Does biochar application alter heavy metal dynamics in agricultural soil?

• Published in: Agriculture, ecosystems & environment ecosystems & environment, 2014-02, Vol.184, p.149-157
• Main Authors: Lucchini, P., Quilliam, R.S., DeLuca, T.H., Vamerali, T., Jones, D.L.
• Format: Article
• Language: English
• Subjects: Agricultural management; Agriculture; Agronomy. Soil science and plant productions; Animal, plant and microbial ecology; Applied ecology; Applied sciences; Bioavailability; Biological and medical sciences; Cadmium; Carbon sequestration; Economics; Exact sciences and technology; Farming; Farms; Fundamental and applied biological sciences. Psychology; General agroecology; General agroecology. Agricultural and farming systems. Agricultural development. Rural area planning. Landscaping; General agronomy. Plant production; Generalities. Agricultural and farming systems. Agricultural development; Heavy metals; Hordeum vulgare; Metal fractionation; Plants (organisms); Pollution; Soil (material); Soil and sediments pollution; Soil and water pollution; Soil contamination; Soil pollution; Soil science
• ISSN: 0167-8809; 1873-2305
• DOI: 10.1016/j.agee.2013.11.018

•Biochar made from forest residue was low in heavy metals.•Biochar application to soil caused a small change in metal fractionation.•The addition of biochar did not alter total metal concentrations in soil or crop plants.•Repeat applications of biochar did not increase the concentrations of metals in soil. Biochar incorporation into soil has been advocated as a potential large scale solution to offset global greenhouse gas emissions. However, the application of biochar to agricultural land must have few if any negative economic and environmental consequences if farmers are to readily adopt biochar as soil amendment. Biochar use as an organic amendment has been recently rising due to its positive effect on soil fertility, but there is still limited information available about longer-term effects, especially with regard to the effects on soil pollutant content and distribution. In a field-scale trial we investigated the effect of single doses of biochar (25 and 50tha−1) and repeat-applications (two years later) of biochar (25+25 and 50+50tha−1) on heavy metal (As, Cu, Zn, Cd, Ni) content and distribution in soil, together with metal concentrations in plants (barley, beans) over repeated cropping cycles. Here we demonstrate that biochar produced from forest residues is of a low risk due to its inherently low metal content and the lack of observed negative effects on crop or soil quality. Although biochar did cause small changes in metal fractionation in soil, it did not alter total metal concentrations in soil or plants. We conclude that the application of wood-derived biochar does not increase the concentrations of metals in this soil, even after repeated applications, and could be safely used for agriculture