Correction factors take account of variables related to methods of production, which reduce or increase the N excretion per animal or the ammonia emissions.

For dairy cows, N excretion is influenced by the level of milk production and the feeding rates of hay, silage, potato and fodder beet as well as the amount of concentrates. For pigs, the crude protein content of feed and the use of phase feeding are important variables influencing N excretion. For housing and yard, measures to take into account include those that minimise fouling of the floor and those that ensure a rapid separation of urine and faeces. For manure stores, coverage of the slurry pit and the frequency of mixing are included as correction factors. The use of low emission application methods for slurry, consideration of the time of year, time of day, and weather conditions in which slurry is applied and incorporation of solid manure after application all have an influence on ammonia emissions and result in corresponding corrections to the model.

The correction factors used in the model are outlined under the Technical Description.