Boron should never be applied when seeding alfalfa with a cereal nurse crop, because cereals are susceptible to injury when boron is in close contact with the germinating seed. Peas, beans and sometimes cereals can be injured by residual boron left from a recent application to alfalfa. Potassium deficiency Potassium deficiency. Pattern of white leaf spots. B.C. Response to lime on acid soil.
Symptoms first appear on the lower leaves as small, white spots along the margins of leaflets.
The areas between the spots eventually turn yellow and die. The margins of older leaves may also turn a pinkish cinnamon colour before turning brown. Fertilize according to soil test results to improve yields. Winter survival may also be improved by the addition of potassium. Phosphorus deficiency is difficult to recognize.