EFFECT OF SEEDING DATE, NITROGEN AND PHOSPHATE FERTILIZER ON GROWTH, YIELD AND QUALITY OF RAPESEED IN NORTHWEST ALBERTA

The effects of seeding data and nitrogen and phosphate fertilizer on the agronomic characteristics of two rapeseed species (Brassica campestris L. and B. napus L.) were studied for a 6-yr period at two northwest Alberta locations. Seeding dates were established at weekly intervals from early May to mid-June. Two fertility levels were established; a control treatment in which no fertilizer was applied and a fertilizer treatment in which nitrogen and phosphorus were applied to meet the requirements of a 1680 kg∙ha−1 crop. Maximum yields were obtained most frequently with seeding periods of mid- to late May for B. campestris and mid-May for B. napus. Seeding date had little effect on plant density or seed quality. Nitrogen and phosphate fertilizer reduced plant densities but increased seed yield where nutrient deficiencies occurred.Key words: Brassica campestris L., B. napus L., seeding date, yield, quality