EFFECT OF IRRIGATION INTERVALS AND BIOFERTILIZATION ON GROWTH, YIELD, OIL PRODUCTION AND CHEMICAL CONSTITUENTS OF ROSEMARY ( Rosmarinus officinalis,L.) PLANTS.

This investigation was carried out aiming to study the effect ofirrigation intervals ( every 7 , 11 and 15 days) and Biofertilization ( nitrobienand phosphorein each at 0 , 3 and 6 g /pot) on growth, yield, oil productionand chemical composition of rosemary (Rosmarinus officinalis, L.), duringtwo successive seasons of 2004 and 2005.The results showed that irrigation every 7 days gave the tallest plant,the highest oil percentage and oil yield/ plant in the first cut of both twoseasons, the highest number of branches/ plant, fresh and dry weights/plant,total carbohydrates , N, P and K percentage in the first and second cut ofboth seasons and gave the highest linalool and P-cymene percentages in theessential oil. Whereas irrigation every 11 days gave the tallest plant, thehighest oil percentage and oil yield/ plant in the second cut of both seasonsand the highest α-pinene, β-pinene, limonene, 1,8 cineol and camphorpercentages compared to irrigation every 15 days which gave the lowestvalues.Nitrobien and phosphorein at 3 and 6 gm/ pot significantly increasedplant height, number of branches/ plant, fresh and dry weights/ plant and oilyield/ plant, and increased the main constituents of the essential oil (γ-Terpenene, 1,8 cineol, linalool , camphor, P-cymene, bornyl acetate and βcaryophyllene percentages ), total carbohydrates, N, P and K contents in thefirst and second cut of both two seasons compared to unfertilized control.Interaction between irrigation intervals and bio-fertilization had asignificant effect on vegetative growth characteristics and oil percentage andoil yield. Irrigation every 7 days and phosphorein at 6 g /pot gave the highestvalues of plant height ( in the first cut), number of branches /plant ( secondcut), fresh and dry weights /plant ( in the first cut, oil yield /plant ( in the firstcut), total carbohydrates, N and P contents in the first and second cut of bothseasons. Whereas irrigation every 11 days and phosphorein application at 6 g/pot gave the highest dry weight/ plant, oil percentage and oil yield/ plant inthe second cut of both two seasons. irrigation every 11 days and nitrobienapplication at 3 g /pot gave the highest β-pinene, 1,8 cineol, camphor andbornyl acetate percentages in the essential oil. Whereas irrigation every 11646 EL-LEITHY ET ALdays and phosphorein at 3 gm/pot gave the highest linalool and P- cymenepercentages in the essential oil.