Effect of fertilizer treatments on growth criteria and qualitative and quantitative yield of fennel (Foeniculum vulgare L.) as a medicinal species

In order to evaluate the growth characteristics, yield components, seed yield and essential oil yield of fennel (Foeniculum vulgare L.) as affected by different fertilizer treatments, a field experiment was conducted based on a randomized complete block design with three replications at the Agricultural Research Station of Ferdowsi University of Mashhad during the growing season of 2009-2010. Treatments were: F1: chemical fertilizer (N, P and K were used with 100, 60 and 100 kg ha-1, respectively.), F2: biofertilizer+1/2 F1, F: biofertilizer, F4: cow manure (30 t ha-1) and F5: F4+1/2 F1. Plant height, yield components such as branch number, umbel, umbelet, seed and 1000-seed weight, fresh and dry biological yields, seed yield, essential oil content and essential oil yield of fennel were measured. The results indicated that the impact of the fertilizer treatments was significant (p≤0,01) on plant height, yield components, seed yield, fresh and dry biological yields and essential oil yield of fennel. The highest yield components with 10 branches per plant, 241,1 umbels per branch, 15,1 umbelets per umbel, 14,8 seeds per umbelet and 2,9 g were observed in the chemical fertilizer+cow manure treatment. The maximum seed yield with 296,5 g m-1 was achieved with the chemical fertilizer+cow manure treatment. Increasing of seed yield in F5 treatment was 15, 52, 111 and 297% compared to chemical fertilizer, cow manure, chemical fertilizer+biofertilizer and biofertilizer, respectively. So, integrated management of organic inputs such as cow manure with other fertilizers could be considered as an ecological approach that can improve yield and bring sustainability for these valuable species.