The Improvement of Nitrogen Use Efficiency (NUE) and Water Use Efficiency (WUE) in Corn (Zea mays L.) on Maryland's Eastern Shore.

The University of Maryland Eastern Shore is located on the eastern shore of Maryland, bounded by the Chesapeake Bay to the west, and Atlantic coastal bays to the east. Effective nutrient management in this location is of critical importance. Excessive application of Nitrogen (N) fertilizers and the subsequent nutrient enrichment of waterways can be blamed for eutrophication in marine, estuarine and riverine systems. Additionally, agricultural practices will have to adapt to climate change that is likely to result in more frequent droughts and water scarcity; drought tolerant seeds has the promise to improve water use efficiency in production of cereal crops. Pioneer and other seed development companies are also addressing the issue of limited water resources by developing drought-tolerant seeds (Service, 2009; Shanahan & Groeteke, 2011). Results of field experiments with variable density seeding using non-drought tolerant and drought tolerant corn seeds in 2013 and 2014 growing seasons on two UMES agricultural fields are outlined.  Harvest data obtained from a combine equipped with a yield monitor and GPS unit are analyzed and compared with experimental layout using appropriate GIS based mapping tools. Critical to the process of nutrient management the creation of N-response curves. To develop such curves, field studies are undertaken to determine optimum N application rates. This three year project (2012 - 2014) centered on corn (Zea mays L.). The experimental layout is a split-split plot design with irrigation as the main plot, N application levels as the sub-plot and seed as the split-split factor. Five (2012) or six (2013, 2014) fixed N fertilizer levels were used. Three irrigation levels were used, full season, partial season and rain-fed only. Two seed types were used in 2013 and 2014, comparing a drought tolerant (Pioneer Aquamax) and a non-drought tolerant seed. Each plot was hand harvested and weighed to calculate an equivalent yield in bushels per acre. Significant effects of seed, Nitrogen and Irrigation were observed. Preliminary efforts with a newly acquired optical sensor based variable rate nutrient applicator are also described.