By Dennis Pennington and Ricardo Costa
Earlier this winter, Michigan experienced above-average temperatures and below-normal snowfall. Going into February 2021, most of the state had about one-third of the expected snowfall. Then winter arrived. Snow fell, as did the temperatures. Some locations in the Michigan wheat growing regions reached air temperatures as low as -18 degrees Fahrenheit. So, is this cold enough to kill wheat plants?
Table 1. Minimum crown temperatures and length of time wheat can tolerate before winterkill damage begins to appear.
Temperature (F) | Maximum length (days) |
|---|
27 | 150 |
5 | 6 |
-15 | 0.5 |
-20 | 0 |
Table 1 shows the temperatures that the crown of wheat plants can tolerate. In the overwintering stage, the crown is below the soil surface. This provides some protection from severe cold temperatures. Snow cover provides additional insulation to help protect the crown. Most states have weather networks where soil and air temperature data can be found. In Michigan, we use Michigan State University’s Enviroweather, which allows you to access data from more than 80 weather stations scattered across the state. Data were downloaded and summarized in Figure 1 below. Two-inch soil temperature is a good proxy for crown temperature.
Figure 1. Air and 2-inch soil temperature data at three locations in Michigan from Jan. 1 to Feb. 19, 2021.
Notice that even while air temperatures dipped to near -20 F, the 2-inch soil temperatures did not drop below 20 F. Nearly all the wheat producing areas of the state have had adequate snow cover to protect the crown. The wheat crop is in really good condition at this point. Winter survival should be very high unless the snow melts and we get ponding, icing and extremely cold temperatures.
Source : msu.edu