巨菌草对黔西北土法炼锌废弃地的生态修复研究

Study on the Ecological Restoration of Pennisetum Giganteum on the Abandoned Land of Zinc Smelting in Northwest Guizhou

黔西北土法炼锌导致植被破坏形成了大量的废弃地,土法炼锌停止后当地部门对废弃地进行了多种形式的修复。通过野外样地试验对比研究引种植物巨菌草(Pennisetum giganteum)以及当地先锋植物醉鱼草(Buddleja lindleyana)、艾蒿(Artemisia argyi)对黔西北土法炼锌废弃地的修复效果。结果显示,在研究区污染土壤和废渣两种基质中生长的巨菌草株高、根长、盖度、生物量均显著高于当地先锋植物醉鱼草和艾蒿,污染土壤中生长的巨菌草要比废渣中的好,其株高较废渣增加23.2%,根长增加36.6%,盖度增加16.7%,地下部生物量增加35.2%,地上部生物量增加33.6%。巨菌草根际土壤重金属(Pb、As、Cd)含量显著高于醉鱼草和艾蒿,能将重金属稳定在根部,从而减少重金属的迁移扩散。废弃地中巨菌草对Pb、As、Cd的富集系数分别为0.85~0.95、3.98~4.50、1.39~1.59,转运系数分别为0.39~0.56、0.17~0.48、1.12~1.30。巨菌草对重金属具有一定的富集转运能力,是一种较好的原位修复植物,随着种植年限和收割次数的增加,基质中的重金属逐渐被带走。此外,巨菌草生物量大、热值高,利用巨菌草修复受污土壤的同时能够产生生物质能,具有较好的环境经济效益。

The indigenous zinc smelting in northwest Guizhou led to the destruction of vegetation and the formation of a large number of abandoned land.After the cessation of indigenous zinc smelting,the local authorities carried out various forms of restoration of the abandoned land,but the effect was not good.A field plot experiment was conducted to compare the effects of Pennisetum giganteum,Buddleja lindleyana and Artemisia argyi on the restoration of zinc smelting wasteland in northwest Guizhou.The results showed that the plant height,root length,coverage and biomass of Pennisetum giganteum growing in the two substrates in the study area were significantly higher than those of the local pioneer plants.The growth of Pennisetum giganteum in contaminated soil was better than that in waste residue.The plant height increased by 23.2%,the root length increased by 36.6%,the coverage increased by 16.7%,the underground biomass increased by 35.2%,and the aboveground biomass increased by 33.6%.The content of heavy metals(Pb,As,Cd)in rhizosphere soil of Pennisetum giganteum was significantly higher than that of Buddleja lindleyanum and Artemisia argyi,which could stabilize heavy metals in roots and reduce the migration and diffusion of heavy metals.The enrichment coefficients of Pb,As and Cd were 0.85~0.95,3.98~4.50 and 1.39~1.59,respectively,and the transport coefficients were 0.39~0.56,0.17~0.48 and 1.12~1.30,respectively.Pennisetum giganteum has a certain ability to enrich and transport heavy metals.It is a good in-situ remediation plant.With the increase of planting years and harvest times,the heavy metals in the matrix are gradually taken away.In addition,Pennisetum giganteum has large biomass and high calorific value.Using Pennisetum giganteum to repair contaminated soil can produce biomass energy,which has good environmental and economic benefits.