Canola Growing: Higher Yields Through Smart Cultivation

The Relationship Between Canola And Rapeseed

Rapeseed and canola are virtually the same crop species; the only genetic difference between them is in the oil’s chemical makeup and fatty acid (FA) profile. Despite rapeseed oil’s numerous industrial applications, it’s unsafe for use in food because of health concerns associated with its over 45% erucic acid content ^{Pandi, W. et al. (2022, May 11). A Review of Erucic Acid Production in Brassicaceae Oilseeds: Progress and Prospects for the Genetic Engineering of High and Low-Erucic Acid Rapeseeds (Brassica napus). Frontiers in Plant Science, 13. https://doi.org/10.3389/fpls.2022.899076.}. While practices for how to grow rapeseed are pretty similar to those for canola, we will narrow our focus to the latter.

Canola originated in Europe and made its way to the Americas via Canada. Canadians employed traditional plant breeding to develop a kind of European rapeseed into canola, a food crop that produces healthful vegetable oil for human use. “Canadian oilseed low in acid” is whence the term “canola” derives.

There are three different canola plant types based on the breeding technology used: open-pollinated varieties, synthetics, and hybrids. The superior performance of synthetic and hybrid seeds often outweighs their higher price tag. Current advancements in breeding and genetic engineering technologies introduce herbicide-tolerant cultivars.

When And Where Is Canola Grown?

Canola (same as wheat) comes in two varieties named after their planting seasons: winter and spring. The growing season for spring variety begins in early spring and ends around autumn, while the growing season for winter crops begins in autumn and ends in summer. In comparable growing conditions, autumn-planted canola typically outperforms spring-planted canola (on average by 20–30%).

Northern regions typically grow spring crops instead of winter crops due to the harsh winters. North Dakota and Canada are prime locations for growing spring crops, while the EU (European Union), China, and the American South Plains are prime locations for growing winter crops.

Optimal Canola Growing Conditions

Canola has a reputation for being a resilient crop that can handle temperature swings with relative ease. It doesn’t require a lot of water and isn’t demanding on the soil either. Because of this, it may be cultivated in a broad range of growing conditions.

What Climate Does Canola Grow In?

To germinate, the plant needs a seedbed that is both moist and heated to at least 35°F (2°C). Soil temperatures of 50°F (10°C) or higher are optimal for quick germination and emergence. With its remarkable adaptability, the crop thrives in a wide range of growing conditions, including the chilly climes of temperate zones. Winter varieties grow well in regions with ample snowfall or quite mild winters.

Spring varieties are not too hardy when it comes to summer heat. Plants’ sensitivity to the growing environment varies with their developmental stage. In particular, temperatures above 86°F (30°C) can severely damage flowering plants compared to those still in the vegetative growth stage. Planting canola earlier in spring will help avoid heat stress during flowering, which might cause floral bud abortion and other problems.

Using weather data collected by EOSDA Crop Monitoring, crop producers may determine if their fields have a suitable microclimate and, if so, which variety will grow and yield the best given the prevailing weather patterns. Temperature, precipitation, wind speed and direction, and many more important meteorological factors are available through our platform.

What Type Of Soil Does Canola Grow In?

Canola grows successfully in a wide range of neutral (pH 5.5–7.0) soils and can tolerate even somewhat saline soils. Good drainage is essential for the crop. Soils with poor drainage reduce the winter crop’s chances of survival during the cold season. The crop does better in winter when grown on fields with good internal drainage or a gentle slope to facilitate surface drainage. Avoid growing the crop in places where drainage has historically been an issue since the plant fails to grow well in standing water.

Planting Canola

Be careful not to till the soil too much before planting canola, since this could cause the seedbed to dry up. Today, a growing number of crop producers are using no-till cultivation methods instead of conventional ones. In zero tillage, press wheels establish optimal seed-to-soil contact.

The ideal canola sowing depth is 0.5–1.5 inches (1.2–3.8 cm). If planted too deeply, growing canola seeds won’t be able to push their way out of the soil, which means fewer stands and delayed emergence. Because of the longer time it takes for seeds to emerge, crops’ competition with weeds and seed treatments protecting them from pests may not be as successful.

It is not advisable to plant varieties that are non-tolerant of herbicides in fields still containing residual herbicides, especially those with ALS inhibitors like sulfonylurea and imidazolinone. You should know the field’s herbicide history, ideally dating back three to five years.

How many canola plants per square foot (meter) should there be? Crop producers usually aim to grow 7 to 10 plants per square foot (8 to 11 plants per square meter). Standard grain drills with a row spacing of 6–10 inches (15–25 cm) work just fine. There will be less weed competition and a reduced chance of wind shattering right before harvest if rows are spaced somewhat narrower.

Apply precision canola planting to ensure even vegetation and maximum yield from your fields. You may find out how productive your fields were in previous growing seasons using EOSDA Crop Monitoring productivity maps based on vegetation data collected over time. Low-productivity areas of the field may require higher seeding rates. With the help of productivity maps, you can divide the field into sections and plant seeds at varying rates in each.

Care For Canola Plants

The key procedures for crop care include providing timely nutrients and irrigation, weed control, and pest and disease management, particularly through crop rotation — all to grow a healthy and productive crop. Now, let’s explore these practices in more detail.

Efficient Nutrient Management

Nitrogen (N), phosphorus (P), potassium (K), sulfur (S), calcium (Ca), and magnesium (Mg) are the most important elements for vigorous crop growth. Also, boron plays an important role in canola plants by promoting root development and early establishment.

The fertilizer form and application timing are critical concerns. Crops will benefit from granular or pelleted elemental S only if applied for no less than a few years before growing them. On the other hand, nutrients in readily available form, like urea, provided either before or during sowing, with extra amounts applied during the canola growing season, might promptly boost yields. Nutrient application timing, form, and rate optimization are key to maximizing yield while minimizing fertilizer runoff.

Timely Irrigation

Crop management, crop variety, and expected yield are three of the main elements that determine plants’ overall water requirements. During its growing season, canola can use up to 20 inches (500 mm) of water, with the most water-intensive stages requiring up to 0.3 inches (7.5 mm) of moisture each day.

The crop needs the most irrigation in the late vegetative stages and again during the flowering stage. At these times, water stress can cause a significant loss in yield. To avoid it, keep the soil moisture content above 50% of the active root zone soil moisture during the canola growing season.

Data on soil moisture at both the root and surface levels is available in EOSDA Crop Monitoring, allowing you to stay vigilant about it at all times, especially during critical growth periods. As soon as you notice that the soil lacks moisture, you can immediately begin watering.

Pest And Disease Control

Flea beetle management, especially seed treatment, may be needed in canola growing regions after a warm winter or in the event of hot, dry conditions following planting. Lygus bugs (tarnished plant bugs), root maggots, cabbage worms, cutworms, armyworms, cabbage seedpod weevils, alfalfa loopers, cabbage and turnip aphids, diamondback moths, and a few more insects can cause issues for the crop.

Common diseases, such as the following, can impede canola growth and development and, in the most severe case, the yield:

• Blackleg (Phoma lingam) can result in serious yield losses in sensitive cultivars, particularly in warm and humid growing areas. Yield reductions of as much as 50% have been documented on certain farms in western Canada ^{Blackleg. Canola Encyclopedia. Canola Council of Canada.}. Minimizing losses calls for regular scouting and implementing an integrated disease control approach.
• Downy mildew (Peronospora brassicae) tends to develop in damp, chilly growing environments and normally disappears as soon as the temperature grows. Crop rotation and the use of disease-resistant varieties are two ways to keep the pathogen at bay.
• Alternaria black spot (Alternaria brassicae) thrives in damp, wet environments; however, fungicides can stop it in high-risk canola growing regions.

To identify infestation hazards, harness the Disease risk tool in EOSDA Crop Monitoring, taking into account both the crop’s growth stage and weather conditions. Remote field monitoring allows large-scale crop producers to send scouts directly to areas at risk for a more thorough examination and the development of effective pest and disease management strategies.

Herbicides And Weed Management

For young canola to grow healthy, typical herbicide use has been kept to a minimum. However, this forced a fresh strategy in the battle against weeds. Modern herbicide-tolerant (HT) cultivars offer such an alternative. With the ability to withstand glyphosate, glufosinate, or imidazolinone, hybrids can be planted earlier, and there are more technological systems to choose from, providing farmers with greater leeway. The plant, once established, is resistant to weeds if you follow agricultural practices for uniform crop emergence and development.

Regular Crop Rotation

The biggest problem of growing canola as monoculture is increased disease pressure, especially from blackleg. At the very least, planting the crop should be kept apart for a year, ideally two to three. Plants growing on canola stubble produce 10–20% less than those growing on grain or pulse stubble. Farmers should use integrated pest, disease, and weed control strategies while growing canola in a rotation that includes this crop on a two-year basis. To identify and eliminate pests and other issues related to the short-interval rotation, it is crucial to scout fields frequently and thoroughly.

It may be necessary to reduce the frequency of growing canola in the rotation if there is a trend towards more serious and ongoing issues, which can be acknowledged by keeping records. You can keep crop rotation records of all your fields in EOSDA Crop Monitoring, with data broken down by season. Providing additional information, such as the soil type and irrigation method, will allow for greater control in the future.

How Long Does It Take For Canola To Grow?

Even excluding the cold season, winter canola plants grow longer than spring plants. The usual growing period for the spring variety is between 87 and 100 days. In the meantime, the winter variety needs 129–163 days to actually grow and another 120–150 days to overwinter. Winter varieties go dormant in the rosette stage and stay that way till early spring.

How To Harvest Canola

Since canola is an indeterminate plant, meaning it grows continuously throughout its life, some of the seeds will be immature during harvest season. The partial greenness of the stems will persist. If the pods rattle when you shake them, it indicates the crop is ripe.

So, when is canola harvested? Pay attention to the grain moisture content rather than the dates. The ideal moisture content to harvest canola seed is 8–10%. Damage from shattering caused by strong winds, hail, or birds can be catastrophic, so don’t delay harvesting. Under perfect growing conditions, you can aim for a yield of 40–50 bushels per acre (2.7–3.4 tons per hectare).

There are two methods for how canola is harvested: one involves direct combine harvesting of the crop, while the other involves desiccating or swathing the field beforehand. Direct harvesting is preferred in conditions of high humidity and with uniformly mature crops across the field. Desiccation is the way to go with uneven crop maturity, weed infestations, and calm weather forecasts. Consider swathing the crop if your crop isn’t maturing evenly and you are expecting harsh weather.

When scheduling dates for canola harvesting, it’s helpful to have access to an accurate weather forecast for your field through EOSDA Crop Monitoring. This will alert you to any impending hail, strong winds, or heavy precipitation. To maintain high yields, harvest your fields before bad weather hits.

Paving The Way To More Sustainable Canola Growing

The old ways of canola crop production and haphazard input application aren’t going to cut it for the big agriculture players anymore if they want to stay ahead of the competition. Luckily, more effective and sustainable ways to grow canola are within reach through precision agriculture. Variable rate seeding, accurate weather forecasts, site-specific fertilizer plans, precision irrigation, and disease risk alerts all contribute to increased yields while benefiting lands and communities. To ensure our shared future in the face of growing environmental and food security concerns, it is essential to use data-driven, resource-conserving canola farming practices.