Effect of Azotobacter chroococcum and Different Rates of Nitrogen Fertilizer on Coneflower (Echinacea purpurea L. Moench) Yield and Phytochemical Properties

The effects of biological and chemical fertilizers were studied on quantitative and qualitative yields of coneflower in a factorial experiment carried out at the agricultural research farm in Parsabad, Ardebil. The experiment was based on a randomized complete block design with four replications. The experimental factors included N fertilizer (N0 = 0, N1 = 75 and N2 = 150 kg ha^-1) and Azotobacter (inoculation with A. chroococcum bacteria SW22 strain = B1and non–inoculation = B0). The morphological traits such as plant height, number of lateral shoots, shoot fresh and dry weight, root fresh and dry weight, number of flowers per plant, and phenol, nitrogen (N), and phosphorus (P) concentration were measured. The results showed the significant effects of the treatments on the growth parameters. Inoculation with Azotobacter + 75 kg N ha^-1 improved important parameters, such as shoot dry weight (40.42%), root dry weight (60.02%), and the number of flower plant1 (65.68%). Additionally, phenol, N, and P concentration in the plants treated with Azotobacter + 75 kg N ha^-1 were 25.11%, 34.6%, and 39.8% higher than those of the control plants, respectively. The results indicate that the use of biological fertilizers is a good choice to reduce the use of chemical fertilizers as an important tool to contribute to sustainable agriculture.