SBIR Phase I: Development and Commercialization of Nitrate-Selective Sensors for Precision Agriculture

This Small Business Innovation Research (SBIR) Phase I project will demonstrate proof of concept and validate the feasibility of translating a molecular receptor for nitrate anion into a highly-selective and sensitive soil probe. Ultimately, these sensors will fulfill the need for real-time monitoring of fertilizer application in environmentally sustainable precision agriculture. Both the ion-selective electrode and chemically modified field effect transistor interfaces currently used for nitrate monitoring are capable of measurements only in aqueous media. These sensors rely solely upon non-specific interactions for their selectivity due to a general lack of nitrate selective receptor components. This limitation preempts their use in soil media where highly competitive interferents diminish response. The first innovation proposed herein is the development of a sensor incorporating a rationally designed and intrinsically selective host molecule, which will provide the affinity for nitrate needed to enable monitoring in soils on a molecular level. This technology will then enable a second innovation: a field-embeddable soil sensor network that wirelessly reports fertilizer levels during application in real-time. These innovations will enable molecularly selective sensing in soil, and will pave the way for the development of future molecular sensors for monitoring difficult-to-target anionic and neutral substrates in complex media. The broader impact/commercial potential of this project is the simple need for feeding the world sustainably. Increasing food production capacity by two-fold in the next 30 years, while concurrently decreasing the environmental impact of nonpoint-source pollution has been identified as one of the grand challenges facing the sciences. Nitrate-based fertilizer accounts for almost 60% of the 21M tons of fertilizer applied annually and almost 30% of this is wasted due to seepage, runoff and volatilization. Conserving even 20% of the 2.5M tons of domestic fertilizer that ultimately contribute to nonpoint-source pollution would save growers an average of $45/acre annually, giving rise to an annual market in the U.S. worth approximately $2.1B. Additionally, real-time monitoring of soil macronutrients will enhance understanding of soil chemistry by providing snapshots of the in situ behavior and fate of these chemicals. On a global scale the development of a low-cost and universal probe for soil quality would offer developing areas a novel method for optimizing yields and enabling self-sufficiency in food production. Additionally, these sensors will address the environmental dilemma of groundwater contamination with a foundational solution: limiting the wasteful over-application of fertilizers in food, flower and grain production.