Aims
To elucidate the dominant effects of long-term restoration of different woody plants on the reconstitution of multiple environmental and biological factors in vertical soils of coal mining areas.
Methods
Soil physicochemical properties, soil enzyme activities, soil ionophore, microbial community structure, and soil metabolite distribution characteristics and interaction networks were analyzed at different vertical depths after long-term restoration (20 years) of four woody plant species in the coal mine area.
Results
(1) Phytoremediation increased the soil urease, sucrase, and acid phosphatase activities by 4.23–8.82, 4.52–8.29, and 3.28–5.26 times at 10 cm depth. It also reduced the active element content in the soil, and alleviated the mine toxicity stress of S, Fe, As, Pb, and U in the soil. (2) The Richness index and Shannon index of soil microorganisms increased by 4.77–23.81% and 2.93–7.93% after long-term restoration of woody plants, and the bacterial ecological niche was broadened. The microbial community structure shaped by different woody plants was highly similar, but the community similarity decreased with the increase in relative distance at vertical depth. Soil Cu, Fe, Mo, Na, and pH were important influencing factors of community structure for Sphingomonas, Pseudarthrobacter, Nocardioides, and Thiobacillus. (3) Woody plant restoration increased the abundance of soil metabolites (10 cm depth), and induced metabolites such as Organooxygen compounds, Carboxylic acids and derivatives, and Fatty Acyls as the main microbial regulators.
Conclusions
Woody plants have different patterns of environmental and biometabolic factor configurations for different depths of soil during mine restoration.
