Canola variety, nitrogen, phosphorus, and sulfur fertilization affect yield, quality, and fatty acid profile

Canola yield and quality are important for food, feed, and industrial end-uses. There may be trade-offs between the agronomic and quality aspects of canola production depending on varietal traits and management. The objective of this work was to assess the effects of nitrogen (N), phosphorus (P), and sulfur (S) fertilization on agronomic and quality properties of canola varieties with distinct oleic acid contents. Nitrogen fertilization rates were 0, 25, 50, or 100 kg ha-1, P rates were 0 or 30 kg ha-1, and S rates were 0 or 20 kg ha-1. Canola was grown in 2003, 2004, and 2005 at Brandon, a private farm close to Brandon, and at Lacombe, Canada. Canola yields averaged 2.36 t ha-1 for conventional, 2.53 t ha-1 for low, and 2.2 t ha-1 for the high oleic acid varieties at maximum fertilization of N, P, and S. The high oleic acid variety averaged 75 % oleic acid content, whereas the low variety averaged 65 %, and the conventional variety 62 %. Total saturated fatty acids were greatest with the conventional oleic acid variety, and tended to increase with N, decrease with S, and were not influenced by P. The high oleic acid variety yielded slightly less than the other two varieties but tended to have lower glucosinolate and saturated fatty acid contents. This work could have implications for human nutrition or other end-uses. Current canola varieties and fertility management should be studied to produce canola with quality tailored for the end use.