Evaluation of Essential Oil in Satureja spicigera (c. Koch) Boiss. in Dry Farming under the Effect of Different Organic Fertilizers and Plant Densities

A decrease in agricultural water resources in recent years has led to the cultivation of plants with low water requirements. Creeping savory (Satureja spicigera) is a medicinal species that grows on rock walls in the north of Iran. To evaluate the effects of different planting densities and different treatments of organic fertilizer (O.F.) on creeping savory essential oil (EO) under rainfed cultivation, an experiment was conducted by a split plot design based on RCBD with three fertilizer treatments (rotten cow manure, enriched straw and farm soil), and three planting densities (2.66, 4 and 8 plant/m2). The experiment was carried out in two crop years (2017-2019) in Mehregan Research Station of Kermanshah Agricultural and Natural Resources Research and Education Center. After extraction by water distillation, the EO content and EO yield were calculated and the chemical compounds were analyzed by GC and GC/MS. A total of 13 compounds were identified in the EO, comprising more than 97% of the total compounds. The effects of fertilizer treatments had statistical significance (P≤0.01) in terms of EO content, EO yield, and several chemical compounds. The effects of planting density were significant on the EO yield and chemical compounds (P≤0.01). The highest EO content was obtained in the treatment of rotten cow manure×high density (3.75%) and the lowest EO content occurred from the effect of farm soil×high density (2.78%). The highest EO yield was caused by enriched straw×high density (72.59 kg ha-1). The use of O.F. increased the EO content, EO yield, and thymol content.