Three Year Summary of Yield, Weed Infestation and Other Attributes of Five Alfalfa Varieties Planted October 1994 on the Colorado River Indian Tribes Reservation

Five alfalfa varieties (CUF 101, SW 14, SW8210, Pioneer 5888, and a grower selection originating from CUF 101 and noted as Baldwin Select) that were planted in October, 1994, into large plots (0.75 acres) to obtain actual field harvest data production during the years of 1995-1997. Varietal hay yields were very similar in 1995 until mid summer, when area soil temperatures reached above 100°F at the four inch depth for a period of about 6 weeks. During the summer months Baldwin Select had significantly higher yields than other varieties tested. Statistical differences in accumulated hay yields were noted beginning in August 1995 and continued through 1997. Baldwin Select was the highest yielding variety each year, producing 8.4% more than CUF 101 during this time period, worth $247/acre more an acre than CUf 101. Alfalfa varieties were similar in relative feed value. Yellowing from Empoasca spp. leafhoppers was greatest during the 1995-1996 winter on varieties with fall dormancy ratings of 9 or greater. Weed infestations during late summer 1996 appear inversely correlated with fall dormancy class. All varieties of dormancy classes 8 and 9 were almost 100% infested with weeds during September 1997, although Baldwin Select had significantly less infestation. Differences in plant populations in late September 1997 also appear to be correlated with fall dormancy class