Farmers looking to make the most of their fertility dollars this season can maximize ROI with the same strategy corn yield champions Randy Dowdy and David Hula use.
The two world record holders say their No. 1 practice that’s foundational to growing consistently high yields is soil testing in 1-acre grids and using the resulting information to guide fertility decisions.
“If people are used to going across the field and watching a yield monitor vary significantly, say from 300 bushels down to 200 bushels in a pass, there’s a reason why that is and a lot of it has to do with soil fertility,” says Dowdy, who farms near Valdosta, Ga. “Pulling samples in a 1-acre grid can help you identify where that variability is in the field better than a 2.5-acre grid or a zone sample can.”
“It’s never too late to pull a soil sample. You can always learn from the data and see what kind of fertility is still out there,” adds Dowdy, who set the world yield record for irrigated corn in 2014 with a yield of 503 bu. per acre.
Hula agrees and uses a medical analogy to explain the value of 1-acre grids. “It’s like the more detailed information you can get from an MRI versus an X-ray,” says Hula, who farms near Charles City, Va.
Hula currently holds the world record for corn, which he set in 2023 with 623.8439 bushels of corn per acre. He has set the world record for corn yield six times since 2003.
Today, the two farmers are still focused on growing high yields and work as partners in their Total Acre program to help other growers achieve the same.”
Spring Soil Tests Provide Value
Even as March gets underway, Hula and Dowdy would encourage growers to pull soil tests on any of their acres going into corn.
“Many growers haven’t applied MAP or DAP and potash at this point, and addressing soil pH with lime could still give them some benefit this season,” Dowdy says.
The goal, he says, is to have a soil pH in the neutral to 6.8 range across all acres. “An old timer told me a long time ago, ‘the cheapest fertilizer you’ll ever buy is lime,’ because it’s going to help you get the maximum efficacy from all your nutrients,” Dowdy explains.
Dowdy and Hula advise farmers to prioritize soil tests, starting with any ground they own. “Every acre I own would definitely get tested, starting with the tiled ground because it’s going to give you the biggest ROI versus the not tiled,” Hula says.
Making Assumptions Can Be Costly
Growers who are reluctant to soil test at this point in the year because of costs or timing concerns might benefit from reconsidering, based on one of Hula’s recent experiences.
Hula says he had not limed his farm ground for several years, due to a lack of product availability. “First, the lime quarries broke down, and then they ran out of lime, so we just couldn’t get it done,” he recalls.
As a result, Hula anticipated spreading 6,000 tons of lime across his corn ground this year. But instead of simply making that assumption, he pulled soil samples in 1-acre grids across 4,000 acres.
To Hula’s surprise, soil sample results showed his fields needed a lot less lime than anticipated.
“We only needed 2,600 tons of lime spread,” Hula reports. “Yes, there were costs associated with the testing, but the savings we got was more than enough to cover that.”
Consider Lime Type And Source
If tests indicate soils need a pH adjustment, give careful consideration to the type of lime that will provide the biggest ROI yet this growing season.
“Understand the source of lime, whether you need magnesium or not and also understand whether it is a coarse or a fine-textured lime,” Hula says.
The finer textured lime is what’s needed for spring application. A coarse lime can take a couple of years to break down and become available for soil uptake.
Farmers who applied a coarse lime last fall or even last year do need to be aware of that, so they don’t over-correct on lime applications this spring. “You don’t want a situation where it all kicks in on the same year,” Hula cautions.
“Likewise, don’t use that as an excuse to not lime, if what you applied two years ago still hasn’t shown up. Understand what kind of lime or other fertility need your soils have now going into the season,” Dowdy advises.
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