Effect Of Biochar Based Fertilizer On Remediation Of Cd、cu、pb And Zn In Paddy Soils

A pot trial was conducted in paddy soil to study the effects of biochar and biochar based fertilizer on remediation of heavy metal-contaminated soils. Three typical biochars(Rice straw biochar, Eucalyptus sawdust biochar, Cattle mature biochar) and calcium magnesium phosphate were selected to research the effects of biochar and biochar based fertilizer on leaf lettuce growth, uptake and accumulation of heavy metal, soil physical and chemical properties and speciation distribution of heavy metal. This study could provide a scientific basis for application of biochar and biochar based fertilizer in in-situ immobilization of heavy metal contaminated soil.Results indicated that amendment of biochars and biochar based fertilizers increased soil physical and chemical characteristics except for ammonium and reduced absorption and bioconcentration of Cd, Cu, Pb and Zn in different plant tissues while translocation factor of shoot increased with amendment of biochars and biochar based fertilizers.Biochars and biochar based fertilizers could reduce the proportion of exchangeable Cd, Cu, Pb and Zn in soils while the proportion of Cd, Cu, Pb and Zn in a more stable form increased. Not all fractions of heavy metals in soil promoted absorption of heavy metal in lettuce, Exchangeable, Carbonates were the main factors which infect absorption of heavy metals in leaf lettuce, Organic matter and Residual were not easy absorbed by leaf lettuce. Exchangeable, Carbonates were bio-available fractions in paddy- lettuce system.Above all, compared with Eucalyptus sawdust biochar, Cattle manure biochar and Rice straw biochar showed great potential in remediation of heavy metals contaminated soils considering soil amelioration, heavy metals immobilization and plant growth and absorption of heavy metals.