Studies On Benefits Of Different Vegetation Restoration Patterns On Iron Tailings

In this paper, different restoration patterns were studied in iron tailings. Species composition and importance value, and soil physical-chemical characteristics had been investigated, and the benefits of the vegetation restoration had been analyzed, as well as seed germination rate of pot experiment had been counted in different restoration patterns.The results were as follows:(1)The trend of changes in speciesα-diversity index of the vegetation under different restoration patterns was in the similar way, and for the richness index and diversity index, the different patterns were ranked in descending order as follows: seabuckthorn-mulberry mixed >amorpha forest >pure sabina forest >tin tile.(2)Compared with control bare tailings, soil bulk density in seabuckthorn-mulberry mixed forest pattern, amorpha forest pattern and pure sabina forest pattern had respectively reduced by 6%, 15% and 14%, and those of foreign soil improvement pattern and semi-foreign soil improvement pattern had respectively increased by 12%.(3)Total porosity in seabuckthorn-mulberry mixed forest pattern, amorpha forest pattern and pure sabina forest pattern had respectively increased by 16%, 1% and 8%, foreign soil improvement pattern and semi-foreign soil improvement pattern had respectively reduced by 25% and 23%.(4)Capillary porosity in seabuckthorn-mulberry mixed forest pattern, amorpha forest pattern, pure sabina forest pattern, foreign soil improvement pattern and semi-foreign soil improvement pattern had respectively reduced by 19%, 16%, 4%, 17% and 21%; non capillary porosity in seabuckthorn-mulberry mixed forest pattern, amorpha forest pattern, pure sabina forest pattern had respectively increased by 118%, 46% and 22%, foreign soil improvement pattern and semi-foreign soil improvement pattern had respectively reduced by 44% and 25%.(5)Soil capillary water contents in seabuckthorn-mulberry mixed forest pattern, amorpha forest pattern, foreign soil improvement pattern and semi-foreign soil improvement pattern had reduced by 18%, 7%, 31% and 35%, respectively, while the pure sabina forest pattern had increased by 21%.(6) Soil improvement can significantly improve organic matter content and soil fertility of iron tailings, while increments of organic matter content were different in different improvement patterns. Organic matter content in every layer of soil in seabuckthorn-mulberry mixed forest pattern, amorpha forest pattern, pure sabina forest pattern and semi-foreign soil improvement pattern decreased with the soil depth and there were certain surface gathering characteristics in all the patterns, and organic matter was mainly distributed in 0~10 cm soil. Organic matter in foreign soil improvement pattern was more evenly distributed, and its content had a decreasing trend after the first increase.(7) Soil nutrient status of iron tailings had a change after soil improvement, and the content of total P and total K had increased, and the bigger increment appeared in total P. Total P in seabuckthorn-mulberry mixed forest pattern, amorpha forest pattern, pure sabina forest pattern, foreign soil improvement pattern and semi-foreign soil improvement pattern were 2.13 times, 27.01 times, 36.98 times, 48.70 times and 50.07 times compared with control tailings soil.(8)The contents of total N in seabuckthorn-mulberry mixed forest pattern and semi-foreign soil improvement pattern had increased and reached 10.57 times and 1.29 times of which in control tailings soil. The contents of total N in amorpha forest pattern, pure sabina forest pattern and foreign soil improvement pattern had reduced by 39%, 28% and 46%, respectively.(9)Soil improvement can significantly improve the soil available N and available K. The increments of them were different in different soil improvement patterns, while the change trend was basically same and there was a certain surface gathering characteristic in all the patterns.(10)The content of available P in seabuckthorn-mulberry mixed forest pattern and foreign soil improvement pattern had increased and reached 1.15 times and 1.12 times compared with control tailings soil, whereas the contents of available P in amorpha forest pattern, pure sabina forest pattern and semi-foreign soil improvement pattern had reduced by 63%, 85% and 22%, respectively.(11)The restoration results of different vegetation restoration patterns were ranked from high to low as follows: seabuckthorn-mulberry mixed patterns, semi-foreign soil improvement pattern, foreign soil improvement pattern, amorpha forest patterns and pure sabina forest patterns.(12)Potted seed germination rates were ranked as follows: Sorbifolia>Caragana intermedia>Mixed Pastures>Lespedeza Spiraea>P.tabulaeformis>Larch. Caragana intermedia and Sorbifolia were the preferred species for improving tailings soil, and direct seeding can be allowed in tailings soil improvement without fertilization, which can achieve a good effect of improving ecological environment.(13)The comprehensive benefit of vegetation restoration was very significant: the measure of mining wasteland covered with vegetation can not only solve the problem of soil erosion and control the soil erosion of the tailings, but also get the income, high-yield fruit, which could greatly improve the mining area people’s living standard.