Lemon blam, Melissa officinalis L. is one if one most important members of the family Lamiaceae.
The word Blam is an abbreviation of Balsam, which means the chief of sweet - smelling oils.
Lemon blam is a vigorous perennial herd with a pleasant lemon scent. It is native to Southern Europe, West Asia and North Africa but it has been naturalized and cultivated widely elsewhere.
Lemon balm was used as an aromatic and medicinal plant since Ibn- al- Betar period.
It was widely used to treat all nervous system disorders. German research has shown that the volatile oil calms the central nervous system. It is considered to have antispasmodic activity too. The essential oil of M. officinalis L. leaves and shoot tips are of interest for pharmacology due to their sedative, antispasmodic, bacteriostatic and antivirus activity.
Accordingly, due to pharmaceutical importance of this plant from one side and severe shortage in scientific research about the plant from other side, this project had been conducted to study the effect of some Agricultural Factros on dry matter and oil yields.
This project had been conducted in the experimental station of Jahad Daneshgahi at Karaj, Tehran in 1997.
In this study, effect of nitrogen fertilizer levels (50, 100, 200 and 300 Kg N/ha), phosphorus fertilizer levels (25, 500, 100 & 150 /Kg P2O5/ ha), spacing (15, 30, 45 & 60 cm) and harvesting stage (stage 1: the first cut is done when the plants reach 15 cm in height, stage 2: harvesting starts together with the second cut of stage 1: when the latest reach 15 cm high again, stage 3: the plants are harvested in the beginning of flowering stage, stage 4: the plants are harvested when they reach a full- blooming stage).
All four experiments were conducted in RCB design in three replications separately.
Leaves and stems’ dry weight and oil content of different cuts and finally dry matter and oil yields were calculated.
Results indicated that 200 Kgs N/ha, 100 Kgs P2O5/ ha, 15 cm spacing and harvesting in first stage are recommended to give the highest dry matter and oil yields in these experiments.