Crop rotations compared with continuous canola and wheat for crop production and fertilizer use over 6 yr

Abstract

Local economic, logistic, soil, and weather conditions have made appropriate rotations vary from one area to another. Seed yield and fertilizer use in rotations were compared with continuous cropping for 6 yr in the southeast Peace region of Alberta, Canada. Canola (C) (Brassica napus L.), wheat (W) (Triticum aestivum L.), pea (P) (Pisum sativum L.), barley (B) (Hordeum vulgare L.), and flax (F) (Linum usitatissimum L.) were grown in 12 treatments [i.e., continuous canola (CC) and wheat (WW) and rotations of W–C, P–W–W, C–W–W, C–C–W, P–C–W, C–P–W, W–B–C, B–W–C, F–W–C, and F–C–W]. Canola yield increased with 1 or 2 yr breaks from canola. Within rotations, there was a trend to lower canola yield on canola stubble compared with other crop stubbles. Wheat yield was generally lower in WW than in rotations. Among rotations, wheat yield tended to be greater on pea stubble compared with canola, wheat, barley, and flax stubbles. Averaged over 2010–2015, the canola yield benefit from rotations was 0.632 Mg ha−1 (19.4%) over CC and the wheat yield benefit from rotations was 0.313 Mg ha−1 (7.2%) over WW. Nitrogen saving was observed when pea was included in rotation.