Canola Agronomy for Intermediate to High Rainfall Dryland
More than 17 Inches of Annual Rainfall – Annual Crop
Spring canola is generally the best fit for a dryland annual crop system, as winter canola is challenging to plant in the dry conditions that typically follow harvest.
Winter Canola vs. Spring Canola
- It is difficult to germinate canola if it is planted into dry soil after harvest. Most annual crop areas grow spring canola for this reason.
- If significant rains occur in August or early September, winter canola can potentially be seeded with good results.
General Seeding Tips for Canola
- Canola seed is small and must be planted into shallow moisture to germinate.
- Consistent planting depth is critical. Adjust your drill and reduce your speed so your seeding depth is between 0.5 and 1 inch.
- Canola seed can be successfully broadcast in the right conditions. If high moisture prevents conventional seeding, broadcasting seed is an option.
- Air seeders make it easier to regulate the amount of seed planted.
- The cross slot drill is successful for planting canola in high-residue fields, particularly when accompanied by hydraulic control for planting depth.
- Canola seed flows like water. If you are using a conventional grain drill, monitor your seeding rate carefully. Consider taping off every other indent in each seeding disk.
- You can use a bulking agent to regulate the amount of seed planted. A modest amount of 11-52 fertilizer can be used, but banding high rates of fertilizer next to the seed will hurt germination.
- Don’t mix your varieties. If you are planting generic and specialty varieties in different fields, clean out your drill when you switch canola varieties. Generic seed will contaminate your specialty seed, causing you to lose your premium.
Seeding Winter Canola
- You can plant winter varieties on annual crop dryland if soil moisture is adequate to germinate the seed at 0.5- to 1-inch planting depth. In most areas of the Pacific Northwest, early September is the latest you should plant winter canola.
- Seeding date can be early August to mid-September depending on climate. Canola should be at the four-leaf stage (dinner plate size) before the first hard frost.
- Seeding rates generally range from 2.5 to 4 lbs./acre.
Seeding Spring Canola
- Should be planted just after spring wheat.
- Seeding rates range from 4 to 7 lbs./acre with 5 lbs. being a typical figure.
- Modern spring varieties are vigorous and more resistant to frost damage. If frost hits during early flowering, the plants will usually recover and keep blooming.
General Fertility Guidelines for All Canola
- Use the following formula to estimate your fertilizer requirements for canola: Nutrient Application = (Yield Goal x Per Unit Recommendation) – Soil Contribution.
- Nitrogen: Recommendations range from 6 to 10 lbs. of available nitrogen per 100 lbs. of expected yield. Heavy residue from the previous grain crop will increase the required nitrogen.
- Phosphorous: Recommendations are generally around 1 lb. of available phosphorous per 100 lbs. of expected yield.
- Potassium: Most western soils are high enough in potassium that an additional application does not produce a yield response. Consult with your agronomy professional for potassium recommendations.
- Sulfur: Canola responds well to sulfur. Recommendations are typically in the range of 1 to 2 lbs. per 100 lbs. of expected yield. Many growers apply a minimum level of 20 lbs. of sulfur, even if the soil test shows adequate levels.
- Boron: Thus far the only micronutrient shown to produce a yield response in canola. Consult with your agronomy input provider for Boron recommendations for your area.
- Canola emergence can be hindered by banding nitrogen too close to the seed.
Fertility Guidelines for Winter Canola
- In dryland areas, each 10 bushels of wheat per acre can produce about 300 to 400 lbs. of canola. For example, if you produce 60-bushel wheat, expect approximately 2,100 lbs. of canola. If you are new to growing canola, use this as starting point to estimate your yields for fertility management.
- If you are planting into a fallow field in July or August, do a split application of nitrogen between the fall and the spring. Too much nitrogen availability in the summer and fall will stimulate vegetative growth and can depress winter survivability.
- If you have problems managing the low seeding rate through your planter, consider using 11-52-0-0 fertilizer as a bulking agent. The nitrogen content is low enough that seed damage is unlikely.
Fertility Guidelines for Spring Canola
- Depending on rainfall and soil type, spring canola yields can range from 1,200 to 2,500 lbs./acre or more. You can estimate your canola yields based on your spring wheat production. For each 10 bushels of spring wheat, you can expect about 300 to 400 lbs. of canola. For example, if you produce 50 bushels of spring wheat, you can estimate that your canola production will be about 1750 lbs./acre.
- Fertilizer can be applied and incorporated, as with other crops, but do not band significant quantities of nitrogen close to canola seed.
- Split applications of nitrogen have not shown a response in spring canola, but nitrogen can be foliar applied prior to flowering.
- High residues from the previous crop consume nitrogen. Take this into account when determining your nitrogen needs.
The above recommendations are general guidelines only. For publications that provide more specific information, refer to our canola resources.