蚓粪基复合肥施用下土壤-蔬菜体系中Pb的迁移转化特征

Characteristics of Pb Migration and Transformation in Soil-vegetable SystemUnder Application of Vermicompost-based Compound Fertilizers

为开发蚓粪、贻贝壳资源化利用新途径,防范蔬菜地重金属污染风险,将蚓粪与贻贝壳粉和贻贝壳改性物按9∶1比例混合分别制得蚓粪基复合肥(vermicompost-based mussel powder fertilizer,VS;vermicompost-based mussel shell modifier fertilizer,VSC),进一步研究蚓粪及其复合肥施用对苋菜生长、铅(Pb)含量及富集、形态转化特征的影响,结果表明:蚓粪及其复合肥(VS、VSC)施用均可有效促进苋菜生长并降低苋菜茎叶Pb含量,且以VS、VSC处理效果较优;施用蚓粪基复合肥(VS、VSC)可有效降低土壤有效态Pb含量和生物有效性系数;形态分级研究表明,蚓粪基复合肥(VS、VSC)施用可增加土壤Pb有机结合态,降低土壤铅交换态占比.因此,以蚓粪及贝壳资源制备复合肥用于修复Pb污染土壤切实可行.

In order to develop new ways to recycle both vermicompost and mussel shell,and to prevent the risk of heavy metal migration in farmland soil,vermicompost-based compound fertilizers are produced by mixing vermicompost with mussel powder or mussel shell modifier at a ratio of 9∶1 separately being named as VS or VSC,respectively.Then,both vermicompost(V)and vermicompost-based compound fertilizers are added into the soil aiming to reveal their effects on the growth and lead(Pb)enrichment of Amaranth as well as the morphological transformation of Pb in soil.The results show that both V and its compound fertilizers(VS and VSC)can effectively promote the growth of Amaranth and reduce the Pb content in the above edible part of Amaranth,with much better effect found in the treatment with VS and VSC application,and the addition of vermicompost-based compound fertilizers(VS and VSC)can effectively reduce the available Pb contents and the bioavailability coefficient in the soil.Besides,the vermicompost-based compound fertilizers can increase the proportion of organically bound Pb(OM)but reduce that of the exchange state Pb(EXCH).Therefore,it is feasible to use both vermicompost and mussel shell to produce the vermicompost-based compound fertilizers for remediating the Pb contaminated soil.