Atmospheric Emissions of N2O, CH4, and CO2 From Different Nitrogen Fertilizers.

There is a growing interest in quantification of significant sources of greenhouse gas (GHG) emissions from agricultural practices. Efficient N fertilizers and alternative sources of N that produce low GHG emissions from soil are needed to reduce the impact of agricultural practices on global warming. We quantified and compared growing season fluxes of N₂O, CH₄, and CO₂ resulting from application of different chemical N fertilizers, poultry litter, and commercially available enhanced-efficiency N fertilizers as follow: polymer-coated urea (ESN^®), superU^®, urea-ammonium  nitrate (UAN), UAN + AgrotainPlus^® (urease inhibitor), ammonium nitrate (NH₄NO₃), poultry litter, and poultry litter + AgrotainPlus  in a no-till corn (Zea mays L.) production system.  Greenhouse gas fluxes were measured during two growing seasons using static, vented chambers. The enhanced-efficiency N fertilizer ESN delayed the N2O flux peak by 3 to 4 weeks compared to other N sources. No significant differences were observed between enhanced-efficiency N fertilizers and other N fertilizer sources such as UAN, urea, and NH4NO3. Cumulative growing season N2O emission from poultry litter was significantly greater than other N sources. In general, the N2O loss (2-y average) as a percentage of N applied as fertilizer was 0.69 for Super U, 0.98% for UAN, 2.0% for ESN, 0.8% for urea, 1.7% for NH4NO3, and 4.5% for poultry litter.

The CH₄-C and CO₂-C emissions were highly impacted by the environmental factors than the N sources. No particular trend was observed among N sources with regard to CH₄-C and CO₂-C emissions for the two growing seasons of this study. The cumulative growing season CO₂ fluxes were less variable than CH₄, however, no significant differences or trends were observed among N sources.