Activation Energy of Urea Hydrolysis and NH3 Henry Constant Effects on Ammonia Release from CAFOs
Channel: Livestock & Poultry Environ. Learning Community
Date: 03/05/2013

Proceedings available at: www.extension.org/67708

Ammonia emissions from cattle feedlots have been a topic for much debate regarding air quality and environmental impacts. With increasing concern about future regulation of the industry, understanding the fundamentals of ammonia emission and volatilization from feedlots has become crucial. Wu et al. 2003 described ammonia flux as demonstrating a strong environmental dependency on the ammonium concentration, pH, and the product of the acid dissociation and Henry constant. The objectives of this research are to address the production of ammonia via urea hydrolysis and quantify its release from the soil surface based on the Henry constant. This will be accomplished by studying the rate of urea hydrolysis in feedlots systems, as well as by looking at a new approach to measuring the Henry constant. Urea hydrolysis results will be discussed from a variety of feedlot soils at a fixed water content and urea concentration. Measuring the Henry constant includes measuring the gas phase ammonia above the solution and the ammonia present in the solution. The Henry constant values should provide insight as to how feedlot soil matrices deviate from less complex systems. The results of this work will allow for a better understanding of the fate of ammonia in feedlot systems from production to emission.