红壤重金属复合污染修复的生态环境效应与评价指标

Bio-environmental Effects and Index of Remediation of Multi-Heavy Metals Polluted Red Soils

通过对重金属复合污染红壤菜园土和水稻土的培育试验 ,研究施用有机肥和石灰对红壤中生物有效性重金属 (Cd、Cu、Pb)含量、土壤微生物和植物生理过程的影响 .试验结果表明 ,石灰对土壤重金属污染的修复效果比有机肥好 .施用石灰降低了 0 0 5mol/LHCl提取的土壤生物有效性Cu和Pb的含量 ,施用猪粪后显著增加了土壤生物有效性Cd的含量 ,红薯植株中重金属含量的变化与此一致 .土壤生物有效性重金属含量与可溶性有机碳 (DOC)呈极显著相关 .施用石灰和有机肥后 ,土壤微生物数量增加 ,3大菌中放线菌数量与生物有效性重金属的含量之间显著相关 ,但微生物生物量碳只与土壤生物有效性Cd含量显著相关 .红薯根系中重金属含量与土壤生物有效性重金属含量之间显著相关 ,但在茎叶中只有Cu表现出显著相关性 .施用石灰和有机肥后红薯的生理指标大多增加 .土壤生物有效性Cu、Pb含量与红薯的平均蒸腾速率、净生物量和叶面积指数之间表现出很好的相关性 ,但土壤生物有效性Cd含量与红薯生理指标相关性不强 .在红薯苗期 ,土壤生物有效性Cu、Pb与红薯的日平均净光合速率和蒸腾速率之间相关显著 .

A pot experiment was conducted to study the bio environmental effects of lime and organic manure application on red soil and paddy soil derived from red sandstone and polluted by multi heavy metals. The results indicated that liming decreased the content of soil bioavailable Cu and Pb extracted with 0 05 mol/L HCl, while applying hog manure increased that of Cd. Soil bioavailable heavy metals (HMs) showed an apparent relationship with soil dissolved carbon. Applying lime and organic manure has a positive physiological effect on soil microorganisms and sweet potato. Many indexes, i.e. the number of soil actinomycetes, the content of HMs in the root of sweet potato, showed the remarkable relationship with soil bioavailable Cu, Cd and Pb. However, some indexes of soil and plant only relative to one or two soil bioavailable HMs. For example, soil microbial biomass carbon correspondent with soil bioavailable Cd. Only the content of Cu in the stem and leaf showed a notable relationship with soil effective Cu. Soil effect Cu and Pb rather Cd showed remarkable relation with mean transpiration rate, total biomass and leaf area index of sweet potato. The daily mean value in the seedling stage showed a stronger relationship with soil bioavailable Cu and Pb. Therefore these two physiological indexes can reflect the change of soil metallic contamination.