While winter injury in forages is very hard to predict, this winter has presented some very tough
conditions for forage stands, according to Rory Lewandowski, Ohio State University extension educator.

This is especially true of legumes like alfalfa and red clover. Producers and crop consultants should be
prepared to walk forage stands early this spring to assess their condition in time to make decisions and
adjustments for the 2019 growing season.
The soil temperature at the 2-inch depth is associated with the temperature of plant crowns. The coldest
2-inch soil temperatures recorded since Jan. 1 at the Ohio State University Agricultural Research
Stations occurred in late January to early February, falling to 17.8 F at Northwest.
To put this in perspective, temperatures in the 5 to 15 F range as measured at or just below the soil
surface can begin to damage perennial legumes. So, it appears that the soil temperatures this winter did
not pose a concern.
The greater concern we have for injury this winter is associated with the rapid freeze/thaw cycles and
saturated soil conditions. These cycles can cause plants to be physically lifted (i.e. heaved) out of
the soil.
The greatest potential for heaving is with taprooted legumes like alfalfa and red clover. This heaving
exposes the plant crown, making it more susceptible to cold air temperatures and physical injury. In
severe cases, heaving breaks off the taproot, effectively killing the plant
Forage stand health evaluation and winter injury assessment needs to be done by getting out into the
field once there is 3 to 4 inches of growth from the plant.
In addition to counting the legume plants per square foot, a count of the total stems per square foot is
also useful because healthy plants can often produce more stems per plant thereby compensating for
potential yield loss from fewer plants per square foot.
After counting the plants, dig up all the plants in a one-foot square area for every 5 to 10 acres and
examine the crown and roots of the plants.
An alfalfa plant density of 10 plants per square foot in a 2-year-old planting is minimum, while 5 plants
per square foot in 3 year or older planting is minimum for normal yields.