Soil temperatures are getting close to the point where winter wheat might be damaged, says Joel Ransom, North Dakota State University extension agronomist.
The critical soil temperature for the most winter hardy varieties developed by NDSU is about -4 degrees F.
For varieties developed in states to the south, the critical temperature is approximately 14 degrees.
Soil temperatures in some parts of the North Dakota where there is little or no snow cover are starting to get low enough that the less winter hardy varieties are at risk, Ransom says.
In addition to variety, the size and health of the plant can impact how well the crop will tolerate the cold.
"Generally, plants that have four or more leaves in the fall can withstand a more prolonged period of cold than smaller plants because they have more reserves in their crown," Ransom says. "Fields that have a history of no till and have a good level of crop residue from the previous season may insulate the soil to a degree, much like snow cover."
The recent snow and the warmer weather is great news for winter wheat., he says. Until the recent cold snap, the mild weather has been a positive for winter wheat because prolonged cold probably is more damaging than a brief but very cold period.
"We sampled our winter wheat field just before last week's cold weather and found excellent vigor and regrowth, which indicates that the crop has not been damaged as of yet," Ransom says.
With 700,000 acres planted this fall, which is the most winter wheat acres since 1985,"the potential impact on the winter wheat crop in the state is not trivial," Ransom says.
The success of a crop of winter wheat making it to harvest in North Dakota has been fairly high. During the past 50 years, the percentage of the planted acres that were not harvestable averaged only 6%.
"This does not mean that there isn't a risk," Ransom says. "During that 50-year period, there were several years when losses were approximately 40% of the acreage."