However, in some cases, macronutrient, especially nitrogen, potassium, and magnesium, may simply be present in insufficient quantities. For example, if a grower neglects to add dolomite to the potting mixture because the pH is at an acceptable level, deficiencies of magnesium will result. Nitrogen, potassium, and magnesium are readily leached from sandy soils, such as those in some areas of Southern California, and in these cases, a complete fertilizer program is necessary. Since most of the now out-dated fertilizer recommendations for palms emphasized the application of large amounts of nitrogen and gave little attention to potassium, palms are often found deficient in this latter element. Adherence to sound cultural practices and a complete fertilizer program are essential to avoid nutrient deficiencies and to attain optimal growth of palms.
Chemical interactions affect the solubility of elements and their subsequent availability to plants.
Organic soils tend to fix copper. Generally, the best solution is applications of sulfur, incorporation of organic materials, and the use of mulches. Soluble forms of phosphate fertilizers can also tie up iron, manganese, and zinc. Root problems due to poor aeration, disease, mechanical damage, temperature extremes, and improper planting, inevitably lead to nutritional disorders since damaged or low-respiring roots are unable to take up essential elements. In fact, root damage is one of the leading causes of nutrient deficiencies in palms, especially of some micronutrient.