Effects of High Electroconductivity Field Conditions on Production of Six Alfalfa Varieties on the Colorado River Indian Tribes Reservation

Five alfalfa varieties were planted and grown under grower conditions on a field section that had high conductivity, while two varieties were planted and grown on a section of the same field much less affected. CUF 101, the variety grown in both areas, was the highest yielding variety in both area. Reduction in CUF 101 hay yield due to high conductivity was approximately one ton/acre in the first year of production, with a large amount of this noted in the first cutting. Yield reductions of CUF 101 due to field area and associated electroconductivity were greater the second year, with an average of 0.29 tons/acre/cutting. Total yield difference for CUF 101 was 1.72 tons/acre for the eight harvests for which data were available. Yield differences between the areas was greatest in the early spring and late fall of the first harvest year, with differences not noted in the June cutting; in year two yield differences were approximately 37% for each cutting. Salado was the second highest yielding variety in the high electroconductivity area in 1998, and equaled CUF 101 in yield from this area in 1999. Sal-T-96 and Leivas Best yielded less than 90% of CUF 101. Sal-T-96 also had the greatest number of weeds, due in part to very slow germination and fewer plants per acre compared with other varieties