UAN and Water
While it may be a common belief that the water content found in UAN is enough to prevent losses, the reality is the water content may be enough to be the catalyst for volatilization losses.
For example, if UAN is banded at a rate of 60 gallons per acre, this would be the equivalent of 0.018 inches of rain. Or if a grower were to broadcast UAN at a rate of 60 gallons per acre, the moisture content would be equivalent to only .0006 inches of rain.
Simply put, these levels of moisture are just not enough to incorporate UAN and eliminate the risk of volatilization losses.
“The truth of the matter is that the water content for most UAN rates and common application methods can be a catalyst for volatilization, not prevent it,” said Eric Vogel, product marketing manager for Koch Agronomic Services (Koch). “The research tells us that if we want to minimize losses with applied UAN, we need to adequately incorporate our UAN or utilize a nitrogen stabilizer.”
Adequate incorporation means incorporating nitrogen into the soil by more than half an inch via rainfall or irrigation or to a depth greater than two inches into the soil via mechanical incorporation. A study from Oregon State University supports this by illustrating that urea, which makes up 50 percent of the nitrogen content in UAN, required approximately 0.8 inches of uniform precipitation, either rainfall or irrigation, to be adequately incorporated and help reduce volatilization losses1.
UAN can be broadcast or surface applied but needs to be adequately incorporated so the fertilizer is not left on the soil’s surface where it can be at risk from volatilization losses. If it remains too long, it could become subject to loss.
Protecting Your Investment
“In the past, growers have trusted AGROTAIN to stabilize their nitrogen in UAN,” said Vogel. “And it worked really well. In a study from North Dakota State University, AGROTAIN reduced volatilization by 52 percent up to 14 days after it was applied compared to untreated UAN2. But now we’ve got something that works even better.”
ANVOL® nitrogen stabilizer from Koch delivers the longest-lasting urease inhibitor protection over a wider range of soil environments. With the dual-active ingredients of Duromide and NBPT, ANVOL provides above-ground protection against volatilization, significantly reducing volatilization losses from both urea and UAN. Adding ANVOL’s high active ingredient concentration to urea for surface applications can help boost yield results compared to untreated urea.
In a 2020 study conducted in Nebraska, conditions created a worst-case loss scenario that are not typically seen in the spring, with 17 days between application and an incorporating rainfall measuring greater than a half-inch. Averaged across three nitrogen rates (60, 120 and 180 lbs), ANVOL nitrogen stabilizer provided a 37 bu/ac advantage over untreated UAN3. While dry weather is not common during the window for spring applications, this scenario represents the magnitude of above-ground losses that can occur in UAN.
"By slowing the hydrolysis down, ANVOL extends the window of time growers may need if they don’t get adequate rainfall or aren’t able to mechanically incorporate their fertilizer after it’s been applied,” said Vogel. “By using ANVOL, growers get the help to keep the nitrogen where it’s needed so their crops can reach their yield potential.”
To learn more about ANVOL and how you can protect your UAN investment, visit KochAgronomicServices.com and contact your KAS representative.
The underlying data was provided by 1Oregon State University, 2North Dakota State University and 3Real Farm Research under a Research Trial Financial Support Agreement with Koch Agronomic Services, LLC and neither the universities, institutions, nor the individual researchers referenced, endorse or recommend any product or service. Improvements in yield and nutrient use efficiency may not be observed in all cases.