Effect of Nitrogen and Plant density levels on yield and yield components of fennel (Foeniculum vulgare L.)

ABSTRACT: In order to study the effect of n fertilization and plant density levels on yield and yield components of fennel in Birjand, Iran, a study was carried out in research field of agriculture and natural resources research center of southern Khorasan in 2010. The study was a spatial and temporal split-plot experiment based on a randomized complete block design with three replications. the main plot was n fertilization level at five levels of 0, 40, 80, 120 and 160 kg.ha-1 and the sub-plot was the density at three levels of 10, 15 and 20 plants per m2. the studied traits included umbel number per plant, umbellet number per umbel, fruit number per umbel, umbel number per m2, 1000-seed weight, and fruit yield which were measured and compared at two cuts. it was found that n level and plant density significantly influenced all studied traits, but their interactions were not statistically significant for the traits. The increase in n level from 0 to 120 kg.ha-1 increased umbel number per plant, 1000-seed weight and fruit yield by 16.6, 40.6 and 39.8%, respectively. but, it did not significantly affect umbellet number per umbel and fruit number per umbel. although the increase in density from 10 to 20 plants per m2 resulted in 42.4 and 35.2% increase in fruit yield and umbel number per plant, respectively, and increased umbel number per m2 by 2.86 times, umbellet number per umbel, fruit number per umbel and 1000-seed weight were decreased by 15, 11.25 and 7.1%, respectively. fruit yield and umbel number per plant were higher in the first cut than in the second cut, but 1000-seed weight was 54.5% higher in the second cut than in the first one. In total, it can be recommended to use n fertilization level of 120 kg.ha-1 and the density of 20 plants per m2 in the cultivation of fennel in Birjand, Iran.