Canola Agronomy for Irrigated Land
Canola Can Be an Excellent Water Management Tool
Irrigation can range from marginal water addition to intensive irrigation where over 40 inches of water are available. In areas where there is not enough irrigation water to grow intensively managed crops, winter canola can be an excellent water management tool. The soil profile can be filled in the fall when water demand is low and spring irrigation can be stopped early – allowing water to be diverted to other fields.
Double Crop Opportunity
In the long growing season areas of Eastern Washington, canola can be used as a double-crop option. By planting a short-season winter variety, such as Largo, the canola can be harvested by late June, leaving enough time for a second crop, such as sweet corn or buckwheat.
Winter Canola vs. Spring Canola
- If irrigation water is limited, winter canola can be an excellent option.
- Water can be pulled from the canola field in the spring and diverted to more water-intensive crops for the summer.
- With pre-irrigation, winter canola can be planted in late August or early September – as long as it reaches the four-leaf stage (dinner plate size) before the first hard frost.
- Winter canola produces a deep root system and starts spring growth early. Flowering and seed production occur in the spring. In late June, the crop is maturing and beginning to dry down. Winter canola is often harvested by late July.
- Spring canola is a good rotation alternative in areas where winter canola is less likely to survive. Modern spring hybrid varieties produce excellent yield and provide good options for weed control.
General Seeding Tips for All Canola
- Canola seed is small and must be planted into shallow moisture to germinate.
- Consistent planting depth is very important. Adjust your drill and reduce speed so your seeding depth is between .5 and 1 inch.
- Canola seed can be successfully broadcast in the right conditions. If high moisture prevents conventional seeding, broadcast seed onto the field.
- Air seeders make it easier to regulate the amount of seed planted.
- Canola seed flows like water. If you are using a conventional grain, 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 Roundup Ready and non-GMO varieties in different fields, clean out your drill when you switch canola varieties. Roundup Ready seed will contaminate your non-GMO seed, causing you to lose your premium. Non-GMO plants will die by Roundup applications, causing you to lose part of your stand.
Seeding Winter Canola
- Seeding rates generally range from 2.5 to 4 lbs./acre.
- 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 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 more vigorous and generally more resistant to frost damage. If frost hits during early flowering, the plants will usually recover and keep on 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 is Boron. 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
- For each 10 bushels of wheat per acre, you can produce about 350 to 400 lbs. of canola under irrigation. For example, if you produce 110-bushel wheat you can expect approximately 4,125 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 are having 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, irrigated spring canola yields can range from 2,200 to 3,000 lbs./acre or more. You can estimate your canola yields based on your spring wheat production. For each 10 bushels of spring wheat, expect about 300 to 400 lbs. of canola. For example if you produce 80 bushels of spring wheat, you can estimate your canola production will be about 2,800 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 a nitrogen foliar application can be applied prior to flowering.
- High residues from the previous crop consume nitrogen. Take this into account when figuring your nitrogen needs.
- Winter Canola: If the soil profile is well charged in the fall, winter canola requires only modest irrigation in the spring. Many growers will water a few inches once spring growth is well underway and then apply no additional water for the rest of the season.
- Spring Canola: Water requirements for spring canola are similar to spring wheat. Depending on moisture-holding capacity, most growers water spring canola until the late bloom stage.
The above recommendations are general guidelines only. For publications that provide more specific information, refer to our canola resources.