In the Furrow
Corn Crop Nearing the End
By Will Duffie County Extension Coordinator

A couple of weeks ago I discussed the process on how to estimate a yield on a corn field.

It is always fun to estimate a yield when the potential is positive, but this is not always the case. I would like to continue the discussion on how a cob and its kernel mature to a state of harvest since harvest will soon be upon us.

Growers across Burke County are anxious about the upcoming corn harvest. As a matter of fact a frequent question this week is "when will my corn be ready to harvest?" This is a very valid question, but the answer will vary based upon numerous environmental factors.

The corn kernel develops a specific pattern based upon time and weather. Under good growing conditions corn that was planted in late March to early April will be ready for harvest the first to the middle of August.

Common terms when determining maturity are 'Milk Line' and 'Black Layer'. If you break a cob in half and look at the kernel, the separation of milk and dough in the kernel is called the milk line. Once the milk line has fully dropped to the bottom of the kernel it has reached the black layer, or point at which the kernel no longer needs water.

A kernel at the black layer will typically be at 30 to 40 percent moisture. After the black layer has formed, kernel moisture will drop at 0.75 percent per day. In dry hot weather corn can dry as much as 1.5 percent per day. Harvest will begin around 25 percent moisture, but the majority of corn will be harvested at 15 to 18 percent.

Let me end with an example. Irrigated corn at 50 percent milk line will probably reach black layer in 12 to 14 days. Then be ready for harvest at 20 percent in 17 to 21 more days. Therefore harvest would begin in approximately 5 weeks. For questions contact the UGA - Burke County Extension Office at 706-554-2119.