|Jokela, W - UNIVERSITY OF VERMONT|
Submitted to: American Society of Agronomy
Publication Type: Abstract Only
Publication Acceptance Date: September 11, 2001
Publication Date: N/A
Technical Abstract: Agriculture is estimated to be the largest source of atmospheric ammonia (NH3), contributing an estimated 80-90% of the annual NH3 emission. Ammonia volatilization represents a loss of plant available nitrogen (N) to the farmer and a potential contributor to eutrophication in neighboring aquatic systems and low-N input forest systems. The main sources of agricultural NH3 are urea excreted by animals and urea containing fertilizers. Within the agriculture sector, the largest losses from manures are thought to occur during land application (35-40%), followed by losses during housing (30-35%), grazing (10-25%), and then manure storage (5- 15%). Each of these sources can be managed to reduce NH3 emissions. For example, lower NH3 emissions can result from: diets with lower levels of crude protein to reduce urinary N excretions, housing and manure management systems that quickly capture urine, restriction of grazing time, surface covering of manure stores, and incorporation of land applied manure. A whole-farm NH3 emission model will be reviewed; results show that NH3 losses can be substantially reduced, but significant improvements will require a whole-farm systems approach. A coordinated research effort is needed to study NH3 emissions from all the sources of various animal feeding operations, in order to develop optimal strategies to manage NH3 on a whole-farm basis.