How long can emergence be delayed before yield is affected?
Oct. 27, 2020
Dave Nanda, Ph.D., SGD director of genetics, weighs ears. PHOTO CREDIT: Indiana Prairie Farmer/ Tom Beckman.
A new feature in the Corn Watch ’20 program were emergence plots that flagged plants in specific rows based on when they emerged. Different-colored flags marked plants that emerged on the same days, starting with the first day. The goal was to determine if plants that emerged later still produced ears, and if so, if the ears were as large as those from plants that emerged first.
First, note that this was a demonstration, not a replicated trial. In 10 side-by-side rows, 1/1,000 of an acre was measured off and plants in those rows were marked based on which day they emerged. The first plants emerged on May 23, 10 days after planting. Plants were flagged each day afterward, with plants emerging on or after the fourth day receiving the same color flag.
“We followed these plots all year, and yes, some plants which emerged later struggled,” said Dave Nanda, Ph.D., director of genetics for Seed Genetics Direct. “However, some plants which emerged four days or more behind the first plants still produced decent ears, and in a few cases, plants which emerged on time struggled. What we saw wasn’t as black-and-white as you might think.”
Harvesting ears In most rows, most plants emerged uniformly, often on the same day. In several rows, in fact, all but a couple of plants emerged together, making a statement about modern planting technology.
However, in two rows, emergence was spread over four or more days. Heavy rain occurred after planting and soil appeared to wash over those rows. They may have also been pinch rows on the planter.
Nanda and Tom Beckman of Indiana Prairie Farmer hand-harvested ears on these two rows and weighed ears with different flag colors (ie: days of emergence). The average weights per ear were:
First day: 0.59 pound
One day after: 0.64 pound
Two days after: 0.62 pound
Three days after: 0.49 pound
Four or more days after: 0.49 pound
“Plants which emerged within the first two days performed very well,” Nanda said. “In fact, weights from day one and day two were a bit higher than those emerging the first day. If you can get plants to emerge within a couple days of each other, it appears you should be okay. Ear weight tended to fall off for plants emerging three to four or more days late.”
However, the plot showed Nanda that more than uniform emergence is at play.
“Plant spacing is just as critical, maybe more so,” he added. “If a plant emerging late didn’t have a neighbor, it still did well. We must recognize that other factors influence individual plants besides just when they emerge.”
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.