What's Hot at the PPDL

April 2, 2019

Winter Heaving of Alfalfa

Keith Johnson, Purdue Extension Forage Specialist​

Heaving of alfalfa taproots is a stress that elevates crowns and taproots above the soil surface and occurs when we have extreme temperature swings during winters with moist soils. Damage levels may vary widely from year to year.  Alfalfa fields should be scouted in early spring for evidence of winter injury and heaving. Note that as temperatures warm in April, scouting for the presence of alfalfa weevil should be a routine task as well.

 

If heaving occurs and plants survive, cutting height needs to be adjusted so crowns are not severed from the taproot when mowing occurs. Heaving can cause wounds to the taproot which results in the possible movement of pathogens into the alfalfa. In severe cases, growers may need to seed alternative forages to meet the forage inventory needs of livestock owned by the producers.


Click image to enlarge


Figure 1. Winter heaving of alfalfa lifts the crown above soil line, making it susceptible to injury from insects, mowing and pathogens.