Soil temperatures in four winter wheat fields were measured throughout the 2014/15 winter. Plotting soil temperatures against various ‘hardiness” curves can provide an early indication if there is a concern for winter injury or winterkill. I had posted initial data (up to beginning of March – http://cropchatter.com/early-indicators-for-wheat-survival-in-2015/), and presented that data at the Winter Cereals Manitoba AGM middle of March.
However, the figure is now updated to include data up until middle of April when the weather stations were removed from the fields.
Figure 1: 2014/15 Soil Temperatures Measured at 1 Inch Depth in Four Winter Wheat Fields
Data Source: MAFRD AgWeather Program
Since majority of winter wheat acres are considered “well-hardened” and soil temperatures didn’t reach levels that went below the “high hardiness’ curve, winterkill isn’t expected to be a large concern based solely on soil temperatures measured in these fields over the winter. However, since soil temperatures at one location did dip below the “mid hardiness’ curve, or at some locations got close to that curve, some areas within fields may be impacted where there was perhaps minimal snow cover due to lack of stubble, etc. Each field should still be scouted and assessed as growth resumes in earnest over the next few weeks.
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.
Submitted by: Pam de Rocquigny, Provincial Cereal Crops Specialist, MAFRD