Dynamics of selenium speciation and reservoir in seleniferous soil of Punjab, India, and potentiality of biochar as a soil amendment to redu

Occurrences of seleniferous soil are an environmental concern in Punjab, India. This study focuses i) to investigate the dynamics of Se speciation and reservoirs in this soil in relation to a) the seasonal rice-wheat crop rotation and b) the crop residue burning, and ii) to explore biochar as a soil amendment to reduce the plant bioavailability of Se in the soil. The first objective will be addressed by Se and Fe K-edge XANES analysis of natural soil samples collected from the field at different rice and wheat cultivation stages. The second objective will be addressed by performing laboratory batch experiments for selenate and selenite sorption onto rice straw biochar, followed by Se K-edge EXAFS analysis of the biochar. This study will develop our understanding of Se cycling under the fluctuating redox conditions and the possible role of temperature in the process. It will also contribute to developing mitigation measures for reducing Se toxicity in regions with seleniferous soils.