Factors influencing the loss of fertilizer nitrogen into the atmosphere as N2O

In 1979–1981, experiments were carried out at four field stations near Mainz, Germany, to determine the loss of fertilizer nitrogen into the atmosphere as N 2 O. Evolution rates from the soil into the atmosphere were measured by using the closed chamber technique. An automatic sampling and analyzing device was developed which allowed frequent determinations of N 2 O evolution rates (one every 1.5 hours). The N 2 O production rates were correlated to the surface soil temperature according to the Arrhenius equation and showed a diurnal rhythm with amplitudes reaching, sometimes, 1 order of magnitude. It seems that most of the N 2 O emitted into the atmosphere is produced in the uppermost soil layer. N 2 O evolution was stimulated by rain and increased with increasing soil moisture content. Application of fertilizer caused a dramatic increase of N 2 O evolution rates with values up to 1000 μg N 2 O–N m −2 h −1 . The magnitude of the fertilizer‐induced N 2 O evolution rates was dependent on the type, the application form, and the amount of fertilizer used. The total loss of fertilizer nitrogen as N 2 O was in the range of 0.001 to 0.94%.Based on these figures, as well as on data from the literature, the total source strength of mineral fertilizers for atmospheric N 2 O is calculated to 0.02 to 8 Tg N 2 O–N yr −1 .