Stalk lodging and ear drop impact corn yields

By Peter Thomison

(The following is reprinted from the OSU Extension C.O.R.N. newsletter for Oct. 30-Nov. 6.)

COLUMBUS — The heavy rains and strong winds (plus snow in some areas) forecast this week increase the potential for stalk lodging and ear drop, which could impact yields and slow grain harvest.

The loss of one “normal” sized ear per 100 feet of row translates into a loss of more than one bushel/acre. An average harvest loss of two kernels per square foot is about 1 bu/acre.

According to an OSU agricultural engineering study, most harvest losses occur at the gathering unit with 80 percent of the machine loss caused by corn never getting into the combine.

In the past, European corn borer tunneling through ear shanks played a major role in causing ear drop. The widespread planting of Bt ECB resistant hybrids has minimized this problem.

Drought stress issues. Reports of ear drop this year have been associated with drought stress and specific hybrid genetics. Drought stress and high temperature conditions resulted in premature ear shank deterioration that promoted ear drop.

Certain hybrids are more susceptible to ear drop under such stress. In an OSU research study conducted at 10 locations in 2011 and 2012 involving a comparison of three hybrids, we observed no ear drop in 2011, whereas in 2012 year ear drop was readily evident in one of the three hybrids at all locations.

In order to minimize ear drop losses in problem fields, some seed companies are recommending that farmers run their corn head as high as possible while adjusting ground and header speed for maximum ear retention.

Header height. Operating the corn header higher than normal may reduce the loss of ears flying out of the header during harvest. Fields exhibiting ear drop and stalk lodging should be harvested promptly. The presence of ear drop and stalk lodging probably outweigh economic benefits of field drying.

By late October to early November, field dry down rates will usually drop to 1/4 – 1/2 percent per day and by mid-November, probably 0 1/4 percent per day. By late November, drying rates will be negligible.