ECO-CBET: Foliar applied plant-activated nitrogen delivery agents for sustainable crop production.

农业对美国的经济、健康和国家安全至关重要。氮肥在农业中被广泛使用，以确保消费者获得充足和营养丰富的粮食供应，并为农民提供足够的经济回报。然而，目前的土壤氮肥输送途径和做法对于使用不到50%施肥量的作物来说是不有效的。这种对氮肥的低效使用继续在美国和世界范围内造成普遍而令人头疼的环境问题，从地下水污染、有害的藻华、富营养化到对水和空气质量产生负面影响的气态N2O污染物的排放。该项目的总体目标是开发一种基于叶面的肥料输送过程，通过直接向叶片而不是土壤施入氮素和其他养分，从而有效地向作物输送氮素和其他养分。为了推进这一目标，该项目的主要研究人员建议将氮肥封装到功能化的纳米颗粒载体中，将氮直接输送到植物中。这些载体将被设计成喷洒在植物的叶子上。特殊的靶向配体将被附着在N纳米颗粒载体的表面，并帮助引导它们到达植物中需要它们的位置。这一项目的成功完成将通过发展新的基本知识造福社会，这些知识可用于指导设计和部署更有效和更可持续的氮肥输送过程。通过学生教育和培训将进一步造福社会，包括指导5名博士后、1名博士后学者和18名REU本科生。农田土壤氮肥已造成氮素循环的严重失衡，造成不可持续的环境后果。管理氮素循环是一项长期的工程重大挑战，只有通过彻底改变氮肥在作物上的应用方式才能应对。该项目的总体目标是通过高效、有针对性和植物激活的氮素利用，实现基于叶面的应用，从而改变氮素和其他养分向作物的输送。该项目的具体目标是：1)开发生物相容的载体颗粒(N载体)，用于从农业副产品或地球上丰富的矿物中有效地输送N；2)将植物生物识别分子嫁接到N载体上，使植物的叶绿体成为靶标，从而提高N的同化效率；3)开发分子和多尺度运输模型，以预测N载体在叶表面的转移和分配，以及与内部细胞表面的相互作用；4)量化N载体的生命周期、环境效益和相对于土壤施N肥的风险。为了实现这些目标，该项目的首席研究人员建议汇聚和整合不同领域/学科的想法和工具，包括纳米技术、界面工程、颗粒和多相传输、植物生物工程、环境工程和环境可持续性。该项目的成功完成具有潜在的变革性影响，通过开发更高效和可持续的氮肥输送过程，可以推进高效和可持续管理N周期的目标。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Agriculture is critical to the economy, health, and national security of the United States (U.S.). Nitrogen fertilizers are widely utilized in agriculture to ensure an abundant and nutritious food supply for consumers and adequate financial returns for farmers. However, current soil nitrogen (N) fertilizer delivery routes and practices are not efficient with crops using less than 50% of the applied fertilizer loads. This inefficient usage of N fertilizers continues to cause pervasive and vexing environmental problems in the U.S. and worldwide ranging from groundwater contamination, harmful algal blooms, eutrophication to the emission of gaseous N2O pollutants that negatively impact water and air quality. The overall goal of this project is to develop a foliar-based fertilizer delivery process that could efficiently deliver N and other nutrients to crops by applying the to the leaves directly rather than to the soil. To advance this goal, the Principal Investigators of this project propose to encapsulate N fertilizers into functionalized nanoparticle carriers that deliver the nitrogen directly into the plant. These carriers will be designed to be sprayed onto the plant leaves. Special targeting ligands will be attached onto the surfaces of the N nanoparticle carriers and help guide them to the locations in the plants where they are needed. The successful completion of this project will benefit society through the development of new fundamental knowledge that could be leveraged to guide the design and deployment of more efficient and sustainble N fertilizer delivery processes. Further benefits to society will be achieved through student education and training including the mentoring of five PhD students, one postdoctoral scholar, and ~18 undergraduate REU students.Soil-based nitrogen fertilization of cropland has created severe imbalances in the nitrogen (N) cycle with unsustainable environmental consequences. Managing the N cycle is a perennial engineering grand challenge that can only be met by a radical transformation in the way that N fertlizers are applied to crops. The overall goal of this project is to transform the delivery of N and other nutrients to crops by enabling foliar-based application with highly efficient targeted and plant-activated N utilization. Specific objectives of the project are to 1) Develop biocompatible carrier particles (N-carriers) for efficient N delivery that are derived from agricultural byproducts or earth-abundant minerals; 2) Graft plant-biorecognition molecules onto the N-carriers to enable the targeting of plant chloroplasts to increase N assimilation efficiency; 3) Develop molecular- and multi-scale transport models to predict N-carrier translocation and distribution through the leaf surface, and interactions with internal cell surfaces; and 4) Quantify the life cycle, environmental benefits, and risks of N-carriers relative to soil-applied N fertilizers. To achieve these objectives, the Principal Investigators of this project propose to converge and integrate ideas and tools from various fields/disciplines including nanotechnology, interfacial engineering, particulate and multi-phase transport, plant bioengineering, environmental engineering, and environmental sustainability. The successful completion of this project has the potential for transformative impact through the development of more efficient and sustainable N fertilizer delivery processes that could advance the goals of an efficient and sustainable management of the N cycle.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.