|Title||The addition of biochar to serpentine soils reduces metals release and phytotoxicity to tomato plants|
|Publication Type||Conference Paper|
|Year of Publication||2014|
|Authors||Herath, Indika, Wickremasinghe Subash, Rajakaruna Nishanta, Nawaratne Ayanthi, and Vithanage Meththika|
|Conference Name||Conference Paper June 1014|
Serpentine soils release heavy metals into the environment. We investigated the potential of woody biochar (BC), a waste byproduct of dendro-power industries in Sri Lanka, as a soil amendment to immobilize and reduce the phytotoxicity of bioavailable Ni, Cr and Mn in serpentine soil. Metal release experiments were carried out to investigate the release kinetics of Ni and Mn in BC amended/un-amended serpentine soil. A pot experiment was conducted using tomato (Lycopersicon esculentum L.) to evaluate the effects of BC on reducing phytotoxicity. Three BC applications, 1.0, 2.5 and 5.0% (w/w), were used for both metal release and phytotoxicity experiments. Metal release experiments demonstrated that Ni and Mn leach rapidly from BC amended and un-amended serpentine soil during first 60 min and equilibrium is reached after 120 min. The 5.0% BC amendment decreased Ni and Mn release by 52 and 36%, respectively, compared to the BC un-amended soil. The amount of metal released decreased significantly with increasing BC application. The biomass of tomatoes grown in 5.0% BC amended soil was about 40-fold higher than that of BC un-amended soil. Bioaccumulation of Cr, Ni and Mn decreased by 93-97% in tomatoes grown in the 5.0% BC amended soil compared to the BC un-amended soil. Our results suggest that the use of BC as a soil amendment could be an economically viable alternative strategy to immobilize and reduce the phytotoxicity of heavy metals in serpentine and other metal-enriched soil.