An award-winning corn grower gives some practical advice on how to get the most bushels out of your crop
By Jackie Clark
One of the stars of Corn Warriors, a reality-TV-show-style corn competition in the midwestern U.S., recently gave 2020 Great Ontario Yield Tour attendees some insight into how he raises high-yielding corn year after year.
Dan Luepkes farms in northern Illinois and has placed in the top three entrants of the U.S. National Corn Growers Association yield contest since 2015. He has claimed first place in various categories annually since 2016.
Though Illinois and Ontario may have slightly different growing conditions, “some of the principles and mainstays that we do can help” producers regardless of where they farm, said Luepkes.
Typically, growers in the American Midwest apply ammonia and lime in the fall or spring before planting. They may also till in the fall or spring. Farmers will aim to plant in good time and use starter fertilizer. They’ll apply both pre- and post-emergence herbicides and side dress. Some growers will use fungicide.
Luepkes uses some, not all, of those strategies on his corn. For example, he’s “not a big lover of ammonia mainly for soil biology reasons. I think it’s kind of hard on things. … We’re mostly using 32 per cent with sulphur added.”
He also incorporates some additional management strategies to take his corn yields to the next level.
“Maximizing corn yields requires a strategic approach and knowledge of critical strategies,” he said.
High yields start with high crop potential, which, in turn starts with hybrid selection.
Look at the field, soil type, and crop heat units of the hybrid, Luepkes said. “I really like to lean towards those (hybrids with) very high emergence scores.”
Plant a population that makes sense for your potential yield level, he added. From there, you determine how you want to manage the crop.
“We have tillage with deep ripping on some wetter ground, but we also do a lot of no till. I keep trying to do more and more of that,” he said. The benefits of no till include cost savings on labour and equipment.
“Feed plants based on yield goals,” Leupkes said. “Do you have a high yield environment? … If you’ve got a 200-bushel yield environment, don’t fertilize for a 300-bushel yield environment” because you’ll lose money.
To improve the environment, you can work on your soil, balancing magnesium and calcium to create more optimal conditions, he explained. That process will take several years.
Another important way to preserve yield is diligent scouting. “I’m in my fields every day,” he said.
Leupkes applies nitrogen (N) three to five times in the season. He applies N at planting, and tank mixed with the pre-herbicide application. He also side dresses using a Y-drop, and, later, applies N through irrigation.
“We’re trying to spoon feed our nitrogen,” he explained.
High soil potassium (K) and phosphorus (P) also contribute to high-yielding corn.
“If you don’t have (high soil P and K), it doesn’t mean you can’t have high yields. But you will have to supplement quite a bit through the year with readily available P and K,” he added.
Leupkes also pays close attention to micronutrients.
“We’re finding that sulfur is, more and more, a key to high yields,” he explained. “We’re adding quite a bit; it’s mixed in with all of our nitrogen.”
Factors that may inhibit yield include shallow roots, compaction, diseases, insects, weeds, drought and heat stress.
Limited sunlight during grain fill is another factor that may limit yield. “Sunlight is just as important as any fertility,” he said. And, unfortunately, it isn’t a factor you can control.
Overall, “there is no silver bullet,” to achieve high yields, Leupkes explained. You need a “dedicated management system.”
He uses a four-quarter strategy, which divides corn development into four general developmental stages and focuses on key management activities for each stage that boost yield. The four stages are establishment, ear development, pollination, and grain fill.
Establish a stand
“Stand is a very crucial time for yield,” Leupkes said. Uniformity is important because “we want all those ears on the same node, at the same height.”
So, it’s “very critical to get (the plants) out at the same time and, to do that, you have to have them at the same depth,” he explained. You need to have “a good, level seedbed,” and may need to use a row cleaner in no-till systems. If conditions are rough, you’ll need to plant slower to ensure uniform depth.
“We spend a lot of time on the planter” to make sure it performs well in the field, he added.
He believes his starter fertilizer strategy “is a key component to higher yields,” he said.
He applies fertilizer in-furrow and two bands three inches down and three inches to either side of the seed, he explained. Applying the fertilizer on both sides of the seed allows him to cut salt load.
“I call it the relay system. Think of it as handing off a baton,” Leupkes said. He includes N, P, K, and potentially micronutrients or sugars in furrow, which holds the plant until about the V3 to V4 stage. “Then that plant is getting long enough roots that it’s going to go over and reach that (three by three) band,” he said.
In terms of pesticide applications, he likes “to get that done before we get to the V5 to V6 stage,” to avoid stressing the corn plant, he explained.
Plants will determine ear size around the V6 stage, Leupkes said.
“I believe that, by adding extra nutrients, and a lot of that is in our planter fertility, we can influence (ear size). I believe, in general, (our corn has a) couple more rows around than if we were not using an extensive starter program,” he explained.
Leupkes often takes a tissue test around V7 on contest corn and in some other fields. Through these tests, he can identify limiting nutrients.
“I would say you have to be in a fairly disease-ridden area or have had problems with it in the past to pay for a V5 to V6 fungicide pass. … We have done some at V12,” he said. You want to keep your corn as stress free as possible while the ear is developing.
The length of the ear is established in the V8 to 12 growth stages, he added.
“What we’re trying to do at VT is to make sure not to abort any. We don’t want the plant stressed around that time,” Leupkes explained. So, he ensures adequate water and nutrients, which he applies in some fields with drip or pivot irrigation.
“We want to have our micros right. That’s kind of when boron would come into effect,” he added.
Producers should also scout for pests. “Watch your silk clippers really closely,” he added.
Farmers can make yield gains through additional late-season water and fertility.
“This is where a corn crop can be made,” Leupkes said. “You can have a 16 by 35 ear of corn that’ll make 200 bushels and you can have a 16 by 35 ear that’ll make 300 bushels. It’s all about kernel depth and weight. Sometimes, you don’t want to get so wrapped up in ear size, (but) you want to think about keeping that plant really healthy late and keeping it fed well. Hopefully, the weather cooperates with you.”
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