In order to study the effects of biological and chemical fertilizers on quantitative and qualitative yields of purple coneflower, an experiment was carried out during 2010-2012. The morphological traits such as plant height, number of lateral shoots, shoot fresh and dry weight, root fresh and dry weight, number of inflorescences per plant, number of flower buds per plant, and essential oil content and yield were measured. The results showed significant effects of the treatments on the growth parameters. In the second year, the mixture of the three bacteria plus mycorrhizal inoculum improved important parameters such as shoot dry weight (40.42%), root dry weight (60.02%), and number of inflorescences per plant (65.68%). Interestingly, these values were not significantly different from obtained results by the chemical fertilizers. Additionally, the essential oil content in plants treated with the mixture of the three bacteria were 152.14% and 25.11% higher than the control plants in the first and the second year, respectively. The essential oil yield in plants treated with the mixture of the three bacteria was higher than those treated with the chemical fertilizers in two years. The results indicate that using biological fertilizers is a good choice to reduce the use of chemical fertilizers as an important tool to contribute to a sustainable agriculture.

Purple coneflower (Echinacea pupurea L.) is an ornamental-medicinal plant belonging to Asteraceae family. It has long been used as an herbal medicine. In order to study the effects of biological and chemical fertilizers on quantitative and qualitative yields of purple coneflower, an experiment was conducted at Department of Horticultural Science and Landscape, University of Tehran. The trial was arranged based on a randomized complete block design, with eight treatments and three replications. Treatments were included control (no fertilizers), nitrogen-fixing, bacteria: Azospirillum lipoferum (AL), Azotobacter chrococum (AC), phosphorus solubilizing bacterium Pseudomonas fluorecens, (PF), Glomus intrradices inoculum (GI), the mixture of the three bacteria and the mixture of the three bacteria plus the mycorrhizal inoculum. According to the results of HPLC, Catechin content was high at herbage in both years. In addition, the best results have been taken from the AL and AC with the control. Caffeic acid, chlorogenic acid and Epicatechin contents were higher during the first year of the herbage, and control, AC and AL treatments gave high value. Ferulic acid was high in the herbage during the first year and generally high values were obtained from PF and GI treatments. Quercetin content was high in plant root during the first year with AC application.