The effect of different levels of Ammonium Sulfate on photosynthesis pigments, essential oil content, yield and component of improved summer Savory (Satureja hortensis L. cv. Saturn)

In order to study a the effect of different levels of Ammonium Sulfate on photosynthesis pigments, essential oil content and components in summer Savory, an experiment was conducted based on randomized complete block design (RCBD) with five treatments and three replications on Karaj climate conditions. The treatments included five levels of ammonium sulfate consist of: control (without fertilizer), 40, 60, 80 and 100 kg/h of ammonium sulfate that were applied as split application (three weeks after sowing). At full flowering stage, the plant samples of all treatments were harvested and measured for the desired attributes such as Chlorophyll a, b and total, carotenoide, essential oil percentage, yield and components (consist of 26 compounds by GC-MS apparatus). The results showed significant differences among treatments on some traits measured. Among 26 identified components in different treatments, just 12 combinations were affected by ammonium sulfate fertilizer. Also, essential oil percentage and yield were significantly affected by treatments. With increasing ammonium sulfate concentration, essential oil percentage and yield significantly increased, so that the highest essential oil percentage and yield (3.55% and 49.97 ml, respectively) related to 100 kg ammonium sulfate and the lowest content (2.68% and 16.32 ml respectively) belonged to control. Carvacrol, as the main component in this plant was affected by treatments. The maximum content (52.06%) in 40 kg ammonium sulfate and the minimum content (46.57%) in 60 kg ammonium sulfate were detected. The lowest total chlorophyll content (18.69 mg/g FW) belonged to 100 kg ammonium sulfate and other treatments were placed in a same group.