Essential Oil Production and Sage Growth as Influenced by Treated Wastewater Irrigation and Water Stress

The influence of tap water and treated domestic wastewater (TDWW) at 100% and 60% of the soil available water (SAW) on the percentage and yield of essential oil of Salvia officinalis L. grown on a degraded soil in pots inside a plastic house was investigated.Growth parameters of the plants were also evaluated.Sage was cultivated separately at two densities of 90 and 70 plants per pot, respectively, for 45 and 135 days.After 45 days, TDWW at 100% SAW statistically enhanced height of plants and both leaf fresh and dry weights in comparison with other treatment combinations.After 135 days of growth, comparable results were noted, regardless of planting density differences.Furthermore, maintaining 100% SAW for 135 days led to a significant increase in SPAD values, regardless of the irrigation water source.Essential oil yield and percentage were statistically impacted by treatments only during the 45-day growth period.Essential oil yield followed this order: TDWW at 100% SAW (0.35mL) > TDWW at 60% SAW (0.28mL) = tap water at 100% SAW (0.27mL) = tap water at 60% SAW (0.24mL).In contrast, the essential oil percentage ranked as follows: TDWW at 60% SAW (0.63%) > tap water at 60% SAW (0.55%) > TDWW at 100% SAW (0.39%) = tap water at 100% SAW (0.38%).Based on the current conditions, cultivating sage for 45 days under 60% SAW with TDWW irrigation presents a promising strategy for low-income communities in arid regions for many reasons: it results in higher essential oil percentage, allows for multiple growing cycles, maximizes return, creates temporal work opportunities mainly for women, and generates associated industry.