Effect of Biological Nitrogen Fertilizer (Azotobacter) and Plant Density on Yield, Yield Components and Essential Oil of Anise

To evaluate the effects of biological nitrogen (Azotobacter) and plant density on quantitative and qualitative traits of anise, a field experiment was carried out with a factorial combination of deferent levels of Azotobacter (0, 3, 6 Lit / ha) and plant density (50, 25 and 12.5 plants/m2) based on randomized complete block design with 3 replications. Analysis of variance showed the significant effect of biological nitrogen and plant density on plant height, leaf number, peduncle length, number of fertile umbellete/umbel, biomass, essential oil, seeds yield, harvest index of seed and essential oil. The means comparison indicated that the highest plant height and peduncle length were obtained from 50 p/m2 of plant density. Also the highest biomass yield (6319 kg/ha) and seed yield (1017 kg/ha) were obtained from 50 and 25 p/m2 of plant density with 6 Lit/ha of Azotobacter application, respectively. While, the highest yield of essential oil (130 kg/ha) was obtained from 3 lit/ha of Azotobacter and 25 p/m2 of plant density. The lowest yield of biomass, seeds and oil were obtained from 12.5 p/m2 of plant density and control treatment of nitrogen (0 l/ha of Azotobacter). These trends in yield led to highest amounts of seed and oil harvest index at 6 and 3 l/ha of Azotobacter application, respectively. These results showed the increasing essential oil production at relatively low nitrogen.