Establishing good winter canola stands
Getting a good stand is the first step for any winter canola producer--and goes a long way toward achieving the ultimate goal of having a successful crop, said Mike Stamm, K-State Research and Extension canola breeder. Planting date, planting depth, and soil moisture are all important factors that can affect stand establishment of winter canola in Kansas.
In general, it is best to plant canola six weeks before the average date of the first killing frost of 28 degrees in central and south central Kansas, or eight to ten weeks before for southwest Kansas, he said.
"Planting at about this time will allow for enough time for plants to have the right amount of growth for good winter survival and canopy development," Stamm explained. "If winter canola is planted too late, you'll likely end up with small plants that may not have enough food reserves to survive the winter well. If it is planted too early, you may end up with too much growth that can deplete soil moisture and nutrient reserves."
Excessive growth may also elevate the growing point or crown, increasing the chance of winterkill, he added. This can be a problem when heavy residue is left in the seed row without tillage.
If soils remain dry this fall, dryland producers should probably delay planting as long as possible until moisture conditions improve and soil temperatures cool, Stamm said. Producers should not wait too long, however.
"In central Kansas, winter canola should be planted by Sept. 25. In south central Kansas, winter canola should be planted no later than the last week of September. In southwest Kansas, winter canola should be planted by Sept. 10 at the latest to try to avoid winterkill problems. Irrigated producers should not delay their planting date beyond the optimum time because of unusually warm soil conditions," the K-State plant breeder said.
Seed placement is critical for successful germination, emergence, and stand establishment, he added.
"In general, you'll get the best germination if you place seed one-half to one inch deep. Under drier conditions, you may have to plant deeper to get to moisture, but don't plant canola more than one-and-a-half inches deep," he said. "If you have to plant it that deep, you can expect delayed emergence and reduced vigor. Also, soil crusting following a heavy rain can result in a poor stand."
With planting depth being so important to getting good emergence, producers should pay close attention to tractor speed when they're planting, Stamm said.
"Producers must plant slower when planting canola than when planting wheat--preferably five miles per hour or slower," he said.
Row spacing is less critical than planting date and seeding depth, he added. The most common row spacing for canola is between six and 15 inches, he said. That allows for rapid canopy closure and weed control. Yields are similar with row spacings in this range, with good weed control.
Some producers are experimenting with canola planted in 30-inch rows, using planters instead of drills, Stamm said. By using planters, producers are able to get more accurate depth control, precision seed metering, and better residue removal from the seed row.
"As a general rule, yields may be reduced by about 10 percent when planting in 30-inch rows instead of 15-inch rows under dryland conditions. However, producers are able to reduce their seeding rate from five pounds per acre to between two-and-a-half and three-and-a-half pounds per acre, eliminating some inner row competition among plants and saving on seed costs," he said.
Planting a hybrid cultivar with prolific branching will increase the profitability of canola planted in 30-inch rows, he added.
Successful canola stand establishment
Many factors contribute to getting a successful stand of winter canola in Kansas, said Mike Stamm, K-State Research and Extension canola breeder. The following is a brief listing of important considerations from Stamm.
--Well-drained, medium-textured soils are best for winter canola establishment.
--Soil pH of 5.5 to 7.0.
--When planting canola after crops such as sunflower, soybean, alfalfa, or cotton, remember that they share several diseases with canola. Planting canola continuously is not recommended and is uninsurable. Often, canola is planted after grass crops such as wheat, oats, and corn because these crops do not share diseases with canola.
--Fields with heavy winter broadleaf weed pressure should be avoided if possible. If planting where heavy broadleaf weed pressure exists, consider planting a Roundup Ready cultivar.
--Be aware of the herbicide history of potential sites. Winter canola cultivars are sensitive to sulfonylurea and triazine herbicide carryover. Commercial varieties with tolerance to sulfonylurea herbicide carryover can be planted the fall following a spring sulfonylurea application.
--A weed-free seedbed is critical to establishing winter canola.
--Weeds must be controlled chemically, mechanically, or with a combination of both methods prior to planting. Canola seedlings are not competitive with weeds.
--A seedbed with many large clumps results in poor seed placement and seed-soil contact. An overworked seedbed may be depleted of moisture and will crust easily, potentially inhibiting emergence.
--Soil testing, including a profile sample for nitrogen and sulfur, is important in determining fertilizer needs.
--Fertility needs are similar to winter wheat; however, canola needs slightly higher levels of nitrogen and sulfur.
--Canola requires more sulfur than wheat because of its high content of sulfur-containing proteins. Sulfur deficiencies are most common on coarse-textured and low-organic-matter soils.
--Nitrogen applications must be carefully balanced. Too little or too much fall-applied nitrogen may negatively affect winter survival. One-third to one-half of total nitrogen (based on expected yield) should be fall-applied.
--Applying high rates of fertilizer in-row at planting is not recommended because canola is sensitive to ammonia and salt damage. Preplant broadcast application is the safest method.
--Apply lime so that pH is in the range of 5.5 to 7.0 and early enough so the lime has time to react.
--No added phosphorus is required if the phosphorus soil test is above 30 parts per million. More potassium should be applied if soil test levels are under 125 ppm.
--No matter what herbicide program you use, the most important thing to remember is to control weeds early in the fall.
--Before applying herbicides, take care to ensure there are no traces of problem herbicides, such as sulfonylurea herbicides, in the sprayer equipment.
--An insecticide seed treatment is recommended for control of green peach aphids and turnip aphids through Jan. 1.
--Monitor canola stands for: grasshoppers, army cutworms, flea beetles, aphids, and root maggots.
--The best control of canola diseases is achieved through careful rotation.
--Maintaining proper rotation intervals, planting disease-free seed, and using fungicide seed treatments are important management practices to slow the spread of blackleg disease.
For further information, see the newly revised Great Plains Canola Production Handbook, at any local extension office, or www.ksre.ksu.edu/library/crpsl2/mf2734.pdf.