Ammonia emissions from organic housing systems with fattening pigs

The aim of this study was to determine the level and variations in ammonia emissions from buildings and outside yards, with different manure removal systems, for organically raised fattening pigs. Ammonia emissions were determined at three farms with organically raised pigs. Amongst other differences, farms mainly differed in manure removal system at the outside yard. Measurements were carried out during two measuring seasons, with two categories of pigs: fatteners of 45 and 80 kg. Excreting behaviour was analysed by video observations and ammonia emission was measured by the ventilated chamber technique. There were clear differences in ammonia emission between farms (probability, P<0.001), varying between 0.0 and 7.7 g d−1m−2 from the buildings and between 3.6 and 17.6 g d−1m−2 from the outside yards. Location (inside/outside) and degree of fouling of the floor area also had significant effects on ammonia emission (probability, P<0.001). Differences in ammonia emissions between farms were probably mainly related to the manure removal system, design of the building and frequency of cleaning of outside yard. The farm with daily scraper cleaning and the farm with the slatted floor system had significantly lower emissions than the farm with bi-weekly manual removal of manure from a solid floor.