Effects of N Fertilization and Irrigation on Nitrification and Denitrification Pools of N2O: Acetylene Inhibition Microplot Study.

Assessment of nitrification and denitrification pools of N₂O is required for mitigation of the effects of agricultural practices on global climate change. We established a study to measure the emissions of N₂O originating from nitrification and denitrification in response to additions of water in the acetylene incubation study in situ following the application of 150 kg N/ha as NH₄NO₃ in September 2013. We implemented the system of Li-Cor 8100A automatic chambers coupled with LGR 23r N₂O analyzer for continuous monitoring of CO₂ and N₂O emissions in the short-term microplot study. Several irrigation events were implemented following N fertilization. The levels of acetylene at 10 Pa of C₂H₂ and no acetylene were established prior to the initial irrigation event to discriminate between nitrification and denitrification borne N₂O. The results indicate the majority of nitrification-related N₂O emissions occur within the first 24 to 36 hours of N fertilization. The further spikes in N₂O emissions are related to denitrification, which is predominant source of N₂O emissions at saturated conditions. The fitting parameters for predictions of nitrification and denitrification pools of N₂O in response to soil temperature and moisture conditions are being determined.