Spring and Winter Canola: Tillage

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Pub 811: Agronomy Guide > Spring and Winter Canola > Tillage

Excerpt from Agronomy Guide for Field Crops
Order OMAFRA Publication 811: Agronomy Guide for Field Crops

• Conventional Tillage
• Mulch Tillage and No-Till
• Field Variability
• Crop Rotation Considerations
• Site and Rotation Considerations

Conventional Tillage

Most canola is grown using conventional tillage. Lumpy seedbeds interfere with seed-to-soil contact. Fall primary tillage is preferred on clay or clay loam soils so that spring tillage establishes a suitable seedbed. However, keep spring secondary tillage to a minimum to preserve soil moisture and minimize the risk of crusting.

Mulch Tillage and No-Till

Seeding canola with no-till and reduced tillage systems can be successful provided the seeding equipment can place the seed below the residue and in firm contact with the soil. Seed firming wheels press seed into the bottom of the seed trench, improving depth control and seed-to-soil contact. Residue management at harvest in the year prior to no-till or minimum-till seeding is key to success. If crop residue (straw and chaff) is not spread uniformly, seeding equipment cannot operate properly to achieve good seed placement, and seedlings will have difficulty emerging through a mat of residue. Uneven residue distribution also creates an ideal habitat for slugs. No-till canola into cereal residue is not recommended due to risk of stand loss from slugs.

Field Variability

Canola does best on well-drained fields with a minimum pH of 5.5. Fields with variable drainage and pH will have variable stands and yield. Canola performs better on uniform fields. On soils with low moisture holding capacity, spring cereals are more resilient to dry growing conditions than spring canola.

Crop Rotation Considerations

Canola responds to well-drained fields with a minimum pH of 5.5. Crop rotation is the best defence against disease buildup. Rotations of no less than 3-4 years between canola will reduce soil disease build-up. To reduce the incidence of sclerotinia white mould, maintain a 3-4 year rotation with non-host crops.

Rotation is also important to manage herbicide carryover, since canola is particularly sensitive to triazine and ALS (Group 2) products. Carryover will be greater following a dry year and is dependent on soil factors such as pH or organic matter. Environment has a major effect on herbicide persistance. Consult herbicide labels and OMAFRA Publication 75, Guide to Weed Control.

Corn should not follow canola in the rotation. Corn roots establish a strong relationship with vesicular arbuscular mycrorhizae (VAM) fungi, which aids in phosphorus uptake. VAM colonization of corn seedlings is diminished when corn follows canola, resulting in increased incidence of phosphorus deficiency.

Site and Rotation Considerations

In addition to the above considerations, establishment and winter survival of winter canola will be most successful where:

• fields have good soil drainage (both surface and sub-surface) so that water never ponds. Root heaving is more common when canola is planted in heavy or poorly drained soils where ice accumulation has occurred.
• good snow cover is available to protect the rosettes from low temperatures and dessication
• moderate climate occurs. Winter canola is slightly less winter-hardy than winter wheat.

Avoid production of canola and tame mustard on the same farm. Winter canola can be controlled in a spring-seeded crop with tillage but may remain as volunteer plants in a no-till situation. Include effective methods of volunteer plant control in your rotation. Do not locate winter canola in areas (i.e., within 5 km) where rutabagas are grown, because both crops are hosts for turnip mosaic virus. Serious crop losses have occurred in rutabagas from this disease. Sporadic problems in the past did occur with winter canola roots entering tile drains in Huron County and areas close to Lake Huron, but not elsewhere. The reasons for this are unclear. Avoid planting winter canola in recently tiled fields and fields where tiles may remain wet all year.