CAREER: Toward an improved understanding of the impact of silicon on arsenic, iron, and carbon biogeochemical cycling in rice paddy soils

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Rice is a staple crop for nearly half of the people on Earth, yet its quality and quantity are affected by arsenic (As) with consequent impacts on global human health and food security. Silicon (Si) addition to rice paddy soil has been proposed as a potential mitigation strategy since the dominant form of As in rice paddies shares a root-uptake pathway with Si in rice; however, addition of Si may inadvertently impact other biogeochemical cycles such as iron (Fe) and carbon (C) in soil, depending on the source of Si used. Thus, before Si addition can be proposed as a feasible strategy to mitigate arsenic uptake by rice globally, fundamental scientific questions must be addressed. Accordingly, the goal of this project is to understand how different sources of Si added to soil will affect a) As uptake and accumulation in rice, b) Fe plaque formation and mineralogy (which influences As mobility), and c) carbon dioxide and methane production and efflux. The outcomes of this work will increase the basic scientific understanding of altered Si on As, Fe, and C cycling in rice paddies, and may identify an affordable and practical solution to the arsenic-in-rice problem with consequent benefits for the global society. Furthermore, the outcomes of this work have a strong educational component and will be widely disseminated to rice-growers through partnerships with non-profit organizations, and to the scientific community through peer-reviewed publications and conference presentations. This research will have both laboratory and field components and the investigations will span the nanometer to meter-field scale. A major component is the establishment of a new outdoor research-education laboratory, the Rice Investigation, Communication, and Education (RICE) Facility. The RICE Facility will be constructed -with ongoing aid of students in the Landscape Design program- at the University of Delaware (UD), and will enable field experiments in rice paddy mesocosms during summers and allow the integration of research with educational outreach objectives. The overarching educational goal is to increase the representation of underrepresented groups in (geo)science by providing scholastic opportunities for female and economically-disadvantaged students. Specifically, a) an annual 1-day summer-camp entitled Soil is Life will be developed at the RICE Facility for students from the all-female middle-school Serviam Academy, b) a high-school student from Newark High School will be paid to work on this project at the RICE Facility annually during summer months, c) a new undergraduate course will be developed that integrates soils and sustainability, and d) this project will directly train graduate students on this interfacial field of study. The proposed research and education will propel the career as a young scientist, support her continual development into a successful teacher-scholar at University of Delaware, and support her ongoing commitment and efforts to increase the integration and representation of underrepresented groups in (geo)science.