Average (±SD) of aboveground plant biomass and root biomass of tomato and lettuce (n= 3, FYPM2 and FYPMR2 for tomato had only one replication). Bars with different letters show significant difference at P<0.05. control 1; soil without any amendment, control 2; soil with amendment of Cr mine tailing debris, WBPM1; wood-derived biochar + poultry manure amended at 10% rate in Cr mine tailing debris-contaminated soil, WBPM2; wood-derived biochar + poultry manure amended at 20% rate in Cr mine tailing debris-contaminated soil, FYPM1; cow manure –derived biochar + poultry manure amended at 1-% rate in Cr mine tailing debris-contaminated soil, FYPM2; cow manure-derived biochar + poultry manure amended at 20% rate in Cr mine tailing debris-contaminated soil, WBPMR1; wood-derived biochar + poultry manure amended at 10% rate in Cr mine tailing debris-contaminated soil, WBPMR2; wood-derived biochar + poultry manure amended at 20% rate in Cr mine tailing debris-contaminated soil, FYPMR1; cow manure –derived biochar + poultry manure amended at 1-% rate in Cr mine tailing debris-contaminated soil, FYPMR2; cow manure-derived biochar + poultry manure amended at 20% rate in Cr mine tailing debris-contaminated soil.