The Development Sensor-Based Algorithms and On-the-Go Application for the Improvement of Nitrogen Use Efficiency (NUE).

Management of the Soil Nitrogen Cycle is of critical importance to the health of entire ecosystems. Excessive application of Nitrogen (N) fertilizers and the subsequent nutrient enrichment of waterways can be attributed to eutrophication in marine, estuarine, and riverine systems. Presently, worldwide nitrogen-use-efficiency (NUE) is said to be less than 50 percent. The remainder of this N is left to enrich the atmosphere as well as ground and surface water, with potentially serious negative impacts. Proper and efficient management of N application minimizes pollution of groundwater and optimizes profits for producers. Assessment of within–field crop variability is critical for improvement of NUE. With appropriate design of sensor and sprayer combination on tractor booms the sensing, calculation of sensor based nitrogen application rates, and nitrogen fertilizer spraying can be implemented on-the-go with microprocessor-based sensing and actuation. Critical to this process is the creation of N-application algorithms. To develop such algorithms, field studies are undertaken to determine optimum N application rates. The first two years of this project (2012, 2013) centered on corn (Zea mays L.) raised under two or three water conditions (irrigated full season, irrigated partial season, and non-irrigated). Five (2012) and six (2013) fixed N fertilizer levels were used. The 2013 experimental year added a drought-tolerant seed as an additional experimental factor. Each plot was hand-harvested and weighed to calculate an equivalent yield in bushels per acre. Significant effects of both Nitrogen and Irrigation were observed.

Key words: Nitrogen, Fertilizers, Irrigation, Yield