APPLICATION OF SELECTED MACRONUTRIENTS (N, K) IN DECIDUOUS ORCHARDS: PHYSIOLOGICAL AND AGROTECHNICAL PERSPECTIVES

The literature is replete with reports of foliar applications of macronutrients, especially, nitrogen (N) and potassium (K) and the inconsistency of tree responses to those applications. Genotype-specific parameters may affect the capacity for foliar nutrient delivery. Seasonal and physiological patterns of tree nutrient demand and soil and management variables which impact soil nutrient mobility and tree capacity for soil nutrient uptake are also relevant. Site-specific variation including environmental variables, soil conditions and fertilization and irrigation management may also influence the consistency of response to foliar fertilization. Our working premise is that a positive response to foliar-applied macronutrients, such as N and K, may be anticipated when soil nutrient acquisition is inadequate to meet tree nutrient demand, and significant quantities of nutrients can be delivered foliarly, absorbed from leaf surfaces and translocated to sites of utilization within the tree.