The Effect of Drought Stress on Soybeans, with Management Strategies

Drought conditions before and during harvest can have severe consequences for your soybean crop. Drought can cause substantial yield reductions, especially during R4 to R6 growth stages, reducing both seed quality and your income.
Drought damage can result in smaller and lower-quality seeds, and cause problems such as pod shattering and compromised grain composition. All of these issues can significantly diminish the market value of your crop.

Learn about the effects of soybean drought stress, understand the financial consequences of leaving drought conditions unchecked and explore ways to mitigate drought stress on soybeans through practices such as planting drought resistant crops.

Agronomic and economic effects of soybean drought stress

Late-season drought stress, particularly from full-pod stage of R4 through full-seed stage of R6, can hurt yield most.¹
Late-season drought can cause:

• Up to 20% less pod production as a result of flower and pod abortion
• An average seed protein increase of 4%, and a seed oil decrease of 2%²
• Early plant death in the most severe cases
• Pod shattering during harvest
• Seeds sprouting within pods when rainfall follows drought stress

You won’t be surprised to learn that the negative effects of soybean drought stress can hit your bottom line hard, leading to:

• Potential loss of some crop insurance protections if drought mitigation practices aren’t properly implemented
• More volatile prices
• Increased irrigation costs, if irrigated

Ideal soybean harvest moisture to reduce harvest loss

First, it’s important to know the ideal soybean harvest moisture as well as moisture levels at different soybean growth stages approaching harvest³

(Kelley, Kenneth W., and Ignacio A. Ciampitti)

Soybean seed quality is generally optimal when the crop is harvested at about 13% moisture, though you should always make a harvest plan with your trusted adviser to ensure you account for regional harvesting conditions. University research has found that harvesting outside of this moisture level can cost you. That’s especially true in a drought, when sub-13% moisture can knock even more cents per bushel off your crop compared to if your crop is too moist.⁴

Practices to mitigate soybean drought stress

Now that you know what to aim for in terms of harvest moisture, it’s time to turn to specific practices and strategies that can optimize yield even during a drought.

1. Implement water conservation techniques

In times of limited rainfall, adopting conservation tillage such as no-till or minimum till can keep moisture in your soil. Planting cover crops can similarly support this goal and cut back on evaporation of ground water.
If some or all of the farmland you manage is irrigated, consider investing in efficient equipment and technologies such as variable-rate irrigation, which can optimize water-use efficiency.⁵

2. Adjust planting and harvesting schedules

Adjustments to your planting and harvest schedules can mitigate potential drought risks such as limited soybean harvest moisture.
For example, earlier planting dates can help your crop establish deeper root systems that can withstand potential drought conditions.
Another approach is to plant several different varieties of soybeans with varying relative maturities. This can help spread your risk across the growing season, enabling you to harvest some crops early, ahead of the most severe drought conditions.
Finally, if you find yourself in the thick of a late-season drought, look to harvest remaining soybean fields as quickly as possible to limit the risk of damage to crop health (and your bottom line).

3. Select varieties of drought resistant crops

If you operate in a drought-prone area or you have reason to believe drought is possible in the coming season, work with your trusted adviser to select seeds with soybean drought tolerance. These seeds have been developed to function in water-minimal environments.⁶
You can also consider planting in narrow rows. This encourages more rapid canopy development, which shades more surface area and helps to limit water evaporation.

4. Modify your combine to harvest drought-stressed soybeans

If drought compromises your soybean crop quality, you might need to make a few combine adjustments. This can include slowing down your harvesting speed to accommodate for weak or lodged plants. You might need to make subtle adjustments for harvesting smaller-than-normal soybean plants, such as decreasing concave clearance, adjusting rotor speed or narrowing the openings of sieves. Double-check your insurance policy for risks such as combine fires amid dry conditions and ensure you’re following any recommended or required protocols to limit fires.⁷

5. Adapt bin storage to accommodate dry soybeans

Be careful about over-conditioning of dry soybeans once they are placed in your bins. Already-dry soybean grains can expand in storage. That can damage your bin and even void bin warranties.⁸
Work with a trusted adviser to determine how to safely store your soybeans to maintain crop quality and economic viability.

Experts are available to help you make your soybean harvest decisions amid drought conditions. 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. “How Drought Affects Corn and Soybean Growth and Yield.” No-Till Farmer, 14 June 2023, www.no-tillfarmer.com/articles/12564-how-drought-affects-corn-and-soybean-growth-and-yield. Accessed 21 Apr. 2025.
2. “Physiological Response of Soybean to Drought Stress.” Scientific Reports, Nature, 2023, www.nature.com/articles/s41598-023-28354-0. Accessed 21 Apr. 2025.
3. Kelley, Kenneth W., and Ignacio A. Ciampitti. Soybean Growth and Development. Kansas State University Agricultural Experiment Station and Cooperative Extension Service, 2017, https://bookstore.ksre.ksu.edu/pubs/soybean-growth-and-development-poster_MF3339.pdf. Accessed 21 Apr. 2025.
4. Swartz, Mike. “Harvest Considerations for Overly Dry Soybeans.” Michigan State University Extension, 27 Sept. 2023, https://www.canr.msu.edu/news/harvest_considerations_for_overly_dry_soybeans. Accessed 24 Apr. 2025.
5. “Soybean Irrigation.” Soybean Research & Information Network, www.soybeanresearchinfo.com/agronomics/soybean-irrigation/. Accessed 21 Apr. 2025.
6. Glewen, Richard, et al. “Drought Effect on Corn and Soybean and Alternative Management Considerations.” Integrated Crop Management News, Iowa State University Extension and Outreach, 21 July 2023, https://crops.extension.iastate.edu/post/drought-effect-corn-and-soybean-and-alternative-management-considerations. Accessed 21 Apr. 2025.
7. Hanna, Mark, and Greg Brenneman. “Combine Settings for Drought.” Integrated Crop Management News, Iowa State University Extension and Outreach, 21 Aug. 2012, https://crops.extension.iastate.edu/cropnews/2012/08/combine-settings-drought. Accessed 21 Apr. 2025.
8. Hellevang, Kenneth J. “Considerations When Conditioning Too-Dry Soybeans.” North Dakota State University Agriculture, https://www.ndsu.edu/agriculture/ag-hub/ag-topics/crop-production/drying-storage/considerations-when-conditioning-too-dry-soybeans. Accessed 21 Apr. 2025.