Saskatchewan farmer Sheldon Dowling describes his first experience with intercropping as interesting. In fact, the results from his pea-canola experiment in 2017 were so interesting that he decided to try it again this year.
“Interesting is the key word,” said Dowling, who farms near MacDowall, Sask., near Prince Albert.
“It’s pretty counter-intuitive to apply no fertilizer and have a stand like that.”
Dowling is always looking for ways to increase net farm returns. So, when he started to hear about canola-pea mixtures, he thought he’d give it a try.
In 2017, he seeded a combination of Mosaic peas, a maple variety known for its standability, and Nexera 2024 canola, a Clearfield variety with improved pod-shatter resistance.
He sowed the canola at a reduced rate of about 4.2 pounds per acre. The seeding rate for the peas varied from 90 pounds per acre up to 120 lb.
He also left a test strip of Nexera canola without peas, again sown at a reduced rate of 4.2 lb.
Dowling did not apply fertilizer to any part of the field, although residual phosphorus levels were relatively high, he said.
Growing conditions in the MacDowall area were less than ideal last year.
The best mono-cropped canola fields on Dowling’s farm yielded in the mid-30 bushels per acre.
But when it came time to harvest the field intercropped with peas and canola, the results were a pleasant surprise.
The intercropped areas yielded an average of 19 bu. per acre canola and 15 bu. per acre peas, with no fertilizer costs.
By comparison, the test strip that contained canola only yielded in the neighbourhood of 10 to 12 bu. per acre and no peas.
Conclusion? The nitrogen fixed by the companion pea crop generated an additional seven to nine bu. per acre of canola.
Dowling sold the peas for a bit more than $15 per bushel and the contracted Nexera canola generated $12.50 per bu.
“My net return on that field was pretty good,” he said.
“It stood up amazingly well,” he added.
“The crop knitted very well together.… It combined like a dream.”
Dowling said the biggest challenge was post-harvest management.
The peas and canola matured at different times and moisture content in the two harvested crops was variable.
In the first few loads that he took off, the moisture content of the peas was 18 percent and the moisture content of the canola was 13 percent.
At those moisture levels, the crops needed immediate attention, he said.
When he finished harvesting the field a bit later in the fall, both crops had dried down considerably. The later-harvested material was binned and put on air until Dowling could get around to separating the two crops.
“The logistics of cleaning it is probably the biggest (issue),” he said.
“It’s another step that you don’t normally have to do.”
“If you were going to do (a lot) of your canola acres that way … you’d probably want to set up a pretty high capacity cleaner.”
Flea beetle pressure was also less evident on the intercropped field compared to his other canola fields.
“There were virtually no shotgun holes” in the leaves of the intercropped canola, he said.
“It’s like the flea beetles went into the intercropped area and said, ‘wait, something’s not right here,’ and they left.”
Varietal selection is also an important consideration. A late-maturing pea variety, combined with a Clearfield canola that is well-suited for direct combining, would be the optimal combination.
Intercropping is a relatively a new concept in Saskatchewan but those who buy into the idea are expanding their acreages.
Lana Shaw, research manager at the South East Research Farm (SERF) near Redvers, Sask., has been conducting intercropping research trials since 2012.
She said commercial growers in southern Saskatchewan are expanding their intercropped acreage fairly quickly.
Chickpea-flax is probably the most widely used combination in the south, but growers are also experimenting with canola-peas.
“There’s … several thousand acres (of commercial chickpea-flax) planted this year. In fact, there might be as much as 10,000 acres that were planted,” Shaw said.
“Some of those acres, I’ve heard, didn’t establish successfully but there will still be several thousand acres that are harvested this year, so that’s a significant increase from only a few hundred acres when I first started researching this (in 2012).”
Shaw said the most obvious benefit of intercropping chickpeas and flax is the fact that flax uses moisture and nutrients late in the growing season, prompting the chickpeas — an indeterminate crop — to stop flowering and focus on filling seeds.
“The flax is using up moisture and nitrogen at the end of the season when chickpeas need terminal stress,” said Shaw.
“Chickpeas need to have moisture deficiency and nitrogen deficiency to stop flowering and stop producing leaves and begin filling pods.”
Another synergistic benefit that Shaw’s program is hoping to measure is disease control, specifically ascochyta control in chickpeas.
Shaw said evidence suggests that intercropped chickpeas require fewer fungicide applications than mono-cropped chickpeas.
“The commercial producers who are trying chickpea-flax are finding that they don’t need to spray as much (to get the same level of protection),” Shaw said.
“They’ll spray fungicides once or sometimes not at all if it’s a very dry season, compared to as many as four or five fungicide applications in the monocrop.”
“That’s an example of an economic benefit where we don’t necessarily need to have an increase in yield in order to have a net economic benefit because we’re decreasing production costs.”
Another intercrop combination that’s showing significant potential in Shaw’s research program is large green lentils and yellow mustard.
When planted together, lodging is significantly reduced in the lentils, meaning fewer harvest losses, less in-field spoilage, a cleaner sample and reduced risk of damage to harvest machinery.
In SERF trials last year, the harvested yield from inter-cropped large greens was equivalent to that of mono-cropped large greens under similar management systems.
On top of that, the lentil-mustard mixture produced about 300 lb. of yellow mustard per acre.
“The total yield was higher and it was easier to harvest the lentils.”
Like every new cropping venture, Shaw suggested that growers should start small and expand their acreage as their experience increases.
“I’m not surprised to see that intercropping is spreading from farmer to farmer, but it does surprise me a bit to see how many acres some farmers are trying,” she said.
“There’s people that are putting in 1,000 acres of something that they’ve never tried before.”
Shaw said Twitter is a great resource for interested growers to gather information on intercropping.
There is a growing community of growers and researchers who are using the social media platform to share ideas and experiences, she said.