Diffusion analysis of N2O cycling in a fertilized soil

The behavior of nitrous oxide (N₂O) in fertilized soil was studied in terms of soil fluxes, the production rates at various depths and the turnover in soil. The diffusive losses of N₂O to the atmosphere calculated from soil N₂O profile compared favorably with the flux directly determined with a closed chamber technique. The estimate of N₂O production rates at several depths demonstrated that the sites of N₂O production was only near the soil surface. The calculated residence time of N₂O in the entire soil column studied was only 1.4 hour during active emission period and less than 1 day even in the later period having trace N₂O emission. The prolonged N₂O emission observed after the active phase was due likely to a lasting N₂O production rather than a supply from the soil N₂O reservoir. The results suggested that most N₂O in soil was emitted quite promptly to the atmosphere after its production. A minor role of soil as an N₂O reservoir is emphasized from the viewpoint of the origin of groundwater N₂O. This revised version was published online in August 2006 with corrections to the Cover Date.