为了检验重金属污染土壤间套种修复技术的长期实际应用效果，在大田条件下将东南景天（ Sedum alfredii Hance）与玉米（Zea mays）间套种，并设置加入柠檬酸与EDTA混合添加剂的处理，以及单种东南景天作为对照，通过5次田间试验（约3 a），连续监测植物产量、重金属含量以及土壤重金属变化情况。结果表明，各处理土壤镉、锌随着试验的进行逐步下降，套种和套种+混合添加剂处理经过5次种植后土壤达到国家土壤环境质量二级标准，土壤镉从1.21～1.27 mg kg-1降为0.29～0.30 mg kg-1；锌从280～311 mg kg-1降为196～199 mg kg-1；但是土壤铅在试验前后没有显著变化。混合添加剂未表现出强化东南景天提取重金属的效果。东南景天重金属浓度和提取效率没有出现逐年下降的现象。单种东南景天地上部生物量在后4次试验中均较套种高，重金属的总提取量也较高。然而，间套种可生产符合饲料卫生标准的玉米籽粒，第4季达到食品卫生标准。从收获的东南景天计算得到的提取量占土壤镉下降的贡献率为32.5%～36.5%，玉米提取仅占0.47%～0.60%，其余63.0%～66.9%为淋溶等其他因素的作用；锌也相似。表明在该酸性（pH4.7）土壤上，Cd/Zn向下淋溶和东南景天提取均起重要作用。
In order to verify the effectiveness of long-term application of the technology of inter-cropping remedying heavy metal contaminated soils, a 3-year field experiment was conducted to have three treatments and 5 croppings, Treatment IC (inter-cropping of Sedum alfredii Hance and corn (Zea mays)), Treatment Mono-cropping ( Sedum alfredii Hance ) and Treatment IC + MC (mixture of chelators consisting of citric acid and EDTA). Plant yields and heavy metal contents in plant and in soil were monitored for comparison. Results show that the total Cd and Zn in the soil decreased continuously with the progress of the experiment. After the 5 croppings, the soils in Treatments IC and IC MC were remedied to meet the criteria of the National Standard for Soil Environmental Quality (GB15618 -1995). Soil Cd decreased from 1.21~1.27 mg kg-1to 0.29～0.30 mg kg-1 and soil Zn from 280~311 mg kg-1 to 196～199 mg kg-1. But no significant change was observed in soil Pb. MC did not enhance much phytoextraction of heavy metals from the soil. Heavy metal content in the plant of S. alfredii Hance and heavy metal phytoextraction rate of the plant was not decreased with the year. Mono-cropping of S. alfredii Hance was higher in biomass production than the plant in intercropping in all the four rounds and so in total phytoextraction of heavy metals. However, in Treatment IC, the corn turned out to meet the hygienical standard for feed and even the hygienical standard for food in the fourth cropping. Calculation based on harvested S. alfredii Hance shows that the plants contributed 32.5%~36.5% to the decrease in soil Cd, while corn did only 0.47%~0.60% and the remaining 63.0%~66.9% was attributed to leaching loss `and other factors. Soil Zn was in a similar case. These findings indicate that in the studied acid soil (pH 4.7) downward leaching and S. alfredii Hance .phytoextraction both play important roles in reducing soil Cd and Zn.
周建利,邵 乐,朱凰榕,卫泽斌,吴启堂.间套种及化学强化修复重金属污染酸性土壤——长期田间试验[J].土壤学报,2014,51(5):1056-1065. DOI:10.11766/trxb201308110369 Zhou Jianli, Shao Le, Zhu Huangrong, Wei Zebin, Wu Qitang. Phytoremediation of inter-cropping with chemical enhancement of heavy-metal-contaminated acid soil: a long-term field experiment[J]. Acta Pedologica Sinica,2014,51(5):1056-1065.复制