The effect of ammonium sulfate on growth indices, morphological and phytochemical ‎characteristics of summer savory (Satureja hortensis L. cv. Saturn)‎

In order to evaluate, the effect of different levels of ammonium sulfate on morphological and phytochemical characteristics of summer savory, an experiment based on randomized complete block design (RCBD) with five treatments and three replications on Karaj climate conditions was conducted. The treatment including five levels of ammonium sulfate consist of: control (without fertilizer), 40, 60, 80 and 100 kg/ha of ammonium sulfate that as split application was applied. At full flowering stage, the plant samples of all treatments were harvested and desired factors such as morphological characteristics (plant height, lateral shoot number, plant diameter and stem diameter), biomass, Antioxidant activity, polyphenolic compounds, rosmarinic acid and carvacrol contents were measured. With increasing levels of ammonium sulfate, plant height, number of lateral shoots, plant diameter, stem diameter, internode length and dry matter yield were significantly increased. The highest antioxidant activity was observed in 40 kg ammonium sulfate treatment and increasing in ammonium sulphate concentration was decreased antioxidant activity. The maximum content of rosmarinic acid (10.93 mg per g dry weight) related to 80 kg ammonium sulfate treatment and the lowest content (6.85 mg per g dry weight) was measured in control. The highest amount of carvacrol (6.92 mg per g dry weight) was obtained in 80 kg of ammonium sulfate treatment, followed by 40, 60 and 100 kg treatments on the same level and the minimum content (5.05 mg) in control were detected. According to the results, the treatment of 80 kg/ha of ammonium sulfate, in addition to increasing growth and yield factors, inhansed the amount of carvacrol and rosmarinic acid.