WHAT PREDICTS NITROUS-OXIDE EMISSIONS AND DENITRIFICATION N-LOSS FROMEUROPEAN SOILS

N2O emissions and denitrification N-losses, precipitation, air tempera ture, soil moisture, bulk density and content of mineral N were monito red in 9 different agricultural soils in 6 European countries througho ut the vegetation period (April to September) 1992 and 1993. N2O emiss ions and denitrification N-losses were log-normal distributed , reflec ting 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 varia bles to climate and soil variables was made through the use of correla tion analysis. The mean N2O emissions from soil were significantly cor related with the soil properties clay, organic C and mineral N content and the amount of applied mineral N fertilizer. The best prediction o f the N2O emission rates (r(2) = 0.734) was achieved by multiple linea r regression using the soil parameter clay and mineral N. Only 50% of the observed variation could be explained by the factors C-org and min eral N, which describe the substrate availability for microbial proces ses. No successful statistical model was found for the prediction of d enitrification N-losses.