Research Starter Grant: Biogeochemical and grain-arsenic impacts of rice-residue incorporation into rice paddy soil

University Of Delaware, Newark DE

Investigators

Abstract

The contamination of rice grains by arsenic is a global problem. Since arsenic is a poison, rice consumption may pose a threat to human health. This project aims to decrease the arsenic concentration in rice grains and thus protect human health from rice consumption by amending soil with soluble silicon (Si). Increased dissolved silicon can decrease root-uptake and grain-levels of arsenic due to competition for plant-uptake of arsenite (the dominant form in rice paddy soil solution) by dissolved silicon because arsenite and silicon share an uptake pathway in rice. While the total amount of silicon in soils is high, the soluble (and thus plant-available) silicon is much lower, particularly in older (more weathered) soils where most rice is grown and where silicon accumulating plants (such as rice) mine silicon out of soil and are removed. Return of silicon to soil from rice residues with a high Si content may decrease arsenic uptake/grain storage, increase yields, and thus protect human health. Since fresh plant material may promote greenhouse gas production, this project will test the effect of rice husk ash (which is high in silicon) on decreasing arsenic uptake and concentration in rice grains. If proven effective, this management practice could be adopted worldwide, including small-holder farms in the developing world, with minimal cost or change to current management strategies. This project will allow for the purchase of a closed-vessel microwave digestion unit which will aid the Principal Investigator, Dr. Seyfferth, in establishing her research group and allowing her and her group to conduct basic science for years to come. Finally, Dr. Seyfferth has a proven record of involving members of underrepresented groups in science, which will continue throughout this project and in future projects.