Response to early season frost injury

Name and Position/Title:  
John Holmes, Extension Field Agronomist, and Dr. Roger Elmore, Extension Corn Specialist

Fiscal Year Submitted: 

POW Title and Number: 
101 Corn and soybean production

Response to early season frost injury

On May 9th early morning temperatures dropped to 29o F in north central Iowa.  Many farmers had planted early and already had corn in the V4-V5 stage.  This corn was seriously injured by the frost.  Farmers and agronomists needed to know how to assess the injury and whether or not to re-plant the fields that received injury.

What Did You Do?  
The first step was to provide interviews to KGLO, KWMT, WHO, and smaller radio stations in the area to discuss the injury and provide scouting tips.  The May 10 and May 17 issues of CROP HAPPENINGS newsletter discussed the frost injury and the potential for recovery.  More than 25 farmers called and discussed frost injury over the phone from May 10 through May 20.  Eight field visits were made to inspect fields that did not seem to be recovering.   A field meeting was held near Duncombe in cooperation with a local Pioneer Hi-Bred Seeds dealer on May 18.  Approximately 40 persons attended.  Agronomists from Pioneer and from ISU Extension spoke and worked with farmers individually to assess injury and determine recovery potential. 

Plants were marked and recovery progress was monitored in a field near Kanawha.  Dr. Roger Elmore, Extension Corn Specialist, also staked plants and monitored their recovery in a field near Story City.  He rated the injury and followed the plants through harvest.  His findings were presented at the Crop Advantage Series meetings in Ames, Mason City, and Fort Dodge.

Results:  As a result of the programming, farmers learned how to evaluate fields for recovery from frost injury.  They used the information we provided to make re-plant decisions.  In three instances farmers had initially planned to re-plant fields but chose to allow them to continue to recover after a field visit by John Holmes.  A total of approximately 100 acres was evaluated.  Those fields recovered and yield an average of 185 bushels per acre.  Re-planted corn would have yielded approximately 120 bushels/acre.  Six thousand five hundred (6500) bushels more corn was produced on these fields as a result of the field visits.   Using a corn price of $5/bushel, the value of the increased production was $32,500 on only one hundred acres.  Many other farmers evaluated their fields individually and allowed their fields to recover.  Two fields visited by John Holmes were determined to be too seriously injured to recover; therefore, these fields (30 acres) were re-planted to soybeans.  Both attained excellent soybean yields.

Information from Dr. Roger Elmore’s presentations greatly increased understanding about frost recovery of corn.  His information indicated that corn does not always recover when injured by frost.  Sixty-one responses were received from persons attending his presentations at three Crop Advantage Series meetings in January, 2011.  Forty-nine percent (49%) of those responding rated his talk as excellent; and forty-one percent (41%) rated his presentation as good. 

Page last updated: June 22, 2011
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