Corn growers sometimes walk away from their crop at this point in the growing season, thinking there’s little to nothing they can do now to influence final yield and harvest outcomes.
It’s a mentality David Hula says he understands, especially this year.
“We spent a lot of time getting the right hybrid in the right environment, controlling the weeds, controlling insects, and getting the fertility out, and in that last quarter some growers, you know, sometimes they lack experience or are just tired of spending money,” Hula tells business partner Randy Dowdy, in the latest edition of their Breaking Barriers With R&D podcast.
Yet the two champion corn growers say there is still time to influence harvest outcomes.
Late-Season Yield And Test-Weight Potential
Brian Herbek, who works with Hula and Dowdy via their Total Acre program, has leaned into their advice.
“I found out a couple of years ago, there’s a lot of hidden yield out there that a lot of us leave on the table,” Herbek reports.
What he learned from the two corn yield champions is corn has the genetic ability – some hybrids more so than others – to pack starch into its kernels late-season to create higher test weights.
As a result, the Deweese, Neb., corn grower says he started scouting fields late-season to determine which ones are candidates to receive what Hula and Dowdy call “the finishing pass,” an application of fungicide or nutrients or some combination of the two.
“It’s not for every field. I’ll tell everybody that right now, there are certain fields that don’t deserve that attention,” Herbek says. “But if you know what you’re looking for, and you have that potential, that application does makes sense, but you’ve really got to know what’s out in your field.”
When Nitrogen And Fungicide Use Makes Sense
Farm Journal Field Agronomist Ken Ferrie recommends checking fields to consider what an insufficient amount of Nitrogen (N) at this point in the season could mean to yield results.
“Plants running out of N at R4 run the risk of tip abortion,” he notes, as a for instance. “At R5, tip kernels are going to get light, and if it’s a D hybrid, it’s going to cost you in late fill.”
Ferrie describes D hybrids as those that need nitrogen during grain fill to max out yield.
”Depth of kernel comes at the end of grain fill — the last half of the 60 or so days after pollination through black layer,” Ferrie explains. “They need to stay green as long as possible and finish the season strong. Many new hybrids are D types.”
Hula says a fungicide application now can help make sure corn leaves and stalks stay greener longer, putting more energy into kernel development.
“If we can pick up a half a pound or a pound more test weight, that’s a bonus,” he says. “The other thing I want to say about green stalks, particularly for guys where residue management is a problem – the green stalks at harvest are going to deteriorate or decay much faster than those that are not green.”
Why Care About Test Weight?
Test weight is commonly used by buyers as a way to evaluate grain quality. A higher test weight indicates a greater proportion of the grain’s volume is filled with the nutrient-rich endosperm, meaning more available energy and nutrients, says Todd Whitney, Extension educator at the University of Nebraska-Lincoln, in an online article.
High test-weight corn is generally more valuable to buyers, though the extent of this value can vary. Some buyers prefer higher test-weight grain due to its higher starch content and better storage properties.
One thing to note here: While hybrid genetics play an important role in test weight determination, there is no correlation between test weight and yield potential of a hybrid. Corn grain in the U.S. is marketed specific to a 56-lb. bushel regardless of test weight.
“Corn farmers are often concerned with low test weight because that means local grain buyers may have to discount the market grain prices paid. In addition, if you were to deliver a semi-load of low test weight grain (e.g., 52 lbs/bu) then this specific load would contain less ‘56-lb bushels’ and you would be paid less for the load on a per volume basis,” explains Dan Quinn, Extension corn specialist at Purdue University, in an online article.
“Whereas, if you were to deliver a semi-load of high test-weight grain (e.g., 58 lbs./bu.) then that load would contain more ‘56-lb. bushels’ and you would be paid more for the load on a per volume basis,” Quinn writes.
What To Look For In The Field Now
Here are some of the factors Herbek takes into consideration as he evaluates which fields warrant another pass of fungicide, fertility or both:
Crop Quality: More yield potential or a heavier test weight has to be available for product applications to provide sufficient ROI. Plant tissue tests can help identify nutrient deficiencies and guide late-season applications.
Additional factors that affect crop quality that Herbek considers are pest and disease pressure, standability and stalk quality, and moisture availability.
Crop maturity. Hybrid maturity and planting date have been found to influence susceptibility to yield loss from foliar diseases, writes Mark Jeschke, agronomy manager for Pioneer, in this online article.
He says later planted fields and/or later maturing hybrids can be more vulnerable to yield loss because they are still filling grain while disease development is peaking in late summer. Therefore, these later fields are often more likely to benefit from a fungicide application.
Herbek says he also takes into consideration each hybrid’s growing degree days, and how long he has before his crop reaches the finish line.
“We’ve got, I’m guessing, probably 45 to 50 days yet to put something in that kernel and give us some extra test weight,” he says. “So we still have some time to influence it yet.”
Herbek also offers some thoughts on how farmers can improve next season’s corn crop by prioritizing their planter and planting practices. You can catch the details on Breaking Barriers With R&D at Farm Journal TV and YouTube.
Your next read: Breaking Barriers with R&D: Split the Planter, Split the Risk
