Predicting N2O emissions from agricultural land through related soil parameters

An empirical model of nitrous oxide emission from agricultural soils has been developed. It is based on the relationship between N(2)O and three soil parameters - soil mineral N (ammonium plus nitrate) content in the topsoil, soil water-filled pore space and soil temperature - determined in a study on a fertilized grassland in 1992 and 1993. The model gave a satisfactory prediction of seasonal fluxes in other seasons when fluxes were much higher, and also from other grassland sites and from cereal and oilseed rape crops, over a wide flux range (<1 to >20 kg N(2)O-N ha(-1) y(-1)). However, the model underestimated emissions from potato and broccoli crops; possible reasons for this are discussed. This modelling approach, based as it is on well-established and widely used soil measurements, has the potential to provide flux estimates from a much wider range of agricultural sites than would be possible by direct measurement of N(2)O emissions.