What predicts nitrous oxide emissions and denitrification N-loss from European soils?

N2O emissions and denitrification N-losses, precipitation, air temperature, soil moisture, bulk density and content of mineral N were monitored in 9 different agricultural soils in 6 European countries throughout the vegetation period (April to September) 1992 and 1993. N2O emissions and denitrification N-losses were log-normal distributed , reflecting high temporal changes. While small flux rates (< 2 g N ha(-1) d(-1)) were detectable every day, high rates (> 10 g N ha(-1) d(-1)) were measured after fertilization. An attempt to relate the emission variables to climate and soil variables was made through the use of correlation analysis. The mean N2O emissions from soil were significantly correlated with the soil properties clay, organic C and mineral N content and the amount of applied mineral N fertilizer. The best prediction of the N2O emission rates (r(2) = 0.734) was achieved by multiple linear regression using the soil parameter clay and mineral N. Only 50% of the observed variation could be explained by the factors C-org and mineral N, which describe the substrate availability for microbial processes. No successful statistical model was found for the prediction of denitrification N-losses.