Late-emerging plants contribute to yield...or do they?
May 26, 2020
Even emergence is a key topic in meetings of corn growers who are dedicated to producing as many bushels per acre as possible. To find out just how important even emergence in corn is, companies that sell planting equipment, and even some farmers, have taken to marking time of emergence in 1/1,000-acre sections of row, using different colors of flags to mark the corn seedlings that emerge on the same day. In most of these cases, they leave the flags all season so they can follow those 1/1,000-acre sections to harvest. Sometimes they shuck the ears and lay them out in order, plant by plant. Some people even weigh the corn once they shuck it, ear by ear. The goal is to determine how much later-emerging plants cost them in terms of yield potential.
Based on talks at planter clinics and high-yield meetings, the differences can be substantial. Some claim that a delay of more than a couple of days can result in a plant that produces a smaller ear. If the delay stretches out to several days, it may produce a barren plant with no ears at all.
Dave Nanda, director of genetics for Seed Genetics Direct, thinks plants with no ears are worse than weeds. That’s because they compete with other plants for water, sunlight and nutrients but produce nothing. Yet unlike weeds, you can’t take them out with herbicides or a cultivator.
So, just how much delay in emergence does it take to end up with corn plants that don’t produce as big of an ear, or no ear at all? Nanda will attempt to answer that question by monitoring the Corn Watch ’20 field, planted May 13 in central Indiana, as well as two fields planted April 20.
After April 20, the weather turned wet and very cold, with temperatures bottoming out around 27 degrees Fahrenheit on May 9. Most of the seedlings in the April-planted field were emerged but had not yet unfurled leaves when the lowest temperature occurred. The biggest percentage of seedlings emerged within 48 hours, but there were stragglers stretching out to seven days after the first plants emerged.
One theory is that, since it was so cold and all seedlings were growing slowly until the temperatures warmed, that late-emerging seed may catch up and experience less impact on ear size than normal. Corn Watch ’20 is an opportunity to demonstrate whether this theory holds true, even though it’s not replicated research.
The Corn Watch ’20 field is sponsored by Seed Genetics Direct. Reports on the field’s progress are provided all season (#CornWatch20); read the latest Corn Watch ’20 articles here. Stories are written by Tom Bechman.