Kevin Hursh, P.Ag.
I received an email recently from a young producer in Alberta who saw me touch on the topic of intercropping at a UFA-sponsored event a few years ago. This producer, and a few other young producers in the area, are now trying various intercrops. He reached out to see if I was still intercropping and whether I had any advice.
It’s a big topic and I have lots of opinions. I don’t pretend to be an expert, but I’ve done some intercropping, both intentional and unintentional, and I’ve listened to the experiences and opinions of other producers as well as researchers.
Here, for what it’s worth, are my thoughts on growing two crops together, harvesting them at the same time and then separating the seed.
Philosophical motivation
In theory, it makes sense that growing two or more crops at the same time should be better for the soil than monocropping. Maybe that’s the case, but it’s difficult to prove. On the other hand, intercropping can make subsequent crop rotation more complicated and it can increase weed pressure if herbicide choices are limited.
If intercropping makes you feel more sustainable or you think it qualifies as regenerative agriculture, good for you. Whatever floats your boat. Personally, I don’t give much credence to a philosophical motivation. I like to try new approaches that may provide an economic advantage.
Practical advice
Choose crop combinations where the seed can be easily separated. I once grew maple peas with barley and had a terrible time separating the two after harvest.
Weed control is another issue. The chickpea – flax mix benefited from having pre – emergent herbicide Authority registered for both crops. If you’re growing canola with peas, you probably want to use Clearfield canola to have a good herbicide option for both. Some crops will tolerate a herbicide that isn’t registered, but non-registered uses are not a good idea.
The crops should have similar maturity. No use having one ripe and shelling out while you’re waiting for the other to mature.
You also need to decide if you’re growing both crops in the same row, or if you’re seeding alternating rows. Can you make your seeding equipment work for both crops at the same time? What about fertilizer placement?
Overyielding doesn’t always happen
If you listen to the success stories, growing two crops together results in more total product and a higher return per acre. This can happen, but it doesn’t always happen. Even if you’re lucky enough to improve the total yield, remember that you still have the time and expense of separating the two crops.
Grain cleaning
Separating crops isn’t always as simple as it seems. A high level of dockage may be concentrated in one or the other of the crops, thus requiring another cleaning operation to make it marketable.
It’s tough to separate the crops as they are harvested, so that means binning the mixture and separating it later. For moisture determination, I’ve sometimes manually separated enough of the grain to do separate moisture tests on each to make sure they’re safe for storage.
Crop combinations with a purpose
In my opinion, intercropping is more viable when the secondary – the support crop – has a purpose. In the case of chickpeas with flax, the flax can potentially act as a buffer to stop disease spread. It can also suck up extra late season moisture to help hasten chickpea maturity. Flax straw is often baled or burned, but a relatively small amount of flax in a chickpea crop isn’t likely to pose a residue problem.
I’ve tried chickpeas with a small amount of Canary seed and I actually like that mixture better than chickpea – flax. The Canary seed matures and doesn’t shell out as you wait for the chickpeas to ripen. And the Canary seed seems to thresh quite well when the two go through the combine.
For both flax and Canary seed, if growing them in the same seed row as chickpeas, I’d recommend a low seeding rate of less than 10 pounds per acre while keeping the chickpeas close to their normal seeding rate. If doing alternating rows, full seeding rate should be used on each crop in its respective row.
Pulse crops can provide nitrogen for an oilseed or cereal crop, and that may be important if nitrogen fertilizer prices remain in the stratosphere. Some crops, like certain varieties of peas, are prone to lodging and intercropping may solve that problem.
Having a purpose for an intercrop makes more sense to me than simply throwing two crops together and hoping for some sort of magic.
Unintentional intercrops
This year on two brown mustard fields, I had terrible crop emergence in some specific areas of the fields. I attributed this to residue of a Group 2 herbicide from two years previous – the 2021 drought didn’t allow the herbicide to break down properly.
In the bare areas, I used a disc drill to seed maple peas. The disc drill didn’t kill what little mustard was growing so I ended up with an intercrop even though that wasn’t the original intention. I had this happen many years ago in a large green lentil crop where brown mustard volunteered.
When life gives you lemons, make lemonade. When life gives you an intercrop, harvest it and separate the seed.
Crop insurance considerations
In Saskatchewan, intercrops can be insured under a “Diversification Option.” The premiums you pay on other crops are averaged and that’s what you pay for the acres of intercrop. Similarly, if you are in a claim position, your average payment per acre on your other crops becomes your payment per acre on the intercrop.
I’ve been part of discussions with Saskatchewan Crop Insurance Corporation on other options to provide yield loss coverage for intercrops, but there seems to be no simple way to come up with an insurance procedure that makes sense.
Future of intercropping
Variable rate fertilizer gets a lot of attention. What if we could vary the seeding rates of intercrops to optimize production? Developing a proper prescription may be easier than it is with fertilizer, but this isn’t an area receiving a lot of research.
Some producers have long found success with intercropping. Widespread adoption probably isn’t on the horizon, but some novel crop combinations do look interesting.
