Rainfall Sunday night totaled more than 5 inches in parts of south central and eastern Nebraska. Soils became saturated, resulting in flooding and ponding. Other areas of Nebraska’s corn growing area need rain.
According to the National Agricultural Statistics Service (NASS) Nebraska Crops Progress and Condition Report, 77% of the state’s corn had been planted as of May 11, with 18% having emerged.
- Smaller seedlings are more susceptible than larger seedlings.
- The effect of standing water on germinating seeds is not well known.
- Some hybrids will probably respond better than others, yet differentiating among poor and good hybrids is not possible due to limited data.
- A germinating seed is a living organism and as such requires oxygen to survive.
- In flooded soil conditions, the oxygen supply will become depleted within approximately 48 hours.
- Cool air temperatures help to increase the possibility of survival.
- Yet, we would not expect survival of germinating seeds to be greater than that of young plants; they should not be expected to survive more than four days.
After the waters recede, confirm plant survival by examining the color of the growing point of the seedlings if present. The radicle (root) and coleoptile (shoot) should appear white or cream colored. Seeds could be cut in half to determine if turgor pressure is still present. If the seed is extremely soft and does not hold form, it probably will not survive. Surviving plants will resume growth within three to five days after the water recedes.
A decision to replant should be made only after assessing stands and considering the economics of replanting or converting the acreage to soybean or another crop. For example, corn planted prior to May 15-25 may yield about 87% of corn that was already planted at 35,000 plants per acre if diseases and insects do not affect the replanted seed or seedling. On the other hand, a stand of 20,000 plants per acre planted before May 15 that survived flooding could yield about 85% of corn planted the same time that has 35,000 plants per acre. Replanting in this example may be hard to justify.
If stands are extremely poor, consider replanting; be aware though that conditions can quickly change with several good days of weather.
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