Winter Canola Research at Montana State University
Decision time is fast approaching for winter canola seeding. Genetic technology has improved and some producers in Montana are having success with winter canola. Dr. Perry Miller, Cropping Systems Professor at MSU has been researching winter canola. Below are a few of his thoughts. For additional questions, please reach out to Dr. Miller by email (pmiller@montan.edu) or call (406-994-5431)
• Yield: Winter canola is a fragile system that is a game-changer when all the pieces line up correctly. However, due to the fragility of the system, what works in one location may not work in other areas of Montana. In plots near Bozeman, potential yield increase is twice that of spring canola. Average potential is closer to one and a half times the spring canola yield. If winter canola doesn’t survive the fall and winter, the crop can be a total loss.
• Harvest: Winter canola maturity is significantly more variable than spring canola due to overwinter stand injury. The end result is over-ripe sections of field shattering while other areas are too green to cut. Swathing is not an option in wind-prone Montana because of shattering. Shatter-resistant varieties are less than 5 years out. Shatter resistance will increase seed costs, but also increase the ease of harvest. Current chemical desiccant and pod sealant options increase harvesting costs. Reports from farmers yield variable success with pod sealant products.
• Chemical fallow: Chemical fallow is more likely to have moisture reserve to prevent seedlings from desiccating. We have tried several instances seeding winter canola on
various crop/cover crop stubbles in summer. If we get half an inch of rain to germinate the crop, and no rain for the next month, the crop will fail.
• Seeding date: Mid to late August establishment is ideal in dryland Montana, but it is often difficult to get dryland winter canola emerged in August. If you seed in September, you may not have the heat units to get it to the ideal minimum of the four-leaf stage. If you seed in July, the canola may get too large and require mowing/grazing. In addition, you have increased winter injury if crowns start to elevate off the soil surface.
• Seed density: We looked at high (18 seeds per square foot) and medium (9 seeds per square foot) seed densities with September seed dates. High densities established better. However, there is experience in central plains that suggests lower seed densities establish more vigorous ground-hugging cabbage.
• Fertilizer: Our 4-location seed date trial includes N and S fertilizer treatments. When we were focusing on recropping after wheat, we found that full N rates did not harm, and even helped with seedling establishment, partially because with late seeding, we were in a race to get seedlings big enough to survive winter.
• Insect Pests: Beware of flea beetles and grasshoppers. If canola is emerging in late August, it may be the only green thing for miles around. Grasshoppers can damage seedlings very quickly.
Montana State University U.S. Department of Agriculture and Montana Counties Cooperating. MSU Extension is an equal opportunity/affirmative action provider of educational
