mining causes major damage to the local ecological environment in alpine coal mining regions. It is important to evaluate the effectiveness of different artificial restoration options for revegetation and soil reclamation of coal mine tailings, in order to optimize the ecological restoration process. In this study, three restoration measures [revegetation of untreated mine tailings (R), revegetation with soil replacement (R-S), and revegetation and fertilization (R-F)] were implemented. Differences in vegetation community composition, plant growth and soil parameters under the different restoration measures, undisturbed grassland (UG) and untreated coal mine tailings (CK) were monitored and compared after 5 years. The main results were: The artificial grasslands that were developed under R, R-S, and R-F treatments differed in their botanical species composition, and there was significant variation in plant growth characteristics, including vegetation ground cover, height, density and above-ground biomass (P<0.05). Soil organic matter content increased significantly (P<0.05) in R, R-S, and R-F treatments, compared to CK. Compared with natural undisturbed grassland, the three artificial restoration treatments R, R-S, and R-F had inferior soil quality including soil fertility and pH value, at the end of the 5 year study period. Plant growth parameters were positively correlated with soil total nitrogen, soil organic matter, and especially with soil total phosphorus. Thus, synergistic promotion should be developed between the soil and plants. A single method such as artificial revegetation used alone is not conducive to ecological restoration. The combined use of artificial revegetation in conjunction with soil replacement or fertilization, proved to be effective for ecological restoration of coal mine tailings at this alpine site. From the perspective of effective vegetation restoration and cost reduction, treatments that include fertilizer, especially organic fertilizer are likely to perform better than replaced topsoil treatments. Using these cost-effective synergies arising from plant-soil interactions, reclamation of coal mine tailings and grassland ecosystem restoration would be facilitated.

Key words: restoration measures, alpine coal mining region, coal mine spoils, vegetation characteristics, soil properties