复垦铅锌矿尾砂库的植被恢复和基质演变

VEGETATION RESTORATION AND SUBSTRATE AMENDMENT OF A RECLAIMED LEAD-ZINC MINE TAILINGS POND

为探讨铅锌矿尾砂库经植物原位修复的生态恢复效果,以广西阳朔铅锌矿尾砂库综合治理示范工程为研究对象,连续3年(2018—2020)对实地观测植被恢复情况、新增植物生长情况及复垦铅锌矿库区尾砂重金属含量、土壤酶活性及理化性质的观测与测定。结果表明:尾砂库经人工种植的芒(Miscanthus sinensis)和三裂叶葛藤(Pueraria phaseoloides)2种耐性植物对尾砂中重金属存在植物稳定作用;库区植被新增物种逐年升高,且以豆科和菊科植物为主;尾砂的过氧化氢酶、脲酶与磷酸酶活性先增后减,蔗糖酶活性显著性增加;尾砂的肥力和保肥能力均有所提高,其中尾砂的总氮含量从1.14 g/kg增加到2.19 g/kg,有机碳含量从9.50 g/kg增加到21.01 g/kg。由此表明,在相似自然条件的矿山废弃地生态修复中,可考虑从葛属和蒿属的植物中筛选目标植物;植被恢复会加快尾砂库库区植物群落的次生演替;铅锌矿尾砂库经人工植被恢复能加快尾砂基质的演变,使生态系统实现自行恢复并达到良性循环。

For the purpose of studying the in-situ plant restoration effect of ecological restoration on lead/zinc mine tailings pond, the comprehensive treatment demonstration project of tailing reservoir in Yangshuo lead zinc mine was chosen as the study object, to investigate and analyze the tails physical-chemical properties, heavy metals and enzyme activity in three reclamation years, and vegetation restoration and the growth of new plants were observed on-site for 3 consecutive years(2018—2020). The results showed that the artificially planted Miscanthus sinensis and Pueraria phaseoloides, two tolerant plants in the tailings bank, could stabilize the heavy metals in the tailings. The newly added species of vegetation in the reservoir area increased year by year, mainly Fabaceae and Asteraceae;catalase, urease and the phosphatase activity first increased and then decreased, the invertase activity increased significantly;the fertility and fertilizer retention capacity of tailings were improved and the total nitrogen content of tailings increased from 1.14 g/kg to 2.19 g/kg. The organic carbon content increased from 9.50 g/kg to 21.01 g/kg. This showed that in the ecological restoration of mine wasteland with similar natural conditions, the target plants from Pueraria and Artemisia should be selected;vegetation restoration would accelerate the secondary succession of plant communities in the tailings reservoir area;the artificial vegetation restoration of the lead-zinc mine tailings reservoir could accelerate the evolution of the tailings substrate, promote the restoration of ecosystem and maintain its well-ordered ecological cycle.