Effect of Nitrogen and Phosporous Fertilizers on Seed Yield and Essential Oil of Anise (Pimpinella anisum)

To study the effect of nitrogen and phosphorous fertilizers on seed yield and essential oil of anise a field experiment was carried out in research field of Agricultural and Natural Resources Research Center of Yazd province in 2004-2005 growing season-using factorial arrangement in randomized complete block design with three replications. Nitrogen fertilizer as urea at five leves (0, 50, 100, 150, 200 kg ha-1) and phosphorous fertilizer as triple super phosphate at five levels (0, 100, 200, 300, 400 kg ha-1) were applied. Results showed that the effect of nitrogen fertilizer on seed yield was highly significant (P < 0.01). Application of 100 kg ha-1 urea had the highest seed yield (848.9 kg ha-1) and control treatment had the lowest (687.7 kg ha-1). Phosphorus fertilizer also significantly (P < 0.05) affected seed yield of anise. The highest seed yield (811.1 kg ha-1) was obtained in 100 kg ha-1 of phosphorus fertilizer and the lowest seed yield (725.9 kg ha-1) was achieved in control treatment. Nitrogen × phosphorus interaction effect on seed yield was significant (P < 0.01). The most suitable fertilizer treatment for seed production was 100 kg ha-1 of nitrogen plus 100 kg ha-1 of phosphorus fertilizers with seed yield of 930 kg ha-1. Effect of nitrogen fertilizer on essential oil yield of anise was highly significant (P < 0.01). The highest essential oil yield (19.5 L ha-1) was obtained by application of 100 kg ha-1 of nitrogen fertilizer and the lowest (9.5 L ha-1) in the control treatment. Phosphorous fertilizer had not significant effect on essential oil production. In general, for seed and essential oil production in anise, application of 100 kg ha-1 of nitrogen and 100 kg ha-1 of phosphorous fertilizers was suitable treatment.