In order to investigate the effect of different irrigation intervals and different mineral nutrition on seed yield of ajowan, an experiment was conducted at the agricultural research station, University of Siatan in 2011. For this purpose a split plot experiment based on a Complete Randomized Block Design with three replications was used. Treatments included three irrigation intervals (7, 14 and 21days) set as main factor, mineral nutrition level was (Nitrogen 120 kg ha- 1, Potassium 150 kg ha-1, Phosphorus 200 kg ha-1, Zinc 25 kg ha-1, Magnesium 25 kg ha-1 and control). Results indicated that irrigation had significant effect on umbel per plant, umbels per m2, 1000 seed weight, seed yield per m2. With increasing irrigation intervals, umbels per m2, umbels per plant, 1000-seed weight and seed yield per m2 were decreased. Mineral nutrition had significant effect on umbel per plant, umbels per m2, seed yield per m2. Our results showed that the maximum seed yield per m2 was obtained in irrigation intervals 7 days with Nitrogen.
