The effect of application of Vermicompost levels and Nitrogen on some of Agro-morphological traits, Photosynthetic Pigments and Essential oil content of Hyssop (Hyssopus oficinalis L.)

Hyssop is herbaceous perennial plants belong to Lamiaceae family that it has small blue flowers borne on the upper part of the branches with up to 60 cm tall. The essential oils of hyssop are widely used in cosmetics, sanitary and food industries.
Distilled aqueous extract of aerial part of the plant has antioxidant and antimicrobial activities also it has high antivirus activity against AIDS. The indiscriminate use of chemical fertilizers in intensive agriculture has increased crop performance, but the undesirable results of this action is the pollution of water resources, reducing the quality of agricultural products and destroying ecosystems.
Application of organic fertilizers such as vermicompost, beside of reducing the use of chemical fertilizers, improves the physical and microbial conditions of soil by supplying the nutrients required of plant. In this research considering the importance of hyssop in different industries, the effect of vermicompost and nitrogen fertilizer were studied on quantitative and qualitative traits of Hyssop. In order to study the effect of vermicompost on some traits of hyssop, a field experiment was carried out based on a randomized complete block design with three replicates during 2015/2016. Treatments consisted of 0, 5, 10, 15 ton ha-1 vermicompost and 75 kg N ha-1. In this study plant height, stem diameter, number of lateral branches, total dry weight, essential oil content, chlorophyll a, chlorophyll b, total chlorophyll, total anthocyanins and total flavonoids were measured . The results indicated that percentage of essential oil varied from 0.48 to 0.62 in flowering branches of Hyssop plant. The greatest plant high, stem diameter, number of lateral and flowering branches as well as total dry weight was gained by application of vermicompost in high level at full flowering stage. The greatest amount of vermicompost (15 ton ha-1) had significantly affected on chlorophyll, carotenoid, total flavonoids and anthocyanins. Vermicompost levels had a promoting influence on most of growth traits and it increased significantly on essential oil accumulation at 1% of probability level. With enhancing levels of vermicompost the essential oil content was increased and use of 15 ton ha-1 vermicompost produced the maximum (2.46 g m-2) essential oil yield. In this study application of vermicompost with decreased harmful chemical inputs improved the most measured traits. Overall, utilization of 15 ton ha-1 compared to other levels of treatments had suitable effect on content of essential oil, photosynthetic pigments and agro-morphological characteristics in Hyssop.