Interaction of the rate of P and K fertilization on the yield response of three forage legume species

A response surface model was used to study the interaction between the rate of P and K fertilization on yield of three legume forage crops: alfalfa (Medicago sativa L.), trefoil (Lotus corniculatus L.), and red clover (Trifolium pratense L.). The results suggest that the soil test calibration recommendations developed for P or K on forage legumes are relatively insensitive to the rate of the other nutrient applied. Key words: Alfalfa, red clover, trefoil, soil test calibration, response surface model