Late-Season Corn Field Checks Could Prove Interesting

You won't know what you have until you pull back shucks.

Published on: Aug 8, 2011

Jim Facemire, Edinburgh, Ind., has already declared that his dryland corn will likely be his worst crop in some 37 years of farming. He's been through droughts and dry spells before, but nothing that hit as early and as hard after such a late, wet start as this year. Yet others say they've got a reasonably good crop on the way.

Bob Nielsen, Purdue University corn specialist, reflects the case of two worlds as well. Checking corn around Lafayette, Ind., he was fairly pleased with what he found. Most ears are developing normally and there should be a reasonably good crop on the way in most fields. The northwest Indiana area defined by Lafayette on the south edge got a 10-day head start on planting in mid-May most people in the Eastern Corn Belt didn't get.

Yet in northeast Indiana what Nielsen sees is a lot of corn planted late, struggling to pollinate and develop properly. He has already issued bulletins about how stress affects corn, particularly when it comes at pollination. It can cause late silk emergence, so late that most or all of the pollen is gone, and it can contribute to poor pollination and kernel set in many ways.

At the least these areas will likely see more tip abortion than normal. Filling those last kernels on the tip is one of the last things that the plant does. If the plant decides it needs to make sure the other kernels get finished instead, it's likely to abort kernels nearer to the tip of the ear.

To determine if corn pollinated, you can pull back shucks and do the silk and shake test, Nielsen says. If silks stay attached to the ear, then those potential kernels didn't form. If the ovule was fertilized properly and a kernel is developing, the silks should fall off the ear, especially if the ear is shaken.

Severe cases of stress can produce ears with irregular kernel set. You may find everything from blank cobs to ears with scattered kernels. Most of that can likely be tracked back to the temperature and moisture conditions at pollination.

One other factor may prevent even irrigated fields from producing super yields. Like last year, nighttime temperatures have remained high over many areas during the critical period for corn development. That tends to result in more energy use up in respiration and less starch made and deposited in the kernels.