A challenging start to the growing season in the Upper Midwest has soybean producers facing widespread issues with small, yellow plants. For many, the root of the problem isn't immediately visible above ground. But Certified Crop Adviser Missy Bauer says it lies in the soil.

"This spring, we had the coolest May nights and warmest June nights in 14 years," Bauer explains. This erratic temperature swing led to a condition called the carbon penalty - a soil process that's been punishing crops since emergence.

Understanding the Carbon Penalty

The carbon penalty occurs when soil microbes, awakened by warmer temperatures, rapidly break down last year's crop residue. This process requires nitrogen and other nutrients, effectively locking up key elements before young plants can access them.

"This is a hard carbon penalty," Bauer emphasizes. "It just locked the beans up, and that added stress."

In southern Michigan, northern Indiana, and southwest Ohio, many growers delayed soybean planting due to cold May nights, pushing it as late as Memorial Day or early June. When the warmth finally hit, microbial activity spiked, further stressing late-planted beans already working to catch up.

How to Break the Cycle

Bauer says one solution that paid off this year was using liquid fertilizer with the planter. This method helped beans access nutrients early and combat the stress caused by the carbon penalty.

The good news? Growing Degree Days (GDDs) in July are trending above average in the Lake Erie region, helping soybeans recover. "Basically, we're back on track," Bauer says. "Maybe we're just a little bit behind last year, but we're knocking on average."

Technology Steps In: Spray Drone Rescues Yellow Beans

Another innovation came from B&M Consulting's Kameron Barrow and CCA Bill Bauer, who tested a spray drone treatment on yellow soybean patches near Coldwater, Michigan.

Tissue samples revealed a manganese deficiency. In response, a 5% manganese liquid fertilizer was drone-applied at half a pound per acre on July 10. Just five days later, Barrow says, the yellowing was gone in treated areas.

"We left a check strip untreated, and the yellow is still there," Barrow says. "This just shows how we can now leverage spray drone technology to manage crops more precisely and effectively."

With weather normalization and the use of both fertility tools and ag tech innovations, Midwest growers have a real shot at salvaging soybean yields this season.