First, for those who wondered where winter was, the last few days gave you your answer. The disappointing aspect is the lack of any significant moisture with the storm. The entire State of Kansas now rates from abnormally dry to a sliver in extreme southern Kansas of extreme drought. At least the little bit we received was better than nothing. If you have been paying attention to the agricultural newsfeeds for this part of the nation, you have probably seen preliminary concerns regarding damage to the 2018 winter wheat crop from the extreme cold temperatures we had around New Year’s Eve. Let’s discuss this briefly today.
First, as a winter annual, winter wheat enters dormancy as winter approaches and goes through physical and chemical changes that allow it to overwinter. The term is winterhardiness. Wheat is most winterhardy at the beginning of winter. It can lose all of its above ground vegetative growth and be fine as the growing point of the plant is below ground at the planting depth of the seed. A well-established wheat plant can withstand very harsh conditions and be fine, especially with soil moisture and snow cover. Why is the agricultural community so concerned with this year’s crop?
• Large acreage was planted late and the weather didn’t allow for what would be the desired level of development regarding roots, tillers, and ground cover. This means a shallower root system and less cover to protect the growing point and roots likely not in contact with decent soil moisture. Well-developed above ground growth helps protect the growing point by insulating the soil and shading it from water loss due to evaporation. Also with fewer tillers a little damage is magnified. A well-tillered wheat plant can lose some tillers or even the main growing point and still yield. In fact on a well-tillered plant some tillers don’t produce a head. There aren’t any extras with much pf the area’s wheat.
• A lack of snow cover also causes concern as the snow acts as blanket to insulate the soil and keep it warmer to help protect the growing point. Wheat can withstand extremely cold air temperatures much more easily with only a light snow cover.
• The length of the below freezing temperatures also causes concern as it can cause soil temperature at the growing point to fall below freezing. The average soil temperature at 2 inches for all but the Hays reporting station was below freezing during the first week of January for K-State reporting stations. That isn’t the end of the world if it weren’t for this last point.
• The soil in much of Kansas is dry, extremely dry in much of the state. There are two concerns because of this that have caused concerns regarding winterkill. Dry soil means stress on the root system and growing points and in essence results in a less winterhardy plant more susceptible to cold temperatures. Often times winterkill is the result of the combination of cold temperatures with dry soils and is almost like freeze-drying the plant. With adequate moisture the plant would likely have been fine. The second factor is that dry soil cools faster than wet soils, much faster. Water has a high heat capacity compared to the mineral part of the soil. Many soils were quite dry so they cooled more and stayed cold.
We won’t know how much damage the wheat crop sustained until later.

Dr. Victor L. Martin is the agriculture instructor/coordinator for Barton Community College. He can be reached at 620-792-9207, ext. 207.