Fall Harvesting of Alfalfa in North Dakota Impacts Plant Density, Yield, and Nutritive Value

Alfalfa (Medicago sativa L.) is often not harvested in North Dakota during the fall because producers fear the risk of winter-kill and stand reduction. The objective of this study was to determine the impact of a fall harvest on plant density, forage yield, and nutritive value of alfalfa. Two replicated experiments were planted and evaluated in Fargo, ND. Experiment 1 was conducted from 2004 to 2008 and Experiment 2 from 2007 to 2011. Treatments in the two experiments were either a 3-cut system with no fall harvest or a 4-cut system with a fall harvest. Analysis was conducted across experiments and years. In certain years, plant density was significantly reduced when alfalfa was harvested in the fall. The 4-cut system, which included a fall harvest, had significantly greater seasonal forage yield. The total seasonal forage yield for the 4-cut system was approximately 1.04 to 3.88 Mg/ha greater than that of the 3-cut system. However, including a fall harvest decreased forage yield in the first cut the following season. In general, a fall harvest of alfalfa increases seasonal forage yield without reducing stand persistence and overall forage nutritive value.