ABSTRACT
The present study was carried out during two successive seasons at the Experimental Farm of Cultivation and Production of Medicinal and Aromatic Plants Department, National Research Center, Giza, Egypt.The aim of this study was to investigate the effect of differc-t nitrogen levels on the yield and essential oil production of Ocimum cimericanum.Herbage yield was significantly increased with nitrogen fertilization especially at high levels [40, 60 and 80 kg N/fed]. Both fresh and dry yield of herb [ton/fed] in both seasons were significantly influenced. Similarly, the same effect was obtained on leaves fresh and dry yield per feddan [4200 m[2]]. The highest herb and leaves yields were obtained as a result of 60 kg N/fed. The highest oil percentage was associated with the highest nitrogen dose [80 kg N/fed] in most cuts of both seasons. All nitrogen doses significantly increased oil content [mi/plant] comparing to unfertilized plants. In all cuts of both seasons, 60 kg N/fed produced the highest oil content. The maximum total oil yield [ml/plants or 1/fed] were obtained with 80 and 60 kg N/fed in the lst and 2nd seasons, respectively. All identified compounds were observed in the essential oil of all treatments. The major compound was found to be eugenol followed by methyl chavicol. Generally, the higher the nitrdgen was applied, the higher the methyl chavicol was produced; the opposite was true with eugenol.As a conclusion we may recommend the fertilization of Ocirnum arnericanurn L. plants with 60 kg N/fed as ammonium sulfate to maximize herb, leaves and oil production either per plant or per feddan