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K-State Agronomy eUpdates

Department of Agronomy

Kansas State University

1712 Claflin Rd.

2004 Throckmorton PSC

Manhatan, KS 66506

785-532-6101

agronomy@ksu.edu

Extension Agronomy

Winter canola fall management practices

Winter canola cultivars exist today that make production possible across much of Kansas. When a winterhardy cultivar is planted at the optimum time, canola can survive the extremes of Kansas climate. With a current futures price for 2015 crop around $9.10 per bushel delivered to Goodland, canola is showing profitable returns for the coming year.

The winter canola planting window arrives for Kansas by late August or the first week of September. Now is the time to make decisions to ensure a successful start to the 2014-2015 growing season. Here are some key points to consider as you decide whether winter canola can be a profitable crop for your farm.

Where will winter canola grow in Kansas?

  • The most common production areas are central and south central Kansas under dryland conditions, and southwest Kansas under irrigated conditions. In recent years, canola production has expanded north of the I-70 corridor.

Is insurance available and what are the plant-by dates?  

  • Insurance is available for canola in all counties adjacent to and south of I-70.
  • Yield and revenue protection are available in the following counties: Barber, Gray (irrigated only), Harper, Kingman, and Sumner.
  • Coverage in other counties is available by individual written agreement (yield protection only) if certain criteria are met, including records for at least the three most recent years of production history for canola or a similar crop.
  • Because of the Labor Day holiday, producers have until September 2 to apply for insurance with their agent.
  • To qualify for full benefits of the coverage, including replant payment if necessary, canola needs to be planted between August 25 and September 25 in southwest Kansas; between September 10 and October 10 in Barber, Harper, and Sumner counties; and between September 1 and September 30 in Kingman County and all other eligible counties.
  • We have been working with the Risk Management Agency to expand written agreement coverage north of I-70.

Variety Selection

  • Variety selection should be based on the following traits: winterhardiness, seed yield, oil content, disease resistance, maturity, lodging susceptibility, and shatter tolerance. 
  • Producers have the option of selecting either open pollinated varieties or hybrid varieties.
  • The majority of the varieties grown in the southern Great Plains are open pollinated. These varieties have been consistent performers for producers as canola acres have risen.
  • More hybrid varieties are being grown each year. Hybrids tend to have larger seed size, vigorous fall growth, and greater yield potential under ideal growing conditions.
  • Herbicide resistance options include Roundup Ready and Clearfield.
  • Varieties with tolerance to carryover of sulfonylurea (SU) herbicides applied to a previous crop (e.g. Finesse, Glean, Maverick) can be planted in the fall to avoid the long plant-back restrictions these herbicides have for canola. 
  • Consider selecting two or more varieties with differing relative maturities to spread out harvest and reduce risk. 

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 could be a potential solution for 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 allowed 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.
  • 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.
  • Make sure you are aware of the herbicide history of potential sites. Winter canola cultivars are sensitive to SU and triazine herbicide carryover, and these products have long plant back restrictions (often 18 months or greater).

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 canola 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 is preferred. 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. 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 adequate 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 drill setup 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 are significantly lower than where residue has been burned or where tillage has been performed. No-till producers should ensure that drills are properly set and consider using a drill 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 works quite well.

Seeding Date, Rate, Depth and Row Spacing

  • The general rule is to plant canola six weeks before the average date of the first killing frost (28 degree F) in central and south central Kansas, or eight to ten weeks for southwest Kansas. This allows adequate time canopy development and root growth to improve winter survival. Planting too late will result in small plants with insufficient reserves to maximize winter survival. Planting too early may result in excessive growth that can deplete soil moisture and nutrient reserves. Excessive growth may also elevate the growing point or crown, increasing the chance of winterkill. This can be a problem when heavy residue is left in the seed row without management.
  • Drought conditions have improved across most of the state, but over 88% of Kansas is included in the D1-Moderate Drought condition. Therefore, dryland producers should consider planting as soon as insurance allows while soil moisture conditions are favorable for stand establishment. In northern Kansas, winter canola should be planted by September 15 and in central Kansas winter canola should be planted by September 25. In far south central Kansas (Barber, Harper, and Sumner counties), winter canola should be planted by October 1. In southwest Kansas, winter canola should be planted by September 7 to try to avoid problems with winterkill.
  • The most recent 3-month outlook from the NOAA projects the weather in all of Kansas for August through October to be wetter and cooler than normal.
  • Winter canola will compensate for a poor plant stand; however, it is important to obtain as uniform a stand as possible to facilitate optimum plant development, winter survival, weed control, and uniform plant maturity. A seeding rate of 5 pounds per acre (approximately 500,000 seeds per acre) is recommended for open-pollinated varieties in narrow row spacing. Because of the higher seed costs of hybrids, it is recommended to plant them on a pure live seed basis. The recommended seeding rate is 250,000 to 350,000 pure live seeds per acre in narrow rows. Hybrids tend to have increased seedling vigor, more vigorous branching, and a greater number of seed pods.
  • It is important to check drill calibration. Some drills may require a speed reduction kit to obtain the optimum rate without damaging seed. Some producers planting on 7.5-inch spacing will plug every other row unit and plant on 15-inch spacing so the drill does not have to be slowed as much.
  • Seed placement is critical for successful germination, emergence, and stand establishment. Best germination occurs with seed placed ½ to 1 inch deep. Under drier conditions, canola may be planted deeper (not greater than 1.5 inches), but delayed emergence and reduced vigor may occur. Soil crusting following a heavy rain can result in a poor stand. Canola emergence can be greatly reduced when using a deep furrow opener followed by a heavy rain prior to emergence, since soil can fill in the furrow, resulting in a deeper than intended seeding depth.
  • To ensure proper seeding depth, producers must plant slower than when planting wheat (preferably 5 mph or slower). Finally, it is important to check seeding depth in each field. 
  • Rows spaced between 6 and 15 inches are preferable for rapid canopy closure and weed control. Yields are similar with row spacings in this range. Narrower rows may also promote rapid canopy closure (more efficient light interception) and reduce shattering prior to harvest.
  • More producers are experimenting with canola planted in 30-inch rows. Producers are able to obtain more accurate depth control, precision seed metering, and residue removal from the seed row with row crop planters. As a general rule, yields may be reduced by 10% going from 15 inches to 30 inches under dryland conditions. However, producers are able to reduce their seeding rate to 2.0 to 3.5 lbs per acre (about 200,000 to 300,000 pure live seeds for hybrids), eliminating some inner row competition among plants and saving on seed costs. Planting an open-pollinated variety or hybrid with prolific branching will also increase the profitability of canola planted in 30-inch rows. 
  • Plant-to-plant uniformity at emergence is critical for optimum plant development, overwintering, and improved weed control.

Plant Nutrition and Soil Fertility

  • Soil testing, including a profile sample for nitrogen (N) and sulfur (S), is an important tool in determining fertilizer needs. If you have questions, contact your local Extension office. All nutrient applications should be made based on soil test recommendations. Canola fertility recommendation programs can be found at:

http://www.agronomy.ksu.edu/soiltesting/

  • Fertility needs are similar to winter wheat; however, canola needs slightly higher levels of N and S.
  • Applying high rates of fertilizer in-row at planting is not recommended because canola is sensitive to ammonia and salt damage (“phytotoxic effect”). However, new research by Oklahoma State indicates that a low rate of DAP or MAP (30 to 40 lb/acre of product) is beneficial and not detrimental to yield. The best management practice for banding fertilizer should separate the fertilizer from the seed by two inches to avoid direct contact. Preplant broadcast application is also acceptable.
  • Lime: Apply lime so that pH is in the range of 5.5-7.0 and early enough so the lime has time to react.
  • Phosphorus (P) and Potassium (K): No added P is required if the P soil test is above 30 ppm. Soil K levels are generally adequate in much of Kansas but deficiencies are increasing. Additional K should be applied if soil test levels are less than 125 ppm. 
  • Sulfur: Canola requires more S than wheat because of its high content of sulfur-containing proteins. Sulfur deficiencies are most common on coarse-textured and low-organic-matter soils. Sulfur can be applied at any time from preplant until the canola plant breaks dormancy in late winter. Apply S based on the soil test recommendation. Sulfate-sulfur (SO4-S) soil tests should be above 10 ppm or fertilizer should be applied. If no soil test is available, an application of 20 lb/acre S is recommended.
  • Nitrogen: Pre-plant N applications must be carefully balanced, as too little or too much fall-applied N may negatively affect winter survival. One-third to one-half of total N (based on expected yield) should be fall-applied. At least 35 lb/acre but no more than 80 lb/acre of actual N is the general rule for fall applications. Winter survival, plant vigor, and yield potential all can decrease without applying fall N.

Weed Management

  • A clean seedbed is critical to establishing winter canola. Small canola seedlings compete poorly with established weeds. However, once a good stand and canopy are established, canola suppresses and outcompetes most winter annual weeds. 
  • No matter what herbicide program you use, the most important thing to remember is to control weeds early in the fall. 
  • Trifluralin and ethalfluralin are effective at controlling many common problem winter annual weeds, but each requires mechanical incorporation.
  • Grass herbicides such as Select EC, Assure II, and Poast are labeled for cool-season grass control in canola.
  • Roundup Ready (glyphosate tolerant) canola varieties are available, providing excellent control of many problem weeds. Glyphosate is not labeled for application once the plant has bolted after dormancy.
  • Clearfield canola varieties are available and provide another herbicide resistance option for controlling winter annual grasses.
  • Before applying any herbicides, care must be taken to ensure there are no traces of problem herbicides, such as sulfonylurea herbicides, in the sprayer equipment.

Insect Management

  • An insecticide seed treatment is highly recommended for control of green peach aphids and turnip aphids through fall and early winter.
  • Monitor canola stands for the following fall insect pests: grasshoppers, diamondback moth, flea beetles, aphids, and root maggots. Several products are labeled and provide good to excellent control.

Disease Management

  • The best control of canola diseases is achieved through careful rotation. Canola should not be planted on the same field more than once every three years and should never be planted continuously.
  • Blackleg (Leptosphaeria maculans) is the most serious disease threat to canola.  Maintaining proper rotation intervals, planting disease-free seed, and using fungicide seed treatments are important management practices to slow the spread of blackleg.

For further information, see the Great Plains Canola Production Handbook, at your local Extension office, or: http://www.ksre.ksu.edu/bookstore/pubs/mf2734.pdf

 

Mike Stamm, Canola Breeder
mjstamm@ksu.edu

John Holman, Cropping Systems Agronomist, Southwest Research-Extension Center, Garden City
jholman@ksu.edu  

Kraig Roozeboom, Crop Production Agronomist
kraig@ksu.edu

Ignacio Ciampitti, Crop Production and Cropping Systems Specialist
ciampitti@ksu.edu