In the February 13, 2015 issue of the Agronomy eUpdate, we described some apparent winterkill on heavily grazed wheat in southwest Kansas. There has also been tiller loss throughout northwest Kansas and occasional symptoms of winterkill injury to crowns on some fields of wheat in far northwest Kansas counties. Tiller loss is more widespread than outright winterkill.
Temperatures have fluctuated considerably this fall and winter, starting in November with a sudden and sharp plunge to very cold conditions. The wheat was bigger than normal and actively growing at the time of the sharp drop in temperatures, which helped make the wheat more prone to injury. Since that time, temperatures have fluctuated from unusually warm to unusually cold. Snow cover has been limited for the most part, so the survival of the wheat depends on crown depth, soil conditions around the crown, exposure of the plants to north winds and pools of cold air, moisture conditions of the soil, residue protection, varietal differences, and perhaps other factors.
Some preliminary varietal differences have been noted in at least one demonstration plot at this time, but we will have to wait and see whether these differences persist after greenup, and whether the varietal responses are consistent across different areas before drawing any conclusions about winterhardiness of varieties.
The photos below are from Cheyenne and Thomas counties, taken on Feb. 19.
Figure 1. Many fields have a heavy mat of topgrowth that has been burned back by cold temperatures. All photos taken Feb. 19, 2015 by Jeanne Falk Jones, K-State Research and Extension.
Figure 2. After removing most of the topgrowth, it is evident that the foliage has been burned back all the way to ground level.
Figure 3. In this case, after pulling up a plant and slicing it open, it is evident that the crown is brownish and dead.
Figure 4. Comparison of crown with winterkill injury (left) and healthy crown.
Figure 5. Where the plants are alive and well and the crown is healthy, there are new leaves emerging through the mat of dead foliage.
Jeanne Falk Jones, Sunflower District Extension Agronomist
Jim Shroyer, Crop Production Specialist Emeritus