土壤改良剂联合间套种技术修复重金属污染土壤:田间试验

在田间条件下,验证通过盆栽试验初步筛选出的几种改良剂在玉米和东南景天间套种修复重金属污染土壤的大田实际应用效果.研究结果表明,施用改良剂蘑菇渣肥、云母和沸石能有效降低玉米籽粒和茎叶中的Cd和Pb,玉米籽粒Cd和Pb含量均达到食用标准.蘑菇渣肥显著增加了东南景天对Cd的提取量,腐植酸显著促进了东南景天对Pb的吸收,因此,蘑菇渣和腐植酸可以应用于玉米和东南景天套种系统.施用云母和沸石可以显著提高土壤pH值,降低土壤可交换态Cd/Pb含量,从而降低二种植物对Cd/Pb的吸收;然而,施用蘑菇渣肥和腐植酸却增加土壤可交换/吸附态Cd/Pb含量.植物根系吸收Cd的稳定常数显示该有机吸附态Cd难于被玉米根系吸收.

Applying soil amendments to co-cropping system for remediating heavy metal contaminated soil: Field experiment.

The field experiment was carried out to verify the feasibility of applying the selected soil amendments in a real case of phytoremediation with the co-crop of Sedum alfredii and Zea mays. Results showed that application of mushroom manure or mica or zeolite significantly decreased Cd and Pb contents in maize straw and grain, and Cd and Pb concentrations in corn grain were below the limit value of the Chinese food standards (GB 2762-2012). The phyto-extraction of Cd by S. alfredii was increased by the treatment of mushroom manure, and humic acids increased significantly the phyto-extraction of Pb. Therefore humic acids and mushroom manure were suitable soil amendments to be applied in the co-cropping system of S. alfredii and maize. The application of mica and zeolite significantly increased the soil pH and decreased the exchangeable Cd and Pb in soil, and accordingly, the uptake of Cd and Pb by the two plants were also reduecd. However, the treatment of mushroom manure or humic acids increased the exchangeable or adsorbed Cd and Pb in soil, the stability constant of Cd absorption by plant roots indiacated that these organic-matter-adsorbed Cd was difficult to be up-taken by maize roots.