Effects of foliar application of micronutrients (Fe and Zn) on yield, yield components, and essential oil of fennel (Foeniculum vulgare Mill)

Foliar application of micronutrients is a useful technique for rapid absorption of minerals in the plants and avoids soil contamination. To evaluate the effect of foliar application of micronutrients (iron and zinc) on yield, yield components, and essential oil of fennel (Foeniculum vulgare Mill.), an experiment was conducted as factorial based on randomized complete blocks design with three replications at the Faculty of Agriculture, University of Zanjan during the growing season of 2012. In this experiment, the effect of foliar application of Fe (using ferrous sulphate) at four concentrations (0, 1, 2 and 3 gr.L-1) and foliar application of Zn (using zinc sulphate) at three concentrations (0, 2 and 4 gr.L-1) were investigated. Results showed that the majority of measured traits including number of umbels per plant, 1000-seed weight, grain yield, essential oil content and essential oil yield were significantly affected (p≤ 0.01) by combined application of iron and zinc. Therefore, the highest grain yield (2637.96 kg ha-1) was obtained in foliar application of Fe + Zn at a concentration of 0.2%. In addition, the highest essential oil content (2.88%) and essential oil yield (75.71 kg ha-1) were obtained in combined application of Fe 0.3% and Zn 0.2% and the lowest content of mentioned traits was obtained in control.