The Effect Of Enhanced Nitrogen Fertilizer Use To Reduce Nitrous Oxide Emission Under Different Cropping Systems In Central Montana.

Nitrous oxide is a greenhouse gas and a gas involved in the photochemical oxidation of ozone layer. Interest in nitrous oxide (N₂O) emission is due to its high global warming potential and long shelf life in the atmosphere. Nitrous oxide (N₂O) is emitted from the soil during nitrification and denitrification processes. Inhibiting these processes will reduce the amount of N₂O emitted to the atmosphere. A field experiment was carried out to investigate the effect of enhanced nitrogen fertilizer source in reducing N₂O emission under different cropping systems in central Montana. The experiment was carried out in split plot design with three replications. The main plots were two tillage treatments (conventional till and no till). The subplots were factorial combination of two N rates (0 and 90 kg N ha^-1) and two nitrogen sources (regular urea and enhanced N fertilizer). Enhanced N fertilizer contains both urease and nitrification inhibitors. Spring wheat and camelina were used as test crops. Pre-weighted nitrogen fertilizer was applied both for spring wheat and camelina plots. Twenty ml of N₂O samples were collected at 0, 0.25 and 0.5 hr from closed chamber at different days since fertilizer application and measured using Varian 3800 GC.  Averaged for both spring wheat and camelina, the results showed that application of N fertilizer increased the flux of N₂O emission to the extent of 300% compared to the control (0 kg N ha^-1). This increased N₂O flux was reduced to the extent of 93% with the application of enhanced N fertilizer source compared to urea. The no till system resulted in higher flux of N₂O emission than conventional till. In some cases, spring wheat resulted in higher N₂O flux than camelina.