Effect of plant density on quality and quantity yield of Thymus vulgaris in dry farming conditions in seven provinces of Iran

To find the most suitable location and planting density of Thymus vulgaris at dry farming condition, an experiment was conducted in a randomized complete block design in split plot arrangement with three replications in seven provinces of Iran. The experimental treatments consisted of plant density (4, 6 and 8 plant/m2), year (1 and 2 years after planting) and location (Tehran, North Khorasan, Isfahan, Kurdistan, Kermanshah, Gilan and East Azerbaijan). The traits comprised of plant height, canopy diameter, dry matter of aerial parts, yield and content of essential oil in full flowering stage. The results revealed that interactions of density, location and year were significant on all studied traits. The highest dry matter (1734 kg/h) and essential oil yield (16.84 kg/h) of aerial parts was obtained in 8 plant/m2 density in Gilan. The maximum and minimum of essential oil content was observed in samples from Isfahan (1.96 percent) and East Azerbaijan (0.50 percent), respectively. Based on our findings, it seems that cultivation of Th. vulgaris in higher density could cause higher production of dry matter and essential oil yields under dry farming conditions in Iran