With aphanomyces threatening peas and lentils, what can producers do to keep pulses in the rotation?
Pulse growers are being urged to go up to eight years between plantings of either peas or lentils, which dominate pulse acres in the province.
“Our susceptible crops are pea and lentil and, to a lesser extent, dry bean. The disease is pretty widely spread, pretty much all the way across Alberta,” said Jenn Walker, research manager with the Alberta Pulse Growers Commission.
The commission, like other pulse organizations, recommends growing pulses every four years, both to meet growing demand and to break up disease cycles.
“It’s important for us to communicate that rotation is important and if growers pull out the pulse because of fear of aphanomyces, they are actually intensifying the potential for disease in canola and cereals,” said Walker.
And growing pulses every four years is definitely doable, she added.
The good news is there are aphanomyces-resistant pulse crops such as soybeans (an oilseed, but one that fixes nitrogen), fababeans and lupins.
“Really what we’re seeing now is that a producer can grow a faba or soybean where it is appropriate, with good potential for lupins as we learn more,” said Walker.
Favourites under siege
Aphanomyces, a soil-borne pathogen that attacks roots of infected plants, has been a nightmare for many growers.
It can spread across fields, particularly in wet years and while there may not be clear signs of an infestation initially, yields can be slashed with wide swaths of the crop looking like they’ve been drowned out. When pulled, the roots of severely affected plants may be little more than a wisp. Growers report that pea fields seem more susceptible than lentils, but scientists say both can suffer severe yield loss.
And they say it can take many years for spore loads to decrease to the point where you can safely grow peas or lentils again.
“In some locations, we’ve found some recovery after four years, whereas in other locations, we’re pushing six to seven years and we haven’t seen recovery yet,” said Syama Chatterton, an Agriculture Canada plant pathologist in Lethbridge.
But shifting to something other than peas and lentils would be a huge change.
In the past five growing seasons, those two crops have accounted for anywhere from 91 to 96 per cent of Alberta pulse acres, according to Statistics Canada data. In contrast, fabas have been around two per cent of acres during that time (2016-20) while soybeans barely make the StatsCan report and lupins don’t show up at all.
But the federal agency’s estimate for this year also shows a significant drop in pea acreage. While Alberta growers have grown 1.8 million acres of peas in three of the last five years, this year’s total has dropped to just over 1.4 million acres. (However, wheat acres have also gone down with canola and barley acres grabbing the land that had gone to wheat and peas last year.)
Fababeans have seen an uptick in acres this year (nearly 60,000 acres versus 35,000 or less in the past four years) but they “are quite different from other pulses,” said Walker.
“They are a very long-season crop, so they require a lot of days to complete their life cycle,” she said. “They need to be planted early, and they will be one of the last things harvested.”
The markets for fababeans — both for human food and feed — are expanding, she added.
A staple food in North Africa and the Middle East, they are the highest-protein pulse grown in Alberta, which makes them very attractive for poultry and swine rations. They can be used in cattle rations as well.
Fababeans offer lots of options, since they can be grown in high-tannin or low-tannin varieties.
“We have a lot of research going on to support the basic agronomy,” said Walker. “Pulse growers themselves have really done a lot of work on the agronomy side. That makes them a plausible, unique, attractive option.”
Former provincial pulse agronomist Mark Olson agrees.
“Fababeans make good sense because they have been researched in Alberta for quite some time,” said Olson, who now works in the private sector. “It’s definitely a good crop to look at.”
A different sort of pulse
Olson has also been helping investigate the use of lupins in the province.
Two varieties of lupin are being tested in Canada; one in Manitoba and one in Alberta. Both varieties have resistance to aphanomyces.
“There are 280 species of lupin, but there are only a few that are agriculturally important,” he said. “One is the narrow leaf blue lupin, and the other is the white lupin.”
The narrow leaf blue lupin is more suited to Alberta, and the white to Manitoba. Koralta Agri-Business has started growing narrow leaf blue lupin of the Boregine variety in Alberta and growing contracts will be awarded in August 2021, he said. AgCall, another Calgary-based company, is assisting with the commercialization and research of lupin.
Narrow leaf blue lupin is grown extensively in Australia and is used primarily in feed applications. However, it can also be used in food applications. Companies in Europe use the narrow leaf blue lupin in plant protein applications such as yogurt, ice cream, salad dressings, and mayonnaise, said Olson.
“The narrow leaf blue lupin likes soil pH below 7.2 so it rules out a lot of the brown and dark-brown soil zones because their pHs are quite a bit higher,” he said. “The Europeans and the Australians I checked with are pretty adamant that soil pH has a huge impact on the narrow leaf blue lupin.”
Provincial research found narrow leaf blue lupin are earlier maturing than white lupin — somewhere between late pea and early fababean, said Olson. (White lupin maturity is similar to soybean, which is why it’s being looked at for Manitoba.)
Use is expanding — an eastern Canadian company is making a lupin hummus and the pulse is also used for products such as the high-protein Blue Menu pancake mix (a Loblaws’ President’s Choice label).
In addition to high protein (34 to 40 per cent), lupins have very low starch levels (less than two per cent).
“It falls in between fababean and soybean in terms of its protein, but it has very little starch,” said Olson. “The oddity is it has an oil to it. A lot of pulse crops have one to 1.5 per cent oil. They are quite low in oil. But lupin will have, depending on the species and variety, between six to eight per cent oil and fat.
“There’s a possibility of utilizing the oil in products like salad dressing and stuff.”
Lupin will grow best in the black and thin black soil zones, where there are enough frost-free days with lots of moisture and high organic matter.
Olson said that researchers are also looking at winter pulses in the far south, and there has been new variety development in winter pea and winter lentil.