Effects of Foliar Application of Calcium Compounds on Formation and Development of Pistachio (Pistacia vera L.) Nuts

This study aimed to investigate the role of calcium in formation of nut and preventing loss of nuts in pistachio cv. Abbasali. Four calcium compounds including calcium nitrate (3/1000), chelate calcium EDTA (1/1000), nano chelate calcium (1/1000) and chelate calcium amino acid (1/1000) were sprayed five times on foliage of 20 years old trees in pistachio garden of Binalud- Neishabor Agricultural Company. The experiment was in factorial based on randomized complete block design with three replications, carried out for two years (2012-2013). Foliar fertilization was started at the end of pollination and repeated for five times with ten days intervals. The results showed that the effects of calcium compound, number of sprayings and interaction of them were not significant on number of nuts per cluster. The effects of calcium compounds were significant on percentage of kernel, splitting and leaf calcium at 5% and on percentage of fruit calcium at 1% levels of probability. Calcium nitrate with 0.16% and nano chelate calcium with 0.13%, had the highest and lowest of fruit calcium contents, respectively. Interaction effects of chelate calcium amino acid and five times spraying were significant on ounce (p ≤ 0.01). The effect of year was also significant (p ≤ 0.01) on number of nut per cluster, percentages of blank fruits, splitted fruits and leaf calcium content. Generally, chelate calcium EDTA with five time applications had the most effects on ounce, and percentages of kernel and leaf calcium content.