Direct and indirect effects of biochar on the mobility of metals and nutrients in contaminated soils: a two-column leaching experiment

International audience; Biochar is a charred carbon-enriched material intended to be used as a soil amendment to sequester carbon and enhance soil quality. Addition of biochar to soil has many environmental and agricultural benefits, including waste reduction, energy production, carbon sequestration, water resource protection, and soil improvement. Biochar has been reported to boost soil fertility and improve soil quality by raising soil pH, increasing moisture holding capacity, attracting more beneficial fungi and microbes, improving cation exchange capacity (CEC), and retaining nutrients in soil. Biochar usually has a greater sorption ability than natural soil organic matter due to its greater surface area, negative surface charge, and charge density what can be an important set of properties for soil protection and reclamation procedures. Another major benefit associated with the use of biochar as a soil amendment is its ability to sequester carbon from the atmosphere-biosphere pool and transfer it to soil. Unfortunately many of described effects of biochar addition in soil are not well understood and bring many doubts about the potential cost and benefits of its use in agriculture. In many cases biochar studies bring very opposite results depended on many factors eg. feedstock, biochar production technology, soil properties, climate or plant used in the experiment. The main objectives of the session is to: • Highlight the potential cost and benefits of biochar as an effective soil amendment. • Discuss main factors influencing quality of biochar in context of its effective use in soil. • Present the state of knowledge about mechanism of BC-soil and BC-plant and microorganism interactions. • To identify the main problems of biochar analysis and its use in soil environment. The purpose of the session is to bring together researchers working on biochar use in agriculture, horticulture and soil reclamation interested in sharing their experiences in international, multidisciplinary group, developing collaboration for scientific projects and publications.”