不同原材料生物炭对土壤重金属Cd、Zn的钝化作用

Immobilization of soil cadmium and zinc by different raw material derived biochars

以质量分数0.1%、1.0%不同原料的生物炭(砻糠炭、木炭、竹炭)作为化学钝化修复材料,以空白土壤(CK)和钙镁磷肥作为对照,通过为期90 d的土壤培养试验,研究不同钝化材料及施用量对降低农田土壤重金属镉(Cd)和锌(Zn)污染风险的效果。结果表明,相同施用量的钙镁磷肥比生物炭更有利于酸性土壤改良;各处理中1.0%木炭对土壤有机质含量提升效果最好(P<0.05);与空白对照相比,各处理对土壤Cd、Zn均表现出显著的钝化作用,相同施用量的木炭、砻糠炭比钙镁磷肥的效果更好,其中0.1%木炭钝化效果最佳。在相同施用量下,生物炭整体上更有利于降低土壤酸可提取态Cd、酸可提取态Zn含量,而钙镁磷肥更有利于增加残渣态Cd、残渣态Zn含量。

Biochars made from different materials(husk charcoal,wood charcoal,bamboo charcoal)with mass fractions of 0.1%,1.0%were used as chemical immobilization materials,blank soil(CK)and calcium-magnesium phosphate fertilizer(CaMgP)were used as comparisons to investigate the effect of different biochar materials and their dosages on reducing the risk of cadmium(Cd)and zinc(Zn)pollutions in the farmland soil,by an incubation experiment for 90 d.The results showed that,CaMgP was more suitable for the improvement of acid soil than biochar under the same application amount.Treatment of 1.0%wood charcoal showed the best effect on increasing soil organic matter content among all the treatments(P<0.05).All the treatments showed significant immobilization effects on Cd and Zn in the soil compared with the blank control.The effects of wood charcoal,husk charcoal were more effective than CaMgP under the same dosages,among which 0.1%wood charcoal had the best immobilization effect.Biochar showed a better effect on reducing the acid extractable Cd and Zn contents in the soil with the same dosage as other materials,while CaMgP was more suitable for increasing residual Cd and Zn contents.