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Fertilizers are commonly applied to improve the yield and quality in orchards. Leaf analyses are usually used worldwide for conscious fertilization. However, there may not be linear relationships always between leaf and fruit nutrient contents. On the other hand, fruit quality problems are directly related to fruit nutrient contents. Therefore, fruit analyses assessed together with leaf analyses are more reliable in assessing nutritional status of orchards. Fruit analyses on the other hand are possible with the reference values to be established for fruits. In this study, 260 apple orchards were selected from Isparta province of Turkey in where apple is cultivated intensively. Fruit samples were taken at 6 different periods covering the timeframe from June drops to harvest and the reference values representing deficiency and excess limits for N, P, K, Ca, Mg, Fe, Mn, Zn and B in each period were determined. To determine the reference values for all sampling periods, the regression curves were created by using the reference values of each period. A decrease was observed in reference values of all nutrients with increasing number of days from the full bloom. The cultivar-induced differences were also put forth in assessment of fruit analyses. Cultivars were compared in 68 orchards composed of different cultivars grafted on seedling rootstocks and at full-yield in two districts with different soil characteristics. Cultivars were found to be significant for all nutrients, except for N, Fe, Cu and Zn and the greatest values were observed in Granny Smith. [ABSTRACT FROM AUTHOR]

This study was conducted to investigate the possible use of flower analyses in assessing the nutritional status of apple orchards at the initiation of vegetation. In successive years, samples were taken from 150 orchards at the initiation of bloom for flowers and at seven different time points covering the timeframe between 14 and 98 days after full-bloom for leaves. When the flower nutrient contents were ordered from lowest to highest, the lower and upper percentage quartile was accepted as the reference value for each nutrient and as the cutoff for nutrient deficiency or excess. Reference values were 3.33–3.98% N, 0.46–0.54% P, 2.10–2.47% K, 0.39–0.51% Ca, 0.25–0.31% Mg, 67–110 ppm Fe, 35–65 ppm Cu, 20–31 ppm Mn, 37–50 ppm Zn and 55–79 ppm B. Correlations between nutrient contents of the flowers and leaves sampled at all time points were also investigated. The presence of significant correlations showed that flower analysis can be used to determine the nutritional status of apples. Positive outcomes were observed for P, Mg, Mn and B. In addition, cultivar-induced differences were also observed in flower for Ca, Mg, Fe, Mn, Zn and B. [ABSTRACT FROM AUTHOR]