Ammonia and nitrous oxide emissions as affected by nitrification and urease inhibitors

Abstract Nitrogen (N) gaseous losses have environmental and economic implications. Ammonia (NH3) volatilization and nitrous oxide (N2O) emissions from a volcanic soil were concurrently quantified using intact lysimeters, after application of the equivalent to 100 kg N ha-1 with and without urease (NBPT) and nitrification (DCD) inhibitor: Urea, Urea+NBPT, Urea+DCD, Dairy slurry and Dairy slurry+DCD. A control treatment (-N) was also included. Treatments were distributed on a randomized block design and evaluated during 28 days. Ammonia was analyzed for NH4 by colorimetry, while N2O was estimated by gas chromatography. Total emissions were estimated by addition of daily fluxes, and results were analyzed by ANOVA. Ammonia was the main N loss, with 35 to 43% and 5% to 16% of the total N applied in Urea and Dairy slurry (P0.05). The use of DCD reduced N2O emissions by 44 and 8% in the same treatments, respectively (P