As if 2025 hasn't already tested producers enough, Midwestern corn growers are now preparing for what may be one of the trickiest fall harvests in recent memory.

"It's been a long time since I've seen a corn crop set up for this much difficulty," says Doug Houser, a digital agriculture specialist with Iowa State Extension. He cites two primary concerns: elevated disease pressure and moisture variability within fields-factors that could complicate machinery performance and increase kernel losses.

Farmers are strongly advised to scout fields early and often, using drones when possible to evaluate disease intensity. Prioritizing fields where stalk deterioration is advanced may be critical to avoiding further lodging and irreversible yield loss.

To help navigate these challenges, Houser recommends five key adjustments to combine settings as harvest begins:

Rotor/Cylinder Speed
Corn test weights are expected to vary drastically within the same field due to uneven moisture levels. Reducing rotor speed can prevent high-moisture, soft kernels from crackione of the most common causes of grain loss in tough seasons.

Concave Settings
With disease-weakened corn and high kernel moisture, wider concave spacing helps reduce breakage. Houser warns that overly narrow settings will likely damage softer grain during threshing.

Fan Settings
In diseased fields, kernel density can be lower. Adjust fan speed cautiously to avoid blowing lighter kernels out the back of the combine. Houser suggests doing periodic walk-arounds to inspect for kernel losses near the residue spreader.

Sieve and Chafer Adjustments
Start wide and adjust down. Gummy, deteriorated corn leaves can clog the sieve quickly, particularly in areas with southern rust or similar foliar diseases. Proper sieve spacing can help maintain consistent grain flow.

Ground Speed
While few growers like to slow down, reducing ground speed could be the most important step this fall. Weak stalks are more prone to lodging, and faster harvesting could leave too many ears on the ground. "We've got to get it in the bin before worrying about drying costs," Houser cautions.

2024 Combine Sales Reflect Market Trends
As a backdrop, the machinery market reflects broader caution: U.S. combine sales dropped 31% in June 2024 compared to the previous year, according to the Association of Equipment Manufacturers (AEM). This decline could indicate tighter on-farm budgets-and make proper combine setup even more critical for those planning to stretch their equipment another season.

Expert Advice: Timing Is Everything

"I know the temptation is to wait for lower moisture and drying cost savings," Houser says. "But if those ears are on the ground or mold-damaged before they hit the bin, it doesn't matter."

For growers, the message is clear: Scouting early, prioritizing troubled fields, and fine-tuning combine settings will be essential to making the most of every acre in 2025's unpredictable harvest window.