Reduce Damage After Flooded Corn Field or Soybean Crop During Harvest

The unpredictability of the weather from one year to the next might be the only thing you can predict in crop production. At times, you pray for rain, and at others, you hope it will stop. Excessive soil moisture can have a cascading effect on plants, stunting their growth, leaching away essential nutrients and leaving them struggling to access oxygen.

In soybeans, flooding can reduce yields by almost two bushels per acre every day that soils are continuously saturated after V4, and yield losses can be even higher during R3-R5.¹ Additional losses can be caused by pod shattering, seed sprouting or fungal growth.² Corn is similarly vulnerable, especially when low nitrogen availability coincides with flooding at the V6 stage, where just 24 to 96 hours of saturated soil can reduce yields by as much as 30%.
While you can’t control the weather, there are several things you can do to reduce flood damage in your fields and prepare for any future unpredictable weather events.

Four ways to reduce water damage in corn and soybeans

Variety selection

When evaluating your seed options before planting, consider whether available varieties have any genetic tolerance to waterlogging. Several soybean varieties can withstand four days of saturated soils with minimal impact on yield.³ Additionally, look for corn hybrids that have stronger stalks and roots to resist lodging and that are less susceptible to fungal pathogens like Phytophthora or Fusarium root rots.
If you end up with a flooded soybean field or flooded corn field this season or next, these varieties can protect your yields until the waters recede.

Seed treatments

The right seed treatment can be a reliable line of defense against the effects of flooding that could ruin your harvest. These seed treatments primarily prevent fungal pathogens, such as Pythium and Phytophthora, from becoming a serious problem during wet conditions.
Corn or soybeans planted during early spring into cool, wet soils, especially in previously flooded corn or soybean fields, can provide the perfect breeding grounds for fungi. A fungicide seed treatment can actively work against these pathogens in the soil. However, not every fungicide works against every fungal pathogen. You’ll need to conduct your due diligence to determine the types of pathogens your fields typically harbor and which seed treatments will be most effective against those pathogens.⁴

Field management

If you frequently battle flooded fields, it may be best to invest in a more effective drainage system. These systems might be channels or ditches to redirect surface water away from your fields or a subsurface solution such as tile drainage.
Flooded corn fields or flooded soybean fields with heavy clay soils can benefit from either type of drainage; however, tile drainage can often improve soil aeration, enhance root growth and increase nutrient uptake.
While drainage systems help move excess water off the field, crop rotation complements that effort by improving soil health and reducing disease pressure. By rotating between two, three or even four crops, you can break the pathogen cycle and reduce the incidence of soilborne diseases.

Nutrient management

Flooding can significantly impact soil nutrients, particularly nitrogen. Leaching, runoff and denitrification can deprive plants of the nutrients they need to maximize their yields.
For corn, maintaining a higher baseline level of soil nitrogen can help buffer against the losses caused by flooding. This is especially important during the early vegetative stages, when plants are preparing for key growth phases.⁵ Plan to apply adequate pre-plant nitrogen and, if necessary, supplement it through side-dress applications to enhance crop resilience and minimize the risk of yield loss.
In soybeans, the situation is a little different. While soybeans typically fix their own nitrogen, flooding can damage root nodules and impair nitrogen fixation. Research suggests that supplemental nitrogen applied after flooding can provide a limited rescue effect if applied under the right conditions.⁶ However, it’s not a guaranteed fix. If the soybeans are already forming pods or if root health is severely compromised, the benefit may be minimal.
Flood damage can’t always be avoided, but careful variety selection, seed protection, field drainage management, and nutrient planning can help preserve yield potential when more than enough rain comes. By anticipating these risks and managing them proactively, you give your crops and your bottom line the best chance to recover.

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.

________________________________________________

Endnotes

1. Edwards, Laura. “Chapter 50: Seasonal Hazards.” iGrow Soybean: Best Management Practices, South Dakota State University Extension, Mar. 2020, extension.sdstate.edu/sites/default/files/2020-03/S-0004-50-Soybean.pdf.
2. Conley, Shawn, and Grover Shannon. “Assessing Flood Damage to Soybean.” Insect and Plant Disease Diagnostic Clinic Blog, University of Wisconsin–Madison, 20 June 2013, ipcm.wisc.edu/blog/2013/06/assessing-flood-damage-to-soybean/.
3. Sullivan, Tina, Rodrigo Onofre, and Chandler Day. “Soybean Response to Standing Water and Saturated Soils.” Agronomy eUpdates, Kansas State University Research and Extension, 22 May 2025, eupdate.agronomy.ksu.edu/article/soybean-response-to-standing-water-and-saturated-soils-642-1.
4. Dorrance, Anne. “Seed Treatments for Watermolds and Fungi That Affect Soybean in Ohio.” Corn Newsletter, Agronomic Crops Network, Ohio State University Extension, 18 Jan. 2017, agcrops.osu.edu/newsletter/corn-newsletter/2017-1/seed-treatments-watermolds-and-fungi-affect-soybean-ohio.
5. Thomison, Peter R., and Allen Geyer. Effects of Flooding and Ponding on Corn. AGF-118-95, Ohio State University Extension, 6 Mar. 2017, ohioline.osu.edu/factsheet/agf-118.
6. Gaska, John, Spyros Mourtzinis, and Shawn Conley. “Can Nitrogen Rescue a Flooded Soybean Crop?” Soybean Research and Information Network (SRIN), 3 Feb. 2025, soybeanresearchinfo.com/research-highlight/can-nitrogen-rescue-a-flooded-soybean-crop/.