International audienceThe addition of exogenous ammoniacal nitrogen to slurry can be used to study the influence of ammoniacal nitrogen concentration or the presence of different ions on ammonia emissions. This preliminary study aimed to test the validity of such a direct incorporation of ammonium salts to slurries in relation to ammonia volatilization. It was conduted using cylindrical glass volatilization chambers an 15N-labelling techniques. Labelled pig slurry was prepared by direct addition of 15N-(NH4)2SO4(15N-AS). The fate of total ammoniacal nitrogen was followed for 48 h from surface application to soil. The analysis of isotopic excess (E%) of volatilized ammonia 0.25, 2, 6, 12, 24 and 48 h after labelled slurry application suggested that the added N4+ behaved as the endogenous NH4+ initially present in the slurry. An average TAN-15N (total ammoniacal nitrogen) recovery of 97.5% (CV 2%) was obtained. During this study, no immobilization or nitrification of slurry-derived nitrogen was noticed.Description d'une procédure de marquage de l'azote du lisier par ajout direct de sulfate d'ammonium enrichi en N15 au cours d'une étude cinétique de volatilisation de l'azote des lisiers