Interaction of Nitrogen Fertilizers and Plant Density on Physiological Characteristics, Yield and Yield Components of Canola (Brassica napus L.)

Nitrogen fertilizer application and optimal density are important factors in increasing yield of canola. This study was carried out in order to investigate the effects of nitrogen fertilizers and plant density on some physiological characteristics, yield and yield components of Canola, as a factorial experiment in a randomized complete block design with three replications at Sheshdeh region of Fasa in 2018-2019. Nitrogen fertilizer factor in 12 levels including a1: urea (recommended) before planting and stem elongation, a2: urea (recommended) before planting, stem elongation and heading, a3: urea (recommended) in stem elongation and heading, a4: urea ( under recommended) before planting and stem elongation a5: urea (under recommended) before planting, stem elongation and heading, a6: urea (under recommended) in stem elongation and heading, a7: ammonium sulfate (recommended) before planting and stem elongation, a8: ammonium sulfate (recommended) before planting, stem elongation and heading, a9: ammonium sulfate (recommended) in stem elongation and heading, a10: ammonium sulfate ( under recommended) before planting and stem elongation a11: ammonium sulfate (under recommended) before planting, stem elongation and heading, a12: ammonium sulfate (under recommended) stemming and heading and density factor in three levels 50, 70 and 90 plants m-2.  Results showed that the effect of fertilizer on number of Raceme per subbranch and per plant was significant at 5% level and the effect of plant density on 1000 seed weight, total plant weight, seed yield and oil yield was significant. Ammonium sulfate (following fertilizer recommendation) had the highest number of Raceme per subbranch (48.6 per subbranch) and raceme per plant (73.5 per plant) in the shoot and bud stages. The highest biological and grain yield (12840 and 4258 kg.ha-1, respectively) were obtained at plant density of 50 plants.m-2. density 50 was significantly higher than 70 in terms of grain yield. Overally, the density of 50 plants.m-2 and the use of ammonium sulfate in the shoot and bud stages had the highest yield of Canola.