Soil temperatures in five winter wheat fields were measured throughout the 2015/16 winter. Plotting soil temperatures against various ‘hardiness” curves can provide an indication if there is a concern for winter injury or winterkill.
The figure below illustrates the soil temperatures up until early April in five winter wheat fields across Manitoba, plotted against various ‘hardiness’ curves.
Figure 1: 2015/16 Soil Temperatures Measured at 1 Inch Depth in Five Winter Wheat Fields
Data Source: Manitoba Agriculture AgWeather Program
Since majority of winter wheat acres were considered “well-hardened” and soil temperatures didn’t reach levels that went below the various hardiness curves, winterkill isn’t expected to be a large concern based solely on soil temperatures measured in these fields over the winter.
We also worked with Western Ag to get the Manitoba data onto the Winter Cereal Survival Model, available at the following link: http://www.wheatworkers.ca/FowlerSite/winter_cereals/WWModel.php. The data on the website also indicates soil temperatures were not reached that would impact winter wheat survival.
Early Assessment of Growth. From early reports of producers and agronomists bringing in winter wheat plants from the field or conducting the ‘bag test’ to assess winter survival, regrowth has been noted which is also good news.
So between early assessments and the measured soil temperatures, winter wheat survival looks promising to date. Keep in mind these early indicators shouldn’t stop you from assessing your own winter wheat fields though. Each field should still be scouted and assessed as growth resumes in earnest over the next few weeks.
Submitted by: Pam de Rocquigny, Provincial Cereal Crops Specialist, Manitoba Agriculture
Note: You will notice the hardening curves end beginning of April as I don’t have data to continue the curve to May 1st. However, imagine a curve for each line continuing upward until approximately the -2°C mark.
For more information on winter wheat production, visit Manitoba Agriculture’s website at https://www.gov.mb.ca/agriculture/crops/production/winter-wheat.html