Source and rate of nutrients may change the yield and aroma profile of Zataria multiflora Boiss.

A two-year field study was conducted to explore the influence of fertilizer sources on Zataria growth and quality characteristics. Treatments comprised control (no fertilizer), synthetic fertilizer, cow manure, vermicompost, and combinations of synthetic fertilizer with cow manure or vermicompost. Synthetic fertilizer was applied at 109kg ha-1 urea, 58kg ha-1 triple superphosphate, and 52kg ha-1 potassium sulfate (N50 P25 K25 ). Organic fertilizers were applied at 5tons ha-1 , and combined treatments comprised half rate of both organic and synthetic sources. The results indicated that young plants benefited from readily available nutrients released from synthetic fertilizer and produced 37% and 50% more biomass compared with sole cow manure and vermicompost, respectively. The highest biomass (167g m-2 ) and oil yield (3.63g m-2 ) were obtained from the combination of synthetic fertilizer and cow manure in established plants. The oil concentration of plants that received either cow manure or vermicompost were higher than synthetic fertilizer. Linalool was the dominant oxygenated monoterpene and represented 82% and 88% of the essential oil in 2023 and 2024, respectively, when cow manure was used. The findings of this research further substantiate the idea that Zataria represents a valuable source of antioxidant compounds, with potential for industrial exploitation.