Effects of nutritional treatments on quantitative and qualitative yield of Echinaceae purpurea L.

Purple coneflower (Echinacea purpurea L.) is one of the most wellknown medicinal plant species with high economic value worldwide. In Iran, this species' roots and shoots are used in herbal medicines. Many types of phytomedicine are commercially produced from Echinacea aerial portions for boosting the nonspecific immune system and treating the common cold. Environmental and health costs of chemical fertilizers have led researchers to meet plant nutritional needs using chemical, organic and biological fertilizers. The present study aimed to investigate the effects of organic and biological fertilizers on morphological traits, shoot and root dry matter, and essential oil percentage and yield in the leaves and stems of coneflower plants. This experiment was conducted on a randomized complete block design with three replications at the Research Institute of Forests and Rangelands, Iran, in 2018-2019. Treatments included control, NPK (N50P25K25; N75P35K35 and N100P75K75 Kg.ha-1), manure (30, 60 and 90 ton.ha-1), vermicompost (5, 10, and 15 ton.ha-1), N50P25K25 fertilizer + 30 ton.ha-1 manure, N50P25K25 + 5 ton.ha-1 vermicompost, biological fertilizers including Glomus intraradaices + G. mosseae, Azospirillum + Pseudomonas, Thiobacillus + 5 ton.ha-1 vermicompost and Thiobacillus + 250 Kg.ha-1 of sulfur (S). Before applying fertilizer treatments, a soil analysis was done. After applying fertilizer treatments, the physical and chemical properties of the soil were also determined. The treatments were selected based on the fertilizer requirements of the plant as well as soil test results. Parameters such as plant height, leaf, stem, and flower numbers, root penetration depth, root volume, leaf, stem, root, and flower dry matter, leaf, stem, and flower essential oil, and essential oil yield of leaves, stems, and flowers were evaluated. At the full flowering stage, samples were taken from aerial segments of plants in all treatment groups. After shade-drying, the samples through a Clevenger-type apparatus were hydro-distillated to obtain the essential oil. The oil percentage, as well as yield, was calculated based on the dry weight. The results showed that the highest leaf and stem dry matter was observed in the 15-ton.ha-1 vermicompost treatment. A 5-ton.ha-1 vermicompost treated with NPK fertilizers displayed the highest flower dry matter. On the other hand, the highest root dry matter was obtained in the treatment with 30 tons.ha-1 manure + NPK fertilizers. The highest flower essential oils yield was obtained in ton.ha-1 manure + NPK fertilizers. The highest leaf + stem oil yields were found at the flowering stage in 15 tons.ha-1 vermicompost. Also, NPK treatment + 30 tons.ha-1 of manure resulted in the highest yield of flower essential oil. 15-ton.ha-1 vermicompost treatment yielded the highest stem and leaf essential oil yield. Only the organic fertilizer group (CM vs. V5) and the biofertilizer group (GM and GI vs. T) showed an increase in flower essential oil yield compared to the other nutritional treatments. In the leaf+stem essential oil yield results, all comparisons between treatment groups showed a significant effect, except for the organic fertilizer group (CM vs. V5). Compared to the NPK group, the biofertilizer and organic fertilizer group yielded the highest leaf+stem essential oil yield. It was concluded that biological fertilizers treatment combined with organic fertilizers could be a suitable alternative to chemicals in the sustainable production of this valuable medicinal plant. These findings suggested that biofertilizers and organic fertilizers can benefit Echinacea purpurea cultivation because, when combined, they enhance the essential oil percentage and yield.