污泥植物处理后对玉米生长及土壤重金属含量的影响

为了探明植物处理后污泥作为肥料施用后对后续作物和土壤的影响,将植物处理后的污泥混于土壤,种植后续作物玉米(Zea mays),测定作物产量以及土壤和作物的重金属含量.结果表明,污泥施用2a后仍有肥效,其玉米生物量显著大于无污泥的对照处理,且单种植物处理后的污泥肥效要优于无植物或套种处理的污泥.施用污泥后的2a内,4季玉米的茎叶和籽粒Zn、Cd、Cu和Pb含量均符合饲料标准;但第3季以后玉米籽粒才可作为食用.施用污泥后土壤重金属含量随时间而下降,Zn的年消失率为32%~35%,Cd为28%~33%,Cu为18%~30%,Pb为15%~23%;施用污泥的土壤重金属年下降率高于对照和化肥处理.污泥施用于土壤2a后,表层土壤全Zn和全Pb含量与对照处理已无明显差异.

Maize growth and soil heavy metal changes after application of phyto-treated sewage sludge

In order to study the effect of the application of phyto-treated sewage sludge on heavy metals in soil and maize(Zea mays) growth,experiments in plots with successive maize crops after applying the phyto-treated sludge were conducted with the monitoring of heavy metals in soil and crop.Results showed that the application of sludge to soil was still beneficial to maize during 2 years and the maize biomass with sludge was better than that of control.The treatment with mono-crop treated sludge resulted in the highest yield.Concerning the concentrations of Zn,Cd,Cu and Pb in maize,all harvests of corn and the stem and leaves of maize could be used as animal feeds during 2 years.But only the corn grains of the third harvest and there-after could be conformed to the food standards.The concentrations of heavy metals in soil declined with time,the annual disappearance rates were 32%~35% for Zn,28%~33% for Cd,18%~30% for Cu and 15%~23% for Pb,and the disappearance rates were higher for the sludge treated soils than that of control and the chemical fertilizer treated soils.The total concentrations of Zn and Pb in the up-soil layer treated with sludge did not show significant difference with the control after 2 years.