How to Minimize Field Losses Before and During Harvest

Before Harvest: Pre-Harvest Management

Pre-harvest losses can result from weather, prolonged field exposure, stalk deterioration, lodging, ear drop, and pod shatter. Scouting fields before harvest and using grain moisture, crop condition, and potential for additional loss to establish harvest priorities can help minimize losses before the combine enters the field.

Monitor Grain Moisture and Crop Maturity

Monitor grain moisture and physiological maturity closely. In corn, black layer indicates physiological maturity and the end of dry-matter accumulation in the kernel. As corn dries down in the field, continue monitoring stalk quality and ear retention because lodging, ear drop, and harvest losses can increase with delayed harvest.

In soybeans, excessively dry conditions can increase pod shatter and header losses. Harvesting within an appropriate moisture window can help reduce shattering while maintaining grain quality and avoiding unnecessary moisture-related handling or storage problems.

Check Stalk Strength and Crop Condition

In corn, perform push or pinch tests to evaluate stalk integrity. Prioritize fields with stalk rot, weakened stalks, lodging risk, or poor ear retention in the harvest schedule. Moving vulnerable fields earlier can reduce the risk of additional field losses as harvest progresses.

Prepare Clean Storage and Equipment

Before harvest, thoroughly clean bins, trucks, augers, combines, and other grain-handling equipment. Removing old grain and foreign material helps reduce grain carryover, weed-seed movement, stored-grain pest problems, and potential grain-quality issues.

During Harvest: In-Field Adjustments

Mechanical losses can occur at the header, threshing, and separating systems. Check losses regularly and make adjustments based on crop conditions, field variability, and the combine manufacturer's recommendations.

Inspect and Maintain the Header

For soybeans, maintain a sharp cutterbar and properly adjusted guards, hold-downs, and reel. As a starting point, reel speed is commonly set approximately 10–25% faster than ground speed, then adjusted according to crop conditions. Reduce reel speed if excessive reel action is increasing pod or bean shatter.

For corn, focus on proper stalk-roll speed, gathering-chain operation, deck-plate spacing, header height, and ground speed. Proper header adjustment helps minimize ear loss and maintain consistent crop feeding into the combine.

Manage Lodged or Leaning Crops

When harvesting lodged crops, reduce ground speed as needed and, where practical, make passes against the direction of crop lean. In severely lodged soybeans, ground speeds around 2.5–3.0 mph may be appropriate, depending on field conditions and combine performance. Adjust reel speed and position as necessary to gather lodged plants without increasing pod-shatter losses.

For lodged corn, slowing down and harvesting against the direction of lean can improve ear gathering and reduce header losses.

Match Ground Speed to Crop Flow

Adjust travel speed according to yield, crop condition, and field variability. The goal is to maintain sufficient crop flow through the threshing and separating systems without overloading the combine. High-yielding areas may require slower ground speeds, while lower-yielding areas may allow faster travel without sacrificing threshing or separation performance.

Measure Actual Field Loss

Don't rely on appearance alone—measure losses in the field.

After the combine has harvested a representative section, stop and back up approximately 15–20 feet to expose the harvested area. Use a measured sampling area appropriate for the crop and loss being evaluated, and count the kernels, seeds, pods, or ears remaining on the ground.

For corn, approximately two kernels per square foot represent one bushel per acre. For soybeans, the conversion depends on seed size: roughly three to five seeds per square foot can represent about one bushel per acre, with four seeds per square foot serving as a reasonable rule of thumb for medium-sized beans.

Whenever possible, also measure pre-harvest loss in an unharvested area. Comparing pre-harvest losses with the amount remaining behind the combine helps distinguish crop-related losses from losses caused by the harvesting equipment and can indicate whether adjustments are needed at the header, threshing, or separating systems.

Regular scouting, accurate loss measurements, and timely combine adjustments can help protect yield and improve harvest efficiency throughout the season.

If you have any tips or feedback, we would love to hear them in the comments!

For more information on preventing field losses before and during harvest, explore these resources:

• https://nuseed.com/us/prevent-grain-loss-and-breakdowns-before-harvest-for-a-successful-harvest/

• https://www.sound.ag/blog/how-to-optimize-your-harvest-timing

• https://extension.psu.edu/preparing-grain-storages-for-harvest

• https://crops.extension.iastate.edu/post/corn-drydown-and-stalk-quality

• https://cropwatch.unl.edu/2023/how-estimate-harvest-losses-soybeans-and-corn-fields/