IMPACT OF IRON CHLOROSIS ON MACRO- AND MICRO-NUTRIENT BUDGETS IN PEACH

Fertilizers are used on fruit trees to maintain an adequate nutritional status. In this paper an estimation of the amounts of macro- (N, P, K, Ca and Mg) and micronutrients (Fe, Mn, Cu and Zn) required over one year in a peach tree is presented, by measuring the amounts lost (per tree) in four major nutrient removal events: winter pruning, flower abscission, fruit harvest and leaf fall. This is a first attempt to obtain a framework for the macro- and micronutrient needs of an average peach tree in a typical Mediterranean orchard. Samples from three very different peach orchards (Prunus persica L. Batsch) grown on calcareous soils were used for this estimation. The macronutrient yearly needs (in g tree^-1) were estimated for the chlorotic trees to be in the ranges 120-220 for N, 9-30 for P, 150-260 for K, 70-220 for Ca, 15-50 for Mg, 0.4-1.1 for Fe, 0.2-0.5 for Mn, 0.2-0.6 for Cu and 0.1-0.3 for Zn. In the case of control (healthy trees), the yearly nutrient demands were considerably higher, in the ranges 230-360 for N, 23-40 for P, 330-500 for K, 100-415 for Ca, 24-85 for Mg, 0.6-1.8 for Fe, 0.4-0.7 for Mn, 0.3-0.8 for Cu and 0.2-0.4 for Zn.