When most farmers think about intercropping, peas and canola come to mind, which has to date probably been the most common pairing for an intercrop system. But research by Lana Shaw at the South East Research Farm (SERF) in Redvers, Sask., has shown that other combinations — like chickpeas and flax or mustard and lentils — have benefits too.
The additional diversity that comes with intercropping (growing two crops together in the same field) can provide multiple benefits such as increasing productivity, reducing pest and weed issues, preventing lodging, improving harvestability, adding efficient nutrient use and mitigating risk.
Shaw has found that combining less competitive crops is a good intercrop strategy. “I’ve been putting some crops that struggle together and doing this strategically,” said Shaw during a presentation at the Regenerative Agriculture conference in Brandon. “We’re finding partnerships where they’re providing benefits to each other.”
An example is mustard and lentils. “Mustard as a monocrop is not worth a lot, and in our area, it would not be considered an adaptive crop,” said Shaw. “If you combine it with a large green lentil, which is also not a suitable crop for the Redvers area, you’ve got a combination that you can export into areas that are neither mustard nor lentil country.”
In 2017, Shaw grew a trial lentil and mustard crop at SERF that produced 40 bu./acre of large green lentils and six bu./acre of mustard, providing almost $100/acre more value than would have been expected with monocropping. The intercrop was also easier to harvest because the mustard improved the standability of the lentils.
The mustard was seeded at a rate of 3.1 lbs./acre. The lentils were supposed to be seeded to target a plant population of 70 plants per m², but were mistakenly seeded at a much higher rate of 117 plants per m². The higher seeding rate proved a good experiment, showing that increasing the seeding rate of pulses in an intercrop can produce more grain per unit area than a monocrop.
Intercrops are self-insuring
Shaw has also conducted trials with flax and chickpea intercropping showing reduced ascochyta and earlier maturity in the chickpeas, even in areas of the field that had problems such as being too wet or high in nitrogen. The flax used the moisture and nitrogen early in the season, keeping it from affecting the chickpeas. The intercrop had fewer green seed, more even senescence, shorter maturity and required less inputs, especially fungicides.
In all intercrop combinations, Shaw’s advice is to pick one of the crops to be a winner and target that crop’s seeding rate and fertility accordingly. “Things are not always predictable,” she said. “Intercrops are self-insuring because you end up with one of the crops compensating if the other one falls behind.”
Shaw added that she doesn’t like a 50/50 intercrop because it’s harder to decide which one should be the main focus when making fertility decisions or if there are problems at harvest time. GN