For the most part, it appears little alfalfa winterkill has occurred in Wisconsin, reports University of Wisconsin forage specialist Dan Undersander. The most notable exception is in five counties in southwestern Wisconsin extending into northeastern Iowa. “In that area, we’re seeing 20-30% stand loss,” says Undersander. “Those are stands where more than 50% of the plants were killed. They’re no longer salvageable.”
Most of the affected stands in the area, Undersander adds, are in low spots where ice and standing water were the main problems. “However, some was on hilltops and likely due to the snowmelts in January with some ice sheeting and some exposure to cold. The situation is also clearly worse where stands were harvested in late fall.”
In other parts of the state, winterkill was restricted to small areas, mostly in low spots. “In northern Wisconsin it’s still greening up, so we won’t really know for another week or so if there’s been any significant damage there,” he says.
Dan Martens, University of Minnesota extension educator for Stearns, Morrison and Benton counties, reports there have been scattered reports of winter stress on alfalfa in central Minnesota. “There are some spots, not whole fields, where we would anticipate some problems with winterkill.” Most likely to be affected, he says, are hilltops where wind blew snow cover clear during the winter and low spots where February and March rains led to ponding followed by freezing.
Martens advises alfalfa growers to check their fields for problems. “This would be a good time to go out there and do stand assessments. Look for areas with uneven growth, perhaps focusing on those hills and low spots.”