Corn Illustrated Weekly: Drought Damage Assessment Is Tricky Business

Ear diameter biggest question mark.

Published on: Jul 23, 2007

If you want to get a glimpse of how well your corn hybrids survived the dry weather in May through late June that gripped parts of the Midwest, here's a tip. Head to several of your cornfields and pull back some shucks. Count the number of rows, or rings, around the ear. Be sure you know the typical number of rows per ear for each hybrid before you check.

Bob Nielsen, Purdue University corn specialist, agrees it's a key item to check. He's getting variable reports across the region as to whether the number of rows per kernel of ear are down this year or not. Obviously, in the hardest-hit drought areas, number of rows does seem to be down for any given hybrid. In other areas where rainfall has been near normal or even above normal- yes, there may be a spot or two (more like a dot or too in the eastern Corn Belt), numbers of rows per ear are normal.

In the western Corn Belt where conditions were much better earlier in the season, Nielsen would not expect a problem in number of rows per ear. Farm Progress sources report that Nebraska was very good early, with plenty of rain. There was a dry-out, but not until two to three weeks ago.

There is great variability normally in the number of rows of kernels per ear between hybrids, says Dave Nanda, a plant breeder and consultant for the Corn Illustrated project. Counts may typically range from 16 to as many as 22 rows of kernels per ear. There still may be some hybrids out there that typically put on only 14 rings of kernels, but the most advanced hybrids seem to lean toward a higher number of rows.

The problem with drought early in the season is that the corn plant determines how many rows per ear it will set relatively quickly, soon after the growing point is above ground. Most people look for the first factor in yield, the number of rings of kernels per ear, to be determined around the V6 to V 8 stage. That means there are six to eight leaves with leaf collars visible on the plant. In many area, what rain has fallen so came largely after that time.

Jim Facemrie, host farmer for the Corn Illustrated Plots, Edinburgh, Ind., checked a few ears within the past few days. He shucked one ear only to find 14 rows on a hybrid that typically has more rows than that.

However, that doesn't single a crop disaster. Ear length also comes into play, if conditions are better then, it's too late to change number of rows on the ear, but the cob cam be longer, with more kernels pollinated and filled. Still later, if conditions are favorable with plenty of rain, the ear can compensate again and pack more starch and other plant matter.

If you haven't walked your field, now might be a good time to do so.