Mechanistic models of ammonia (NH3) release from liquid manure in 30 available publications are reviewed. They include models of NH3 release in animal houses, from slurry applied fields, from constructed manure stores, from an anaerobic lagoon and from flooded rice and soil systems. The models are decomposed and their general structure is synthesized as a core model combined with some submodels. The theoretical bases of the models are compared. The general model structure, core model and diA