Estimates of N2O and CH4 fluxes from agricultural lands in various regions in Europe

According to the revised 1996 IPCC guidelines, several emission factors are needed to calculate national inventories of N2O emissions from agriculture. To estimate the direct N2O emissions from mineral soils, an emission factor of 0.0125 kg N2O-N per kg N applied is currently being used. From recent literature data it was clearly shown that real N2O emissions could differ substantially from this value. Based on the IPCC methodology an inventory of N2O emission from agriculture in Europe (EU-15) has been made. In 1996, the N2O emission was estimated at 672 Gg N2O-N. The N2O emission per country varied between 10 and 177 Gg N2O-N. The N2O emission per ha agricultural land in the various countries varied between 1.7 and 14.2 kg N2O-N ha(-)1. Highest N2O emissions per ha were found in countries with a high agricultural intensity, such as the Netherlands, Belgium-Luxembourg, Denmark and Germany. Agricultural soils are a sink for atmospheric methane. An oxidation capacity of 2.5 and 1.5 kg CH4 ha(-1) yr(-1) was put forward for grasslands and arable land, respectively. Based on land use data of 1993, the CH4 sink of agricultural lands in EU-15 was estimated at 303.5 Gg CH4. In general, it could be concluded that N2O emissions from soils (327 Tg CO2 equivalents) are far more important than its sink function for CH4 (6.3 Tg CO2 equivalents).