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Title: MANAGING AMMONIA EMISSIONS FROM DAIRY COWS BY AMENDING SLURRY WITH ALUM OR ZEOLITE OR BY DIET MODIFICATION

Author
item Meisinger, John
item Lefcourt, Alan
item Van Kessel, Jo Ann
item WILKERSON, VICTOR - LAND O LAKES, PORTLAND,OR

Submitted to: The Scientific World
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/13/2001
Publication Date: 10/1/2001
Citation: MEISINGER, J.J., LEFCOURT, A.M., VAN KESSEL, J.S., WILKERSON, V. MANAGING AMMONIA EMISSIONS FROM DAIRY COWS BY AMENDING SLURRY WITH ALUM OR ZEOLITE OR BY DIET MODIFICATION. THE SCIENTIFIC WORLD. 2001.

Interpretive Summary: Animal agriculture is a significant source of atmospheric ammonia. Ammonia volatilization represents a loss of plant available nitrogen to the farmer and a potential contributor to eutrophication in low-nitrogen input ecosystems. This research evaluated on-farm slurry treatments of alum or zeolite and compared three diets for lactating dairy cows for their effectiveness in reducing ammonia emissions. Ammonia emissions were compared using a group of small wind tunnels which captured the ammonia emitted from the exposed manure receiving various treatments. The addition of 2.5% alum or 6.25% zeolite to raw dairy slurry reduced ammonia volatilization by 60% and 55%, respectively, compared to untreated slurry. The alum conserved ammonia by acidifying the slurry while the zeolite conserved ammonia by lowering the solution-phase nitrogen through cation exchange. The use of alum or zeolite also reduced soluble phosphorus in the slurry. Ammonia loss from manure collected from lactating dairy cows was not affected by three diets containing the same level of crude protein but differing in forage source (orchardgrass silage vs. alfalfa silage) or neutral detergent fiber (NDF) content (30 vs. 35% NDF). Ammonia losses from the freshly excreted manures occurred very rapidly and included the excreted urea plus some unidentified labile organic nitrogen sources. Ammonia conservation strategies for manures will have to be active within the first few hours after excretion in order to be most effective. The use of alum or zeolites as an on-farm amendment to dairy slurry offers the potential for significantly reducing ammonia emissions from the storage phase of a manure management system.

Technical Abstract: Animal agriculture is a significant source of atmospheric ammonia (NH3). Ammonia volatilization represents a loss of plant available nitrogen (N) to the farmer and a potential contributor to eutrophication in low-N input ecosystems. This research evaluated on- farm slurry treatments of alum or zeolite and compared three diets for lactating dairy cows for their effectiveness in reducing NH3 emissions. Ammonia emissions were compared using a group of mobile wind tunnels. The addition of 2.5% alum or 6.25% zeolite to raw dairy slurry reduced NH3 volatilization by 60% and 55%, respectively, compared to untreated slurry. The alum conserved NH3 by acidifying the slurry to below pH 5 while the zeolite conserved NH3 by lowering the solution-phase N through cation exchange. The use of alum or zeolite also reduced soluble phosphorus in the slurry. Ammonia loss from manure collected from lactating dairy cows was not affected by three diets containing the same level of crude protein but differing in forage source (orchardgrass silage vs. alfalfa silage) or neutral detergent fiber (NDF) content (30 vs. 35% NDF). Ammonia losses from the freshly excreted manures occurred very rapidly and included the urea component plus some unidentified labile organic N sources. Ammonia conservation strategies for manures will have to be active within the first few hours after excretion in order to be most effective. The use of alum or zeolites as an on-farm amendment to dairy slurry offers the potential for significantly reducing NH3 emissions from the storage phase of a manure management system.