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United States Department of Agriculture

Agricultural Research Service

Research Project: MANAGING THE FATE AND TRANSPORT OF NITROGEN, CARBON, AND AMMONIA IN ANIMAL MANURES TO IMPROVE ENVIRONMENTAL QUALITY Title: Ammonia emissions from land application of manures

Authors
item Meisinger, John
item Steinhilber, P -
item Hutchinson, H -
item Mcgrath, J -

Submitted to: Agricultural Experiment Station Publication
Publication Type: Experiment Station
Publication Acceptance Date: July 1, 2010
Publication Date: July 15, 2010
Citation: Meisinger, J.J., Steinhilber, P., Hutchinson, H., Mcgrath, J. 2010. Ammonia emissions from land application of manures. Agricultural Experiment Station Publication. CDROM: Ammonia training module, Univ, MD Coop. Ext. Serv.

Interpretive Summary: Ammonia volatilization, the loss of ammonia as a gas, can be a major nitrogen loss process for surface-applied manures. There is growing concern that manure management practices are contributing to ammonia losses in the Mid-Atlantic region, which can reduce air quality by forming regional haze and increase nitrogen losses to streams and estuaries like the Chesapeake Bay. Agriculture can be a major source of ammonia, with land application of manures being a major source of ammonia. Direct in-field measurement of ammonia losses in Maryland and in other countries have shown that surface applied liquid dairy manure losses ammonia rapidly over the first few days after application, with 35-60% of the manure ammonium-nitrogen (15-30% of the total nitrogen) commonly lost the first day. In contrast, poultry litter losses ammonia slowly over several weeks, with 3-10% of the ammonium-nitrogen (1-2% of the total nitrogen) commonly lost the first day. However, unincorporated manure does not lose all of its ammonium-nitrogen to the atmosphere; liquid manure commonly retains 30-60% of its ammonium-nitrogen while poultry litter commonly retains 55-90% of its ammonium-nitrogen. The final amount of ammonium-nitrogen retained is also affected by amount and timing of rain events. Other main factors affecting ammonia loss from all manures are application method (incorporation vs. broadcast), the time until incorporation, and the intensity of the tillage implement used for incorporation. In addition, local weather elements such as rainfall, temperature, and wind can affect ammonia losses; as well as the soil’s infiltration rate and residue cover. The most effective method to minimize ammonia losses is immediate incorporation by tillage or by direct injection. Previous ammonia loss estimates used in the Maryland Nutrient Management Program have been reviewed, updated, and summarized into ammonia conservation estimates which can be directly integrated into Nutrient Management Plans. The updated ammonia conservation estimates provide for general categories of manure based on % dry matter, such as liquid dairy slurry and solid poultry litter. They also allow for the timeliness of tillage operations after application, and for the intensity of tillage. This updating and integration of modern ammonia loss estimates into Nutrient Management Planning will improve the estimate of plant available N for Nutrient Management Consultants in private industry, NRCS, and the Extension Service. Improving estimates of plant available N will improve the crop’s N efficiency from manure, and will reduce N losses to the environment.

Technical Abstract: Ammonia volatilization can be a major nitrogen (N) loss process for surface-applied manures. There is concern that current manure management practices are contributing to ammonia losses in the Mid-Atlantic region with subsequent reductions in air quality and increases in N losses to streams and estuaries. Agriculture has been estimated to be a major source of ammonia to the atmosphere, and land application of manures can be a major contributor to agriculture’s ammonia emissions. Direct field measurement of ammonia losses by micrometeorology techniques in Maryland and in other countries have shown that surface applied liquid dairy manure losses ammonia rapidly over the first few days after application, with 35-60% of the manure ammonium-N (15-30% of the total N) commonly lost the first day. In contrast, poultry litter losses ammonia slowly over several weeks, with 3-10% of the ammonium-N (1-2% of the total N) commonly lost the first day. In addition, unincorporated manure does not lose all of its ammonium-N to the atmosphere. For example, unincorporated liquid manure commonly conserves 30-60% of its ammonium-N while poultry litter commonly conserves 55-90% of its ammonium-N; the final value remaining is largely affected by amount and timing of rain events. Another major factor affecting ammonia loss from all manures is application method (incorporation vs. broadcast), the time until incorporation (measured in hours for high-loss sources like liquid manure), and the intensity of the tillage implement used for incorporation. Factors such as environmental conditions (rainfall, temperature, and wind), and soil conditions (infiltration rate and residue cover) also affect ammonia losses. The most effective method to minimize loss is immediate incorporation by tillage or direct injection. Previous ammonia loss estimates used in Maryland Nutrient Management Planning have been reviewed, updated, and summarized into ammonia conservation estimates which can be directly integrated into Nutrient Management Plans. The updated ammonia conservation estimates provide for general categories of manure based on % dry matter, such as liquid dairy slurry and solid poultry litter. They also allow for the timeliness of tillage operations after application, and for the intensity of tillage. This updating and integration of modern ammonia loss estimates into Nutrient Management Planning will improve the estimate of plant available N for Nutrient Management Consultants in private industry, NRCS, and the Extension Service. Improving estimates of plant available N will improve crop N-use efficiency from manure, and will reduce N losses to the environment.

Last Modified: 4/25/2014