Field experiment was carried out at an organic farm during 2005- 2006 and 2006-2007 seasons. This experiment was carried out to study the efficiency of biofertilization and compost amendment in presence of Trichoderma harzianum on dehydrogenase, macronutrients uptake, polyphenol oxidase and peroxidase activity, oil yield and oil composition of marjoram. Obtained data showed that higher activity of dehydrogenase in rhizosphere and polyphenol oxidase & peroxidase were observed with dual application of biofertilization and organic manuring in presence of T. harzianum rather than each one individually. Similar trend of results was observed with N, P and K uptake since the highest records appeared with dual application of biofertilization and organic manuring. There isn't significant difference of oil yield between the chemical fertilization treatment and biofertilizers plus compost full dose treatment.

key words: Marjoram, biofertilization, organic manuring, T. harzianum, dehydrogenase,
macronutrients uptake, marjoram essential oil yield and oil composition.