Recent rains have caused a lot of ponding in low lying areas of the fields. What effects would ponding or flooding have on corn plants? Below are some facts:
• Under flooded conditions plants can’t breathe and 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 is affected.
• Duration of ponding or flooding is critical. Cooler temperatures after flooding will help the survival of the young plants. Warmer temperatures above 75-80 degrees F following flooding can kill the plants.
• Corn plants which are partially submerged may continue breathing, photosynthesizing and living. Obviously, the longer they are under water, the lower their survival rate.
• 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 from the flooded areas.
• 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.
• 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. Replanting may be necessary if there is significant stand loss.