| The growth of plant and the health of human is threatened by extreme barren and high heavy metal concentration of tailings. So it is necessary to improve the soil environment of tailings through tesearches. This study is Vanadium/Titanium Magnetite tailings. Firstly, it analyzed and evaluated the pollution of heavy metal of the soil in tailings and surrounding of tailings. Then it screened the green manure plants for local environment. Selecting plant green manure individually and combine green manure and sludge compost to improve the environment of tailings. Discussed the change of nutrients, availability of heavy metals and microbiological in tailings.It analyzed and evaluated the pollution of heavy metal of the soil in tailings and surrounding of tailings. The results showed that the level of comprehensive pollution was moderately-polluted of the soil surrounding tailings and it was heavily-polluted of soil in tailings. It analyzed in single element and showed that Cd was polluted moderately and Zn was slightly-polluted of the soil surrounding of tailings and Cd was heavily-polluted, Cr, Cu and Zn was moderately-polluted in tailings, and the total amount of Mn was 1.69 times of soil background value of Hebei Province in tailings.Through analyzing of the germination rate, survival rate, growth and biomass of three kinds of legume(alfalfa, white clover, adsurgens) and 9 kinds of grasses(ryegrass, vetiver, Zoysia, bluegrass, tall fescue, Elymus), then showed that alfalfa, ryegrass, tall fescue were more suitable for the growth in the test tailings.Through selecting plant green manure individually, green manure and 5% sludge compost combined and green manure and 10% sludge compost combined to improve the environment of tailings. The results showed that after improvement, the p H was lowered, the content of DOC, nitrogen, available phosphorus was increased significantly, and the quantity of bacteria, fungus, actinomycetes was increased significantly. The soil fertility and microbial environment got better. The availability of heavy metals was changed, the available Cd, Mn and Zn were reduced, but the available Cu was increased.This study suggests that alfalfa, tall fescue, perennial ryegrass can be used as green manure plants for ecological restoration in tailings. The effects improvement of the two joint modifying means was significantly better than planting green manure individually. It considered the economic benefits,combined 5% sludge compost was the best way to restore tailings ecological security environment. |
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