Gaseous emissions from dairy manure storage

Several management systems require a separate storage facility for effluent and manure, following collection and prior to land application. Slurries, with solid content ranging from 5 to 15%, are stored in weeping walls, lagoons or ponds. Manures, containing a solid content above 15%, are generally stored as a stack. Storage ponds and lagoons generally consist of aerobic and anaerobic storage areas. The effluent or slurry is initially stored anaerobically then moved into an aerobic pond. The emission of ammonia (NH3), nitrous oxide (N2O) and methane (CH4) from ponds and lagoons is affected by pre-treatment, surface crust, loading methods and environmental factors such as temperature and wind speed (Misselbrook et al. 2001). Storage of solid manure occurs in either heaps or stacks. Aerobic composting or anoxic decomposition can occur during storage. Losses of NH3, N2O and CH4 from solid manure stores is dependent upon the predominance of aerobic composting and anoxic decomposition, storage method, temperature, manure origin, precipitation and whether or not the store is covered.