Abstract: Studies on plant-soil interactions are important for restoration ecology, and are of great significance when designing artificial restoration methods because they can indicate the extent to which vegetation restoration affects soil properties. In this study, we focused on Elymus nutans, Poa crymophila, and Puccinellia tenuiflora growing on coal gob piles in an alpine coal mining area, and monitored the variations in soil nitrogen, phosphorus, potassium, organic matter, pH value, vegetation coverage, and correlations between those indicators at different times after restoration. The main results were as follows: Soil total nitrogen did not significantly change over time but soil total phosphorus increased by 17.39% (P<0.05) and soil total potassium decreased by 12.77% (P<0.05) after 4 years of restoration. Soil available nitrogen, soil available phosphorus, and soil available potassium decreased significantly by 49.68% (P<0.05), 66.07% (P<0.05), and 18.67% (P<0.05), respectively, in the first 4 years of restoration. Soil organic matter content increased significantly by 7.92% (P<0.05) and 43.02% (P<0.05) after 2 and 4 years restoration, respectively. The soil pH increased as a result of the slow transition from acidic to neutral soil. Vegetation coverage showed no significant variation after 2 and 4 years of restoration. There were significant correlations among the soil nutrient elements, except for soil total nitrogen. There was a significant negative correlation between plant coverage and soil pH. Based on these results, a key factor for the ecological restoration of coal gob piles is to supply available nutrients in a timely manner to satisfy the requirements for plant growth.

Key words: alpine coal mining area, cultivation period, coal gob piles, soil properties