The truth about UAN loss: Why stabilization matters more than you think

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Every spring, several industry-wide misconceptions continue to guide management decisions, leaving millions of pounds of nitrogen unprotected to disappear into the air before crops ever have a chance to use them.

Each of these misconceptions carries the same underlying assumption: taking a few extra minutes at application does not materially change the outcome. However, these misconceptions leave nitrogen exposed to avoidable loss.

Urea ammonium nitrate solution, or UAN, is widely believed to be a lower-risk nitrogen source, and stabilizers are often forgotten.

“Around 20 percent of nitrogen in UAN can be lost in as little as three to seven days, and, if conditions are right, that number can increase to 40 percent,” said Matt Fryer, technical agronomist with Koch Agronomic Services.

These losses are significant enough to affect yield potential, return on investment and overall nitrogen-use efficiency.

“Taking an extra five minutes to add a stabilizer to the tank can help protect one of the most important inputs for an operation,” Fryer said.

Misconception 1: “Less urea means less loss.”

Some people think because UAN contains less urea it is at lower risk for loss; however, the urea portion of UAN, which makes up 50% of the total N content in UAN, is highly vulnerable to volatilization loss due to critical relative humidity. The ammonium portion is more stable, and nitrate is immediately susceptible to loss through leaching or denitrification if soils are wet.

“Although UAN has less urea-N compared to the same nitrogen rate applied as urea, volatilization loss from UAN is more consistent than urea due to the differences in the critical relative humidity, when the fertilizer starts to absorb moisture from the air, of each fertilizer. Moisture is one of the key ingredients needed to start the volatilization process, which begins at 18% air humidity for UAN and 70% humidity for urea,” Fryer said. “That difference means UAN is vulnerable under a much wider range of environmental conditions.”

Misconception 2: “The water in UAN helps incorporate nitrogen.”

The amount of water in UAN is far too low to move nitrogen into the soil profile. At typical application rates, its water contribution is only a fraction of what is needed for incorporation.

“We need at least half an inch of rainfall or irrigation to move urea nitrogen into the soil,” Fryer said. “UAN applications do not provide that amount of water, even at impractical application rates.”

Misconception 3: “Knifing in UAN will prevent loss.”

Knifing below the soil surface can reduce volatilization but only when slot closure is consistent and the placement is at least two inches deep.

“Many injection rigs do not fully close the slot, and that leaves nitrogen exposed,” Fryer added. “In those situations, volatilization can be even more severe because the nitrogen is sitting in moisture. In some cases, an open slot can lead to faster loss than a surface application.”

Misconception 4: “It’s cold, so I don’t see the need for stabilizers.”

Cold conditions slow volatilization but do not eliminate it.

“Cold temperatures slow the volatilization process, but they do not prevent it,” Fryer said. “Without an incorporating rainfall event, the same amount of nitrogen can still be lost. It just happens over a longer period.”

Misconception 5: “I’ll just apply more N to make up for the loss.”

Adding extra nitrogen may seem like an easy fix, but it can increase the percentage of nitrogen lost because of the chemical reactions that occur during hydrolysis.

“When you put more fertilizer in a given area, the pH around the application site spikes higher,” Fryer said. “That increases the amount of nitrogen that converts to ammonia gas and is lost to the air.”

Why protecting UAN matters

Nitrogen is one of the most valuable and carefully planned inputs in crop production. Losing a significant portion within a week can undermine both productivity and profitability. These losses are made even more concerning because they happen silently and often go unnoticed until yield potential is compromised.

However, stabilizing UAN requires only minutes at application and can protect nitrogen across days and weeks of environmental exposure.

“I often compare it to a paycheck. If someone told you they would take 20 to 40 percent of your salary at some point during the year and could not tell you when, would you agree to that?” Fryer asked. “Yet, that is exactly what takes place with the nitrogen budget when UAN is applied unprotected.”

How ANVOL™ helps protect UAN

ANVOL™ nitrogen stabilizer delivers long-lasting urease inhibition through its dual active ingredients, Duromide and NBPT. By protecting UAN from volatilization, ANVOL keeps more nitrogen available for the crop when it is needed most.

“It is simple,” Fryer said. “Just pour the right rate of ANVOL into the tank before application. It is like adding an adjuvant. That extra step, those extra five minutes, can prevent a major nitrogen loss.”

With an easy mixing process and a mode of action designed for a wide range of soil and weather conditions, ANVOL gives growers a practical and effective way to protect their nitrogen investments.

UAN loss is real, rapid and widely underestimated. Misconceptions about UAN’s behavior after application create gaps in nitrogen protection that can lead to significant financial and agronomic consequences. When the difference between protection and loss comes down to five minutes at the tank, stabilizing UAN is no longer an optional step; it is a practical decision rooted in stewardship, efficiency and return on investment. With the potential for 20 to 40 percent loss in as little as a few days, stabilizing UAN is an essential step in safeguarding one of the most important crop inputs.

For more information on ANVOL, contact your local KAS representative today.

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