Low-cost, field-deployable sensors to monitor nitrate in soil and water

Nitrogen fertilizer is one of the greatest input costs to cereal crop production but the averageefficiency of nitrogen fertilizer use is low. Only 30-60% of nitrogen fertilizer is taken up by crops.Large amounts of nitrogen fertilizer are lost to the surrounding environment representing aneconomic loss to farmers and diminishing air and water quality. These challenges apply to cerealcropping systems around the globe. In addition nitrogen fertilizer loss represents an enormousamount of wasted energy: every kg of nitrogen fertilizer synthesis delivery and applicationgenerates ~1.4 kg of CO -C. Although soil and water nitrate testing has been proven to reduce2 losses and improve profitability adoption of these tests remains limited due to high cost and longturn-around time (samples must be shipped to a laboratory and results are not received for ~1week). In response to these global concerns the National Academy of Engineering identifiedst "Manage the Nitrogen Cycle" as one of 14 Grand Challenges for Engineering in the 21 Century.And on 2018 the National Academies of Engineering Medicine and Science identified low-costhighly sensitive field-deployable sensors as one of "five breakthroughs required to address urgentchallenges and advance food and agricultural science".EnGeniousAg's Phase I proposal aims to develop low-cost highly sensitive sensors that cancontinuously or instantaneously measure nitrate in soil and water. Several novel aspects ofour sensors promise to overcome current limitations with ion selective electrodes including signaldrift non-target ion interference and high cost and have the potential to revolutionize nitrogenmanagement. However at this stage our sensors require several fundamental improvementsbefore commercialization including addressing problems with signal instability and sensor fouling.This Phase I project will allow us to test hypotheses that lead to improvements in sensorperformance and to ultimately validate the feasibility of producing consistently accurate sensors.Success in Phase I will naturally lead us to a Phase II proposal that will be focused oncommercializing the consistently functional sensors for rugged field conditions. At a cost of $1- 2/measurement successful sensor commercialization would provide data that can improveprofitability and reduce the environmental impact of farms across the globe. Soil nitratemeasurements can improve nitrogen fertilizer prescriptions while drainage water nitrate sensorscan measure outcomes and identify fields that would benefit from more intensive nitrogenmanagement practices. No longer would nitrogen fertilizer application decisions be based ongeneralized conventional wisdom or a few soil samples that require days of laboratory processingbefore data are available to the decision maker. In contrast hundreds of instantaneous data pointswould enable up-to-the-minute down-to-the-square-meter decisions. There is a large existingmarket for soil and water nitrate testing that will expand with the commercialization of low-costhighly accurate field-deployable sensors. For example the state of Iowa has 87500 active farmswith an average size of 350 acres. In 2014 the Iowa Farm and Rural Life Poll indicated that 87%of Iowa farmers use plant and soil testing to guide fertilizer inputs and nutrient management.Moreover the 2015 Iowa Farm and Rural Life Poll determined that more than 60% of Iowa farmershave increased use of soil and plant testing since 2013 due to societal pressure to improveenvironmental outcomes as well as new technologies that enable precision nutrient application.University Extension recommends at least one sample for every 2.5 acres of cropland. If weestimate that 50% of Iowa farms annually test plants and soils at the recommended resolution(87500 farms * 50% * 350 acres / farm · 2.5 acres / sample * $10 / sample) total expenditureson testing could exceed $60 million per year. Because Iowa’s 30M corn acres represents ~⅓ of the US corn acreage, the potential nitrate testing market for US corn production alone is likely >$150M annually.