Hutchinson, Kansas
August 31, 2007
Interest is growing in planting
winter canola in Kansas and Oklahoma as part of a rotation with
winter wheat, and a Kansas State
University agronomist said there is still time to consider
it for this winter.
"The last two years have demonstrated winter canola´s ability to
withstand extremes of drought and cold," said Vic Martin,
specialist in annual forages and alternative crops with K-State
Research and Extension. "There is still ample time to consider
planting winter canola this fall as part of dryland and
irrigated rotations."
Martin said adequate public and private seed stocks are
available. The equipment used in canola production is the same
as in winter wheat production.
He answered the following questions regarding canola planting in
the Plains:
What factors should be considered when selecting a site for
canola?
Canola will grow well over a wide range of soil textures,
provided they are well-drained and the pH range is 5.5 to 7.
Soils that tend to waterlog and have standing water are poor
choices. Due to disease considerations, canola should never
immediately follow canola, sunflowers, soybeans, alfalfa or
cotton. Canola can follow winter and spring cereals well, and if
adequate moisture and timely harvest permit, both corn and grain
sorghum. The herbicide program of preceding crops is important.
Most winter canola cultivars are sensitive to sulfonylurea (SU)
and triazine carryover.
What do I need to consider when deciding which variety to
plant?
Local Extension offices and seed dealers can provide information
regarding locally adapted canola varieties. Key considerations
in variety selection include winter-hardiness, seed yield, oil
content, shatter and disease resistance, maturity, and the
potential for lodging. Roundup Ready varieties are available, as
is SU tolerance. I recommend that seed be treated with an
insecticide for fall aphids.
If you are planting a significant acreage to canola, consider
selecting two or more varieties with a range of harvest
maturities to spread out harvesting activities.
What is the best way to prepare the seedbed?
Weeds must be controlled chemically, mechanically, or with a
combination of both before planting. Canola seedlings are not
competitive with weeds immediately after emergence. Since canola
is a small-seeded crop (more than 100,000 seeds per pound), a
proper seedbed is critical to successful establishment. A level,
firm, seedbed with adequate moisture is best.
A seedbed with large soil clumps results in poor seed placement
and seed-soil contact. An overworked seedbed may be depleted of
moisture and crust easily, preventing emergence. Apply pre-plant
fertilizer and herbicide prior to final tillage.
No-till planting is an option, and some experienced no-till
producers have successfully produced canola. No-till production
is more successful where soil has been no-tilled over a long
period of time.
Opportunistic no-till planting is riskier. When properly set,
no-till planting produces proper stands; however, stand
maintenance over the winter with heavy residue cover occurs. So,
some producers burn heavy surface residue prior to planting.
What about seeding dates and rates?
After seedbed preparation, the seeding date is perhaps
the most critical factor in winter survival.
The rule of thumb is to plant canola six weeks prior to the
average date of the first killing frost in the area. This allows
adequate time for the plant growth needed for winter survival
and the canopy development important in weed control. Planting
too late will result in plants with insufficient reserves to
maximize winter survival.
Planting too early can result in excessive growth that may
deplete soil moisture and nutrient reserves. Excessive growth
also may cause elevation of the growing point and increase the
chances for winterkill. Research underway at K-State is
indicating planting earlier, rather than later in the planting
window is better for winter survival.
Winter canola has a large capacity to adapt to extremes of plant
populations. A harvest population of four to ten plants is
ideal.
However, it is important to obtain as uniform a stand as
possible within this range to facilitate weed control, uniform
maturity and thinner stalks. A rate of 5 pounds per acre
(approximately 500,000 to 600,000 seeds per acre) is
recommended. Irrigated production can support slightly higher
rates. If planting significantly earlier than the optimum date,
reduce the rate by 1 pound..(per acre? Conversely, increase the
rate by 1 pound if planting significantly later than the optimum
date. Checking the drill calibration is very important. Some
drills may require a reduction kit to obtain a 5-pound rate
without damaging the seed.
As a small-seeded crop, seed placement is critical to successful
germination, emergence, and stand establishment. Ideally, the
best germination occurs with seed placed ˝ to 1 inch deep. Under
drier conditions, canola may be planted deeper, but delayed
emergence and reduced vigor are likely. In combination with
deeper planting, a heavy rain resulting in soil crusting often
leads to a poor stand. To ensure proper seeding depth, producers
may have to slow down groundspeed, compared to wheat planting´s.
Check seeding depth for each field planting; it´s important.
Narrower row spacing is preferable for canopy closure and weed
control. However, a row spacing up to 15 inches is acceptable.
With that in mind, Kansas State University agronomist Vic Martin
has developed the following answers for questions he´s
frequently asked. Martin, who is based at the K-State Research
and Extension South Central Experiment Field in Hutchinson, is a
specialist in annual forages and alternative crops.
What do I need to consider regarding fertility management? As
always, a soil test, including a profile nitrogen (N) test, is
important in determining fertilizer needs. Information on proper
soil sampling is available from your local Extension office,
crop consultant, or fertilizer applicator. Fertility needs are
similar to those for winter wheat, except in that canola needs
slightly higher levels of nitrogen and sulfur. Do not apply
in-row fertilizer at planting, as canola is extremely sensitive
to ammonia and salt damage. Drills allowing for banding of
fertilizers away from the row are normally acceptable, but the
safest method is to broadcast pre-plant.
Lime: Apply so pH is in the range of 5.5 to 7.0 (6.0 to 7.0 is
preferable). Do so early enough that the lime has time to react.
Phosphorus and Potassium: Soil potassium levels generally are
adequate in much of Kansas, but deficiencies are increasing.
Phosphorus soil test levels above 30 parts per million (ppm)
require no added P. Where needed, broadcast these nutrients
prior to planting, according to soil test recommendations.
Sulfur: Canola requires more sulfur than wheat does, because of
its high content of sulfur-containing proteins. Sulfur
deficiencies are most common on coarse-textured soils and soils
with low organic matter content. Base sulfur applications on
test recommendations.
Nitrogen: Pre-plant N applications must be carefully balanced.
Too little or too much fall-applied N may negatively affect
winter survival, so we recommend basing fall applications on a
profile N test. One-third of total N or roughly 30 to 50 pounds
N per acre (based on expected yield) should be fall-applied.
Applying no fall N
can decrease winter survival and/or yield.
What about weed management? This is another reason for a clean
seedbed. Canola does not compete well with established weeds.
(Once a good stand and canopy are established, however, canola
suppresses and out-competes most annual weeds until harvest.)
With incorporation, Trifluralin and ethalfluralin are effective
at controlling many common problem winter annual weeds. Several
grass herbicides are labeled for cool-season grass control in
canola. Roundup Ready (glyphosate-tolerant) canola varieties are
available, too, providing
excellent nonselective control of many problem weeds, but
glyphosate is not labeled for application once the plant has
bolted after dormancy.
Before applying any herbicides, take care to ensure there are no
traces of problem herbicides, such as SUs, in the spray
equipment.
And what are the recommendations for controlling insects? Seed
treatment is highly recommended for fall control of aphids.
Other fall insect pests that should be monitored include
grasshoppers, army cutworms, flea beetles and root maggots. If
necessary, several insecticides are labeled for use on canola
and provide good to excellent pest control.
What if I want to graze livestock on canola? Is that possible?
Canola can provide excellent grazing in late fall and early
winter, prior to dormancy. But, it should be viewed as
opportunistic. In some years, fall growth will be inadequate for
grazing, so producers should not rely on winter canola as the
primary focus of their fall/winter
grazing program. Planting earlier than normal is recommended.
The canopy should be at least 6 to 8 inches tall.
As a rule, grazing canola significantly decreases yield
potential. Overgrazing often results in stand loss. And, care
must be taken to prevent bloat and monitor for potential nitrate
toxicity. With that said, though, canola can often provide
excellent grazing for up to two months.
More information about growing canola as a winter crop is
available on the K-State Research and Extension Web site:
http://www.oznet.ksu.edu
(search for canola).
K-State Research and Extension is a short name for the Kansas
State University Agricultural Experiment Station and Cooperative
Extension Service, a program designed to generate and distribute
useful knowledge for the well being of Kansans. Supported by
county, state, federal and private funds, the program has county
Extension offices, experiment fields, area Extension offices and
regional research centers statewide. Its headquarters is on the
K-State campus in Manhattan. |
|
