Study corn plants prior to harvest to see what when right and what when wrong with your nitrogen management strategy. Use this time to set yield expectations for this year and make corrections for next season.

“As we get closer to black layer evaluate corn for nitrogen uptake,” says Daniel Lundeen, Channel technical agronomist in Illinois. “If you didn’t have enough nitrogen you’ll see a Styrofoam-like look to the stalk’s pith.”

When nitrogen runs short you’ll see firing in the lower leaves as nitrogen is cannibalized from the bottom of the plant up. While some cannibalization is expected in even a good year, excessive stalk cannibalization could lead to harvest troubles. If your stalk is cannibalized be sure to perform the pinch or push test and if 10% to 20% fall it could mean you’ll need to harvest that field early.

In addition to investigating the stalk, it’s important to understand what the corn roots are doing and how that affects the plant’s access to nitrogen.

“Look below the ground—the majority of nutrient and water come in through the roots,” says Doug Kirkbride, Syngenta agronomist. Factors such as the crop’s genetics, compaction, insect feeding, planting depth and nutrients in the soil all affect the plant’s overall nutrient uptake through roots.

As you examine roots you might find you applied nutrients right, but an error at planting pinched the crop’s access to nitrogen. Use this information to plan how you’ll handle next planting season to avoid compaction, mitigate insect feeding risks, optimize planting depth, select resistant genetics or improve nitrogen application timing.

“If you’re doing one nitrogen application do two, if you’re doing two do three,” Lundeen says. “Spread our your risk.”

Nitrogen is the gas that makes corn yield grow, make sure you learn from this year to avoid cutting yield short in 2018.