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Valencia orange trees [Citrus sinensis (L.) Osb.], budded on sour orange (C. aurantium) rootstock, were sprayed with four different potassium salts during 1995 and 1996. Twenty 5-year-old trees were sprayed once per month with one of the following material. K0: distilled water, K1: potassium green (a compound of different potassium salts, 35% K2O), K2: potassium nitrate (35% K2O), K3: potassium citrate (35% K2O), or K4: potassium sulfate (51% K2O). The vegetative growth occurred in three distinct successive cycles, i.e., spring, summer, and autumn. These cycles differed in time of commencement, duration and termination with respect to season. All potassium treatments significantly increased the shoot length and number of leaves/shoot for the three growth cycles. However, potassium green was superior overall other treatments. Percentage of leaf miner infestation was reduced at all potassium treatments. Potassium applications significantly increased leaf contents of N, P, K and decreased Ca and Mg levels.

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