[Changes in essential oil content/composition and shoot aerial yield of lavender [Lavandula officinalis L.] affected by different treatments of nitrogen]

Nitrogen is one of the very effective elements in increasing the phytochemical and agronomical yield of medicinal plants. Therefore it is necessary to examine the effect of nitrogen on essential oil and dry matter production of lavender. This research was carried out to evaluate changes of essential oil content and dry matter of lavender under different nitrogen treatments for reduces of nitrogen fertilizer uses. The study was conducted at the research field of Islamic Azad University [IAU], Shahr-e-Rey branch, on basis of Randomized Complete Block Design [RCBD] with 4 replication and 7 treatments. The treatments were spraying of 0, 1.5, 3, 4.5, 6 and 7.5 percent N and 180 kg ha[-1] nitrogen as urea. Different traits including plant height, stem diameter, branch number, leaves and stems dry weight, foliage dry and fresh weight, essential oil content and composition were recorded. Effect of treatments on all of the plant traits [p<0.01], essential oil content and linalool [p<0.05] were statistically significant differences. The highest amount of plant height and number of stems was observed in spraying of 4.5 percent nitrogen per hectare. Also, the maximum stem diameter, shoot fresh weight, stem, leaves and shoot dry weight, and essential oil content, linalool and 1,8-cineole was obtained in soil treated with 180 kg of nitrogen per hectare. The foliar application of 4.5% of N ha[-1] and 180 kg N ha[-1] treatments hadn't significantly effect on shoot dry weight and essential oil content. The results showed that nitrogen spraying at appropriate concentration could be improved growth and essential oil content, and also, reduced nitrogen using, contamination, and cost production