Q: How are our recent cold temperatures going to affect the wheat crop?
A: K-State Agronomist Jeanne Falk-Jones addressed this question in an article last week, allowing us the opportunity for a “guest answer.”
We have had good growing conditions for the wheat, basically since drilling this fall. The wheat has had the opportunity to put on lush top growth because of the extended period of warm temperatures. Because of the lush wheat, there is concern with the cold temperatures through the end of the week.
Usually I think through several questions, when wondering if the wheat is going to be negatively affected by the cold temperatures. They include these three:
1. Has the wheat had the opportunity to harden off to prepare for the cold conditions?
2. How well established is the root growth?
3. How well protected is the crown area of the plant?
First, I think the hardening off of the wheat is a definitely a concern. When we go from T-shirt weather and barely freezing overnight lows to staying below freezing for a predicted 96 hours, the wheat hasn’t really had a chance to harden off.
So what is hardening off? Hardening off is the process of plants becoming more acclimated to colder temperatures. It can also mean that individual plant cells accumulate more solutes that can lower their freezing point, much like antifreeze in your pickups’s radiator. Cells in the crown area are the most important part of the plant for getting acclimated to the cold temperatures. The crown is the growing point of the wheat plant and is currently under the soil being insulated from the cold temperatures.
For the root systems, it is important to know that top growth of the wheat plant is not always telling the whole story of the root system. It is a good idea to dig up a couple plants and look at their root systems. Plants that have a good crown root system (roots coming off the crown and not the seed) and two or more tillers will tolerate the cold better. If plants have a few secondary roots and no tillers, they are more susceptible to winterkill and desiccation of leaves, especially if the soil remains dry.
And finally, when looking at your wheat, pay attention to the location of the crown of the wheat plant. If wheat was planted between 1.5 and 2 inches deep and the seed slot was closed well with soil, the crown should be protected from the cold temperatures. Trouble can arise when the crown of the wheat plant is set shallower in the soil. This can be caused by shallower planting, the wheat plant emerging through a thick layer of residue or the seed slot not being completely closed.
It is also important to note the soil temperature at the crown area. Based on information on freezing temperatures for wheat, winterkill is possible if the temperatures in the crown area (approx. 1 inch below the soil surface) fall into the single digits. Any type of insulation will help buffer the cold temperatures – residue, snow, and even just soil moisture in the crown area.
