ABSTRACT
The orchardman is exposed continually to commercial interests touting the advantages of foliage application of nutrients. Possible advantages of foliage nutrient applications would appear associated with periods and/or situations in which the capacity for natural acquisition of nutrients by fruit trees is reduced. The “efficiency” of foliage nutrient applications may be considered from several perspectives: the rapidity of nutrient availability following foliage application, the percentage absorption of foliage-applied nutrients. The efficacy of nutritional sprays would appear to be dependent not only on the absorption of foliage-applied nutrients through the cuticle and epidermal cells but also the transport of these nutrients to fruit and other plant parts. Rapid uptake of foliage-applied nutrients and a temporary alleviation of boron, copper, calcium, iron, magnesium, manganese, potassium, nitrogen, and zinc deficiencies have long been appreciated in fruit trees. Although one annual application of soil nitrogen provided sufficient nitrogen for citrus trees, six or more foliar sprays were required.
