Flooded Corn Fields

DR. ANTHONY OHMES

JACKSON, MO.
   Following the rain, corn fields may be experiencing some ponding soil conditions. The concern with flooding or saturated soils is oxygen depletion. Small seedlings are most vulnerable and information on germinating seeds is limited. In either case, survival will be dependent on length of flood, air temperatures, and in the case of germinating seeds to some level – corn hybrid. Germinating and emerging corn requires oxygen. Soil oxygen in flooded fields is depleted within approximately 48 hours. In general, air temperatures below 77 degrees F will aid in survival during the flooded period of time. Research indicates emerged corn, prior to 6th leaf stage, can survive up to 4 days when air temp is less than 77 degrees F. As air temps increase, this time period can be reduce from 4 days to 1 day. In addition to oxygen depletion, concerns associated with flooding are seed rots, seedling blights and crazy top.
   Once water recedes, growth will resume approximately within 3 to 5 days, this is the time to begin evaluating corn stand and    plant survivability. Healthy radicle root and coleoptile should be white to cream color. Conduct stand counts and utilize replant decision guides to make a determination whether to keep the existing stand. Refer to MU guide 4091: “Corn and Soybean Replant Decisions” at the following link: http://extension.missouri.edu/p/G4091 for more information. ∆
   DR. ANTHONY OHMES: Agronomy Specialist, University of Missouri