Wheat Winterkill Damage Ranges in Kansas, Oklahoma
A few weeks of spring-like weather have helped bring the winter wheat crop out of dormancy in the southern Plains, thus giving clarity to the severity of wheat winterkill damage in Oklahoma and Kansas.
Isolated cases of winterkill are showing up in Oklahoma, particularly on fields that have been grazed, according to Jeff Edwards, small grains specialist at Oklahoma State University. “A cold snap in early March was the one that got us,” says Edwards. “How much winterkill we have, I don’t know. There are a lot of areas where the tillers were burned back a bit, but there is still green tissue at the base of the plant. It’s not down for the count yet; there still is some potential for the wheat to bounce back.”
Major wheat-producing areas of central and south-central Kansas, are showing widespread winterkill, says Jared Jones, field marketer with Mid-Kansas Co-op in McPherson County, Kansas. Close to 20% of the wheat acres in that county are ruined because of winterkill, with surrounding counties affected to a lesser degree. Farmers there are considering whether to abandon affected fields altogether.
“There are some whole fields in which the wheat is completely gone,” Jones says. “But in many cases, the dead spots are patchy, and depend somewhat on soil type, tillage system, or seeding depth.”
Seeding conditions last fall are a major factor in how widespread the winterkill problem is in Kansas. Where fields were dry prior to planting, many farmers had a hard time placing seed at the proper depth. Wheat sown 1 inch deep or less in these dry soils never did get the precipitation needed for secondary roots to grow; nor were there enough tillers to withstand this winter’s below-zero temperatures.
“Our wheat broke dormancy a few weeks ago, and by now you should see where the wheat will make it, and where the crop is completely dead,” Jones explains.
Risk of winterkill is often determined by how low soil temperatures get at the crown level of the plant. Dry areas are most susceptible to the cold as soil moisture can help soil retain heat, protecting the crop. The air temperature above the soil may be 5°F. to 10°F., but in moist soil the temperatures can remain 20°F. to 25°F. above zero. Ongoing drought in the area has caused low topsoil moisture conditions, exacerbating winterkill risk.
Plants that are killed outright will not turn green as the weather warms. Damaged plants will begin to green up, then go backwards and die. There are enough nutrients in the crown to allow these plants to green up, but the winter injury causes vascular damage so the nutrients that are left cannot move, or root rot diseases move in and kill the plants.
You can check to see if your wheat is still alive by digging up the plant – roots and all – take them indoors and see if they turn green. If they stay green, chances are the crop will recover somewhat, although it may not result in top yields.
Crop insurance factors