Does Winter Canola Have a Viable Fit in Montana?.

In 2009, area sown to spring canola in Montana was only 2,000 ha, indicating a lack of adaptation. In western Montana it may be more viable to strive for winter canola production, with a growth habit that matches the growing season to achieve large oilseed yields. After promising variety trial results, we conducted a 2-yr study to determine key factors for winter canola production in no-till wheat stubble at Bozeman, MT. Irrigation was applied once in early September in a gradient from 75 (2008) – 93 (2006) mm at a line source 0 to 20 m away, resulting in high, intermediate, and rainfed soil water zones. Contemporary RR canola varieties were used: DKW 13-69, 13-86, 41-10, and 46-15. Seeding rates of 25 to 400 seeds/m2 were used to evaluate seeding rate response. Stand survival, seed yield, and seed oil content were impacted mainly by September seeding date and the presence of irrigation at seeding (especially in 2008/09); and secondarily by the amount of fall irrigation, seeding rate, and cultivar. In this cold northern climate it was crucial to get the plants growing soon enough to attain the 4-lf stage or larger to enable winter survival; early Sep irrigation was necessary to ensure a timely start. Overwinter survival for the early September seeding date ranged 39 to 49% averaged across irrigation regimes and cultivars. This indicates that seeding rates for winter canola should be 2X spring canola seeding rates to achieve similar plant densities. Seed yield response correlated with spring stand density (r = 0.73 and 0.66 in 2007 and 2009, respectively). In both cases, Sep 3 – 8 seeding dates and a single application of 75 – 93 mm of irrigation at seeding produced the greatest yields. Best management practices were similar between years and resulted in 4,400 kg/ha and 43.2% oil content in 2007; and 3,350 kg/ha and 48.5% oil content in 2009.