Crop Management to Optimize Corn Grain for Ethanol Yield.

Corn demand for ethanol production is rapidly increasing and critical management factors such as nitrogen and hybrid will need to be optimized in order to maximize grain quality for ethanol production.  While nitrogen is usually the most limiting nutrient for grain yield, little is known about how N supply affects the potential of corn grain to produce ethanol.  Our objectives were to analyze the effect of N and its interaction with genetics and location on the grain and ethanol yield (L/Mg grain) of corn.  The experiment was conducted at four locations in IL in 2006 and 2007. Management practices evaluated were N fertilization (0 to 280 kg N/ha) and hybrid selection.  Four hybrids were chosen to represent four distinct end-use grain segments and included typical yellow dent, high fermentable carbon, hard endosperm, and nutritionally enhanced hybrids.  These hybrids were grown at all locations, and at one site each year eight additional hybrids were evaluated.  Location, hybrid, and N interactions influenced both the grain yield and the ethanol yield.  Significant differences among locations were found for grain (2.5 Mg ha^-1) and ethanol yield (12 L Mg^-1).  Nitrogen decreased ethanol yield (15.3 L Mg^-1), but had a positive effect on grain yield across all sites, and there was a significant hybrid x N interaction for grain and ethanol yield.  Large differences among hybrids were observed both for grain and ethanol yield (18 L Mg^-1), and the hybrids with low ethanol yield potential were the most affected by N.  The N rate that optimized grain yield was lower than the N rate which minimized the ethanol yield.  Based on this research a conservative N rate (which optimizes grain yield), combined with hybrid selection can maximize grain yield and optimize ethanol yield.