Some agronomic decisions do provide an annual return-on-investment (ROI) you can count on, according to corn yield champions David Hula and Randy Dowdy. One of those, they say, is soil testing fields in 1-acre grids and then 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 variability is in the field better than a 2.5-acre grid or a zone sample can.”
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.
Dowdy and Hula encourage farmers to prioritize soil tests this fall, 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 ground,” Hula says.
Making Assumptions Can Be Costly
Growers who are reluctant to soil test this year because of costs might want to reconsider, as one of Hula’s recent experiences demonstrates.
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.”
Dowdy and Hula, who work as partners in Total Acre, offered more money-making and saving ideas during their latest Breaking Barriers With R&D podcast, available on YouTube.
Consider Lime Type And Source
The goal, Dowdy 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,” he explains.
If tests indicate soils need a pH adjustment, give careful consideration to the type of lime that will provide the biggest ROI in 2026.
“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 advises.
The finer textured lime is what’s needed for a 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 need to be aware of that, so they don’t over-correct on lime applications this next 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.
Dowdy and Hula addressed the value of soil testing in more detail during their recent conversation with Chip Flory on this episode of AgriTalk. Listen to it here:
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