Abstract :
Spring canola (Brassica napus L. Var Hayola401) is a valuable oilseed crop adapted to northern Iran. In order to study the effect of nitrogen (N) and sulfur (S) on yield and yield component of canola (Brassica napus L.), an experimental study was conducted in a factorial based on randomized complete block design with four replications at Sari Agricultural Sciences and Natural Resources University during winter 2007-2008. Treatments consisted of four levels of nitrogen (0, 40, 80 and 120 kg ha-1) and four levels of sulfur (0, 20, 40 and 60 kg ha-1). The results indicated the significant influence of nitrogen on height of plant, number of pods per plant, number of seed per pod, 1000 seed weight, seed yield and oil percentage. Plots that received highest dose of N (120 kg ha-1) had maximum height of plant, seed per pod, and seed yield. The inverse relationship between seed yield and oil percentage was observed with increasing the nitrogen beyond the 80 kg ha-1. The rate of increasing in seed yield was more than reduction in oil contents when nitrogen was applied at rate of 120 kg ha-1. Sulfur significantly increased percentage of oil content. Minimum of 34.57% was recorded in those plots which received no sulfur (control), while maximum oil percentage (39.14%) was recorded in those plots which received 60 kg S ha-1, there were no significant effects in oil percentage between plots which received 40 and 60 kg S ha-1. Based on the results obtained in this study, 120 kg ha-1of N and 40 kg ha-1of S can be subjected as an optimized combination of N and S for higher seed yield and oil percentage of canola.
