Make last alfalfa cutting before fall dormancy
By David G. Hallauer
Meadowlark District Extension Agent
With a little moisture this fall, we've seen decent regrowth in some stands, raising the question of another harvest. Knowing what the alfalfa plant is trying to do right now, and how the timing of this last cutting can have a long lasting impact on the stand's productivity, may help us determine when--or if--that last cutting should occur. Hay supplies and the chance for increased profit from the stand make the decision all the more difficult.
Agronomically, the plant is trying to store carbohydrates to survive the winter. If root reserves are not replenished before the first killing freeze (24 to 26 degrees), the stand is more susceptible to winter damage that can result in slower greenup and early growth next spring.
With that in mind, make the last cutting prior to fall dormancy so there are 8 to 12 inches of foliage, or four to six weeks of growth time, before the average killing freeze date. This should allow time for replenishment of root reserves. Late September is the northeast Kansas cutoff.
If you decide to make a cutting in to October, beware. If the fall is extended and good regrowth occurs to allow root carbohydrate replenishment, great. On the flip side, the worst thing that could happen would be for plants to regrow 3 to 6 inches and get a killing frost. Root reserves would be at their lowest and the stand could suffer. After a killing freeze, the remaining forage (if any) can be hayed safely, but do so quickly because the leaves will soon drop off.
Instead of cutting, consider soil testing. Testing now gives us a chance to make nutrient management decisions before growth starts next spring.