Prevent Soybean Shattering: When to Harvest Soybeans to Mitigate Damage

Soybean shatter loss adds up: Dropping only four seeds per square foot will cost you one bushel in every acre.¹

Responsible for yield losses up to 100% in severe cases², soybean shatter is closely tied to moisture content. As soybean moisture decreases, the likelihood of pod shatter increases. Discover how soybean harvest moisture and other factors contribute to shatter loss — and learn how to plan accordingly.

Causes and exacerbating factors of soybean shatter loss

A variety of factors play into soybean shatter risk, with weather conditions and insect damage chief among them.

Weather conditions and moisture levels

The optimal soybean harvest moisture range is 13-15%. At 13% moisture content, risk of shatter-related yield loss is low, around 1 to 2% loss.³ But below 11% moisture, soybean shatter loss can become more significant. In one study, researchers documented up to 8% loss when soybean moisture content drops to 9%.⁴

Alternating wet and dry weather patterns increase the risk of pod shatter if soybeans have already dried down to 13% and are then rehydrated with precipitation. Growing-season soybean drought and high temperatures at harvest time weaken pods and increase shatter risk. Alternatively, wetting and freezing patterns in soybeans harvested after the first snow can split pods and shatter seeds. Wet pods can also cause plant material to stick to the grain, impeding grain cleaning. If pods are wet, air temperatures between 27 F and 35 F will hamper grain cleaning the most.⁵

Insect damage

Fields with severe pod-feeding from grasshoppers and bean leaf beetles can face an increased risk of pod shatter. Additionally, late-season spider mite infestations can make pods more brittle and prone to shattering.

How to plan your harvest to reduce soybean shatter loss

Soybean harvest timing and equipment settings play critical roles in reducing the risk of pod shatter.

When to harvest to prevent soybean shatter loss

A key timing issue to reduce shatter loss is the time of day you harvest. Periods of high humidity in early morning and late evening will produce the least amount of shatter loss. If soybeans are already dry (less than 11% moisture), moisture content can drop dramatically and shatter can increase during mid-day, when conditions are hottest and driest.The risk of shatter loss also increases daily for overmature beans still in the field. Selecting soybean varieties with varying relative maturities can help stagger your harvest times and prevent delays.

How to adjust soybean combine settings to reduce soybean shatter loss

In less-than-ideal harvest conditions, it is especially important to maintain optimal soybean combine settings.

• Keep knife blades sharp and tight, and make sure all guards are properly aligned. Ensure hold-down clips keep the knife to within 1/32" of the guards.
• Adjust wear plates so they lightly touch the back of the knife.
• Individual knife sections can be either 1.5" or 3.0". When pods are brittle and at risk of shatter, narrower knife sections may reduce harvest losses by cutting more evenly at higher ground speeds and shaking plants less.⁶
  

Optimal harvest speed to minimize soybean shattering

Improper reel speed and reel position can be responsible for more soybean shatter losses than any other maladjustment.⁷

• Reduce reel speed in relation to ground speed if the reel is throwing beans out of the pods, setting your ground speed to 2.5–3.0 mph. ⁸
• Determining the proper reel speed for your conditions is a judgement call, but in general, using a reel speed about 10% to 25% faster than your ground speed is recommended.

• Position the reel as close to the auger as possible for consistent feeding into the combine.
• Set the height of the reel so that it contacts the top one third of soybean plants⁹
  

While risk of pod shatter increases if the reel turns too fast, stalks may be dropped if the reel turns too slowly. Finding the right balance is key.

Reduce shatter during soybean harvest

Beyond yield loss, shatter can also disrupt crop rotations in subsequent seasons as seeds from shattered pods become volunteer weeds.

Determining the right harvest timing, being conscious of pests and adjusting soybean harvest equipment can help you manage soybean shatter losses, and experts are available to help you make your decisions. Reach out to your seed retailer, a nearby extension office agent or a seed company professional like your regional BASF representative.

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Endnotes

1. “Measuring Harvest Losses in Corn and Soybean.” NDSU Agriculture, 24 Sept. 2021, www.ndsu.edu/agriculture/extension/impact-stories/measuring-harvest-losses-corn-and-soybean. Accessed 7 July 2026.
2. Ndeke, Victoria, et al. “A Review of Factors Affecting Pod Shattering in Soybean (Glycine max).” Research Gate, May 2024, www.researchgate.net/publication/380642297_A_Review_of_Factors_Affecting_Pod_Shattering_in_Soybean_Glycine_max. Accessed 7 July 2026.
3. Lindsey, Laura. “Soybean Pod Shattering and Harvest Moisture.” Agronomic Crops Network, 2017, agcrops.osu.edu/newsletter/corn-newsletter/2017-33/soybean-pod-shattering-and-harvest-moisture. Accessed 7 July 2026.
4. Lindsey. “Soybean Pod Shattering and Harvest Moisture.”
5. Licht, Mark. “Managing Crop Harvest After a Snow.” Integrated Crop Management, 29 Oct. 2019, crops.extension.iastate.edu/post/managing-crop-harvest-after-snow. Accessed 7 July 2026.
6. Staton, Mike. “Reducing Soybean Harvest Losses.” MSU Extension, Sept. 2023, www.canr.msu.edu/resources/reducing-soybean-harvest-losses. Accessed 7 July 2026.
7. Staton. “Reducing Soybean Harvest Losses.”
8. Staton. “Reducing Soybean Harvest Losses.”
9. Anderson, Eric. “Overcoming Soybean Harvest Challenges in 2022 – Lodging and Green Stems.” MSU Extension, Michigan State University, 22 Sept. 2022, www.canr.msu.edu/news/overcoming-soybean-harvest-challenges-shattering-green-stems-and-lodging. Accessed 7 July 2026.