Carrie Knott, Extension Agronomist-Princeton, University of Kentucky
Most of Kentucky is dealing with some sort of record: record low temperature, record snowfall amounts, record windchills. We hope our wheat crop is safe because the snowfall has provided much needed insulation. However many fields in western Kentucky had begun to ‘green-up’ prior to these chilly conditions. Once we begin to thaw out and get consistent warm weather we will need to assess the damage.
To determine if freeze damage has occurred to the wheat, wait until there has been at least 4 days above 40°F. If you inspect before this occurs you may not get a clear picture of the damage because until temperatures reach at least 40°F they are essentially in a ‘refrigerator’ and damage cannot be detected. Be patient, this time of year it may take several weeks before conditions warm up.
Once conditions warm up, inspect a representative area of your field for yellowing and plant death. Pay particular attention to yellowing of the growing point and limp leaves. In most situations 70 to 100 live tillers per square foot will produce acceptable yields. If tiller counts are 50 live tillers per square foot or less then yield reductions of up to 40% may occur. If they are between the 50 and 70 live tillers per square foot then the higher N recommendations of 120 lbs N/A should be considered for the Feekes 5 application.
An additional concern for wheat stands and yield potential is heaving. If extreme temperature changes occur the freezing and thawing cycle may push wheat plants out of the soil. This will result in reduced stands and could ultimately affect yield if heaving occurs on a large percentage of the field.
For now, wait for warmer temperatures before assessing wheat freeze damage.