Field Didn’t Yield Like Expected? Start With These Checks

While harvesting a field of irrigated corn, Quentin Connealy noticed something unusual: The dryland corners were outyielding the acres under the pivot. 

“That’s where it red-flagged for me that something had happened,” said Connealy, who raises corn and soybeans in eastern Nebraska.

That field, like so many others, had hidden challenges that didn’t become obvious until harvest. In this case, saturated conditions early in the season led to crown rot, weakening stalks, and limiting yield under the pivot. 

Eventually, every farmer faces a field that doesn’t live up to expectations. Whether it’s due to uneven emergence, nutrient loss, disease, or weather stress, disappointing yields can happen, even on well-managed fields. The difference between frustration and improvement comes down to what happens next: asking the right questions and digging into the yield equation.

Understanding Corn Yield

Corn yield boils down to three core components: ears per acre, kernels per ear, and kernel weight, said Brent Tharp, technical product manager for Wyffels Hybrids. Each is influenced by different developmental stages and environmental factors.

“Even emergence is more important than picket-fence stands; the corn needs to come up at the same time to maximize yield potential,” Tharp said. That means proper planter settings, consistent seed-to-soil contact, and planting into uniform moisture.

Tharp emphasized the importance of the V6–V12 stages, when potential ear girth and length are determined. Drought, nutrient tie-up from heavy residue, or poor root development during this window can undermine a field’s potential long before tassel. 

Later in the season, kernel weight becomes the final piece of the yield puzzle — and often the most weather-dependent. “At the dent stage, corn still has 40% of its yield left to make,” Tharp noted. “Protecting green leaf area during that period is critical for continued grain fill.”

Silent Sabotage in Soy

While corn yields often spotlight visible issues, such as stand gaps or disease damage, soybean losses can be far more subtle. “Soybeans are resilient, but that also means it’s easier to overlook problems until it’s too late,” said Stephanie Porter, outreach agronomist with the Illinois Soybean Association.

When soybean yields come up short, one of the first things to evaluate is stand uniformity. Poor stands, whether from planting into marginal conditions or compromised seed quality, can lead to disease, and thick-stemmed plants that slow harvest. “You can have a thin stand and still yield,” Porter said, “but uniformity makes a difference.”

Porter said she often starts her diagnosis with a soil test. “pH, drainage, compaction, fertility — these are things we sometimes take for granted, but they’re huge yield drivers for soybeans,” she said. Fields with lingering compaction or drainage issues from wet planting seasons can silently zap yields, with symptoms only becoming obvious in yield maps.

Soybean cyst nematode (SCN) is another silent yield robber farmers need to monitor. As pH rises above 6.5, SCN activity often increases, impacting plant health and yield potential, even when aboveground symptoms are minimal, Porter said.

“Farmers need to treat soybean selection like they do corn hybrids,” Porter stressed. “Choose based on field conditions, not just maturity. Look at disease scores, emergence, and standability.” 

Later-planted soybeans are often at higher risk for diseases depending on environmental conditions, Porter said, adding another layer of complexity to variety selection and fungicide planning.

Staying Green to the Finish Line

As crops approach the finish line, maintaining healthy green leaf area is critical to filling pods in soybeans and adding weight to corn kernels. Diseases, such as tar spot, gray leaf spot, and northern corn leaf blight, can strip corn yield if left unchecked. In soybeans, foliar diseases, including frogeye leaf spot and white mold, reduce the plant’s photosynthetic capacity for pod fill.

Fungicide applications timed around tassel in corn and R3 in soybeans are standard, but late-season scouting can reveal whether an additional pass is justified to protect the upper canopy. Porter emphasized that protecting green leaf tissue late in pod fill is especially important during high-pressure disease years.

A Walk in the Field

One of the biggest mistakes is waiting until the combine rolls to evaluate the crop. “I’d much rather get a call midseason that something looks off than hear about it at harvest,” Porter said.

For Connealy, the lesson hit home last year with crown rot. “It was in a hard-to-access area of the field, so it went unnoticed until harvest,” he said. “If we’d caught it earlier, we might’ve changed our approach.” 

Growers should do one final walk through their fields in early September, urged Mike Hannewald, a field agronomist with Beck’s Hybrids in Ohio and Indiana. “You’re not going in to make a spray decision,” he said. “You’re going in to learn. That late-season walk can tell you a lot before plants dry down and disappear.”

Hannewald said he encourages farmers to pull a few plants, split the stalks, and examine the root structure. “Walking the field isn’t just about looking at the canopy,” he said. “You can learn a lot by digging roots.” 

Managing Yield with Precision

An early September drone flight while fields are still green can reveal stress patterns and anomalies that are easy to miss from the ground or sprayer cab, Hannewald said. “Sometimes, it’s not until you look at the yield map that you realize a problem area existed,” he said. “Having drone images to compare can help explain why that spot came up short, and guide what you can adjust for next year.”

Connealy said he has found Goanna Ag to be a valuable resource to manage irrigation with greater precision. The system connects to moisture probes across his fields, helping him monitor soil conditions under pivots and adjust water applications accordingly. But he doesn’t rely on probe data alone. By combining Goanna’s moisture readings with aerial imagery, he can flag problem areas, such as sandy spots or uneven water distribution, before they show up on the yield monitor. “The imagery helps confirm what the probes might be missing, especially in fields with a lot of variability,” he explained.

Beyond in-season imagery, tools that overlay field maps with weather history, such as rainfall patterns, temperature swings, or growing degree days, can help pinpoint when and where yield-limiting stress occurred. “Those overlays give you context for what the crop experienced, especially if you see something odd on the yield map,” Hannewald said. 

Combining weather data with drone images, moisture probe readings, and scouting observations creates a more complete picture of field performance. But sometimes, it still comes down to trusting your instincts. “Some imagery platforms don’t update fast enough, especially on cloudy days,” Connealy said. “So I still like to ground-truth what I see.”

Lean on Your Team

When yields come in below expectations, Connealy says it’s essential to face the numbers head-on. “When something doesn’t meet expectations, that’s when I talk to people smarter than me,” Connealy said. “Get your actual bushels together and bring your team in — your agronomist, your banker, your marketer. Get everyone on the same page early.”

Postharvest conversations should include open dialogue about compaction, drainage, pH levels, disease pressure, and hybrid performance. “Sometimes, it’s what you didn’t see coming,” Porter said. “But if you don’t ask the questions, you won’t find the answers.”

How to Turn Dissappointment Into Opportunity

A poor-yield year doesn’t have to be a lost year. In fact, it may be a most informative one.

When certain field areas consistently fall short, it’s tempting to lower yield goals across the board. Tharp cautioned that the solution isn’t always to reset expectations — it’s to refine management. “You need to start diagnosing whether it’s something you can control,” he said. “That might mean pulling more soil samples, adjusting fertility in those spots, and experimenting with different strategies.” 

However, he said, some field parts, such as hilltops or sidehills, may have inherent yield ceilings, no matter the inputs. In those cases, variable-rate seeding and fertility can help optimize inputs without overinvesting in underperforming zones. 

Connealy said shifting to variable-rate management has paid off, in yield and profitability. “We do a lot of variable-rate fertility and variable-rate planting now,” he said. “We’re targeting specific rates on specific acres, so we’re not overfertilizing some spots or underfertilizing others. That approach has really taken us to the next level.”