By Phyllis Bongard
University of Minnesota Extension
Farmers have faced many challenges in producing high quality pasture and forage as the weather has alternated between drought and excessive rain. However, alfalfa winter injury was not one of them.
“After a winter with very little snow cover, I expected to see a significant amount of alfalfa injury, particularly since it broke dormancy relatively early in the spring,” explained Dr. Craig Sheaffer, University of Minnesota Extension forage specialist. However, the mild late winter and early spring temperatures just didn’t get cold enough to significantly damage alfalfa, even without much snow cover.
“In northern Minnesota, we had severe drought and little to no forage production in 2023,” said Troy Salzer, University of Minnesota Extension educator, “but surprisingly, the forages came out of dormancy this spring in better condition than I expected.”
Then in a complete 180-degree shift, excessive rainfall in alfalfa growing regions made the first-crop hay harvest extremely challenging. The drying windows were short and some hay was baled wet, which can result in heating, molding, dry matter loss and even spontaneous combustion.
One way to extend the drying window is to use a hay preservative. The upper moisture content threshold will depend on bale type and size but using a preservative adds a degree of harvest flexibility.
Utilizing a wet forage system also has advantages. Taking the forage as haylage or baleage cuts harvest time to one to two days instead of the three to four days needed for baling hay. Harvest conditions were better for second and later crops with wider drying windows.
Mid-August through early September is a good time to seed new stands of alfalfa, complete pasture renovations and take soil tests. It’s also a great time to assess alfalfa stands. A good stand of established alfalfa should have three to five healthy plants per square foot and 40 to 50 stems per square foot. New seedings should have 25 to 30 plants per square foot in the seeding year.
To reduce the risk of alfalfa winter injury in a good stand, avoid harvest from 45 days before the first average killing frost (26F) to the actual first frost, which usually corresponds to sometime in early September or October. Alfalfa can be harvested after a killing frost but leave 6 inches of stubble to catch snow and insulate the crop.
If an alfalfa or mixed alfalfa stand is too thin going into winter, think about terminating it and reseeding in another area. Since the stand is going to be terminated, the forage can be harvested anytime during the fall.
If there are gaps in an alfalfa/grass stand, interseeding in mid-August is an option. However, to be successful, the stand needs to be open or suppressed. Otherwise, new seedlings will be unable to compete with the existing legumes and grasses. Make sure there is good seed-to-soil contact for germination.