Soil layer construction and composition changes in restoration of ecological and geological layer in alpine mining area on plateau

The Muli mining area is located in the alpine region on the plateau.After years of mining, the local ecological system is seriously damaged and the soil resources are extremely poor.Whether the waste soil after mining can be improved into artificial “hydrogels” suitable for vegetation growth and re-greening has become a scientific problem in the process of ecological restoration.Based on this, some researches and experiments on reconstructed soil materials suitable for the growth of alpine meadows in the hinterland of the Qilian Mountains and the optimal formulation for improvement were carried out.The residue from the Muli mining area was selected as the reconstituted soil mineral-based material, while the local sheep manure and commercial organic fertilizer were used as the soil improvement materials.The comparative experiment was divided into two parts:soil construction and artificial soil fertility improvement.The differences between artificial soil and original meadow soil were analyzed through indoor seedling comparison experiments.The results showed that:① Artificial soil with vegetation growth conditions can be constructed by mixing sheep board manure and broken fine pure slag.② The principal component analysis method was used to evaluate the effect of different materials and ratios on soil fertility improvement.It was concluded that the soil construction scheme of muck soil + sheep board manure + commercial organic fertilizer + special fertilizer for pasture(combination 3)was the best, and the pasture grew well, which is the closest to the soil composition of the original meadow.③ A large-area soil construction and fertility improvement plan with sheep board manure dosage of 450 m³/hm², commercial organic fertilizer dosage of 22 500-30 000 m³/hm², and pasture-specific fertilizer of 225 kg/hm² was selected, and the regreening effect is remarkable.In the process of ecological restoration in the plateau alpine Muli coal mining area, the soil construction method was popularized and applied.The application of soil construction method can effectively solve the problem of no soil in the local area, the ecological environment of the mining area can be treated and the high cost of treatment can be saved.This method also provides reference for the restoration of mine ecological geological layers in some similar areas.