If you see small flags in a neighbor’s field, it may not be a test plot. Instead, the flags may denote the days when plants emerged. Different colors mean plants emerged on different days. If corn plants emerged uniformly, flags would be the same color. If the bevy of flags looks like a kaleidoscope, something interfered with emergence.

“It’s always important to judge how evenly corn plants emerge,” says Dan Quinn, Purdue Extension corn specialist. “Flagging a section of several rows side by side is one way to do it.

“You hope most plants emerge and get the same color of flag. Weather shifts, uneven planting depth and planter issues can result in uneven emergence. When emergence is spread over eight to 10 days, yields can suffer.”

Quinn will assist with this Corn Commentary column and project. Reports will include information on one nonirrigated cornfield in Indiana, consisting primarily of silty loam soils, that was planted May 4. Hopefully, lessons coming from this field will apply to your cornfields.

Stark difference

Three years ago, plants in the project field began emerging 10 days after planting, and continued emerging over the next 14 days. Planted the last week of April, cool wet weather affected emergence.

In both 2022 and 2023, the project field was planted during the second week of May, and warm weather followed. In both years, 80% to 90% of seedlings emerged within 24 hours, and emergence was complete within three days. Yields were higher in both ’22 and ’23 vs. ’21.

“Once plants are a leaf stage behind, they never catch up,” Quinn says. “They often act like weeds. If they are two stages behind, they usually don’t even produce an ear.”

HOORAY FOR BLUE! About 80% to 90% of these flags are blue, indicating all these plants emerged within 24 hours of one another in 2023. Weather after planting was warm, vs. cool and wet in 2021.

Across the rows

Farm Progress editors offer a peek at early-season conditions elsewhere:

In Iowa. Growers got a good start, with 10% to 20% of corn in various regions going in during mid- to late April. Rains came across most of Iowa during the week of May 6. By then, one farmer in northwest Iowa hadn’t turned a wheel in six weeks. Yet many people weren’t complaining, because most of the state had been dry, and moisture will be welcome later. — Gil Gullickson, editor of Wallaces Farmer

In the Dakotas. Planting progress early was all over the board, depending on where rains fell. Many areas were dry going into early May, although eastern South Dakota saw heavy rain in mid-April. By the week of May 6, some people were likely finishing up planting things like peas, lentils and wheat, but others were still waiting for drier soils. — Sarah McNaughton, editor of Dakota Farmer

In Kansas. Spring rains were plentiful in central and eastern Kansas, which is dryland corn, soybeans and wheat country. Some were out of the fields during the week of May 6 due to wet soils. Others weren’t affected as much. Soil types and subsoil saturation made the difference. — Jennifer Latzke, editor of Kansas Farmer