PRUNING AND NITROGEN EFFECTS ON ELEMENTAL PARTITIONING AND FRUIT MATURITY IN BING SWEET CHERRY

Six levels of pruning and two rates of nitrogen fertilizer were applie d to 20-year old 'Bing' sweet cherry (Prunus avium) trees over several seasons. Two consecutive years of heavy pruning increased leaf N, P, K. and Cu, and fruit N, P, K Ca, Mg, S, Fe, Si, Zn, and Sr as compared to non-pruned trees. Non-pruned trees had fruits with more soluble so lid concentration (SSC) and color. Higher nitrogen application resulte d in higher concentrations of N, Mn, and Cu, but lower P, K Ca, B, and Mo in the leaf. High N fertilizer also increased fruit N, Mn, Zn, Na, and Sr, but delayed fruit maturity. A major year to year variation wa s observed with leaf N increasing and K decreasing in the heavy croppi ng year. More precise attention to the pruning practices and crop load in addition to fertilizer practice is recommended when interpreting t he results of any leaf mineral analysis.