Thymbra spicata var. spicata, which grows wildly in the flora of Turkey, is known as thyme. A field trial was conducted to determine suitable harvesting time and cutting height for Thymbra, therefore plants in the trial were harvested at two cutting heights in various stages of development in the course of the growing season (pre-flowering, full-flowering and post-flowering). It was determined that the time of harvesting had a significant effect on herbage yields, oil percentage and oil yield. The highest drug leaf yield (3.107 t/ha) was obtained in the full-flowering stage with 10 cm cutting length, essential oil percentage ranged from 1.58 to 2.33%, the highest essential oil yield (70.7 l/ha) was obtained at the full-flowering stage with 10 cm cutting length. As a result of this study, harvesting in the full-flowering stage with 10 cm cutting height was the best treatment in respect of the yield of dry matter and oil for thyme (Thymbra spicata) cultivation.
101were higher than long-term data while rainfalls were high especially in June (Reports of Meteorological Institute of Diyarbakır).The soil of the experimental area is classified as clay loam, with 1.67% organic matter, pH 7.2 and low in total nitrogen, medium in available phosphorus and high in potash in Diyarbakır.In this research, the seeds of wild-growing T. spicata were collected in the Dicle district of Diyarbakır province and sown in a greenhouse in January and Thymbra seedlings were grown to around 10-15 cm height, then they were transferred to the field in rows 30 × 30 cm apart at the beginning of April. Field trials were designed as a split block design with three replications. Harvesting times and cutting heights were considered as main and subplots, respectively. During the vegetation period, plots were fertilized with farm manure (20 t/ha). Plants were weeded and irrigated when needed.Three different harvest frequencies were examined during two years in order to study ontogenetic variation in plants that were harvested in pre-flowering time, full-flowering time and post-flowering time. The investigation used two cutting heights, 10 and 15 cm, designated low and high, respectively, above the soil. Harvesting was done with a handheld cutter with both cutting heights used at each harvest.All plant materials were immediately weighed and dried at room temperature. All data were subjected to the analyses of variance according to a split plot design.The isolation of the essential oils from 20 g of dry herb plants was done by hydro-distillation for 2 h using a Clevenger type apparatus. The essential oil percentage was measured by the volumetric method (WICHTL 1971).
RESULT AND DISCUSSIONThe influence of harvesting times and cutting heights on plant height, fresh, dry and drug leaf yield, essential oil percentage and essential oil yield is summarized in Tables 2 and 3. Statistically significant differences were observed for plant height, fresh herb yield, dry herb yield, drug leaf yield, essential oil percentage and essential oil yield in T....