Even people who were on a nationwide crop tour late last month and who helped form the estimate that the tour group released are questioning their own numbers. As the last half of August turned hot and dry, the talk began to center on how much of the corn crop might suffer from the heat. Most fields in many areas of the country had not black-layered yet. In Minnesota, sweet corn was just reaching the eating stage two weeks ago!
Bob Nielsen, Purdue University Extension agronomist, says that for an individual field that runs out of nitrogen or gets too dry before the black layer forms, the loss can amount to several percent. If you're doing yield checks using the tried-and-true counting of ears, rows of kernels and kernels, your estimate might be somewhat high if you don't back it off for possible smaller than usual kernel size.
Despite the heat in the middle Midwest during the previous two weeks, some in the upper Midwest are still worried about getting the crop mature before frost. An early killing frost would be disastrous in areas where the corn hasn't black-layered by the time the frost would hit. The amount of loss in yield depends upon the stage of corn when it is killed, Nielsen says.
Again, no one is predicting an early frost at this point. It's simply a "what if" situation because there are millions of acres of corn that are maturing behind normal, even after the hot outbreak of the last two weeks.
Meanwhile, USDA ag statistician field crew members were in the field the last week of August, resampling the exact same areas in the exact same fields they visited in late July. The crop report will be issued next week. Chris Hurt, Purdue Extension age economist, believes the trade expected the estimate to go up for corn when the August report was issued. That was of course before the past two weeks. A lot will be riding on the next USDA report.
