Restoration Effects of Supplementary Planting Measures on the Abandoned Mining Areas in the Altay Mountain, Northwest China

Ecological restoration of abandoned mining areas in the Altay Mountain, northwest China, has always been considered a challenging issue due to the wide restoration area and serious devastation. To examine the restoration effects of the experimental measures carried out by our research team in an abandoned mining area in the Altay Mountain since 2010, short-term (2 years) and long-term (9 years) restoration efficiency of two types of supplementary planting measures, sowing commercial seeds (M1) and sowing soil seed banks (M2), were analyzed by calculating the vegetation growth indexes, soil-rock ratio, soil bulk density, and soil moisture content. Results show that both supplementary planting methods can significantly improve the growth status of surface vegetation, which is reflected by the variation of vegetation growth indices. The short-term restoration effect of M1 on vegetation is faster but, over time, the effect of M2 was more prominent. Restoration effects of the M2 on the soil condition were more significant at 30-40 cm of the soil layer, reflected in the higher soil-rock ratio, which is 7.2%. The water storage function of soil has significantly improved under both supplementary planting methods; the remediation effect of method M1 on the soil bulk density is mainly reflected in the surface layer, while the effect of method M2 on the soil bulk density is reflected in deeper (40-50 cm) layer. The results of this study would be helpful to explore the new practices for the restoration of mining areas.