Effects of different soil fertility systems on some physiological characteristics, yield and essential oil of sage (Salvia officinalis L.) under different irrigation regimes

Sage, a popular medicinal plant, is widely used in food and pharmaceutical industries. This research was aimed to study the effects of organic and biological fertilizers on physiological characteristics, yield, and essential oil content of sage (Salvia officinalis L.) under different moisture conditions. The study was conducted in a field experiment in split-plot design with 15 treatments and three replications at Tarbiat Modares University in 2012. Treatments included three irrigation levels (irrigation after depletion of 40% available water, irrigation after depletion of 60% available water, and irrigation after depletion of 80% available water) and five different soil fertility systems (control (no fertilizer) (F0), chemical fertilizer (urea) (Ur), nitrogen fixing bacteria (NFB), vermicompost (V), vermicompost nitrogen fixing bacteria (Vぐ), allocated to main plots and subplots, respectively. Results indicated that the irrigation regimes had significant effect (p 0.01) on all measured traits. Chlorophyll a, b, and dry matter declined with increasing of water stress, but sugar, proline and essential oil content increased. Results showed that the highest values of all measured traits were related to the vermicompost nitrogen fixing bacteria treatment. In addition, results showed that the highest essential oil percentage (1.10%) and essential oil yield (20.50 l ha-1) were obtained in vermicompost nitrogen fixing bacteria treatment under moderate drought stress (I2).