Delay in corn emergence doesn’t tell whole story

Photos by Tom J. Bechman shucked ears of corn lined up
HOW 1/1,000 ACRE FARED: The grower for the Corn Watch ’21 field obtained a kit containing flags from Precision Planting so he could flag emergence by day on one row. Each number is days of delay.
Corn Watch: Other factors besides days to emergence play a role in final production per plant.

Lots of effort went into tracking individual rows in the Corn Watch ’21 field to determine if days of delay in emergence affect production. This is the first in a series of stories that seeks to answer that question. In the conventional-tillage half of the field, the plants in eight rows were flagged as they emerged; in the no-till half, 24 rows — one planter pass — were flagged, plus one additional row flagged by the grower.

Each row flagged represented 1/1,000 of an acre. Just before harvest, two conventional rows, two no-till rows and the grower’s row were shucked by hand. The ears were weighed individually. Spacing between plants was measured. After weighing, ears from these five rows were laid out with the same spacing that existed in the field.

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“What you’re going to see is that while delays in emergence can be important, that one piece of information by itself doesn’t tell the whole story,” says Dave Nanda, director of genetics for Seed Genetics Direct. “Other factors are involved. Plant spacing alone doesn’t tell the whole story either. Each plant is affected by the microclimate around it, which includes soil makeup, moisture availability or surplus, and nutrient availability.”

Grower row

The grower obtained a kit from Precision Planting that allowed him to mark when plants emerged in 1/1,000 of an acre within one row. He picked a row at random and monitored emergence. As it turns out, it was a pinch row, with planter tracks on either side. It was also one of the first rows to emerge.

Within this row, 18 of 31 plants, or 58%, came up together, 10 days after planting. The field was planted April 25, and conditions turned very cool and wet for the next three weeks.

Nine more plants, or 29%, emerged one day after the first plants that emerged. Three plants, or 10%, were delayed two days, and one plant emerged three days late.

shucked ears of corn lined up

PLANT SPACING MATTERS: Here is a section of the same row, showing how ears were spaced in the field. The heaviest ear in the row, with a one-day delay, was next to a 10-inch gap.

At harvest, the average ear weight, including cob, at about 20% moisture, was 0.45 pound. Average eight for ears from plants emerging on the first day was also 0.45 pound. Ears that emerged one day late weighed 0.41 pound each. However, ears emerging two days late averaged 0.46 pound, and the ear from the three-day delay weighed 0.36 pound.

That’s not a decisive advantage for plants without delay, Nanda notes. Plus, throw in that the biggest single ear, 0.66 pound, came from a one-day delay, and the smallest ear, 0.26 pound, also came from a one-day delay.

Spacing sheds some light, Nanda says. The largest ear had a 7-inch gap on one side, but a 10-inch gap on the other. A plant emerging two days late with an 8-inch gap on one side and a 6-inch gap on the other produced a half-pound ear. Yet a plant two days late with an 11-inch gap on one side and a 5-inch gap on the other yielded an ear weighing only 0.39 pound.

“There are other things going on here,” Nanda concludes.

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