North Central Canola Research Program


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The Minnesota Canola Production Centre & Canola Research

The Minnesota Canola Production Centre & Canola Research
Paul Porter, University of Minnesota - $29,549

Many canola growers prefer to see how varieties perform and compare in "field scale" plots rather than small plots. When appropriately designed, field scale plots take into account more field variability in the yield equation by including high ground and ditches. Small plots are typically located in an area of the field where the soil is uniform and well drained to reduce variability among treatments. The large plots allow each variety to be treated with its' respective herbicide so that the varieties are treated like they would be in the grower's field. Many growers not only pick varieties for their yield and disease resistance, but also based on ease of harvest. Comparing harvestability of varieties is not possible in small plots because the equipment is not comparable to what a grower uses.

Research has indicated that N accumulation in canola increases from about 20 lb/ac to 100 lb/ac in a 30 day period beginning twenty days after emergence, with the most N accumulation (about 110 lb/ac) occurring 55 days after emergence (Thomas, 2000). Rainfall during this period of rapid nitrogen accumulation could leach soil N beyond the canola-rooting zone. A top dress application of N, with a little or no N applied preplant and the remainder applied at 4- to 6- leaf stage, could be more efficiently utilized by the plants, which could result in less N needing to be applied. A split application of N would provide growers an additional month to evaluate their canola crop prior to purchasing and applying the additional N.

Winter canola has the potential of producing larger yields than the spring canola currently grown in northwestern Minnesota. Winter canola is seeded in the fall after small grain harvest. It grows to a large rosette plant in the fall and over winters that way. In the spring, most of the old leaves appear frozen and dead however the crown shoots out new leaf growth in early to mid April and is flowering by the end of May. The early flowering avoids the heat stress of July and August and harvest is usually earlier than spring wheat. Winter canola variety trials were conducted in northern Minnesota in the late 1980s with limited success. Most years the trials were seeded on tilled soil , and 'winter kill' resulted. In fall 2001 a National winter canola variety trial was seeded south of Thief River Falls, MN into heavy wheat straw residue. Germination was delayed due to dry weather and poor seed/soil contact. The plants were very small going into the winter and none survived. In fall 2002 a seeding date x seeding rate trial was conducted west of St. Hilaire, MN into approximately 10 inch wheat stubble that had the straw removed by raking and baling it. Plant sizes varied from large 6-leaf to very small 2-leaf. There was good snow cover that winter with excellent survivability. In fall 2003 the trial was repeated just south of Thief River Falls, MN along with the national winter canola variety trial into 12 inch wheat stubble with the straw baled off. The canola was good and healthy going into the winter, but only one range near the gravel road survived to make a crop.

1. Establish agronomic and economical criteria (such as yield, contribution margin, crop quality, lodging resistance, harvestability, and disease resistance) for choosing among canola (Brassica napus L.) varieties and their respective herbicide options.
2. Evaluate canola response to multiple rates of nitrogen (N) applied pre-plant or at the 4- to 6-leaf stage of growth using field-scale equipment.
3. Evaluate the effectiveness of top dressing urea N (46-0-0) compared to Ammonium Nitrate (34-0-0).
4. To determine the cause/timing of winter kill in winter canola to be better able to devise practices to prevent it in the future.
5. To evaluate different winter canola varieties for their ability to survive the winter and produce yield in northwestern Minnesota.

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