Inside The Science – Controlled-Release Nitrogen Explained

ESN Smart Nitrogen is a controlled-release fertilizer composed of 44 percent nitrogen that responds to the same environmental cues as your crops. ESN’s polymer membrane allows moisture to diffuse into the granule, creating a nitrogen solution.

“The technology is in the chemistry of the coating and properly applying it to get a predictable release rate,” says Dr. Alan Blaylock, Agronomist, Nutrien. “ESN protects your nitrogen for 50-80 days, depending on soil temperature. Urea on the other hand, dissolves in a few hours, leading to potential losses by volatilization, leaching, and denitrification.”

This coating protects the nitrogen from loss mechanisms and releases nitrogen in response to soil temperature. ESN drastically reduces nitrogen loss, but according to Dr. Blaylock, “one of the key things to understand about ESN is that it’s not just about preventing nitrogen loss, it’s the continuous feeding that we get from a controlled-release fertilizer.”

Time-lapse photography allows you to see the polymer coating in action here.

How ESN technology works

Coated nitrogen granules

ESN technology uses a flexible polymer coating to encapsulate a nitrogen granule. The coating forms a protective barrier that acts as a semi-permeable membrane surrounding the fertilizer granule. Tiny, molecular-size pores in the polymer coating allow water to enter the granule slowly. The coating protects the N from loss mechanisms, releasing it when the crop needs it most.

Temperature-controlled release

The triggers for releasing the N solution into the soil are moisture and temperature, the same triggers that signal the best conditions for plant growth. Moisture creates an N solution inside the coating, and the solution moves through the membrane at a rate controlled by soil temperature. The movement and rate match the N demand of the growing crop.

ESN’s polymer coating eventually degrades in about 18-24 months in soils. The end products of ESN decomposition are carbon dioxide, ammonia and water.

To learn more about the controlled release difference, click here.

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