How standing water affects fields and yields.
Agronomy Bulletin 97 ─ Flooded Corn
Flooding affects fields differently based on a variety of factors. Manage flooded corn to minimize damage and ensure optimum plant health and yields.
Factors to Consider
- Growth stage
- Root development
- Nitrogen availability
- Air temperature
- Scouting fields
- Consider plant growth stage. Young corn that has not reached the V6 stage is most susceptible to flooding damage and typically can survive flooded conditions for only up to four days. When flooding occurs, there is less oxygen available in the soil. Without oxygen, the corn plant cannot uptake the nutrients and water essential for its survival.
- Understand root development. Excess moisture during the early vegetative stages also can slow down corn root development. If a dry summer follows the flooding period, the plant is unlikely to survive because its root system is not developed enough to access soil moisture.
- Be aware of air temperatures. If air temperature is 75 F or warmer, corn plants are unlikely to survive longer than 24 hours in flooding situations. The warmer temperatures decrease the amount of oxygen in the soil, making it even harder for oxygen to reach the corn plant. Cooler temperatures keep the oxygen available in the soil and can prolong the life of the plant up to four days.
- Monitor for diseases. Corn that survives flooding is at higher risk of diseases such as pythium, corn smut and crazy top. The best disease prevention is to scout flood-affected fields closely, as they may need to be harvested early and at higher moisture levels to reduce yield losses.
- Apply nitrogen. Nitrogen (N) loss is often a result of prolonged ponding or saturated fields. It is important that N-deficient areas are detected early so supplemental N can be sidedressed as soon as possible.
- Scout fields. In addition to scouting for disease and nitrogen loss, closely monitor corn that has been fully submerged to assess plant survival. After flooding, split the stalks and visually examine the lower portion of the stem. It should be white to cream-colored. A darkening or softening of the tissue often precedes the plant’s death. If the corn has not yet emerged, a sign of survival is continued leaf growth three to five days after the water drains.
Cornfields can survive up to four days of flood conditions, depending on various factors. It is important to scout fields regularly for disease, N loss and overall plant health. If there is extreme damage, talk to your agronomist about replanting. For more information, contact your local Mycogen Seeds customer agronomist or trusted agronomic adviser.