Evaluation the effects of Thiobacillus biological and chemical fertilizers on morphological and phytochemical characteristics of Satureja hortensis L.

Satureja hortensis L. is one of the valuable plants belonging to the Lamiaceae family that its leaves and flowering branches contain essential oil. The aim of this study was to evaluate the effects of Thiobacillus biological and chemical fertilizers on morphological and phytochemical characteristics of this plant. The present study was carried out as a factorial experiment based on randomized complete block design with 3 replications in the research farm of Golmakan town in 2019. Experimental treatments included Thiobacillus biological fertilizer (0, 5 and 12 kg/ha) and chemical fertilizer (0, 35 and 70 kg/ha). Plant essential oil was extracted from savory leaves at flowering stage by Clevenger apparatus, then the constituents of the essential oil were analyzed by GC-MS. The results showed that all morphological traits of the plant as well as the quality and quantity of the active ingredients of the essential oil were affected by fertilizer treatments. The combined application of biological and chemical fertilizers led to an increase in the studied traits compared to the non-application of fertilizer. The highest plant height (48.8 cm), leaf dry weight (9.7 g) and essential oil density (3.67%) were obtained in the combined use of fertilizers. The two main constituents of savory essential oil including carvacrol (62.10%) and gamaterpinen (19.04%) showed the highest increase in the treatment composition of 12 kg/ha of Thiobacillus fertilizer and 70 kg/ha of chemical fertilizer (NPK). Based on the results, we found that combinations of biofertilizer and chemical fertilizer could increase the morphological characteristics, quantity and quality of savory essential oil.