Influence of nitrogen fertilizer on the herb yield, essential oil content and composition of Tagetes minuta L.

The effect of 5 levels of nitrogen (0, 50, 100, 150 and 200 kg/ha) on herb yield, content and composition of essential oil of Tagetes minuta was studied in Tehran, Iran. Application of nitrogen fertilizer significantly increased the herb yield, content and percentages of constituents of essential oil of T. ininuta. The largest fresh and dry herb yields (70 and 29 t/ha, respectively) and the highest essential oil content (1.16%) were obtained from the plots that received 200 kg N/ha. GC and GC-MS analyses of the essential oil showed that different levels of nitrogen had significant effect on the essential oil constituents of T minuta. The major components of the essential oil were: p-cymene (4.1-5.0%), limonene (7.5-9.3%), dihydrotagetone (42.5-57.1%), (E)-tagetone (2.3-9.2%), (Z)-tagetone (14.9-17.9%), (Z)-ocimenone (0.8-4.6%) and (E)-ocimenone (2.0-5.1%).