If you didn’t know better, you would think it is spring in the Midwest. During the first week of January, daytime temperatures soared past 50°F in Kansas. The normal high for January is 37°.
Grasses—including wheat—are beginning to green up. In some areas of southern Kansas, the crop is even growing a bit. This is unusual, but is it something to be concerned about? If temperatures suddenly plunge, will the wheat be irreparably harmed?
Jim Shroyer, a Kansas State University research and Extension agronomist, says that despite these temperatures, winter wheat still has winterhardiness and can withstand colder weather.
"As long as nighttime temperatures are below freezing for the most part, wheat will retain its winterhardiness—although not quite the level of winterhardiness it would have in a ‘normal’ winter," Shroyer says.
An occasional period of one to three days where nighttime temperatures do not get below freezing will not cause any significant loss of winterhardiness. If nighttime temperatures consistently stay above freezing for a week or so, however, there will be some loss of winterhardiness, he says.
In winter wheat, the process of gaining and losing winterhardiness is gradual. Winter temperatures fluctuate most years, and the winterhardiness level of wheat tends to ratchet up and down with the temperature changes. After a warm spell in winter, wheat will lose some winterhardiness, but it will regain most of its hardiness back as temperatures get cold again. Wheat that greens up and then goes back into dormancy, however, will not have quite the same level of winterhardiness overall as wheat that remains dormant all winter.
Soil moisture. Shroyer says a bigger concern this year for wheat is dry subsoils.
"Topsoil moisture is generally good to adequate in most of Kansas right now, and this has producers optimistic about the prospects for this year’s wheat crop. But subsoils began the fall in very dry conditions, and this has not yet changed," he says.
"There is definitely more reason for optimism about this year’s wheat crop than there was at planting time," Shroyer explains. "But the dry subsoils could be a problem later this spring if we don’t get more rainfall."
- Mid-February 2012