Wheat response to cold temperatures
Whether the sudden sharp drop in air temperatures across Kansas this week affect the wheat crop that has already emerged to any degree depends on several factors.
First, it might only mean risk of cold injury for fields that were sown relatively early and already had a good above-ground development. These plants would not have had the chance to properly acclimate to the cold temperatures and are more susceptible to winterkill.
Second, the moisture level in the topsoil will be important, as dry soils will get colder more easily than wet soils. Soil moisture was generally good in most of the state except for southwest Kansas (see accompanying article). The cold temperatures will be more likely to cause injury to wheat in fields that were planted early, had some significant growth during September and early October, and were now showing drought-stress symptoms.
There was a severe cold snap in mid-November 2014 that contributed to winter injury on some wheat, and in many cases resulted in winterkill. In 2014, the crop was sown relatively early and had good development in the fall due to warm temperatures in October. These warm October temperatures caused drying of the topsoil and enhanced the potential for cold damage. The weather during the fall of 2014 was also warm which likely provided too few cold enough nights to have allowed the wheat to develop cold hardiness.
The extent of the unusually large and rapid drop in temperatures from well above normal to well below normal is a concern in those early-planted fields which would be more susceptible to injury from the recent cold snap. The first thing we’ll see is burndown of the wheat from these cold temperatures, but if the crown below the soil surface remains alive, the wheat should be fine. We likely won’t know with certainty the extent of the damage until at least a couple weeks of warmer temperatures occur.
Romulo Lollato, Extension Wheat Specialist