While many parts of the Midwest this year escaped the winterkill that plagued alfalfa fields in 2013, Michigan wasn’t as lucky. Nebraska alfalfa growers may find some winter damage, although to a lesser extent, and Manitoba growers are also being urged to assess stands.
Up to 40% of alfalfa fields in Michigan’s eastern Thumb region are estimated as winterkilled, according to a recent Michigan State University (MSU) Extension press release. About 20-25% of fields in other parts of the state also did not survive the winter, say Phil Kaatz and Fred Springborn, MSU Extension agents.
After experiencing a slow 2013 growing season, growers are concerned whether forage supplies in the state will hold up through next winter’s feeding season. Kaatz and Springborn caution producers to carefully plan their forage needs for the year and use alternative forages to make up for low alfalfa supplies.
The timing of one year’s final fall cutting can affect the health of an alfalfa stand the next spring. Some stands, with a fourth cutting taken after Sept. 1, had 75-80% loss. Fields cut only three times showed only around 10% loss, the specialists say.
Nebraska growers should also assess alfalfa stand damage after recent frosts and freezes. Bruce Anderson, University of Nebraska Extension forage specialist, suggests how to do that.
“Don’t just look for frozen or wilting leaves. You need to determine if the growing point was killed,” Anderson says. If alfalfa’s growing point – located inside a cluster of curled leaves near the top of the main stem – has died, new growth must come from new shoots at the crown or from lower branches. Cutting a field will spur regrowth, but that rarely pays, he adds.
“If the value of the hay that comes from harvesting current growth will pay for the harvest costs, it often is worth taking that harvest. I haven’t seen many damaged fields with that much growth, so most of you should just wait for plants to come back on their own,” Anderson says.
The Manitoba Forage & Grassland Association asked its growers to check alfalfa stand health in its May 16 newsletter article, "Evaluate Alfalfa For Winter Injury." "We have just gone thru what is reported to have been the coldest winter in a long time, and if your alfalfa fields didn't maintain a good snow cover, there is the possibility that it may have experienced some winter damage," writes John McGregor, MFGA Extension support.
In Michigan, growers with damaged fields can spot-seed cool-season grasses such as Italian ryegrass. The sooner the better to get the best yield, Kaatz and Springborn say. Don’t re-seed alfalfa into a damaged alfalfa field, they warn. It can cause alfalfa autotoxicity that prevents new seedlings from establishing.
A video showing how to assess an alfalfa stand is available from Dan Undersander, University of Wisconsin Extension forage specialist.