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Count your canola stubble density

Want to optimize next 
year’s yield? Count your stubble density before 
snow flies

While the 2017 crop is going or has gone in the bin, there is one more field operation for canola growers to consider this fall: count your stubble density.

Since seeding rate and plant stand are critical components of optimizing canola yield, says Rob McDonald, a senior agronomist with Bayer Crop Science, actually knowing how many plants were in the field and reached maturity is important information.

“And there is no better time to do it than after harvest,” says McDonald, manager of product excellence for Bayer. The number of plants that emerge after seeding is one indicator of crop density he says, but it’s the number that make it through to maturity that really tell the story. You can wade through standing canola crop in July and August to make a count. But after harvest is so much simpler.

“The plant count for a successful crop is critical,” says McDonald. “If there are too many plants the crop might look good, but the yield isn’t there. And if there are 10- to 12-inch gaps or more between plants in seed rows then you are also losing productivity. There will probably never be perfect spacing over a field, but hopefully you can fine tune it.”

McDonald believes in using a 1,000 kernel weight (TKW) formula with each seed batch to determine the actual seeding rate. Following the old or standard five or six pounds per acre seeding rate for canola results in too many variables, he says. In the Polish canola days the recommendation was often in the seven to nine pounds per acre range.

With the cost of some hybrid canola seed in the $50 to $70 per acre range, nobody wants to waste it by seeding too heavy, and yet there is no point in potentially sacrificing yield by cutting way back on seeding rate, just to save on seed costs. Seed at the optimum rate.

Do I hear the number five?

And what is the magic number for canola plant spacing? This Bayer field research and demonstration work of course is focusing on InVigor hybrid canola varieties. In this third year of the product excellence research, McDonald is saying the number is about five. Five to seven plants per square foot appears to be the ideal density to optimize yields with InVigor canola. That means a seeding rate putting about 10 seeds per square foot in the ground. Anticipating a 50 to 60 per cent seed mortality rate, that seeding rate should deliver a stand that has five to seven plants per square foot.

Whether that figure would apply to all brands of canola, McDonald doesn’t know. But from hundreds of Bayer field scale research plots across Western Canada over the past three years, the five plants per square foot density, so far, consistently has delivered the top yield, regardless of InVigor variety or seed size. The 2017 yield results will be coming in later this fall.

This plot of canola stubble represents almost an ideal canola plant stand with about five to six plants per square foot, seeded with a John Deere 1810 drill. But although it is almost ideal, there are still a few places where the drill missed or plants died leaving eight- to 10-inch gaps in the seed row — nutrients unused, productivity lost.
photo: Lee Hart

Numbers tell the story

And it’s hard to argue numbers with a man who often spends a good part of his day walking canola plots with callipers measuring the diameter of canola plant stems. Plant density obviously will impact stem diameter and ultimately stem strength. Plant density also impacts plant growth, pod and seed development, plant maturity and ultimately yield.

This Product Excellence research program is a huge investment for Bayer in agronomic research. The program has been running for three years. There are more than 30 research sites across Western Canada. Each site is about 60 acres. Each research site is divided into dozens of large scale research plots, each plot being about 20 feet x 180 feet.

Those plots are farmed with conventional seeding, spraying and harvesting equipment. The John Deere 1810 Conserapak drill has been cut down to 10 feet wide for the narrower plots, but otherwise it is the same air drill many producers use. They use a conventional field sprayer and plots are harvested with a John Deere combine. Everything is done field scale so it is as relevant to what commercial producers do as possible.

More will be revealed this winter, but above is Rob McDonald, Bayer Crop Science senior agronomist with two bags/two varieties of high quality InVigor canola seed. While both bags weigh 50 pounds, one variety has double (about three million) or more seeds than the other. Bayer is using its agronomic research to show growers the optimum seeding rate.
photo: Lee Hart

McDonald and six agronomists, along with local teams of student (seasonal) employees, manage the 30 research sites stretching across the prairies from the Alberta Peace River region, through Saskatchewan and Manitoba to North Dakota.

“Our objective with this research program is to determine the best or optimum production practices for growing InVigor canola,” says McDonald. “We know the potential of our variety genetics, but what are the best production practices to really optimize that potential? Do all industry production guidelines apply to growing InVigor canola? That’s what we want to find out.”

This is the third full season for the Bayer Excellence Research program and in some respects it has been a well-kept secret. The first couple of years were mostly about getting sites and plots designed and deciding what type of agronomic research should be done. But as the program gains experience and research data, McDonald says each site is now ready to be launched as an information hub. In 2017 for example each of the Product Excellence sites hosted tours of Bayer product representatives and agronomists. Next year, McDonald says the sites will be open to hosting producer tours. “We are doing lots of interesting research work with InVigor canola and starting next year we are ready to show producers what we are learning,” he says.

No such thing as a dumb question

The agronomic research at all sites will be asking just about every conceivable question about how to grow canola: seeding rates, seeding dates, seeding depth, time of seeding, fertility rates, crop protection options, harvest methods, you name it. If a producer can think of the question, Bayer is probably already looking at it.

“There’s a lot we need to look at, but we are starting out by keeping it simple,” says McDonald. “What is the optimal seeding rate? What is the optimal plant stand to optimize yield? Let’s start with that.”

McDonald and the Product Excellence team believe they have the answer — target the seeding rate to produce a healthy and viable five to seven canola plants per square foot. They’ve tried every combination of seeding rates form one pound of seed to 10 pounds of seed. With those callipers in hand, McDonald can measure large wolfy plants with ¾ inch diameter stalks (at the low seeding rate), to really dense stands of about pencil size stalks at the higher seeding rates.

“In some respects with a quick drive by all seeding rates can look pretty good,” he says. “But when you actually get in there and look at what each plant is producing, look at comparative height differences, look at maturity differences, and then look at yield figures, you learn what difference seeding rate can make.” (There will be a follow up Grainews article this winter on seeding rate information from Bayer Product Excellence plots).

In the meantime McDonald encourages producers to have a look this fall at the true plant count in canola stubble after harvest. How many stems per square foot were harvested? What was the size or diameter range of the various stalks. And look at the spacing of plants within the rows — where there stretches of dense plant stands or conversely other stretches with eight to 10 inch gaps between plants.

Numbers, measurements and photos collected on-farm this fall, will provide useful reference for growers in the next article on Bayer seeding recommendations coming this winter.

About the author

Field Editor

Lee Hart is editor of Cattleman’s Corner based in Calgary.

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