Iowa State University experts say small changes to combine setup, harvest loss monitoring, yield calibration, and residue management can improve profitability and support stronger crop performance next season.
As combines begin rolling across corn and soybean fields, Iowa State University specialists Doug Houser and Luke Fuhrer are reminding producers that harvest success is about more than speed.
According these two experts from Iowa State University Extension and Outreach and the ISU Digital Ag Innovation Lab, small improvements in combine setup and monitoring can significantly reduce grain losses, enhance grain quality, improve yield data accuracy, and support stronger crop establishment next season.
The recommendations were highlighted during the university's 2026 Combine University program, a hands-on training initiative focused on helping farmers better understand combine settings, harvest efficiency, automation systems, and residue management. More information about the program is available through https://digitalag.iastate.edu/combine-university.
1. Identify Where Grain Loss Is Occurring
Before adjusting combine settings, operators should determine where grain is being lost.
Iowa State specialists note that losses can occur before harvest begins, at the header, or within the threshing, separating, and cleaning systems. Understanding where loss originates allows farmers to make targeted adjustments rather than guessing at solutions.
Header losses are often among the largest contributors to total harvest losses. In soybeans, reel position and speed can have a major influence on shatter losses, particularly during dry afternoon conditions.
Experts recommend checking fields regularly and reassessing losses as crop and weather conditions change throughout the day.
2. Measure Losses Instead of Estimating
Even small amounts of grain left in the field can quickly translate into significant economic losses.
The Iowa State team encourages farmers to evaluate multiple locations across the full harvesting width rather than relying on a single observation point. Measuring losses before harvest, at the header, and behind the combine provides a clearer picture of where adjustments are needed.
The message is straightforward: what may look like a minor loss on the ground can represent a substantial number of lost bushels across hundreds or thousands of acres.
3. Continuously Fine-Tune Combine Settings
While manufacturers provide recommended starting settings, Iowa State experts emphasize that no single setup works under all field conditions.
Crop moisture levels, hybrid characteristics, lodging, temperature, and field variability can all affect combine performance. Operators are encouraged to make one adjustment at a time and evaluate the results before changing another setting.
Modern combines increasingly rely on automation technologies that use sensors to monitor grain loss, grain quality, machine load, and throughput. These systems can help optimize performance, but specialists stress that they should complement, not replace, operator observations.
Farmers are still encouraged to periodically leave the cab, inspect grain samples, and check losses behind the machine.
4. Make Yield Data Accurate and Actionable
Harvest is one of the most important data collection periods of the year.
Yield maps influence future decisions on fertility programs, variety selection, variable-rate planting, and other management strategies. However, Iowa State experts caution that yield maps are only as valuable as the data used to create them.
Proper maintenance and calibration of yield monitoring systems are essential. Specialists recommend inspecting sensors, checking grain elevator components, verifying scale accuracy, and completing multi-point calibrations whenever possible.
They also note that grain takes time to move through the combine before reaching yield-monitor sensors. Failure to account for those timing delays can create inaccuracies that distort yield maps and affect future management decisions.
A visually appealing map, they say, is not necessarily an accurate one.
5. Remember That Next Year's Crop Starts at Harvest
Residue management remains a critical but often overlooked part of harvest operations.
The Iowa State team stresses the importance of distributing residue evenly across the full width of the header. Uneven residue can create cooler, wetter conditions that influence spring field operations, seed placement, emergence, and crop uniformity.
As headers and combines continue to increase in size, residue distribution becomes even more important. If farmers must choose between finely chopped residue and uniform spreading, specialists recommend prioritizing even distribution.
Proper residue management can improve field conditions heading into next season and help support more consistent crop establishment.
A Simple Harvest Routine
Iowa State University experts suggest incorporating a straightforward routine throughout harvest:
- Check pre-harvest losses
- Evaluate header losses
- Inspect losses behind the combine
- Monitor grain quality
- Adjust one setting at a time
- Verify yield monitor accuracy
- Assess residue distribution
The overall objective is not simply harvesting more acres per hour. Instead, specialists encourage farmers to find the right balance between capacity, grain retention, grain quality, data accuracy, and residue management.
With grain prices remaining under pressure in many markets, reducing harvest losses may offer one of the most immediate opportunities to protect farm profitability.
For many producers, the experts say, the work of establishing the 2027 crop effectively begins with the performance of the combine in the field this fall.
Photo Credit: John Deere