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Getting the most out of N is increasingly important for a crop production budget. Enhanced efficiency N is available in two ways: stabilizers and controlled release. Both types of technology help maximize nitrogen’s availability to a crop.
These urea granules have been coated with Agrotain nitrogen stabilizer. Photo: Courtesy Agrotain
The Agrotain line of nitrogen stabilizers from Koch Agronomic Services has been the primary product line available in the U.S. nitrogen stabilizer market. These stabilizer products protect against the three major processes in which N can be lost (see sidebar).
“There’s an enzyme that’s called urease that breaks (urea-nitrogen) down. It converts it into ammonium, which is a plant-available form of N,” explains Kruse. What may also happen is urea can break down into ammonia, which is a gas that can leave the soil surface; a farmer has then lost the value of the nutrient.
“So if you can protect urea by slowing that conversion process from urea to ammonium, then more of that N stays in the plant-available form,” says Kruse. “What Agrotain N stabilizer does is interfere with the urease enzyme, so the urea breakdown takes place over a slightly longer period of time — a few days.” Ammonium is then available for the plant when it needs it, Kruse explains.
However, ammonium converts to nitrate throughout the growing season, and can be lost in a rain event. So Koch offers several products, such as Agrotain Plus and Super U fertilizer, that prolong the N in the ammonium form in order to protect against denitrification or leaching.
“So that’s how you get more season-long uptake. It’s not that it’s slowly releasing the N in the soil,” says Kruse. “But it’s protecting the N in the soil from converting into the nitrate form which can be lost.”
When to use a stabilizer
Anytime a grower surface-applies urea and is unable to incorporate it or water it immediately, he can benefit from Agrotain stabilizer because it protects against volatilization. Kruse also says growers in both wet and dry climates can find value in using a stabilizer product.
“Let’s say you’re on a shallow, gravelly soil like in Montana. It’s not very wet there, but the soils can be so shallow that it doesn’t take very much precipitation to move N deep into the soil profile beyond the root zone,” says Kruse.
He also mentions that researchers at Montana State University have recently reported that even in cold climates, where growers might think N applied in the fall will stay there through the winter, substantial N loss can occur.
Tillage is important to consider when choosing an enhanced efficiency product. Kruse says Agrotain shines in no-till.
“When you’re in a no-till situation, you have a lot more enzyme activity breaking down the urea. You’re also prevented from tilling in the nitrogen. It’s sort of that perfect storm of N loss we’re protecting against,” says Kruse.
Agrotain stabilizer is typically applied to urea at dealerships. The protected N can be blended with other nutrients. Kruse says in tests, they’ve seen between a 5- and 20-bushel-per-acre yield advantage by using Agrotain.
For more information, visit agrotain.com.