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

大米是地球上近一半人口的主食作物，但其质量和数量受到砷的影响，从而对全球人类健康和粮食安全产生影响。水稻土中添加硅(Si)被认为是一种潜在的缓解策略，因为稻田中的主要形态As与水稻中的Si具有相同的根系吸收途径；然而，添加Si可能会无意中影响土壤中的其他生物地球化学循环，如土壤中的铁(Fe)和碳(C)，这取决于所使用的硅的来源。因此，在提出添加硅作为一种可行的策略以减轻全球水稻对砷的吸收之前，必须解决基本的科学问题。因此，该项目的目标是了解添加到土壤中的不同来源的硅将如何影响a)As在水稻中的吸收和积累，b)Fe菌斑的形成和矿物学(影响As的移动性)，以及c)二氧化碳和甲烷的产生和排放。这项工作的成果将增加对硅蚀变对稻田中As、Fe和C循环的基本科学理解，并可能找到一种负担得起的、实用的解决稻米中砷问题的方法，从而为全球社会带来好处。此外，这项工作的成果具有很强的教育性，将通过与非营利组织的伙伴关系向水稻种植者广泛传播，并通过同行评议的出版物和会议发言向科学界广泛传播。这项研究将包括实验室和现场两部分，调查范围将从纳米到米场。一个主要组成部分是建立一个新的户外研究-教育实验室，即大米调查、传播和教育(大米)设施。水稻设施将在特拉华大学(UD)景观设计项目的学生的持续帮助下建造，并将在夏季实现稻田中观系统的田间实验，并允许将研究与教育推广目标相结合。教育的首要目标是通过为女性和经济上处于不利地位的学生提供学习机会，增加(地球)科学中代表性不足群体的代表性。具体地说，a)将在水稻设施为全女性中学Serviam Academy的学生设立为期一天的夏令营，题为“土壤就是生命”；b)每年夏季将向纽瓦克高中的一名高中生支付在水稻设施从事这一项目的费用；c)将开发一门新的本科课程，将土壤与可持续发展相结合；d)该项目将直接培训研究生在这一界面领域的研究。拟议的研究和教育将推动她作为一名青年科学家的职业生涯，支持她继续发展成为特拉华大学一名成功的教师-学者，并支持她不断致力于增加(地球)科学中代表性不足群体的整合和代表性。

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.