Nitrogen and potassium fertilization criteria for citrus orchards was not clearly stablished yet, based on regional experimentation. This experiment was carried out in order to compare the effects of combined levels of N and K fertilization on citrus orchard of 'Valência', cultivaded in Adolfo (Northen of São Paulo State -- Brazil). Three levels of nitrogen, 94, 188 and 376 kg.ha-1 as ammonium nitrate and three levels of potassium, 38, 75 and 150 kg ha-1 of K2O as potassium chloride, were combined in factorial design 3 x 3 with 3 replications, during three harvest (1997 to 1999). Fruit productions, fruit tecnological analysis and foliar diagnosis were evaluated yearly. Data showed that the trees kept the productivity with the mininum levels of N and K2O for three years and no response in productivity was observed in this period. Only in the second year, when yield was decreased by climatic factors, it was observed effects of combined levels of N and K2O on juice acidity and soluble solids contents.
citrus; nitrogen; potassium; fertilization
