عنوان مقاله [English]
In order to investigate the effect of sowing date and different nitrogen levels on yield, yield components and active substances of linseed, an experiment was conducted as split plot based on randomized complete block design (RCBD) with four replications during 2005-2007 in Yasouj agricultural research station. Five sowing dates were considered as main plots and four fertilizer levels including 0 (control), 50, 100 and 150 kg/ha pure N from urea source were placed in subplots. The results of complex two-year analysis of data indicated that plant height, number of branches, number of fruits, grain yield, thousand seed weight, leaf area index, dry mater, crop growth rate and oil percentage were significantly reduced in delayed sowing dates. The most yield (1801.12 kg/ha) was obtained at first sowing date (10 March), and significantly decreased to the least rate in the latest sowing date (1 May). Application of 100 kg/ha pure N significantly increased plant height, number of branches, number of fruits, leaf area index, dry mater, and crop growth. The most grain yield was also achieved in use of 100 kg/ha pure N treatment. The most oil (34.6%) and acid linolenic (52.38%) rates was obtained in the first sowing date and the least rates was belong to the last sowing date. Sowing date had no significant effect on acid oleic and acid linoleic rates. The most acid linolenic (52.64%) and acid linoleic (15.36%) were obtained by the use of 150kg/ha pure N and the most acid oleic (20.59%) were obtained in control.