Two field experiments were conducted at the Experimental Station of Medicinal
and Aromatic Plants, Fac, of Agric" Mansoura Univ. during two successive seasons of
2002/2003 and 2003/2004 on marjoram plant, to determine the influence of two rates
of each of nitrobein. phosphorein and yeast on the vegetative growth, yield of herbs,
essential oil and chemical composition. The results showed that although all the treatments improved the growth and
yield parameters, active dry yeast proved to be the most favorable as significant
increases in growth parameters, oil % and oil yield per feddan. The most effective
concentration was 4 gIL before each cut. Hence, this treatment could be recommended for raising marjoram yield,
improving oil quality, lowering the productive costs and consequently minimize the
pollution of the agriculture environment.