evaluation of basil (ocimum basilicum l.) essential oil content and yield under different plant densities and nitrogen levels

a study was conducted to investigate the effect of different planting densities and nitrogen doses on essential oil content and yield in herb and leaves of basil (ocimum basilicum l.). the research was conducted during 2007 and 2008 using split-plot randomized complete block design with four replications. the experiment consisted of four plant densities (30×20, 40×20 and 50×20 cm) as the main plot and four nitrogen levels (0, 50, 100 and 150 kg/ha) as the sub plots. results showed plant density did not have significant effect on essential oil content and essential oil yield in herb and leaves. mean essential oil ratio in herb was 0.49, 0.44%; essential oil ratio in leaf 0.59, 0.54%; essential oil yield in herb 19.4, 23.7 l/ha and essential oil yield in leaf was 12.8, 16.1 l/ha during 2007 and 2008, respectively. the highest essential oil ratio in herb was obtained from 40×20 cm plant density and 50 kg ha-1 n during 2007. nitrogen fertilizer had statistically insignificant effect on oil ratio of herb and leaves during two years of experiment. the highest essential oil yield of herb was obtained from low density(30×20 cm) using 100 kg ha-1 n fertilizer. in general, essential oil yield during 2008 with three cuts was better compared to 2007 with two cuts.