ESN as a Potential Nitrogen Source for Ohio Wheat Production.

Urea and urea-ammonium nitrate (UAN) are the common forms of spring N applied to wheat in Ohio. A relatively new product, ESN, has become available to producers. It is a slow release product that might reduce N loss and provide N later in the growing season. Little is known about its use on Ohio soils and whether it might be used as a possible alternative source for spring N. To test this hypothesis, three rates of ESN, urea, and UAN were spring applied on wheat at Feekes growth stage 3 in 2007 and 2008 on a clay soil at the OARDC Northwest Research Station near Custar, OH and on a silt loam soil at the OARDC Western Research Station near S. Charleston. Experimental design was a two factor randomized block with four replications. Yield, flag leaf nutrient analysis, spike number, and test weight were observed for each treatment. There were yield differences among the three N rates at both sites except 2008 for the Western location. There were no significant interactions between N rate and N source at either location.  Yields were similar among the N sources at the Western site for both years. Yields were significantly less for ESN than urea or UAN in 2008 at the Northwest location. In addition to yield, ESN had significantly lower leaf N concentration and spike number at the Northwest location in 2008.  Spring temperatures were abnormally cooler in 2008 at the Northwest location which may have affected N release from ESN.