Preliminary study of the nutritional status of pistachio in Aegina, Greece.

摘要

Pistachio trees have been cultivated on the island of Aegina, Greece, since 1860. The dominant variety Aegina is one of the finest pistachio varieties in the world. The aim of the study was to collect some information on the inorganic nutrition of pistachio in the area for fertilization recommendations to be more appropriate. Additionally, the causes of two types of symptoms observed in some orchards during summer have been investigated. The first one concerned severe burning or scorching on the tips or edges of the leaves, and the other concerned small, narrow leaves bunched together at the tips of the shoots. Thus, in the first days of August, fully expanded subterminal leaflets from nonfruiting branches from 41 commercial orchards, consisting of pistachio trees var. Aegina grafted onto Pistacia terebinthus cv. Tsikoudia, were collected and chemically analyzed. The results showed that 54% of pistachio orchards presented leaf nitrogen concentration below the critical value; the percentages were 20% in the case of phosphorus and 22% in the case of potassium. Calcium level was within the normal range in all orchards, whereas leaf chlorine was excessive in some cases. With regard to micronutrients iron, manganese and boron, levels were within the normal ranges, 30-50 ppm, 20-80 ppm, and 100-200 ppm, respectively, but zinc was below the critical value in 51% of the orchards tested. As for the symptoms observed, the first type of symptoms should be related to low potassium and/or excessive chloride concentration, whereas the second one should be related to zinc deficiency.