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.