Study of Different Organic Media on Yield Components, Quality and Quantity of Essential Oil of some Savory (Satureja hortensis L.) ecotypes in Gorgan

Essential oils make up a large part of aromatic substances in plants. Generally, essential oils are considered as remnants of main processes of plants metabolism, especially in stressful conditions. Summer savory (Satureja hortensis L.) is one of the most important plants in Lamiaceae family, which it’s more than 30 species grown in the East Mediterranean. It is one of the oldest plants that have been used as vegetables and medicinal and aromatic plants. Dried summer savory has been introduced as one of the most pleasant spices that are planting in large areas of farmland in many countries. Generally, the aerial parts of it, that is usually harvested at flowering stage, has therapeutic effects such as facilitating digestion, stomach tonic, diuretic, astringent, carminative, anti-diarrhea and anti-worm. Summer savory essential oil is used in food (conserves and beverages) and pharmaceutical industries. Various studies on S. hortensis essential oil has been showed that it contains high amounts of phenolic compounds such as Carvacrol, γ-Terpinene, Thymol, p-Cymene, β-Caryophyllene, Linalool and other terpenoids. Organic fertilizers have been known to improve the biodiversity and may prove a large depository for excess carbon dioxide. These fertilizers increase the number of soil organisms by providing organic matter and micronutrients for organisms such as fungal mycorrhizae, (which aid plants in absorbing nutrients), and can drastically reduce external inputs of pesticides, energy and fertilizer, at the cost of decreased yield. Nevertheless they are as effective as chemical fertilizers over longer periods of use. The aim of this project was to study the effects of different organic matters on vegetative and reproductive growth and percentage and components of essential oil in three Satureja ecotypes in Gorgan, Golestan, Iran climate.

This study was designed as a factorial experiment based on Randomized Complete Block design with four replications and done in research farm of Agriculture and Natural Resource, University of Gorgan in 2010. Treatments were cattle manure, municipal solid waste, leaves compost, the mixture of them and control. Three ecotypes of summer savory studied in this experiment were Kordestan, Shiraz and Yazd. The plants were harvested at full flowering stage, when they have the highest essential oil and were dried in oven at 45 °C. The essential oils of dried samples were isolated by hydro distillation for 3 h, using a Clevenger-type apparatus. Statistical analysis was performed by SAS software and the mean comparison were measures by using Duncan tests at 5% level of probability.

The analysis of variance showed that media had significant effect on yield components in summer savory. There were no significant differences between ecotypes and media*ecotype effect on some parameters of yield components. The cattle manure showed positive effects on bush height in this experiment. Hendawy et al (2010) showed that the application of cattle manure and sheep manure had reached significantly the 5% level of plant height and essential oils percentages. They concluded that sheep manure have macro and micro nutrients which provide thyme plants with their requirements from these elements. Essential oil percentage also, tended to increase with application of organic fertilizers either cattle manure, sheep manure or compost. Khalil (2002) showed the effect of two kind of organic fertilizers on Rosmarinus officinalis and Jasminum spp growth parameters and yield components. In this experiment organic manure treatments showed increasing in plant fresh and dry weight. This could be related to positive effect of organic manure on soil texture and fertility. Ahmadian et al. (2006) showed that the animal manure significantly enhanced the number of umbers per plant, the number of seed per plant, the biological and seed yield in Cuminum cyminum. Animal manure significantly enhanced cumin aldehyde and r-cymene and decreased b-pinene, g-terpinene and a-pinene in cumin oil. Due to the results, treatments had no significant effects on essential oil percentages, but were effective on essential oil components. Hussein et al. (2006) showed that compost levels combined with different distances had a pronounced effect on the various essential oil constituents in Dracocephalum moldavica. In this experiment, Although Shiraz ecotype showed the maximum essential oil percentage (1.2 percent) but there was no significant differences between ecotypes. Among essential oil components, the maximum percentages of Carvacrol achieved in mixture media and Yazd ecotype. Control treatment showed the highest amount of γ- terpinen and paracymene in compare to other media. Shiraz and Kordestan showed also, the highest percentages of γ- terpinen and paracymene, respectively. Plants in mixture media had maximum levels of Carvacrol (74.69 percent). Between ecotypes, Yazd had maximum Carvacrol percentages. Between media, Control treatment was maximum contents of γ –terpinen (5.48) and paracymene (1.76) and other treatments had reduction effects on essential oil components. Between ecotypes, the highest γ-terpinen percentage (5/79) was in Shiraz ecotype and the highest p-cymene percentage (1/69) was in kordistan ecotype.

Therefore, by considering the fertilization of savory plants with different organic manure fertilizers in the form of compost that are economic in each region is recommended.