Emissions of NO and N2O from soils

Nitric oxide (NO) and nitrous oxide (N2O) fluxes were measured from agricultural, forest and moorland environments, using chamber techniques. Maximum emissions of NO and N2O were measured from the agricultural soils shortly after fertiliser application (7 ng NO-N m(-2) s(-1) and 91 ng N2O-N m(-2) s(-1)). For the non-agricultural soils the NO flux ranged from -0.3 to 0.5 ng NO-N m(-2) s(-1) and the N2O flux ranged from 1 to 2.7 ng N2O-N m(-2) s(-1). Emissions, however, were increased 2 to 7 fold when N deposition (uplands) and N fixation (alder plantations) contributed to the pool of soil available N. The best predictors of the NO emission were soil NO 3 (-) and soil temperature, accounting for 60% of the variability observed. The prediction of N2O was less successful. Only 30% of the variability could be explained by the soil NO 3 (-) and the soil moisture content, soil temperature did not have a significant effect on the N2O emission.