Agronomy

Fitting Canola into the Crop Rotation

You can substitute winter canola for winter wheat. Farmers should use a two-year or preferably longer rotation before replanting canola. Winter canola works well with double crops such as soybeans. Canola matures typically a week before wheat and has less residue to plant into for the next crop. Canola can also potentially benefit other crops in the rotation by suppressing nematodes. An example rotation could be corn, fall-planted winter canola, double crop beans, winter wheat, double crop beans and then return to corn. This rotation produces five crop harvests in three years.

Site Selection

Like most crops, winter canola does best on medium-textured soils. Winter canola tolerates light or heavy soils, but poorly drained fields need to be avoided. Yields may be reduced if the soil pH level is below 5.5.

Fertility

Soil testing is recommended for developing a fertilizer management plan. Fertilize before planting based on soil test recommendations for phosphorus and potassium. For nitrogen, use a split fertilizer application similar to wheat. Apply about 50 pounds nitrogen per acre in fall and 80 pounds to 100 pounds nitrogen per acre in early spring. Sulfur and/or boron may also be helpful.

Variety Selection

Buy winter-type canola; spring-type is lower yielding in the mid-South. Herbicide-resistant Roundup varieties are available. Additionally, hybrid types of winter canola available from Europe may have superior yields. Yields can vary significantly among canola varieties, and it pays to select good ones. The National Winter Canola Variety Trial program has operated in a variety of states, including Missouri, for the past several years to help in variety selection. It is a good tool for producers to evaluate varieties.

Planting

Winter canola should be planted by the middle of September in central Missouri and by the end of September in southern Missouri. Average seeding rate is 4 pounds per acre to 6 pounds per acre. The lower rate is best under good conditions. Canola should be planted at a seeding depth of 0.5 inch on heavy soils or 0.5 inch to 1 inch on loam soils. Narrow row spacing between 7.5 inches and 15 inches should be used to plant canola.

Weed Control

Canola is generally very competitive with weeds, and post-emergent sprays are usually not necessary where a good canola stand has been obtained. For fall pre-emergence weed control, some herbicide options would include Treflan and Sonalan. For post-emergent weeds, Poast, Select and Assure are available for grass control, and Stinger is a post-emergent broadleaf herbicide labeled for canola. Glyphosate-tolerant winter canola varieties exist, but some end markets demand non-GMO canola.

Insects and Diseases

Insects have not been an issue on spring growth of winter canola, but where winter canola is fall-planted in a no-till stand, an insecticide may be needed to protect new canola seedlings from grasshoppers or other pests.

There are a few diseases that can show up on canola, but they are typically minor in the mid-South. Scerotinia stem rot is one of the most serious canola diseases. Using a multi-year rotation and/or fungicides can reduce sclerotinia yield loss. Fungicides can also help reduce incidence of blackleg, which is another major disease.

Harvest and Storage

Pods and stems will typically turn color at the same time, but some stems may be slow to lose their green color. Using a desiccant such as Reglone or using glyphosate in non-glyphosate tolerant fields can help. In some states, swathing is common, but direct combining is better for the mid-South. A platform (wheat) head should be used. General combine settings would include:

• Run the cutter bar just below lower pods, and set reel relatively high and back.
• Use a cylinder speed of 450 rpm to 650 rpm.
• Establish a fan speed of 400 rpm to 600 rpm.
• Set upper sieve at ¼ inch to ⅜ inch and lower sieve at about ⅛ inch to ¼ inch.
• Adjust concaves to ¾ inch in front and ⅛ inch to ¼ inch in rear.

It is ideal to cut when all pods are brown and seeds are 8 percent to 10 percent moisture, but to avoid shatter, producers may need to harvest at higher moisture and with some immature small pods. For long-term storage, seed moisture should be at 7 percent to 8 percent.

Canola seeds are high oil – they have twice the oil content of soybeans – so handle carefully in hot weather, meaning don’t let canola seeds sit on a truck too long on a hot day after harvest. Canola seeds are small and round and drain out of holes in trucks and combines, so make sure to plug up holes or cover with duct tape.

For More Information

Great Plains Canola Production Handbook (Kansas State)

Canola Resources (Oklahoma State)