‘Feast or famine’ yields will depend on rainfall

A year of have and have nots will likely render this year’s corn harvest as unpredictable.

“Weather has been very variable across the state in this area,” says Matt Nelson, a Channel technical agronomist. “I would say there’s been more zip code to zip code variation in terms of weather all year than I've really seen for the last couple years.”

Water has been key this growing season, making clear which fields experienced rainfall while areas of the Corn Belt faced drought conditions. Wide swings in yield potential can be seen county to county.

“In south central Iowa, the crop looks hit pretty hard, probably 125 bushel an acre yield environment,” says Neal Borgmeyer, a Kruger technical agronomist. “Then you go to east central Iowa, and 300 bushels [per acre] is the potential there. You can definitely tell who got rain, when they got it and how much. It’s feast or famine.”

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Disease Pressure

Drought has kept disease pressure low for many farmers this summer. That may change as temperatures start to cool heading into fall.

“We’re just now seeing disease develop because the last three or four weeks the temperature started to cool down at nighttime,” says Bruce Battles, a Golden Harvest technical agronomist. “The humidity has extended that leaf wetness into the late mornings, and that’s the perfect environment for diseases start to develop.”

A late-season disease flare up is less concerning, as many corn acres have already reached their yield potential.

“Disease can definitely still make an impact, but it will probably be minor considering,” Battles says. “Most of the diseases and lesion development won’t happen until the next couple weeks, and we will be getting even closer to maturity by then.”

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Pest Pressure

Pest pressure has remained standard, although a reduced corn rootworm population has stood out. Cooler morning temperatures and saturated soils from heavy rainfall this spring may be why, Battles says.

“The stars kind of aligned to really knock the pressure down in some areas, especially in central Iowa,” Battles says.

Reduced pressure doesn’t mean corn rootworm can’t bounce back next year, Battles warns.

“I'm still seeing beetles out there in the fields,” he says. “I don't want people to think it’s no longer a problem. There’s probably a lot of egg laying capacity with the beetles that are out there.”

Understanding corn rootworm populations now can help farmers plan for next year.

“It’s a great time to make decisions on corn rootworm management practices, especially if you’re corn-on-corn,” Battles says. “We might want to rotate to another crop in really extreme situations where there’s a lot of beetles this year.”

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Evaluate Nutrient Uptake

Drought conditions may mean greater nutrient deficiencies, which could affect next year’s fertilizer applications.

“If you have low uptake of potassium this year, you may not need to put on your normal rate in fields where you had extremely low yields and didn’t have a lot of nutrients pulled out and carried away in grain,” Battles says. “It’s always good to know those field-by-field scenarios.”

The most efficient way to make nutrient management decisions is to soil sample, Battles says.

“[Inflated prices] is something everybody’s dealing with, and the kneejerk reaction is to cut things short,” Battles says. “You have to have good information to make your decisions. A knee-jerk reaction can really hurt you in the long run and be more costly than what it seemed.”

Make a Harvest Plan

Now is the time to scout fields and make plans for harvest. Variability from field to field means harvest may come quicker than expected, Nelson says.

A wet fall, like in the past few years, can make harvest even more challenging.

“If you’ve got fields that are dying prematurely, we want to make sure we don’t let those sit out for a month,” Nelson says. “All we do is incur more risks with standability and harvest loss. If I were a farmer, I’d be going to my fields and looking at each one right now to figure out a harvest plan.”