Corn needs a variety of nutrients to perform well, and it especially needs sufficient nitrogen (N) throughout the growing season. While there are numerous nitrogen types farmers can use—ammonium sulfate, anhydrous ammonia and urea, to name a few—Ken Ferrie says the source of N matters little.
“Regardless of the source, it’s the break down of the source, the end product—that’s what the corn plants are after,” says Ferrie, Farm Journal Field Agronomist and owner of CropTech Consulting, Inc.
Ferrie uses sugar as an analogy. “There are a lot of ways to get sugar, but in the end they’re all the same. Sugar is sugar, and it doesn’t matter what your ex beer supplier tells you,” he says, chuckling and referencing the Anheuser-Busch advertising debacle.
"You want to keep enough nitrogen available during all corn growth stages so crop growth never slows down," Ferrie adds.
He says nitrogen works in corn like gasoline in a vehicle, fueling crop growth from emergence through maturity. A lack of nitrogen at any point along the way can cause the crop to sputter or stall.
"Corn that’s nitrogen deficient at the beginning of the growing season gives up yield potential," he says. "Nitrogen-deficient corn in the late reproductive stages costs actual yield."
From emergence to V8, corn plants consume less than 2 lb. of N per acre per day. While N uptake is not much because plants are small, don’t underestimate this stage because it impacts overall yield potential, Ferrie notes.
From V10 to V18, the plant consumes 5 lb. to 10 lb. of N per acre per day, known as the rapid vegetative growth stage. Once the plant has reached R1 and is pollinated, the daily usage backs off to about 2 lb. per day.
“When corn hits R1 and drops its daily usage to 2 lb. per day, you still have 60 days of this stage remaining,” Ferrie says. “It’s critical you meet the 2 lb. per day demand, whether you or the soil supplies N, to reach maximum yield potential.”
In the following Boots In The Field Report podcast, Ferrie answers farmers’ questions about nitrogen use in corn. As he often says about corn’s need for nitrogen, “Never let your corn have a bad day. Happy corn, happy farmer.”