Trials have shown reduced disease with a chickpea-flax intercrop, but some are skeptical about a mustard-pulse or canola-pulse mixture
In the midst of diseased lentil fields last year, some growers might have noticed healthier crop stands where wild mustard was present.
“There are a lot of anecdotes where they said the only place where they had any kind of lentils worth harvesting is where they had some wild mustard weeds. The lentils were climbing up the wild mustard and they did better under those conditions than where there wasn’t mustard or canola,” said Lana Shaw, crop researcher at South East Research Farm.
Shaw said she also had good results with a small trial she ran last year, which she is expanding this summer.
“We have a trial this year where we are doing mustard with peas, and mustard with lentils, both yellow mustard and brown mustard,” Shaw said.
“There are some very good reasons to expect less diseases, based on lab results. Mustard type of residues have in the past reduced aphanomyces pressure in susceptible pulse crops, so lentils and peas.”
She said the possibility of biofungicide properties that may reduce root rot is a research area that is only beginning to be explored.
Shaw has researched intercrops for years and her research into a chickpea-flax intercrop had shown a reduced disease incidence and increased tolerance to excessive moisture compared to monocrops.
“The chickpeas hold up better. They mature more consistently, and on the years where we’ve had disease pressure, they’ve held up to disease pressure and lodge less,” Shaw said.
When there is crop disease present, it doesn’t seem to spread as well when there is another other crop in the mix.
If the disease spores land on a non-target plant they are unable to spread, and the microclimate in the canopy is less humid, she said.
“A chickpea crop on its own tends to have a lot of horizontal branches that kind of seal in moisture. Whereas with a flax crop, most of your stems are vertical, so I think there is more air movement, but that is something that we haven’t quantified so far,” Shaw said.
She said growers who want to grow peas or lentils in wet conditions will not add to their risk by adding a small amount of mustard or canola seed.
“A mustard or canola in there at a very low rate, we’re talking like three or four pounds an acre for mustard, and for some kinds of canolas you might do two pounds of a hybrid canola with pea,” Shaw said.
Growers can plant a Clearfield pea with a small amount of Clearfield canola and can have Solo as an in-crop herbicide option.
“If you’ve already got a bunch of Group 2 resistant weeds, than maybe it’s not worthwhile worrying about it and you just go with non-Clearfield mustard with a lentil. It might work fantastic,” Shaw said.
Brent VanKoughnet manages a farm in the Carman, Man., area and is owner of Agri Skills Inc., a company that performs agricultural research and has studied pea and canola intercropping.
“I don’t see it (pea-canola intercrop) much as a moisture strategy, I see it more of a nutrient efficiency strategy. If everything goes well, you can get 60 percent of two different crops,” VanKoughnet said.
He said the canola does reasonably well with very little additional nitrogen added, and that it must be grabbing some nitrogen from the peas.
“It (canola) captures the efficiency of the peas and their ability to produce nitrogen, and if we get that right, can they produce more than they need for themselves and give some of that to the canola? That’s the theory anyway.”
However, when it comes to using canola to help manage diseases in pulse crops, he said most growers need compelling evidence that it works before they try it.
“I think those are long shots. Producers generally want to be clean. If they thought a crop was going to be in trouble clean, they would grow another crop. It’s the reason we’re not growing lentils in Manitoba. We just expect the moisture to be high,” VanKoughnet said.
In experiments at Agri Skills, they were striving for two crops, rather than seeding a small amount of canola to help the peas climb and for possible biofungicide benefits from the canola roots.
But in VanKoughnet’s experience, airflow in the canopy was not improved.
“There is an amazing mass of material when you have 60 percent of a pea crop wrapped around 60 percent of a canola crop. If you ever thought it was tough to scout a canola field, just double that when you’ve got it all woven together with pea vines. You need a machete to walk your way through it,” VanKoughnet said.
He said most growers don’t want to complicate their operations by making their spraying windows harder to hit and limiting their herbicide options.
He said people in his area love growing soybeans because they are simple, easy to harvest and clean.
“You don’t want to upset the flow of efficient commercial operations.”
“When you think of how many farms that have doubled in size in the last decade, just logistics and getting stuff done efficiently matters,” VanKoughnet said.
If there was a market for peas and canola grown together where growers could haul in their mixture directly to without having to clean it, VanKoughnet thinks more growers would be interested.
He said most growers aren’t interested in taking off a crop that requires cleaning before marketing.
“The cleaning is a pain too. It works with a pretty simple corn screen that takes the canola out of peas pretty easily. But it slows things down. It’s just another step and generally people want to be able to move through harvest as quickly as possible.”
Shaw said it’s difficult to track the amount of acres in intercrops because there are no stats available on the practice, but she estimates there were about 20,000 acres in Saskatchewan last year.
“This is a daring comparison, but I think this (intercropping) will be as transformative to agriculture here as no-till was. In 10 years, I think we will see this taking over a lot of the acres,” Shaw said.