We have seen a lot of corn fields that were flooded in the low-lying areas. How does flooding affects corn plants and what can we do about it?
• Like people, if plants can’t breathe, they can’t survive for long. Flooding interrupts the breathing and photosynthetic processes of plants. Obviously, plants which are completely covered by water are at higher risk than those which are partially submerged.
• Oxygen in the soil also gets depleted within 48 hours of flooding and the plant growth functions like nutrient absorption are affected.
• Duration of ponding or flooding is critical. Cooler temperatures after flooding will help the survival of the young plants. Warmer temperatures above 75 to 80 degrees F following flooding can kill plants.
• Plants older than V6 stage survive better because the growing point is above ground after this stage. If the growing point is still below ground, it may start to rot. Healthy growing points will be whitish and the dead plants will be brownish.
• Ear development may be affected by flooding at V5-V7 stage and kernel size and number may be reduced if flooding occurs after V8 stage.
• Flooding may cause nitrogen leaching and deficiency which can lead to lower yields in the flooded areas.
• If a crust is formed when the soil dries, you may have to use a rotary hoe to help the young plants otherwise plants may be yellowish and stunted.
• Seedling blights may also develop in the poorly drained areas. The fungus which causes Crazy top can enter the leaf whorl and infect the growing point. Fungus which causes smuts may enter the plants through tissues damaged by flooding.