**3.4 Poultry manure**

Poultry manure is also used to remediate heavy metals from soil. A study was conducted to study the effectiveness of the adding poultry manure on the bioavailability of trace metals from the contaminated soil after treatment with wastewater [54]. It was applied @ 10 and 20 t ha−1 and found that the addition of manure increased fenugreek biomass and decreased trace metal uptake depending on the combination of composted manures used. Trace metal concentrations in the fenugreek shoots were in the order of Pb > Ni > Zn > Cu > Cd. Soils amended with Poultry litter reduced trace metal concentrations more than composted manure which is true for the plant uptake. It was concluded that following the combined application of composted manure with residues of plant can be effectively used for remediating trace metal concentration in soils and crops. Chicken-manure biochar is used as a soil amendment to immobilize and detoxify heavy metals like cadmium and lead.

Certain plant species are also used to remediate heavy metals. They can accumulate a high amount of heavy metals in upper parts of plants. Indian mustard plant is used for phytoremediation [55]. So, Biocar can also remediate heavy metal toxic soils.
