It’s the end of December and recent storms in colder regions have covered alfalfa with snow, says Bruce Anderson, University of Nebraska Extension forage specialist.
“Nothing can increase the chance of alfalfa surviving winter better than a thick blanket of snow,” he says.
The moderate fall weather helped alfalfa plants harden well for winter, providing a high concentration of nutrients and a low concentration of water in their roots. This enables alfalfa crowns and roots to withstand temperatures down as low as 5 degrees above zero, he says.
“Now, I know this doesn't sound all that cold. After all, air temperatures will get much colder than that. Fortunately, the soil doesn't get as cold as the air above it. And when soil is covered with a blanket of snow, this snow acts like a layer of insulation protecting the ground from bitter cold temperatures. Plus, it reduces the rate that soils and alfalfa roots dry out. This is why winters with little snow cover can cause more injury to alfalfa stands, especially if soils also are dry as they are this winter.”
Fall management practices influence the effect of snow on alfalfa, Anderson says. Leaving tall stubble provides some insulation value itself and the stubble will catch more snow. Harvesting alfalfa other than the so-called risk period from mid-September through mid-October helps it roots winterize well by building up nutrients and reducing water content.