Calcium is only applied other than for liming in cases of definite deficiency. Ca components of foliar sprays. They may be applied either as single-nutrient fertilizers or as supplements in macronutrient fertilizers. The quickest and commonest method of correcting deficiencies is by foliar application. For soil application the latter has the advantage that it is more stable in neutral soils.
Manganese deficiency occurs mainly in slightly acidic to neutral soils.
Indirect improvement of the soil supply may be achieved by using acidifying N fertilizers. Zn is recommended. Boron needs vary widely. A better distribution can be obtained by incorporating the boron in e.g. phosphate or multinutrient fertilizers. Multinutrient fertilizers Since crops often require an additional supply of several nutrients, special combinations with different nutrient ratios offer a considerable simplification and facilitation of fertilizer application.