Management of Dairy Operations to Prevent Excessive Ammonia Emissions

Reprinted, with permission, from the proceedings of: Mitigating Air Emissions From Animal Feeding Operations Conference.

This Technology is Applicable To:

Species: Dairy
Use Area: Animal Housing, Manure Storage
Technology Category: Management
Air Mitigated Pollutants: Ammonia

System Summary

Ammonia emissions data from open-lot and hybrid (combination of free-stalls and open-lots) dairies in the milder climate of southwest US indicated that summer emissions from these facilities were nearly 50% higher than winter emissions. Due to their large surface areas, lagoons and open-lot corrals were the highest contributors of NH3 emissions but little NH3 was emitted from lagoons during the winter months. Within open-lot corrals and free-stalls, NH3 emissions increased with greater manure loading and actively composting manure emitted considerable NH3 even during winter months. While reduction in dietary N intake is known to reduce manure nitrogen content, no information on technologies to mitigate NH3 emissions from these two types of dairy operations is available. Management practices such as frequent removal of manure from heavily loaded areas of open-lots and free-stalls, proper management of lagoons and other manure storage structures, summer irrigation of lagoon effluent during cooler temperatures, and where possible, incorporation or injection of effluent will help reduce excessive NH3 emissions. While frequent scrapping of targeted open-lot corral areas can be achieved without substantial increase in costs, covering lagoons to reduce NH3 emissions will be a very expensive mitigation practice.

Applicability and Mitigating Mechanism

  • Ammonia volatilization rate from dairy manure and processes generated waste water exposed to the environment depends upon total ammonium concentration, pH, moisture content, air velocity, temperature etc.
  • The management practices apply to mitigation of excessive NH3 emitting from open-lot corrals, lagoons, and free-stall surface of dairy operations
  • Existing dairy waste management practices can be adopted to reduce excessive NH3 emissions from critical sites at the dairy operation and during effluent irrigation during summer season



  • Lack of excess fresh or recycled water for frequent flushing
  • Lack of extra storage capacity of retention control structures (RCS) to store additional flushed effluent.
  • Terminating or relocating the composting system out of the dairy operation



Increased frequency of flushing will require more fresh or recycled water as well as a higher storage capacity of an existing RCS or building a new one, adding higher costs to implement this practice. Another substantial cost may be covering large storage and treatment structures such as anaerobic lagoons to reduce NH3 emissions.


Saqib Mukhtar, Atilla Mutlu, Shafiqur Rahman
Texas A&M University System
Point of Contact:
Saqib Mukhtar,

The information provided here was developed for the conference Mitigating Air Emissions From Animal Feeding Operations Conference held in May 2008. To obtain updates, readers are encouraged to contact the author.