The alfalfa field in the foreground likely had good enough snow cover protecting alfalfa plant crowns from extreme winter temperatures.
Bone-chilling cold weather in many parts of the country in early 2014 likely caused unpleasant flashbacks for alfalfa producers who saw crops decimated by winterkill a year ago.
Don’t worry, assures Dan Undersander, University of Wisconsin Extension forage specialist. Alfalfa – and he’s talking about crowns and not topgrowth – can survive soil temperatures of 10-15°F.
“As little as 4” of loose snow will insulate against 16°F of air temperature. The crown is insulated by soil as well. Therefore, the crucial temperature is the temperature at 2-4” below the soil surface,” he says.
As of Jan. 8, the soil temperature of bare ground at a depth of 4” was generally in the single digits above 0°F throughout the Midwest. In areas where there were 4” or more of snow on the ground, though, the soil temperature at a depth of 2-4” was generally 28-30°F. “(That’s) well-above the temperature likely to cause injury to alfalfa,” he says.
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