effect of drought stress on yield, yield components and essential oil in coriander treated with organic and inorganic fertilizers

to study the effect of drought stress during using organic and chemical fertilizers on morphological, agronomic traits and the essential oil of coriander, a field experiment was conducted as split plot based on randomized complete block design in three replications at agricultural research station, college of agriculture, university of torbat heydarieh, iran during growing season of 2010-2011. treatments were consisted of three levels of drought stress (30, 60 and 90 percent fc) and fertilizer treatments [control, npk (60: 60: 40), caw manure (25 ton/ha) and vermicompost (25 ton/ha)]. different traits such as plant height stem diameter, number of branches, number of leaves per plant, fresh and dry weight, herbage yield and number of umbels per plant, number of seeds per umbel, total number of seeds in plant, fruit yield, 1000 seed weight and essential oil percentage and yield were recorded. analysis of variance indicated that water stress and application of fertilizer treatment had significant effect on all studied trait. the maximum herbage yield (5371 kg/ha) and seed yield (3905 kg/ha) were achieved in 90 percent fc combined with npk and mild stress under npk treatment, respectively. the highest essential oil percentage (0.77 percent) and essential oil yield (18.49 kg/ha) were obtained in mild stress by using chemical fertilizers. according to the fact that application of fertilizers in mild stress conditions leads to increase in essential oils yield, using chemical fertilizers under mild drought stress is recommended for coriandering as a medicinal plant.