Effect of Winter Survival Rating On Medicago Sativa Yield.

A study was established at the University of Wisconsin Marshfield research station (Marshfield, Wisconsin 44^o 38’ N 90^o 9’W) in 2005 to examine the interaction of Medicago sativa winter survival score and cutting management on yield and persistence.  Four cultivars ranging in winter survival score from 1.8 to 3.1 were planted and harvested with 2, 3, or 4 cuttings by September 1, each with and without fall cutting. Yields were taken in 2006 to 2009.  The average yields were 10.2, 11.1 and 9.2 Mg ha^-1 for 2, 3, and 4 cuttings by September 1. The average yields with a late fall harvest were 11.7, 12.5, and 9.3 Mg ha^-1 for the same treatments with an additional late fall cutting.  The late fall cutting significantly increased the yield of the 2- and 3- cut system but not the 4-cut system.  The reason for no effect of late fall harvest on the 4-cut system was that an additional late fall cutting reduced yield of cuttings during the next growing season.  It should be noted that not taking a late fall cutting and leaving the residue reduced the quality of first cutting slightly in the spring.