Nathan Gregory has steadily increased his corn yields since the 1980s. And the use of a nitrogen (N) stabilizer on urea can likely take some of the credit on his eastern Arkansas corn and soybean operation.

Gregory farms about 1,800 acres of corn and 2,000 acres of soybeans, which include beans double-cropped after wheat on land that has received more than its share of rainfall the past two years. Keeping N in the field and out of the bar ditch has been a challenge for him and many other growers.

N stabilizers and slow-release N products are helping growers prevent N losses that rob corn of valuable, yield-generating nutrients and potentially create environmental concerns.

 Best practices today, through the use of urease and nitrification inhibitors, minimize N’s off-target movement by reducing volatilization and by maintaining N in the ammonium form, which is less mobile and more efficiently utilized by many crops.

Randy Killorn, Iowa State University (ISU) professor of agronomy, says he and his associates have studied urea coated with a controlled-release Environmentally Smart Nitrogen (ESN) from Agrium more than six years and have seen positive results.

“We’ve seen some good response in yields, but not all of the time,” says Killorn. “Our feeling is that it should be of interest to growers, depending on the cost of the ESN product and the price of corn.”

For Gregory, corn is usually grown after beans or wheat. His source is usually a liquid N at 32%. But he sometimes applies urea coated with Agrotain, an N stabilizer designed to prevent volatilization, when urea contacts moisture and soil compounds that release ammonia into the air.

“The process has likely helped me increase my yields because of better N management,” says Gregory. “In the 1980s, we had yields in the 140-bu. range. We’ve seen that increase from 184 to 190 bu.”

When using urea, he applies it at an N rate of about 200 lbs./acre for his corn. With the heavy spring rainfall and chance for leaching, he counts on the stabilizer to keep the N intact.

“We’ve had good luck with that program,” he says. “When we apply the liquid 32, we knife it in when the corn is about a foot tall. Our corn seems to respond well to both programs.”

Urea normally converts to ammonium-N shortly after it hits the soil, so N from urea can be lost to the atmosphere if fertilizer remains on the soil surface for extended periods of time during warm weather.