UAN Application Method Impact on Ammonia Volatilization Losses

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Half of the nitrogen in UAN is derived from urea and is highly subject to volatilization loss. A quarter of the nitrogen in UAN is in the ammonium form, which can be lost as ammonia in the presence of active urea hydrolysis. Using a urease inhibitor with UAN can prevent volatilization loss and provide positive return on investment.

University of Georgia recently published a study evaluating ammonia volatilization losses from nitrogen applied as dribbled UAN, broadcast UAN, and broadcast urea on tall fescue and bermudagrass forage. Nitrogen losses due to ammonia volatilization ranged from 5 – 20 percent across all methods of application. The amount of nitrogen loss was dependent on environmental conditions, including soil water content, soil temperature, and rainfall.

Dribbled UAN consistently lost less nitrogen than broadcast UAN. Nitrogen losses from broadcast urea were highest when applications were made to moist soil. Volatilization losses were higher when soil temperature was warmer. Perhaps the most intriguing outcome was that at least as much and sometimes more nitrogen was lost from broadcast UAN than broadcast urea.

The results are clear: UAN is subject to appreciable ammonia volatilization loss and should be managed accordingly, to not only decrease losses to the environment but improve agronomic efficiency. Utilizing a urease inhibitor such as ANVOL^™ nitrogen stabilizer or AGROTAIN™ nitrogen stabilizer, can help reduce the risk of nitrogen loss with UAN.

In a study conducted by North Dakota State University, approximately 25 percent of total nitrogen applied as untreated UAN was lost to ammonia volatilization 14 days after application, compared to AGROTAIN treated UAN, where losses to volatilization was 12 percent.

It’s safe to say an UAN investments shouldn’t be left to the chances of weather – protect your nitrogen with a Koch Agronomic Services solution.

Cabrera, M.L., Franklin, D.H. & Kissel, D.E. Method of Applying UAN Affects Ammonia Volatilization Losses. The Fluid Journal, Vol. 26, No. 4 (2018).