If you had corn planted when the weather turned cold last week, you might want to keep a close eye on it, says Nathan Mueller, South Dakota State University Extension agronomist.
Corn is particularly sensitive to low-temperature stress (temperatures below 50 degrees F) during germination, emergence, and seedling stages. Soil temperature readings can be found at the South Dakota Climate and Weather website.
Cold temperature stress on early planted corn this year will be affected by two major mechanisms depending on planting date, Mueller says. The first mechanism is imbibitional chilling injury and cold stress. Corn planted over the weekend (April 26-27) could have had cells ruptured during the uptake or imbibing of cold water, which can lead to nonviable swollen kernels and aborted growth of the radicle (root) and coleoptile (shoot).
On earlier plantings, corn still in the emergence process could have experienced stunting, seminal root system death, deformed mesocotyl elongation, and possible leafing out underground. The second mechanism is delayed and uneven emergence.
It takes 12 days even at soil temperatures near 57 degrees F for corn to germinate and emergence.
If you had corn seed in the ground, he suggests these steps:
•Make a list of the planting date for each field.
•Determine what hybrids were planted where.
•Use planter monitor data or hand written notes to determine response of individual hybrids.
•Talk with your seed representative(s) to determine what differences exist between hybrids you •planted for "stress emergence" scores.
•Scout fields more frequently, either by you or a consultant.
•Evaluate the need to replant. Talk with insurance agents and others before replanting.
For more information about cold temperatures and corn chilling injury, contact Mueller at 605-688-421.Source: SDSU