Corn School: How late nitrogen impacts plants and yield


Corn growers often apply nitrogen later in the season to gain more control of the crop.

At the V10 or V11 development stage, growers typically have a better understanding of how the crop is developing, its yield potential, the growing environment and what the market is willing to pay. There’s also logistics to consider — a late-season N application window makes a lot of sense for many busy growers.

But are there risks when applying nitrogen at such a late stage of development? Could it burn leaves? Would the crop injury have a negative impact on yield?

On this episode of the RealAgriculture Corn School, host Bernard Tobin gets answers to those questions with help from University of Guelph researcher Josh Nasielski and graduate student Gavin Brady.

In 2023, Nasielski and Brady teamed up to test three nitrogen rates — 43, 65 and 130 lbs/ac — applied at V10 using UAN and urea at research sites in Elora, Ridgetown and Winchester, Ont.

The research, sponsored by NSERC Alliance, OMAFRA, University of Guelph, Grain Farmers of Ontario, Corteva and Agriculture and Agri-Food Canada looked at how both nitrogen source and application rate could impact injury and yield.

In the video below, Nasielski shares how UAN produced a higher percentage of both leaf burn and yield loss, compared to similar rates of urea. When both sources were applied V10 at 130 lbs/ac, UAN injury reduced yield by 17 per cent compared to eight per cent for urea.

Tap here for more Corn School episodes.

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Corn School (view all)Season 12 (2023) Episode 1

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