record corn crop ear

540-bushel corn? A specialist talks about it in North Carolina

Timely water makes a “massive, massive” difference in achieving top yields.

North Carolina corn farmers can learn from Kentucky corn farmers, which is why Chad Lee, grain crops Extension agronomist with the University of Kentucky, was brought in for this year’s Blacklands Farm Managers Tour to give pointers on making 540-bushel corn.

“We always learn a lot from our specialists at N.C. State, but it’s always good to get a different perspective,” said Beaufort County Extension Agent Rod Gurganus in introducing Lee at the Aug. 3 tour at Middle Creek Farm in Englehard. At last year’s tour, Dewey Lee (no relation to Chad Lee), Extension corn specialist at the University of Georgia, joined NC State Extension Corn Specialist Ron Heiniger for a presentation on producing 500 bushel per acre corn.

“The biggest challenge for yield loss in Kentucky is how much or how little water we get in July,” Lee said at this year’s tour. “It’s our biggest determination because we have fairly shallow soils that hold about six inches or so on average. It takes about 20 to 25 inches to grow a crop most years.”

Water, water and water

Timely water makes a “massive, massive” difference in achieving top yields, Lee stressed.

If a corn crop receives too little water, pollination fails and seed number and seed size are reduced. If there is too much water, roots get choked for air, transpiration comes to a halt and so does nutrient transport in the plant.

“If we can manage water, we can manage for extremely high yields,” Lee said. “If we have limitations to water management, then our odds for extremely high yields go down and our year-to-year yields are much more variable.”

Chad Lee, left, grain crops Extension agronomist at the University of Kentucky discusses 540 bushel per acre corn with North Carolina Extension Soil Science Specialist Carl Crozier during the Blacklands Farm Managers Tour.

In his research at the University of Kentucky, Lee tested corn populations as high as 60,000 plants per acre in 15-inch rows. “For high plant populations, we need narrow rows and zero competition from weeds to achieve top yields,” he said. “If you’re going to get massively high yields, you have to be aggressive on weed control.”

Additionally, uniform planting, even emergence, even spacing and no compaction are vital. “Compaction for us is one of the number one yield robbers we deal with,” Lee said.

As for nitrogen, simply adding more does not guarantee high yields. “We may need to consider nitrogen more like we consider water: the right amount at the right time makes the difference,” Lee said.

Still, Lee stressed that the corn plant will need a lot of nitrogen to produce top yields. 

All of Lee’s high-yield plots are grown under irrigation with nitrogen applied a minimum of three times and up to four times. “We put a little up front, a little bit at side dress and the remainder somewhere around VTR1 through the irrigation system,” Lee explained.

“Nitrogen deficiency starts at the bottom of the plant and works its way up. Historically for us as long as we’re not deficient right at the kernel, right at the ear, then we’re OK,” he said.

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