Following surface application of slurry to grassland between 1% and 100 % of the ammonia-nitrogen of the organic fertilizer can be lost through volatilization of ammonia gas. For recording various influence factors on the ammonia volatilization after slurry application, three parallel operated windtunnels are used. Researches on the accuracy of this windtunnel system proved the reprodu-cible measuring and quantification of ammonia emissions. The ammonia-nitrogen loss could be minimized through application techniques, which apply the slurry near or into the soil. In comparison to broadcast spreading with a splash plate, the ammonia emissions were reduced by 40% using a trailing hose, between 50% and 60% with a trailing foot and even by 75% using the trenching technique. Extensive research will be carried out to examine the influence of climatic conditions and different kinds of slurry treatments.