Greenhouse Gas Study for Greenhouse gas Reduction through Agricultural Carbon Enhancement network in Bowling Green, Kentucky

Greenhouse Gas Study for Greenhouse gas Reduction through Agricultural Carbon Enhancement network in Bowling Green, Kentucky Alternative N fertilizers that produce low greenhouse gas (GHG) emissions from soil are needed to reduce the impacts of agricultural practices on global warming potential (GWP). We quantified and compared growing season fluxes of N2O, CH4, and CO2resulting from applications of different N fertilizer sources, urea (U), urea-ammonium nitrate (UAN), ammonium nitrate (NH4 NO3), poultry litter, and commercially available, enhanced-efficiency N fertilizers as follows: polymer-coated urea (ESN), SuperU, UAN + AgrotainPlus, and poultry litter + AgrotainPlus in a no-till corn (Zea maysL.) production system. Greenhouse gas fluxes were measured during two growing seasons using static, vented chambers. The ESN delayed the N2O flux peak by 3 to 4 wk compared with other N sources. No significant differences were observed in N2O emissions among the enhanced-efficiency and traditional inorganic N sources, except for ESN in 2009. Cumulative growing season N2O emission from poultry litter was significantly greater than from inorganic N sources. The N2O loss (2-yr average) as a percentage of N applied ranged from 0.69% for SuperU to 4.5% for poultry litter. The CH4–C and CO2–C emissions were impacted by environmental factors, such as temperature and moisture, more than the N source. There was no significant difference in corn yield among all N sources in both years. Site specifics and climate conditions may be responsible for the differences among the results of this study and some of the previously published studies. Our results demonstrate that N fertilizer source and climate conditions need conideration when selecting N sources to reduce GHG emissions.