Corn crops in many parts of the central Midwest are in the process of transitioning from seed roots to the true corn roots.
This is an important transition point for the crop. When root development has progressed like it should, the handoff is seamless. But when that’s not the case, corn crops will show that poor handoff in the form of what Ken Ferrie calls ugly corn syndrome.
The problem typically shows up sometime between V3 and V5. Some contributing factors can be wheel-track compaction, sidewall smearing and herbicide carryover, all of which start to show up visually now and impact crop uniformity.
Ferrie says the plants not affected are starting to pick up rapid growth, and they make the slower growing, more impacted plants more visible.
“Some of these fields were uniform when the seed emerged, because they were living off the seed roots. But now as the transition is starting to take place, we’re seeing this uneven issue, less uniformity, show up,” explains Ferrie, Farm Journal Field Agronomist.
The lack of uniformity can impact yield potential and commonly occurs in a couple of ways:
1. Early in the plants’ life, between emergence through V8, corn roots need to be the same age when the root systems cross other plants in the row. Late-germinating plants are able to sense stress when they cross older plants, and in turn, they’ll start dialing back their yield.
“In our stress plots, even if you remove that older plant later, the stress will have already been done and affect the ear size,” Ferrie says. “This is why we want as many corn plants as possible to emerge within a 48-hour window of each other.”
2. A second scenario occurs when later-emerging plants give up yield because they’re unable to capture sunlight, a result of being shaded out by the older, taller plants.
“It’s pretty true if the plant is one collar behind its neighbor, it’ll only put on about a half an ear,” Ferrie says. “If it’s more than a collar behind, it’s probably not going to produce a harvestable ear.”
As Ferrie has gone on service calls this week, where growers saw even emergence but now some of the corn appears to be a couple of collars behind, he is finding that the corn plants are actually at the same collar. Timely rains can help reduce the impact of uneven growth, moving forward.
“The moisture we got this past week allowed the crown roots to start developing and get this corn back on track,” he says. “Now it can’t speed up the smaller plants and catch up to the bigger plants, but it can get the crop back on track so plants end up in the same maturity range when we go to pollination and black layer,” he says.
What To Look For At Harvest
With the help of some moisture, hopefully, little damage will be done to yields though the crop will be uneven in appearance at harvest.
“This will be noticeable come fall when you go out there, because there will be different heights for the ears. There won’t be that picket-fence stand, photocopied ear count. You’ll see the ear height change, and this will be due to the first nodes in the plants are going to be shorter.”
Most of this problem goes back to farmers not firming the soil enough with the closing wheels at planting to prevent soil moisture from getting away — something to keep in mind for next spring.
“One of the common threads I’ve seen as I investigate these fields is where we used a spoke closing wheel made for no-till but used it in tilled soils. The spoke closing wheels don’t firm soil like the cast tires and the rubber tires,” Ferrie says.
In this week’s Boots In The Field podcast, Ferrie also addresses how the carbon penalty is kicking into gear though parts of the country and impacting corn growth and development. Check out the podcast here.
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