Anaerobic digestion of manure offers the potential benefit of reducing greenhouse gas emissions. As part of the complete life cycle analysis of this technology, nitrous oxide and ammonia emissions following field application of raw and biodigested dairy slurry were measured in a dairy cow production area of Eastern Canada. The experiment was carried out at an experimental farm near Ottawa (ON) in a 24-ha clay loam field after the harvest of spring wheat in the fall of 2005. The biodigested dairy slurry was applied in the middle section of the field, which was subdivided in three sections of 400m x 200m each, while non-biodigested slurry was applied on the end sections. Two micrometeorological towers were set up on the section boundaries to measure energy and trace gas fluxes almost continuously for various wind directions. Each eddy covariance tower was equipped with a 3-D sonic anemometer and a fast-response infrared CO₂-H₂O analyzer. Two Tunable Diode Lasers were used to measure N₂O and NH₃ gradients at 1.5 m and 2.5 m above the displacement height sequentially every half-hour at section boundaries. NH₃ fluxes were also measured by the relaxed eddy accumulation technique using oxalic acid denuder tubes. Background N₂O emissions were measured for 18 days prior to the application of dairy slurry in the field. The dairy slurry application lasted 3 days and the N rate was about 80 kg N ha^-1. The digested manure contained more ammonium than the raw slurry. The fall N₂O emissions were low for both slurry applications, while higher ammonia emissions were measured from the biodigested slurry. During the 2006 snowmelt, total N₂O fluxes for the raw manure was 1.5kg N ha^-1 and 2.4kg N ha^-1 for digested manure. The application of biodigested slurry enhanced the N₂O emission over the two main emission periods by almost 70%.