effect of chemicals and bio-fertilizers on yield, growth parameters and essential oil contents of funnel (foeniculum vulgare miller.)

in order to investigate the influence of bio- and chemical fertilizers on growth parameters and essential oil of fennel (foeniculum vulgare miller.), an experiment based on randomized complete blocks design with five treatments and three replications was carried out. arbuscular mycorrhizal fungi (strain sebacina vermifera) and phosphate dissolving bacteria (genera peseudomonas) were applied as bio-fertilizers. five treatments including t1 as a control (100% recommended dosage of np without inoculation), t2 (50% recommended np without inoculation), t3 (sebacina vermifera + 50% np) t4 (peseudomonas + 50%), t5 (sebacina vermifera + peseudomonas + 50% np) were used.  the results showed that inoculation of bio-fertilizers applied with 50% recommended dosage of np, increased vegetative growth (plant height, number of umbel per plant, plant dry weight) of fennel plants compared to chemical fertilizer treatments only. plants treated with combined of bio-fertilizers (arbuscular mycorrhizal strain sebacina vermifera and phosphate dissolving bacteria genera peseudomonas) had the highest plant height (72.6 cm), number of umbels per plant (45.5), dry weight (36.2 g) and fruit yield per plant (7.7 g). application of bio-fertilizers also increased the amount of n, p and k in plant tissues compared to non-inoculated plants. plants treated with combined bio-fertilizers had the highest amount of n (14.1 mg g-1), p (8.2 mg g-1) and k (9.2 mg g-1) in their tissues, while the least amount of n (8.9 mg g-1), p (4.7 mg g-1) and k (5.9 mg g-1) occurred in plant tissues treated with 50% np fertilizers. the highest essential oil yield was also observed in combined bio-fertilizers + 50% np. however, the least amount of essential oil yield was obtained in plants treated with half dose of chemical fertilizer.