May 3, 2022
Would you like to make hundreds of dollars by investing a few hours scouting cornfields when plants begin emerging?
Order yourself flags in a variety of colors and head to the field. For 30-inch rows, take a rope marked to 17 feet, 5 inches. Mark off several spots at random, and walk those sample areas every day until emergence starts. Place flags of the same color next to plants that emerge each day you visit, using different colors from day to day, until emergence finishes.
You’ve just flagged corn emergence in 1/1,000-acre strips. Pull flags once corn is up or leave them all year. You may even want to hand-harvest a few strips and compare ear weight vs. days of emergence after planting.
Related: Know early stages of corn growth
“Yes, it’s lots of work, especially if you flag 1/1,000 acre in each row of a planter pass for a 24-row planter,” says Dave Nanda, director of genetics for Seed Genetics Direct, sponsor of Corn Watch ’22. “I’ve had the opportunity to view plots where someone else did the flagging, and you can learn much more than you think. It can help you learn about planter performance, and how corn responds when neighboring plants emerge a day to several days earlier.”
Here are some key lessons Nanda has learned through emergence plots:
One row isn’t enough. In 2021, the Corn Watch cooperator flagged one row with a kit provided by a company, Nanda recalls. He picked a pinch row by chance. Seedlings began emerging in that row one to two days before seedlings in most other rows. The emergence in that row was also much more uniform than in most other rows within the field.
All planter rows may not emerge evenly. A flagging strip was set up on each row of a 24-row planter pass in 2021. “We observed a wide variation in time of emergence from row to row across the planter,” Nanda says. “Within the same pass, 80% to 90% of all plants emerged within a day or two in some rows, while as many as 40% of plants didn’t emerge until a week after the first plants emerged in other rows.”
Variation could be caused by changes in soil type, even across one planter pass. It could also be due to seed placement at varying depths, even though depth on each row was set identically. Even on new planters, depth for some rows may need to be set at different slots to obtain the same actual planting depth. Check this in the barn lot by lowering the planter row by row onto wooden blocks and measuring depth of opening disks.
More than emergence affects how well plants produce. There’s no guarantee that plants emerging two days behind will produce nubbins, even though some advertisements imply drastic yield hits.
“Many factors affect how a plant yields, including distance to neighboring plants,” Nanda says.
Plants that emerge several days behind may be at a disadvantage, but it still depends on many factors, including how early emergers are growing. Three years ago, Nanda observed that although plants emerged over an entire week in one strip, there were only minor differences in ear size.
“Yes, you prefer even emergence,” Nanda says. “But it doesn’t always happen. Ears on plants emerging several days late trend toward being smaller, but we have found exceptions every year.”
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