As Ken Ferrie looks at the initial corn harvest results coming in from across the Midwest, he wants to remind farmers that picket-fence corn stands with photocopied plants – uniform stalks and ears – support high yield results.
Ferrie says Mother Nature’s “photocopy machine” didn’t work the best in some parts of corn country.
“There are some great yields out there, but there are some disappointments, too,” says Ferrie, Farm Journal Field Agronomist and owner of Crop-Tech Consulting, Heyworth, Ill.
He advises farmers to consider the following points as they harvest their corn crop and make yield estimates.
There are at least three reasons for uneven ear development this season: In some fields, farmers will see ears that are not uniform as they harvest. This is due to more than one reason, but the big three contributors were aphids, green snap and top kill.
“The top kill came in early in some of these fields and took out the top three leaves, and those fields were at barely 50% milk line,” Ferrie reports. “This lightened up that ear tip and took away the depth of that kernel, especially on your D hybrids.”
He defines a D hybrid as one that can change a lot in weight late season, often flexing in kernel depth.
“Flex in depth will be seen in the weight per kernel, or how much starch is packed into each kernel,” Ferrie says. “These D hybrids are susceptible to yield loss when they have stress in the later part of the season, usually the last 30 days before black layer.”
Don’t ignore poor quality ears when doing yield estimates: Ferrie says as he’s walked fields, he might find most of the ears are uniform but also a smattering of poor-quality ears in 1,000th of an acre, for instance.
“If you ignore those poor ears, you’re going to overestimate yield results,” he cautions. “Likewise, if you’re pessimistic and only choose and count those poor ears, you’re going to underestimate yields.”
He recommends the following yield-estimate steps in fields that are mostly uniform but had some problem with the photocopy process. It involves doing stand counts and taking into consideration both the good, uniform, ears as well as the small, uneven ears.
Here’s the process:
Do a yield estimate on a representative sample of the good ears times the number of good ears. Divide these by 70 or 75 to get your yield estimate of the good corn.
Then attempt to do the same with the uneven ears (ears that are hanging down, ears that the tops are blown off of, etc.), but divide those by 90 to get a yield for the poor ears.
Finally, add these two estimates together to get your final yield estimate for the field.
“This process will eliminate some of the surprises in these uneven-eared fields,” Ferrie says.
“It would be good to make some notes of what has dinged this corn for future use,” he adds. “Sitting in a yield map meeting this winter, trying to diagnose issues is a lot easier if you gathered this information before the combine destroyed the evidence.”
Pictures are worth a thousand words: Ferrie recommends training all combine operators so that when they see an abnormal drop in yield on the monitor to stop, do a quick stand and ear count.
“Take pictures of the ears for the record and let the scouts know what they’re seeing and where it’s happening, so they can collect some data,” he advises. “This will make everything a lot easier when we’re trying to figure this all out during our winter reviews and discussions in preparation for next season.”
For your next read:
Corn Yield Checks In and Out of the Combine
Ferrie: Picking Corn Hybrids For 2024? Here Are Five Tips
How To Plan For Next Year’s Crop With Extreme Weather In Mind
