Emissions of ammonia (NH3) and nitrous oxide (N2O) after application of nitrogen fertilizer

Nitrogen loss from fertilized fields both reduces farmer profits and increases the greenhouse gas in the atmosphere. A scanning FTIR, in combination with Tunable Diode Laser (TDL) NH3 absorption spectrometer, and a difference frequency generation (DFG) laser-based N2O analyzer were used, in combination with a 3D sonic anemometer to measure fluxes of NH3 and N2O from four nitrogen fertilizer treatments at West Lafayette, Indiana in 2013-2014. The experiment involved adjacent fields treated with anhydrous ammonium (AA) and/or side-dress urea and ammonium nitrate (UAN) applications was studied to evaluate the influence of timing and type of N application on N2O and NH3 emissions: 200 kg/ha applied as anhydrous ammonia (AA) with a nitrification inhibitor in fall 2013 to a no-till field (F200NT), 100 kg/ha as AA with a nitrification inhibitor applied in fall 2013 fall and 100 kg/ha N as UAN in spring 2014 to a no-till field (F100/S100NT) and tilled field (F100/S100T), and 200 kg/ha applied as UAN in the spring to a chisel tilled field (S200T). N2O Emission ranged from 0-10 ƒÝgm-2s-1 N2O. N2O emissions from the F100/S100NT, F100/S100T and F200NT were similar. N2O emissions from the S200T treatment differed from that of the other three treatments. The similar N2O emissions from the F200NT, F100/S100T and F100/S100NT applications suggests that the nitrification inhibitor applied in the fall appeared to limit the N loss during the winter. N2O emissions from the S200T application increased steadily after application reaching levels of 20 ƒÝgm-2s-1 at the end of the measurement period. N2O emissions were correlated more with wind speed than air temperature. NH3 emission generally ranged from 0-2 ƒÝgm-2s-1 NH3. Emissions were greatest during the day of application with emissions up to 3 ƒÝgm-2s-1 NH3. NH3 emissions from the F100/S100NT treatment was greater than that from the F100/S100T treatment. Emissions were still evident from the F200NT application in June of the following year indicating that the nitrification inhibitor applied in the fall appeared to limit the N emissions during the winter. NH3 emissions were correlated with both air temperature and wind speeds.