Canola is quickly becoming one of the highest acreage crops
in western Canada. The possible return on investment in canola is very high,
yet some growers do not take advantage of this. In my opinion, canola is a crop
that a lot of farms can improve yield on, not necessarily from fertilizer or
fungicide applications, but from starting it off right with a strong plant
stand (fungicides, fertilizer etc are also important, but we’ll keep this on
topic of plant stand establishment). No fungicide or fertilizer can make up for
a subpar plant stand.
When I talk to some growers, they always seed at 5lbs/ac, no
matter variety. To me this is a thing of the past. Not all varieties are the
same. Do you seed a high thousand kernel weight (TKW*) durum variety the same
as a low TKW durum variety? No (atleast I hope not). So why do it with canola?
Large seeds typically are going to have more stored energy, meaning they are
more vigorous therefore less prone to soil borne disease and seedling mortality.
If you have a smaller seed variety you are typically looking at less vigour and
a higher mortality rate. Knowing this why would you treat a 3.5 gram TKW the
same as 6 gram TKW? It seems now more than ever before there is significant differences
in seed size, especially between some of the Invigor varieties compared to a
Roundup ready variety for example. The TKW weight is posted on every bag you
buy, and even the same variety may differ based on seed lot so keep an eye on
that.
The importance of a strong plant stand in canola really comes
into play in years where you see higher levels of stress whether it be from the
environment or from insects. A strong plant stand according to the Canola
Council is in the 7-14 plants per square foot range, with the critical level
being around 4 plants per square foot. This past week frost was an issue across
southern Alberta, a potential threat to a canola plant stand. If you simply are
throwing out 5lbs of seed you could be under seeding in some situations meaning
that you are only achieving 6 plants per square foot, once a frost hits you may
lose half your plant stand dropping you below the critical level. Once you drop
to this critical level you are opening up your canola crop to scenarios of
delayed, uneven maturity (canola is very “plastic” meaning if it has the room
and nutrients it will branch and increase podding), increased weed competition,
influx of root maggot (root maggots tend to prefer to lay eggs around thick
stemmed canola plants), the potential of having your plant stand decreased even
more by flea beetles (less plants means more flea beetles per plant = more
damage) or a vast number of other factors. If you start out with a good stand
of 10plants per square foot for example, then even if you lose 3-4 plants per
square foot, your crop is still in a good position moving forward to maximize
yield.
It seems like agronomists, retails, the Canola Council and others
emphasize the importance of seeding speed season after season, but every year I
talk to guys going sometimes 7mph on their drill while seeding canola. I
understand the importance of getting all your acres seeded, but slowing down
even a little bit goes a long way. If you are going to fast you open your crop
up to a number of issues, mainly inconsistent seed depth. This is due to
increased bouncing around and soil movement. Having some seed at an inch and a
half and some sitting on top of the soil isn’t what you want to see, and isn’t going
to make for a bin buster of a crop. I like to tell guys to try out some
different speeds and see the difference first hand by hopping off the drill and
identifying depth, or by scouting upon crop emergence to see the difference. Try
some passes at 4mph, 4.5mph, 5mph, even 5.5mph just to see what works best on
your soils and for your drill. I have had a guy go in the 3.2-3.6mph range
because he felt that gave him the best seed placement.
If you are calculating your seeding rate based on your
varieties TKW, leveling your drill to seed at the proper depth, and slowing
down to ensure the seed goes into the ground at the proper depth (as well as
ensuring warm soil temperatures and safe fertilizer rates) then you are well on
your way to a strong “robust” plant stand as I recently heard Doug Moisey of
the Canola Council say on a webinar.
I mentioned the
Canola Council a few times in this blog, I recommend signing up for their
Canola Watch weekly email update which can be done here:
Great info on what’s going on and what to expect in your
canola crops going forward. If you are unsure about your canola stand feel free
to contact your local Canola Council agronomist, any agronomist at your local
retail or a Rep from a canola variety company (Bayer for example) and they
should be able to tell you how your stand is shaping up as you move into in
crop herbicide application timing.
*Note: If you are wondering about the thousand kernel weight
formula see my second blog post titled Big Yields Start with Seeding.
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