Fall cutting management is important to ensuring not only good winter survivability, but also that yield is not lost in spring.
Fall is an important time to ensure that hay fields are properly managed, and attention is paid to details that will help to ensure their survival through the winter. Fall harvest management can be the greatest determining factor of forage stand longevity.
Regardless of whether the hay field is grass or legumes, residual height should be a primary concern for the last cutting of forage. Ensuring proper residual height will allow the forages adequate leaf material to photosynthesize and regrow top growth, root mass, as well as store carbohydrates at the base of the plant to overwinter.
Cutting grasses too late and too low during the later parts of the year, will result in the removal of the carbohydrates the forage stored all summer long. This loss of carbohydrates will reduce bud formation and crown tissue, and inevitability lead to a lower yield in the spring of the subsequent year. Information provided by Michigan State University says that removing 50% of less of leaf mass will result in little to no damage to root structure. After a 50% removal, the damage is great. This is very important when considering winter cutting management and how the plant can bounce back from this harvest and its winter survivability.
With more winter-hardy varieties of alfalfa available, tradition is beginning to be tested with producers taking their final cutting later into the fall. If winter-hardiness is part of the improved genetics utilized on your operation, the improved winter-hardiness could possibly allow the alfalfa to withstand a slightly later cutting. With that said, it is always important to understand your variety and know that improved winter heartiness does not mean push the envelope as far as possible.
If there is proper soil pH and fertility, especially potassium, as well as being well-drained, a later cutting is a possibility. Fall cuttings of alfalfa should have no less than a 4-inch stubble height to ensure enough plant material is present to photosynthesize and rebuild carbohydrate stores necessary to over-winter. It is
Some information for this article came from Michigan State University article Cutting Management for Cool Season Forage Grasses and Ohio State University Time to Take the Last Forage Cutting. Read them out for more information on this topic.