Seeing is believing. When Dan Quinn, Purdue Extension corn specialist, visited the Corn Commentary field in central Indiana in mid-September, he checked out the set of plots that were flagged for emergence last spring. What he found made for an example showing why the preference is for corn plants to emerge evenly.
“Late-emerging plants tend to be at a disadvantage,” Quinn says. “If they are at least one growth stage behind, they usually don’t catch up. The ears they produce usually are somewhat smaller.”
Dave Nanda, a retired plant breeder who watched over cornfields in this series for years, was always adamant about the need to prevent late-emerging plants when possible. He compared them to weeds, sometimes saying they were worse than weeds.
That’s because they compete all season with neighboring plants for sunlight, water and nutrients, and usually contribute a smaller ear to yield, if they produce an ear at all. You can remove weeds with herbicides or mechanical cultivation, but you can’t remove a late-emerging corn plant within the row with those methods.
Late-emergence example
There were not many late emergers in the Corn Commentary field plots. Planted the first week of May, corn began emerging eight days later, thanks to ample moisture and favorable temperatures for growth. Over 95% of all plants in four side-by-side flagged rows, each representing 1/1,000 of an acre, emerged within two days, with most of those plants emerging within 24 hours.
Quinn happened upon two plants in the flagged plots that emerged more than two days later than first- emerging plants. One, emerging about a week late, didn’t produce an ear at all. The other, emerging between two and four days after first emergers, grew into a shorter stalk with a smaller diameter and produced a much smaller ear.
LATE START: Purdue Extension corn specialist Dan Quinn holds the ear from the late emerger still on the plant. A late start for this plant resulted in a much smaller ear, especially in kernel size and kernel depth.
“The ear was 16 rows around and 32 kernels per row, but kernel size was extremely small, especially compared to normal ears on plants that emerged on time,” Quinn says. See the pictures to observe and compare.
“It did its best to make an ear, but there was just too much competition for it,” he explains. “This is kind of anecdotal — it was not a trial or scientific experiment. And late-emerging plants aren’t always affected to this degree. But it indicates what can happen in some cases. It makes the point that you want to give every seed the best chance to germinate and emerge on time.”
Key end-of-season issues in Corn Belt
What issues are cropping up across the Midwest as the 2024 corn-growing season winds down? Are any trends showing up in more than one area?
Here are a few snippets that provide a flavor for what is happening as harvest is underway in most locations. They may not be what you expect. Unfortunately, combine fires and safety around electrical power lines are top-of-mind issues for some.
In Minnesota and Iowa. Minnesota Crop News, an online newsletter from the University of Minnesota, found an article from Joshua Michel, field agronomist in northeast Iowa with Iowa State University, so riveting that it reprinted it with his permission. Why is it critical right now? It is about preventing combine fires, and with super-dry conditions still in many areas, the risk of fires is up. In fact, two known combine fires resulting in total loss of the machine occurred in September in Indiana.
Here are 10 tips from the article:
Keep the machine clean. This is particularly important around the engine and engine compartment. Use a high-pressure washer or compressed air to remove caked-on oil, grease and crop residue.
Frequently check air filters. Ensure they stay clean, either by blowing them out or replacing them. This will help the engine run cooler and more efficiently.
Check coolant and oil levels daily. Pay close attention to engine and hydrostatic pump parts, as well.
Check the pressurized oil supply line to the turbocharger. Look for wear areas that rub and may start an oil leak.
Blow off the engine area daily. Use either compressed air or a portable leaf blower to clean off leaves, chaff and plant material. Waiting until the next morning to do this may make the task more difficult because of the dew.
Remove plant materials. Check for material wrapped on or near any bearings, belts, chains or other moving parts.
Examine the exhaust and any heat-bearing surfaces. Repair leaking fuel or oil hoses, fittings, or metal lines immediately.
Inspect and clean ledges and recessed areas. This is critical near fuel tanks and lines.
Prior to refueling, turn off the combine. Wait 15 minutes to reduce the risk of a spill volatilizing and igniting.
Analyze conditions. Research from South Dakota State University suggests that if conditions are dry wind speeds approach 30 mph and above, fires may be inevitable. During these periods, producers should consider delaying harvest until evening hours when winds decrease, or wait for precipitation. Higher humidity levels may also reduce the potential for field fires to spread.
In Illinois and Indiana. A tragedy in early October claimed the life of a young farmer in western Illinois when his combine caught overhead wires while he was operating within the field. In trying to free the combine from the wires, he was electrocuted. His uncle, coming to his rescue, was seriously injured.
You owe it to yourself and your family to check out Purdue Pesticide Programs Publication 151: Overhead Power and Communication Lines — Don’t Get Grounded. Published in 2023, Purdue PPP Director and Extension specialist Fred Whitford does a deep dive into why doing anything other than calling for help and staying put in the cab, except in emergency situations, is critical.
This booklet explores how electricity works in terms you can understand, and leaves anyone reading it with a healthy respect for electricity.
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