Phosphorus deficiencies do not occur often in small grain production, however. Phosphorus applications may be reduced or may not be needed when small grain is planted after tobacco and other heavily fertilized crops such as peanuts, sweetpotatoes, and vegetable crops. Planting after these crops can reduce production costs. Potassium aids in carbohydrate production and winter survival. The suggested application rate for potassium is 40 to 50 pounds of K20 if needed.
Plants lacking in potassium usually remain small and lack vigor.
Winter hardiness is reduced, and the heads formed are small and compact. Potassium deficiencies seldom occur in small grain. Higher rates of phosphorus and potassium may be needed under an intensively managed system. Sulfur is a constituent of several amino acids. It is involved in electron transport, metabolism, and activities of many enzymes.