Alfalfa winterkill throughout the Upper Midwest will be nowhere near as severe as it was a year ago, says Dan Undersander, forage agronomist with University of Wisconsin Extension.
“In Wisconsin, Iowa, Illinois and Minnesota, it’s still early yet to tell how much damage there has been,” says Undersander. “But from the little we’ve seen so far, the plants are looking pretty good.”
One key factor, he says, is that alfalfa in many parts of the region went into the winter in better shape than it had the year before. “In most areas, we had adequate moisture and good regrowth in the fall. That meant good replenishment of root carbohydrates.”
Adequate snow cover in many areas also protected alfalfa from long periods of extreme cold temperatures this winter. Also positive, says Undersander, are reports that water from melting snow is going directly into the ground rather than ponding up on the surface. “That means that, as cold as it was, the ground was barely frozen in many areas.”
There were exceptions, most notably in western Minnesota, the Dakotas and parts of Nebraska. “In some of those places, they had more of an open winter and lacked snow cover at critical times (i.e., during long stretches of extreme cold).”
While the outlook for less winter injury is favorable overall, spring’s late arrival could still present problems. “We’ve had a longer-than-normal dormant period,” Undersander explains. “And the longer the dormancy, the longer the plant respires. That means the plant may not have the gas in the tank it needs to keep the engine running.”
Growers can get a better idea of how much winter injury their stands experienced by walking fields after the frost is out of the ground. Dig up a few plants and split open the tap roots, he suggests. “If the color is turgid and white (think ‘potato-like’), the plant is fine. If it’s browned or ropey, the plant is dead or dying.”
For more tips from Undersander on assessing the condition of spring alfalfa stands, check this paper on the Wisconsin Team Forage website. Also on the site is the Extension bulletin, Alfalfa Stand Assessment: Is This Stand Good Enough To Keep?