Flat corn in eastern Iowa

July 7, 2016 9:51 AM
Blog Post

Storms hit eastern Iowa yesterday, bringing variable amounts of rainfall and enough wind to blow some corn down. The damage seems to extend across multiple counties, but I witnessed many fields with varying amounts of damage in Linn and Jones counties.



Corn lying flat in Jones Co
Corn blown over near Langworthy, IA on July 6, 2016. Photo by Meaghan Anderson.

It was very interesting to see some fields completely unaffected while others were lying almost completely flat. Damage seemed to be related to hybrid and corn growth stage, along with other environmental conditions affecting the damage. Corn appeared to have three responses to this wind:


  1. the upper part of the corn canopy leaning
  2. root lodging - corn plants lying on the ground with roots pulled out of the ground
  3. greensnap - corn plants broken over

Tasseled corn leaning over in Jones Co
Tasseled corn leaning over in Jones county on July 6, 2016. Photo by Meaghan Anderson.

Plants leaning or root lodged should stand back up with relatively little issue, given some good growing conditions in coming days. There may be yield loss associated with the root lodging; research shows it to be in the 0-30% range up to corn stage R1 (50% of plants silking). Yield losses are generally greater closer to R1. Read more about lodging effects on yield here. Expect that harvest may be slow in areas where corn plants have lodged.


Greensnap is a bigger concern. I saw very little during my windshield tour but those scouting fields will likely discover some. Greensnap results in more clear effects on yield. With a 10% loss of plants due to greensnap, we see about a 10% loss in yield. This is because most corn plants have finished determining potential ear size, leaving them unable to compensate for stand loss at this point in the season. Read more here.

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Meaghan Anderson Field Agronomist in Central Iowa

Meaghan Anderson is a field agronomist in central Iowa and an extension field specialist at Iowa State University Extension and Outreach. Educational programming is available for farmers, agribusinesses, pesticide applicators, certified crop advisors, and other individuals interested in...