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If you apply enough nitrogen early and don’t lose it during spring, you won’t likely need more.
Late N needs are predictable
“A successful, late-season N application is very, very weather dependent, and that’s exactly what makes it attractive,” Mitchell says. “You can predict when it will be an effective practice and when it won’t be. If it’s been warm and wet during spring, it will more than pay for itself. In a year like last year, we would easily see a 1 bu./acre yield increase per unit of N applied.”
Late-season N applications can be particularly valuable in places with inconsistent rainfall, such as on the fringes of the Corn Belt, Mitchell points out. “In these areas, if you apply all the N upfront, either prior to or soon after planting, then you risk throwing it all away or losing a lot of money if it turns out to be a very dry year and the corn can’t take it up,” he says. “In a very wet year, unless you’re able to apply N later in the season to make up for lost N early on, you risk not having enough N available to the crop to optimize yields. So, especially on marginal corn-growing areas, this is a great way to deal with the uncertainty and risk over weather.”
Farmers who can raise a fall cover crop after corn would still benefit from a late-season N application, even if dry conditions prevail, Mitchell adds. “The cover crop will take up the N and release it in the future,” he says. “So the late-season N application is a really good option. It’s much better than putting a whole bunch of N on upfront and taking a risk that it might be wasted.”