Effects of different reclaimed mine land use patterns on the soil properties and water infiltration of opencast coal mines in the northern Loess Plateau, China

The impacts of various reclaimed mine land use patterns on the soil properties and infiltration capacity of mine areas remain incompletely understood. This study was conducted in the northern Loess Plateau to assess the effects of reclamation patterns, specifically vegetation (shrub grassland planted for 3, 6, and 10 years) and agricultural reclamation (mechanized and non-mechanized farmland, both cultivated for 10 years), on the soil properties and permeability of an open-pit coal mine. Original grassland (OG) and farmland (OF) were used as controls. The results show that after 6 years of vegetation reclamation, the soil bulk density (BD, 1.38 g·cm−3), total porosity (TP, 47.88 %), and infiltration rates approached levels similar to those of the OG. After 10 years, the organic matter content (SOM, 8.37 g·kg−1) and average weight diameter (MWD, 0.82 mm) were restored almost to those of the OG. In comparison, after 10 years of agricultural reclamation, SOM (9.22–9.38 g·kg−1) approached the level of the OF. However, compared with the OF, the BD and MWD of mechanized farmland increased significantly by 17.37 % and 154.96 % (P < 0.05), respectively, and the infiltration rates of mechanized and non-mechanized farmland decreased significantly (P < 0.05). Soil porosity was the most important factor affecting soil permeability, accounting for 65.9 % of change in permeability. In conclusion, vegetation reclamation, particularly mixed shrub and grass, led to more pronounced improvements in soil properties and permeability in mining areas compared with agricultural reclamation over a period of 10 years. However, heavy agricultural machinery has a detrimental effect on the soil properties and infiltration capacity of mining areas and should be carefully monitored.