Intercropping still faces unanswered questions

Many producers, myself included, are intrigued by the concept of intercropping — growing two crops together and separating the seeds after harvest.

Interest is at an all-time high, but it’s tough to predict whether the practice will ever command a significant acreage.

Some crops, such as chickpeas and flax, would seem to have natural synergies. Can flax in the crop canopy slow the spread of disease in the chickpeas? Can the addition of flax help chickpeas mature more rapidly and escape frost damage in the fall?

Lana Shaw of the South East Research Farm at Redvers, Sask., is a leading researcher and advocate on intercropping, but despite her work and the work of others, there are still more questions than answers.

Should the flax be seeded in the same seed rows as the chickpeas or should there be alternating rows? What should the seeding rates be for combined crops? And how do you handle fertilizer requirements when one crop can fix its own nitrogen and the other can’t?

Sometimes a crop combination generates more total production per acre than single crops. Other times, it doesn’t work out that way.

Weed control is another issue. I’ve tried intercropping chickpeas with flax and I’d like to try more of it, but in my case weed control is an issue. Herbicide options exist for controlling brassica weeds within chickpeas and within flax, but how do you control wild mustard and stinkweed within an intercrop without killing one crop or the other?

For many other weeds, chickpeas and flax work quite well because sulfentrazone (Authority) is registered on both. The two also work quite well from a crop maturity point of view.

One seldom mentioned benefit may be flax straw management.

One of the barriers to growing flax is that you often end up baling or burning the flax straw residue. When flax accounts for half or less of the total biomass, straw management should be less of an issue.

Other crop combinations are also interesting.

Perhaps some of the lodging and disease issues with large green lentils can be addressed by growing them with condiment mustard. As with the chickpea-flax mix, separating lentils from mustard after harvest is easy, given the difference in seed size.

If you think back to the 1980s and early 1990s, a number of producers were growing canola with peas. With the advent of herbicide-tolerant canola and field pea varieties that lodged less, peola was pretty much phased out. However, it may still have a fit in a Clearfield production system, particularly because Clearfield canola is considered non-genetically modified.

Unfortunately, well-intended policies can sometimes be a detriment.

Saskatchewan Crop Insurance has placed intercropping under its Diversification Option. Producers can average the coverage and premiums of their monocrops and apply this to an intercrop.

While this sounds reasonable, it doesn’t work very well if your intercrop is more valuable than your monocrops, as is normally the case with something like chickpeas and flax. As well, the Diversification Option is limited to no more than 30 percent of your monocrop acreage.

In an age when monocrops are considered unnatural and society wants crop solutions that involve reduced applications of crop protection products, intercropping would seem to offer potential.

However, there’s no big money driving the bus. Agribusiness has no incentive to fund research trials or promote the benefits. Grower organizations and government funding agencies will need to carry the ball.

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