Abstract

Measures against ammonia emissions from dairy houses G. Gustafsson and K-H. Jeppsson Department of Agricultural Biosystems and Technology, Swedish University of Agricultural Sciences, S- 230 53 Alnarp, Sweden. Phone: 040-415488, Fax: 040-415475, E-mail: Gosta.Gustafsson@jbt.slu.se Atmospheric ammonia causes acute toxic injuries to vegetation close to the source and contributes to the large scale nitrogen eutrophication and acidification of ecosystems by long range atmospheric transport of ammonium. Agriculture is a large contributor to nitrogen deposition, hence, measures to reduce ammonia emission is important. Several factors have an influence on the ammonia release in dairy houses; nitrogen content, pH- value, urease activity, C/N ratio, availability of oxygen and temperature of manure; adsorption of ammoniacal nitrogen, sizes of manure surface areas, air movements, ventilation rates and air temperatures. One effective method to reduce ammonia release is by appropriate feeding rations which reduces the nitrogen residues in manure. Emission levels tend to be higher in free stall barns than in tie stalls due to larger areas exposed with manure. Minimising exposed areas is a question of building planning, housing system and manure handling. Frequent removal of faeces and urine promote a low release of ammonia. Flushing or drainage of urine by sloped gutters and drainage channels can reduce the nitrogen content of the manure and the ammonia release. By using bedding materials having a high content of carbon, high capacity to adsorb ammoniacal nitrogen, the ammonia emission from deep litter systems may be reduced. Ammonia release can be reduced if the manure temperature can be kept low. Cooling manure in a manure culvert with a heat pump is an effective but expensive way of reducing ammonia emission. The extracted energy has to be utilized in some way if the technique will become competitive. A cheaper way of cooling manure is by passing incoming drinking water through pipes in the concrete of manure gutters. Air temperature conditions and ventilation rate will also influence the release of ammonia in different ways dependent on the heat balance of the dairy house. Ammonia release decreases at increasing indoor air temperature at specific outdoor temperatures. Furthermore, the ammonia release increases at increasing outdoor temperature due to increased ventilation rate. Ammonia release increases with increasing air movements and air velocities. Therefor, high air velocities around manure surfaces should be avoided by proper design and location of air inlets. Air movements in manure culverts should also be avoided. Air velocities in manure culverts depend on the depth of a culvert. Ammonia release decreases with increasing depth of a culvert. An efficient measure to reduce the ammonia emission is cleaning the exhaust air by the use of biofilters. Keywords: Ammonia, emission, dairy, manure, climate

Published in

Publisher: Nordiska Jordbruksforskares Förening

Conference

Manure- an agronomic and environmental challenge

SLU Authors

• Jeppsson, Knut-Håkan

  • Department of Agricultural Biosystems and Technology, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Animal and Dairy Science
Veterinary Science


Permanent link to this page (URI)

https://res.slu.se/id/publ/6382