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

大米被砷污染是一个全球性的问题。 由于砷是一种毒药，食用大米可能会对人体健康构成威胁。 本项目旨在通过可溶性硅（Si）改良土壤，降低稻米中的砷含量，从而保护人类健康。 由于砷和硅在水稻中有共同的吸收途径，增加可溶性硅可以减少水稻根吸收砷和降低水稻籽粒中砷的水平，这是由于可溶性硅竞争水稻对砷的吸收（水稻田土壤溶液中的主要形式）。 虽然土壤中的硅总量很高，但可溶性（因此植物可利用）硅要低得多，特别是在较老（风化程度较高）的土壤中，大多数水稻生长在那里，硅积累植物（如水稻）从土壤中开采硅并被移除。 高硅含量的水稻秸秆还田可降低砷的吸收/储藏，提高产量，从而保护人类健康。 由于新鲜的植物材料可能会促进温室气体的产生，本项目将测试稻壳灰（硅含量高）对减少稻米中砷的吸收和浓度的影响。 如果证明有效，这种管理做法可以在全世界采用，包括发展中国家的小农户，而成本最低，也可以对目前的管理战略作出最小的改变。 该项目将允许购买一个密闭容器微波消化装置，这将有助于首席研究员Seyfferth博士建立她的研究小组，并允许她和她的小组在未来几年进行基础科学。 最后，Seyfferth博士有一个参与科学代表性不足的群体的成员，这将在整个项目和未来的项目继续证明记录。

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.