Shiva Zaferanchi - Department of Ecophysiology, Faculty of Agriculture, University of Tabriz, Tabriz, Iran
Saeid Zehtab-Salmasi - Department of Biology, Faculty of natural science, University of Tabriz, Tabriz, Iran
SeyedYahya Salehi Lisar - Department of Biology, Faculty of natural science, University of Tabriz, Tabriz, Iran
Mohammad Reza Sarikhani - Department of soil science, Faculty of Agriculture, University of Tabriz, Tabriz, Iran

Marigold belongs to the oldest medicinal plants with various bioactivities, which had been used in ancient times. At present it supplies its material of great significance for pharmaceutical, culinary and cosmetic industry. The continued use of chemical fertilizers causes health and environmental hazards. Vermicomposts are rich in microbial populations and diversity. Biological fertilizers and humic acid increase the availability of nutrients in fertilizers and in those already existing in the soil. The present study aimed to investigate the effect of application of organic fertilizers on yield and some growth parameters of medicinal plant, marigold (Calendula officinalis L.). The study was conducted in 2015 and 2016 at the research farm of Tabriz University. The experimental design was a factorial randomized complete block replicated 3 times. There were two cultivars of marigold and fertilizer treatments including vermicompost, humic acid, biofertilizers (Azospirillum and Azotobacter), vermicompost+ biofertilizers, humic acid+ biofertilizers and control (without fertilizer). Traits such as number of flowers per plant, plant height, flower yield, biological yield and flower harvest index were measured. Highly significant results were found in all the parameters studied. Our results confirmed that the applied biofertilizers had positive effects in combination with either vermicompost or humic acid. Plant performance was the best in vermicompost+ biofertilizers and it was similar or higher than vermicompost treatment. Overall, the results showed that using organic fertilizers had a favorable impact on yield and growth of marigold.

Azotobacter, Azospirillum, Calendula officinalis, Humic acid, Vermicompost