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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]

Apple is grown in various parts of the world and consumed year-long in four seasons. The nutrient contents of fruit constitute the bases for several disorders experienced in storages. Although leaf analyses are used worldwide to assess the nutritional status of fruit trees, they may not yield accurate outcomes for assessment of fruit nutrient contents. Even if leaf nutrient contents are enough or quite high, various physiological disorders on fruits may be resulted from nutrient deficiencies. Fruit analyses should be performed to determine fruit nutrient contents and accordingly to improve flesh quality and to take relevant measures in early periods. In this study, fruit samples were collected for 2 years from 260 apple orchards in Isparta province of Turkey in 6 different periods covering the timeframe from June drops to harvest and fruit nutrient contents were determined from these samples. Firstly, seasonal variations of nutrients were examined. It was observed that fruit nutrient contents decreased periodically and this decreasing was quite faster through the early periods of the vegetation. Secondly, correlations between nutrient contents of the fruits sampled at the last period and the nutrient contents of the fruits sampled at earlier periods were also investigated in this study. Significant correlations revealed that fruit nutrient contents could be traced between the relevant periods and reference values could be established for these periods. Positive outcomes were observed for investigated nutrients except for N, Fe and Zn. [ABSTRACT FROM AUTHOR]