The dominant product in the controlled-release market in the U.S. is ESN, “Environmentally Smart Nitrogen,” a product made by Agrium Advanced Technologies. ESN urea granules are coated with a polymer, and the product is designed to release urea slowly throughout the growing season.

“As moisture and temperature continue to increase, the water basically diffuses through the polyurethane, dissolving that (urea) granule inside the coating,” says Ben Cicora, ESN sales manager. “Then as the temperature heats up, it allows the release of the urea into the soil, and keeps it where and when the plant needs it throughout the growing season.”

He also says growers with a variety of tillage practices could benefit from ESN as long as they’re conscious of timeliness.

“If you’re doing a true tillage situation, make that (ESN) application post-tillage,” says Cicora. He says growers who do conventional tillage tend to do so in the fall and then come back to apply ESN in the spring. “You’ve just got to be conscious that you’re not over-tilling after the product’s been in.

“In a no-till situation, (ESN) works as good or better just because you’re able to leave the product on the ground and let it diffuse and work down into the soil where the plant needs it at the root structure,” Cicora says.

Which fields need ESN

In terms of which types of fields benefit most from ESN technology, Cicora says sandier soils and irrigated crops really see a bump in yield benefit. Throughout the core Midwest, tests done by the company showed a yield advantage of up to 7 to 12 bushels per acre.

But he says the product is flexible and can be used on just about any soil type. Areas that already have high organic matter still benefit from ESN.

“Basically, what ESN is doing is allowing that corn plant to maximize its genetic potential by feeding the plant all season long and not just in a preplant or sidedress application,” says Cicora.

ESN can also be blended with other products like phosphorus or potassium fertilizers, but the company recommends that when a blend is done, the ESN coating material should always be applied last.

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