ARS | Publication request: The Tradeoff Between Alfalfa Yield and Quality

Submitted to: Symposium Proceedings
Publication Type: Proceedings
Publication Acceptance Date: November 10, 2006
Publication Date: November 10, 2006
Citation: Brink, G.E. 2006. The Tradeoff Between Alfalfa Yield and Quality. In: Proceedings of the Forage Industry Extension Advisory Council, November 10, 2006, LaCrosse, Wisconsin.

Technical Abstract: Extensive cutting management research has documented the effects of date and frequency of harvest on alfalfa (Medicago sativa L.) forage yield and quality. Information is lacking, however, on the change in quality relative to yield that occurs as alfalfa matures within individual harvest periods. We determined the rate of change in alfalfa forage quality and yield during each of the periods in which it is harvested. In May, June, July, and September, 'Standfast', 'WL 346', and 'Affinity' alfalfa were harvested initially at late vegetative stage (stem length > 12 inches; no buds, flowers, or seed pods) in Idaho, Pennsylvania, and Wisconsin. Different plots of each variety were harvested every 5 days thereafter to 20 days of maturity. Forage yield and quality were measured for each harvest. Mean yield and quality was greatest in the spring. Rate of dry matter production was greatest in the spring in Pennsylvania and Wisconsin, but was greatest in the summer under irrigation in Idaho. The rate of quality decline at all locations was greatest in early summer, and slowest in late summer. Using an index that combines forage yield and quality into a single term to estimate milk production, 10 to 15 days after late vegetative stage was the optimum time to harvest in the spring, early summer, and fall, while a late summer harvest could be delayed to 20 days without sacrificing quality.