VasilicaOnofreia, Gabriel-CiprianTelibana, Marian Burducead, AminaBenchennoufb, Magdalena Janchevab, Sofia Loupassakib, SpirosGrigorakis b, WalidOuaretc
Calendula officinalis L. (marigold) is a valuable medicinal plant, widely used in traditional and modern medicine, perfumery, the food industry, cosmetics and landscaping. In order to study the effect of organic foliar fertilization on essential oil (EO) content and composition, a field experiment was conducted. Treatments including four different organic foliar fertilizers: Fylo® (F1), GeolinoPlants&Flowers® (F2), Cropmax® (F3), Fitokondi® (F4) and control were set up in a factorial experiment based on split plot design with three replications. On average, in the period between 2015-2016, in the production of fresh inflorescences of Calendula officinalis L., there were percentage increases in foliar fertilized variants ranging from 18% to 29% compared to the control. In order to ensure maximum productivity, it is advisable to harvest 2-3 days in high temperature periods, reaching 4-5 days depending on climatic conditions. The staggering and the dynamics of production highlight in 2015 a maximum of production that was obtained between August 15 and 31, and in 2016, during July 1-15. Moreover, certain variations in the content of particular compounds in EO were found, depending on the fertilization applied. Accordingly, it can be concluded that organic foliar fertilization can considerably improve the essential oil content, without drastic effects on the chemical composition. The changes were also pronounced in secondary metabolism, so the amount of phenols, flavonoids, and antioxidant activity, increased the amount of oil in some treatments to the control.