Profitability of Enhanced Efficiency Urea Fertilizers in No-Tillage Corn Production
Zhou, X., J. A. Larson, H. J. Savoy, X. Yin, M. A. McClure, and M. E. Essington.  2018.  Agronomy Journal, Agron. J. 110:1439–1446 (2018) doi:10.2134/agronj2017.11.0652.

ABSTR ACT This study determined the effects of enhanced efficiency (EE) urea fertilizers relative to ammonium nitrate (AN) on no-tillage (NT) corn (Zea mays L.) yields and net returns (NRs) in Tennessee. Corn yields were from experiments conducted at two N fertilization rates of 123 and 168 kg ha–1 with four replications in a split-plot design from 2013 through 2015 at three locations in middle (Springfield) and west Tennessee (Milan and Jackson). ANOVA analyses were used to identify differences in EE urea treatment yields and NRs. Breakeven and sensitivity analysis was used to compare yield and identify the threshold of positive NR of EE urea fertilizers relative to AN for a given premium price over conventional urea. Results indicated that urea + 20% or 26.7% N-(n-butyl)-thiophosphoric triamide (NBPT) and polymer-coated urea (PCU) provided significantly higher mean yields (2.0 Mg ha–1 more on average) and NRs ($283 ha–1 more) than conventional urea. Notwithstanding, these EE urea fertilizers had lower yields and produced lower benefits than AN in the course of this study. On the other hand, mean yield (8.7 Mg ha–1) and NR ($1012 ha–1) for urea + maleic–itaconic acid copolymer (MICP) were not significantly different from conventional urea (8.3 Mg ha–1 and $959 ha–1). In general, N fertilizer sources behaved similarly among N rates and locations. Given the growing reliance on urea fertilizer in NT corn production in Tennessee, urea + NBPT and PCU offer the greatest potential to improve expected NRs relative to conventional urea.