By Mike Stamm and Ignacio Ciampitti
Winter canola varieties exist today that make production possible across much of Kansas. When a winter-hardy variety is planted at the right time into good soil moisture, plant development is optimized, and the crop will have the best chance at surviving extremes climate.
Deciding when to plant canola this fall may be challenging because soil moisture in the planting zone is depleted statewide. It is often said that it is easier to plant canola after a rain than before one. Although risky, canola has emerged in October following rainfall and survived the winter in Kansas when fall temperatures remain warmer than normal. However, it may be too dry in some cases because the risks of delayed emergence and loss to an early freeze are too great.
The planting window for winter canola arrives in Kansas by early September. Below we are presenting the most critical aspects ranging from variety selection to seedbed preparation to ensure a successful start to the 2022-2023 growing season. A companion article in this eUpdate addresses other management considerations including seeding options, plant nutrition and soil fertility, and pest management.
Variety Selection
Variety selection should be based on the following traits: winter survival, yield, oil content, herbicide tolerance, disease resistance, maturity, lodging susceptibility, and shatter tolerance.
Winter hardiness should be the number one consideration if the crop is being grown in a new area. Producers also have the option of selecting either open-pollinated varieties or hybrids. The majority of the varieties grown in the southern Great Plains are open pollinated. Open pollinated varieties consistently overwinter and have high yield potential. In addition, producers interested in broad spectrum weed control can select Roundup Ready open-pollinated varieties.
Hybrids are being grown in the region and tend to have larger seed size for easier seed metering, vigorous fall and spring growth, and greater yield potential without limitation of resources. Clearfield herbicide tolerance is available in hybrids. Varieties with tolerance to carryover of sulfonylurea (SU) herbicides applied to a previous crop (e.g. Finesse) can be planted in the fall to avoid the long plant-back restrictions these herbicides have for canola. Some varieties that are Roundup Ready also possess SU herbicide carryover tolerance.
Consider selecting two or more varieties with differing relative maturities to spread out harvest operations and reduce risk. If interested in selecting a new variety, consider selecting one variety with known performance in your area in addition to the new variety.
Site Selection
Although canola grows over a wide range of soil textures, well-drained, medium-textured soils are best. Soils where water stands for several days or those prone to waterlogging are poor choices. The soil pH should be between 5.5 and 7.0. Soil pH correction with lime should be considered when growing canola in soil with low pH (less than 5.5).
Be mindful when planting canola following crops like sunflower, soybean, alfalfa, or cotton. These crops share similar diseases with canola. Planting canola continuously is not recommended and it is not insurable. Plant canola after grass crops such as wheat or corn because these crops do not share diseases with canola.
Canola will perform best when adequate time is given after the preceding crop to allow for soil moisture recharge and weed control, and where there is adequate time to get the canola planted early enough to help the plants survive over winter.
Avoid fields with heavy winter broadleaf weed pressure if possible. If planting where heavy broadleaf weed pressure exists, consider planting a Roundup Ready variety. Grassy winter annual weeds are easily controlled by using herbicides that are labelled for conventional, Roundup Ready, or Clearfield canola (e.g. clethodim, quizalofop, sethoxydim). Make sure you are aware of the herbicide history of potential sites. Winter canola varieties are sensitive to Group 2 and triazine herbicide carryover. These products have long plant back restrictions (often 18 months or greater). Be especially cautious about herbicide carryover restrictions when following corn.
Seedbed Preparation
Weeds must be controlled chemically, mechanically, or with a combination of both methods prior to planting because canola seedlings are not competitive with weeds. Open-pollinated varieties typically range from 100,000 to 125,000 seeds per pound and hybrids range from 70,000 to 100,000 seeds per pound. Because of its small seed size, a properly prepared seedbed is critical for successful canola establishment.
A level, firm seedbed with adequate moisture within the top inch is preferred. A seedbed with many large clumps results in poor seed placement and seed-to-soil contact. An overworked seedbed may be depleted of moisture and will crust easily, potentially inhibiting emergence. In addition, this could promote deep placement of the seed.
No-till planting is an option, and some long-term no-till producers have produced canola successfully. With proper settings, no-till planting usually results in very good stands. However, maintaining stands over the winter can be difficult with low disturbance in heavy residue cover. This problem has been overcome by burning surface residue immediately before planting or by using a more aggressive residue manager that removes residue from the seed row. Research in south central Kansas indicates that even with good winter survival, no-till canola yields under heavy residue were lower than where residue was burned or where tillage has been performed.
No-till producers should ensure that drills and planters are properly set and consider using a setup that creates a more disturbed seed row. Using a high-disturbance opener (such as a coulter, residue manager, or hoe-type opener) in no-till can improve winter survival and result in yields comparable to those obtained in tilled fields.
If using tillage, perform the most aggressive tillage as early as possible, with each succeeding tillage operation being shallower than the last. Incorporate fertilizer and herbicide with the last tillage operation. Some producers perform one aggressive tillage operation as early as possible and then control newly emerged weeds chemically. Planting into this “stale” seedbed will help ensure adequate moisture for establishment.
Source : ksu.edu