The Effect of Chemical and Biological Fertilizers on Flower Yield, Leaf Yield and Essential Oil of Lavender (Lavandula angustifolia)

To study the effect of chemical and biological fertilizers on growth and essential oil content of lavender (Lavandula angustifolia Mill.), the present work was conducted in 2012-2013 at the experimental field of Alborz Research Station of the Research Institute of Forests and Rangelands, Karaj, Iran. The experiment was conducted in factorial in the form of a randomized complete block design with three replications and two treatments: chemical nitrogen and phosphorus fertilizers in four levels (N0P0, N0P150, N300P0, and N300P150) and biological fertilizers in four levels (non inoculated control, double inoculation with Glomus mosseae + G. intraradices, inoculation with Pseudomonas fluorescens, and triple inoculation of G. mosseae + G. intraradices + P. fluorescens). Results indicated that chemical and biological fertilizer significantly affected flower yield, flower essential oil content, flower essential oil yield and flower + leaf essential oil yield (P≤0.01). The interaction of the two factors had also a significant effect on flower yield, flower essential oil content (percentage), flower essential oil yield and flower + leaf essential oil yield (P≤0.01). Mean comparison showed that flower yield was the highest in N0P150 × the triple inoculation (3932.5 kg/ha). The highest flower essential oil yield was achieved in N0P150 × the double inoculation with mycorrhiza fungi (114.27 kg/ha). The total essential oil yield of flower + leaf was the highest in N0P150 × the double inoculation with mycorrhizal fungi (144.6 kg/ha) and N0P150 × P. fluorescens (134.73 kg/ha). Generally, results indicated that the triple inoculation of G. mosseae + G. intraradices + P. fluorescens gave the best results of essential oil.