Articles
Optimizing nitrogen, phosphorus and potassium fertilization for pomegranate fruit and juice quality
Article number
1375_9
Pages
61 – 72
Language
English
Abstract
Studies investigating the effects of NPK fertilization on pomegranate have focused mainly on growth and yield, and less on fruit-quality attributes.
Therefore, the major objective of this study was to examine the effects of different concentrations of NPK fertilization on fruit, aril, and juice quality of pomegranate cultivars Emek and Wonderful. Low N and high K fertilizer rates decreased fruit and aril weights for Emek but did not affect Wonderful. High K rates also decreased the number of arils in Emek fruit.
Low N rates increased the risk of sunburn in Wonderful fruit, but reduced peel roughness in Emek. Increased P rates decreased the proportion of rough peel in Wonderful and of black rot disease in Emek, but somewhat hindered red color development of Emek fruit peel.
High K rates resulted in a lower proportion of Emek fruit with rough peel and increased red color development.
In general, low P and high N reduced the proportion of marketable Wonderful and Emek fruit, respectively.
Low NPK increased the TSS-to-acid ratio of Emek juice by reducing its acid content.
Low N also decreased anthocyanin content in Emek juice.
Insufficient P rates enhanced the concentration of phenols and flavonoids in Wonderful and Emek juices, respectively.
Mg and S concentrations in the juices of both cultivars decreased when the trees were grown under low P, but Cu content was higher.
Overall, the effects of different fertilizer-application rates varied between the two cultivars.
Lower N and P and excessive K significantly influenced fruit quality, especially for Emek, an early-maturing cultivar that is harvested 2 months before Wonderful and may therefore accumulate less mineral nutrients during fruit ripening.
The fertilization regime of pomegranates should be adjusted to cultivar characteristics and maturity period.
Therefore, the major objective of this study was to examine the effects of different concentrations of NPK fertilization on fruit, aril, and juice quality of pomegranate cultivars Emek and Wonderful. Low N and high K fertilizer rates decreased fruit and aril weights for Emek but did not affect Wonderful. High K rates also decreased the number of arils in Emek fruit.
Low N rates increased the risk of sunburn in Wonderful fruit, but reduced peel roughness in Emek. Increased P rates decreased the proportion of rough peel in Wonderful and of black rot disease in Emek, but somewhat hindered red color development of Emek fruit peel.
High K rates resulted in a lower proportion of Emek fruit with rough peel and increased red color development.
In general, low P and high N reduced the proportion of marketable Wonderful and Emek fruit, respectively.
Low NPK increased the TSS-to-acid ratio of Emek juice by reducing its acid content.
Low N also decreased anthocyanin content in Emek juice.
Insufficient P rates enhanced the concentration of phenols and flavonoids in Wonderful and Emek juices, respectively.
Mg and S concentrations in the juices of both cultivars decreased when the trees were grown under low P, but Cu content was higher.
Overall, the effects of different fertilizer-application rates varied between the two cultivars.
Lower N and P and excessive K significantly influenced fruit quality, especially for Emek, an early-maturing cultivar that is harvested 2 months before Wonderful and may therefore accumulate less mineral nutrients during fruit ripening.
The fertilization regime of pomegranates should be adjusted to cultivar characteristics and maturity period.
Authors
A. Dag, Y. Lyu, R. Porat, Y. Heler, U. Yermiyahu
Keywords
Punica granatum, juice, TSS, Wonderfull, Emek, fruit quality, aril
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