Corn School: Learning from an emergence flag test trial


How does corn crop emergence after planting play into ear and cob development, and eventually yield?

Earlier in the growing season, Sara Meidlinger, market development agronomist at PRIDE Seeds, set up some flag tests that measured emergence in 1/1000th of an acre, in seven hybrid variety strips.

In this Corn School episode, Meidlinger goes over the results of the trials she set up and how time of emergence after planting — early in the season versus late — affected ear development and cob length and girth.

One of the biggest results from the trial was finding that 15 to 19 days after planting, 99 per cent of plants had emerged

“Our total population was little bit lower than expected,” says Meidlinger. The target was 34,000 plants per acre and 29,000 plants per acre emerged, which in the spring is quite easy to check, but it’s harder to gather that data in the fall she says.

In the video, Meidlinger explains that 15 and 16 days after planting, 80 per cent of the plants emerged, which isn’t perfect, but definitely contributes to yield potential. Plants that emerged on the very last day (day 19) in the trial, didn’t produce an ear at all. (See the video for great visuals summarizing emergence effect on ear development, story continues below)

Meidlinger saw an average of 33 kernel long, 13 kernel around cobs, on the plants that emerged 15 and 16 days after planting, which is a nice size of ear for a twenty to twenty-five hundred heat unit hybrid.

“But then on the later emerged planted — 17, 18, 19, days later, after planting — we saw less consistency in the girth, it was kind of all over the place, and then we also saw less length and smaller kernel size,” says Meidlinger.

Meidlinger says that test weight or moisture wasn’t evaluated, but could be done to get another metric.

Her first recommendation after seeing uneven emergence effects is to look at the planter first to make adjustments. Weed control, nitrogen management, or irrigation management, if it’s an option, are all other ways to maintain even emergence.

Meidlinger adds that going through what actually happened in the field, she saw that weed competition, especially a kochia patch that was glyphosate resistant, impacted her emergence results.

“We know that corn likes it clean until at least V6, so this had weed competition pretty much from the day it emerged,” says Meidlinger.

To carry out a trial on a farm, Meidlinger says that it only requires a bit of time every day at the beginning of the season, and remembering to take the flags out before harvest and suggests it could be done on one pass of the planter to see which rows might be out of calibration.

“You never what value you can get from a little bit of time spent in the field,” she says.

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Corn School (view all)Season 10 (2021) Episode 4

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