By Blake Jackson
Excessive rainfall across parts of Kentucky has left many soybean fields flooded, creating conditions that can significantly reduce crop performance. According to Dr. Mohammad J. Shamim, UK Extension Associate Grain Crops, flooding limits oxygen in the soil, preventing roots from functioning properly even when water is plentiful.
When soil becomes saturated, air pockets fill with water, leaving soybean roots without enough oxygen to produce the energy needed for nutrient uptake, growth, and water absorption. As flooding continues, root systems weaken, nodules become less effective, and plants struggle to recover.
Flood stress affects soybeans in several ways. Plants often experience reduced photosynthesis, slower growth, yellowing leaves, poor root development, and fewer pods. If plants remain completely submerged, photosynthesis and gas exchange stop entirely, causing severe stress that can lead to significant yield losses.
The timing and duration of flooding play a major role in determining crop damage. Soybeans in the reproductive stages, particularly during flowering and early pod development, are much more vulnerable than those in vegetative growth.
Fields with poor drainage or heavy soils also tend to suffer greater losses because water remains longer around the roots.
In addition to flooding, Kentucky is experiencing extended periods of high temperatures. Heat stress further reduces photosynthesis and increases the risk of flower, pod, and seed abortion, especially in soybeans already weakened by saturated soils.
Although recent rainfall has temporarily improved soil moisture, damaged root systems may struggle to access water once fields begin drying, making crops more susceptible to drought stress later.
Because every field differs in soil type, drainage, and crop stage, neighboring fields can respond very differently to the same rainfall event. Careful scouting after flooding is essential for accurately assessing crop recovery and planning future management decisions.
Key Steps for Recovery:
- Wait 3-7 days after floodwaters recede before evaluating fields.
- Check for healthy growing points and new leaf growth as signs of recovery.
- Scout regularly for foliar diseases, especially during the R1-R3 growth stages.
- Consider fungicide applications only when disease pressure is present and crop stage supports an economic return.
- Monitor seed production fields more closely to protect seed quality.
- Watch double-cropped soybeans and poorly drained fields for soilborne diseases such as Phytophthora root and stem rot.
- Consult University of Kentucky recommendations and local crop specialists before making fungicide or disease management decisions.
Photo Credit: gettyimages-kotenko-a
Categories: Kentucky, Crops, Soybeans, Weather