Effect of biological fertilizers on quantitative and qualitative yield of ajowan (Carum copticum L.) at different irrigation levels

In order to investigate the effects of different irrigation levels and biological fertilizers on quantitative and qualitative yield of ajowan (Carum copticum L.), a field experiment was conducted at a farm located in West Azerbaijan province - city Nagadeh, Iran during growing season of 2012-2013. The experiment was arranged as split plot based on Randomized Complete Block Design in three replications. The main plots were allocated to irrigation levels (Irrigation after 50 mm (control), 100 mm (moderate water stresses) and 150 mm (severe water stresses) evaporation from class A pan) and sub-plots were allotted to biological fertilizers (Mycorrhiza, the combination of Azotobacter and Barvar Phosphate-2, Mycorrhiza + Azotobacter + Barvar Phosphate-2 and control). Results showed that by increasing irrigation times from 50 to 150 mm evaporation, plant height, number of umbel per plant, 1000 seed weight, biological yield, seed yield and concentration and content of essential oil in ajowan were significantly decreased. Among the biological fertilizers, combined usage of biofertilizers (Mycorrhiza + Azotobacter + Barvar Phosphate-2) showed greater increment in studied traits than individual consumption. In each irrigation levels (Irrigation after 50, 100 and 150 mm evaporation), the highest seed yield (783 kg/ha) was obtained from combined usage of biofertilizers and the lowest seed yield (400 kg/ha) belonged to control treatment, respectively.