Research has repeatedly shown corn’s yield potential starts declining if plants don’t emerge within a tight timeframe, but dry conditions following planting can wreak havoc on best-laid plans for uniform emergence.
If one in six corn plants is two leaf stages behind the rest, expect a four per cent yield reduction, says Morgan Cott, agronomy extension specialist with the Manitoba Crop Alliance, in this Corn School video.
If there’s a four leaf stage difference, the yield impact doubles to an eight per cent reduction, she notes, citing research done several years ago in Ontario.
“We’re definitely still seeing it. Some corn seeds have germinated with the last rain a couple of weeks ago, and some is looking to start tasseling here, so we’re right across the board,” she says, discussing staging issues in the 2023 crop in Manitoba as of early July.
In some fields, stage-iness can also be attributed to uneven planting depth. “It starts with your planter and making sure maintenance is up to par. And then checking your seed depth once you’re planting in the field, to make sure you’re at that one and a half or at least consistent,” says Cott. “If you’re planting deep, that’s fine, especially this year, but you want everything to be really consistent with depth so that your emergence will be uniform.”
Check out the video below, filmed at the 2023 Crop Diagnostic School at Carman, Manitoba, for more with Morgan Cott on the consequences of uneven staging: