How Wet Will Corn Be At Harvest?

Experts and farmers disagree on when and at what moisture corn may come out of field.

Published on: Aug 10, 2012

Richard Stroshine foresees a lot of corn coming out of the field fairly early because it was planted early. That's why the Purdue University grain quality specialist is warning farmers not to dump 17% corn straight into a bin without drying it and expect to dry it through aeration with a big fan on the bin. Many years that works well. But in most years it hasn't set records for one of the hottest summers ever recorded.

Stroshine fears that if harvest is early and it's still hot, the grain temperature will be so high that the corn won't cool and aerate out properly unless it's dried first.

That's his theory, and he's sticking to it.

When will corn come in? Nobody knows for sure just how long farmers will leave stressed corn in the field before trying to harvest it.
When will corn come in? Nobody knows for sure just how long farmers will leave stressed corn in the field before trying to harvest it.

On the other hand some farmers with low-yield, potentially low quality corn aren't so sure that they won't have to harvest it even earlier. That's because they believe it may fall over. Some of it already has. Some fell over at pollination from the stress. To prevent lodging and get any corn at all, they may have to harvest at 30% and dry it anyway. At least that's one farmer's story, and he's sticking to it.

Then there are other considerations. Even if it can stay in the field long enough to dry down, how well will stressed kernels on irregular ears dry down? Faster? Slower? Because no drought has been this severe since hybrid corn became popular, that's a wait-and-see question. Nobody knows for sure.

Charles Woloshuk, a Purdue plant pathologist, expects ear rots to develop, particularly Aspergillus, which could produce aflatoxin. If that happens, the infected corn will need to be segregated and dried to a lower moisture content than the normal 15%, Stroshine says. Otherwise the fungus will keep growing inside the bin and could produce more aflatoxin.

The good news is it hasn't shown up yet. The troubling concern is that in most other years like this one, it has. Look for an olive-brown, dust-like mold when you peel back the husks. If you find it, consider having the corn tested for aflatoxin before you harvest it. Otherwise, you risk heavy dock if you take it to the elevator and it's positive for aflatoxin, if they accept it at all. You also risk problems with crop insurance, because if you put it in the bin without testing it, what happens in the bin is considered your risk, and is not covered. And if you put it in a bin with corn that isn't infected, you risk infecting the whole bin.

It will be an interesting fall. What would you expect after an interesting, and soon to be notorious, growing season?

Read more scouting recommendations for Aspergillus here.