Manitoba Agriculture, Food and Rural Initiatives
Canola Production and Management
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Field Selection Variety Information Seeding Canola Fertilizer Recommendations for Canola Weed Control Insects Diseases Affecting Canola Harvesting Canola |
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Field SelectionCanola or rapeseed is a cool season crop and therefore yields highest when grown in areas where extreme heat and moisture limitations are not usual. Growing crops that are susceptible to sclerotinia too frequently in the rotation can increase the risk of stem rot.
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Variety InformationChoose varieties carefully to match the conditions in your area and on your field. Varietals characteristics that are the most important to consider are blackleg resistance, lodging, crop maturity, tolerance to herbicides and yield. Yield should be considered last since blackleg resistance and lodging tolerance can have the greatest impact on yield. In recent years herbicide tolerant varieties have become available. With an increasing number of varieties with unique characteristics, selection has become more difficult and important to maximize returns.
Variety performance, acreage, seeding date and crop rotation have effects on yield.
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| Nitrogen (N): | Apply 0-30 lb/acre N following fallow or legume breaking, 30-70 lb/acre N following grass and grass-legume breaking and 70-90 lb/acre N following stubble. High-yielding canola requires high nitrogen fertility. However, excessive nitrogen in the soil has been linked to green seed problems. The primary nitrogen deficiency symptoms are yellowing, starting with the older leaves, and thin, spindly stems. |
| Phosphate (P2O5): | Apply phosphate rates at 30-40 lb/acre as a sideband or 20 lb/acre with the seed. The primary phosphate deficiency symptom is poor root development and reduced branching with thin, spindly branches. |
| Potassium (K2O): | On sandy textured or organic soils, apply potassium at rates of 30-60 lb/acre. Deficiency symptoms are stunted growth with smaller leaves and thinner stems. Eventually, the edges of lower leaves turn brown and drop off. |
| Sulphur (S): |
Apply sulphate sulphur at 20
lb/acre on well-drained soils and grey luvisol (grey wooded)
soils. Sulphur deficiency may occur in many soils and in any
area of the province. A soil test is recommended to establish
the available sulphur status of fields. Canola requires about
twice as much sulphur as do cereal crops. A minor sulphur
deficiency may not be detected visually but results in
significant yield reductions. Major sulphur deficiency symptoms
are most visible on the newest leaves and start with yellowing.
Leaves showing more severe deficiencies may be cup-shaped, with
purple colouration on the edges of leaves. Application of
nitrogen alone to a sulphur deficient soil may actually depress
yields. Application of fertilizer in a N:S ratio of 8:1 to 5:1
will usually supply adequate sulphur. Elemental sulphur must be applied one year before the canola crop to allow time for conversion to sulphate. |
Special Considerations
For a recommended malting barley variety to be acceptable for a malting grade, the grain should contain 10.5% to 13% protein. Protein levels in barley are determined by the amount of available nitrogen plus growing season moisture and temperature conditions. High rates of nitrogen and/or limited growing-season moisture may result in protein content above the acceptable levels.
Weed Control
After canola forms a canopy, it is very competitive and chokes out many weeds. Depending on the relative time of emergence and weed density, herbicides may not be necessary which improves net returns.
Weed seeds that are difficult to remove or cannot be cleaned out of canola and cause downgrading are wild mustard, oriental mustard, brown mustard, ball mustard, cow cockle and cleavers. If canola is going into a field known to be very weedy, consider growing canola varieties that are tolerant to non-selective herbicides.
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InsectsGrasshoppers, cutworms, bertha armyworm, flea beetles, diamondback moths, lygus bugs, and root maggots can damage canola. The insects that are currently monitored are: Links:
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 Diamondback moths
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Canola typically is not desiccated, since the pods shatter easily after desiccation. Desiccation accelerates plant dry-down, not plant maturity. For detailed information on desiccation, consult the MAFRI Guide to Crop Protection. Canola is considered ready to combine when moisture reaches 10% or less and minimal green seed can be found. Pickup speed should match ground speed to minimize shattering losses. Cylinder speed should be about 500-900 rpm. If the cylinder speed is too fast, seeds will crack. Wind speed should be kept low in order to minimize seed losses with the chaff. Canola straw breaks down quite readily. In order to minimize seeding problems in the spring, the straw and chaff should be spread behind the combine rather than placed in a row. Canola is marketed at 10%. For long-term storage, canola should be at 8% to 9% moisture and below 20°C. Once in storage, canola should be
cooled since the seed continues a high respiration rate for up to
six weeks. This respiration rate creates moist areas (sweating) in
the bin that become hot spots. Once binned, canola should be
monitored carefully for heating problems.
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For further information, contact your GO representative.
