Alfalfa (medicago sativa) was grown for five consecutive years on Groseclose silt loam to determine the effects of fertilization and cropping on the amounts of available K in the soil profile and on the yield and chemical composition of the alfalfa. Plant nutrients consisting of 0, 16, 40, 64 and 80 kg P/ha and 0, 60, 150, 240 and 300 kg K/ha were applied annually in a central composite rotatable design in the spring of each year beginning in 1966.