Wheat School: How to avoid leaf burn by UAN


Wheat prices are amazing and everyone wants big wheat yields this year; so how do you achieve them? By paying close attention to your nitrogen applications, of course.

Peter “Wheat Pete” Johnson is hopping mad in this Wheat School episode — mad at himself that is. In the video, he’s standing in a wheat field with leaf-burn — a field that he said was good-to-go.

“Split your nitrogen, because we’ve got a big wheat crop in the ground and we want to make sure we keep it standing; we don’t want it to fall over,” says Johnson. However, low temperature nights, cloudy days, and the fact that the leaves don’t have a cuticle, can cause horrible leaf burn from 28 per cent (UAN) on a second application, he explains. (Story continues below video)

So what can we learn from the field Johnson’s standing in? Variety makes a difference — a variety with a prostrate leaf that leans out and tries to canopy over will burn worse. Streamer nozzles also make a tremendous difference, says Johnson, explaining that nozzles that shoot straight down will cause uniform burn (which isn’t great, of course).

Johnson warns that white frost acts like glue for UAN on the leaf, and that doing your N application when there’s a dew also doesn’t work. The application needs to be done when the plant is dry or when it’s raining.

Dilution is also key, says Johnson, advising using one part water to one part UAN. Finally, Johnson says that thankfully the yield impact will be pretty small, even though photosynthetic area has been compromised.

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Wheat School (view all)Season 12 (2021) Episode 22

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