The practice of intercropping is receiving more attention on the Prairies, and research centres are exploring the possibilities for forage options.

The potential benefits are promising, researchers say, but more work is needed to provide producers with accurate information on how best to apply this method.

“I think it’s really interesting that there’s some combinations of crops that seem to have synergistic relationships when being grown together,” says Lana Shaw, manager of the South East Research Farm (SERF) at Redvers, Sask.

Advantages to intercropping, which is the practice of seeding more than one crop together, can include reducing the risk of disease and pests, improved resilience and increased total yield and crop value.

“If they’re able to reduce the amount of pesticides and fertilizers used on these intercrops, then even if they get very much the same yields or even a little less yield, it may still be more profitable than the crops that are grown by themselves,” says Shaw.

Ongoing studies by Manitoba Beef and Forage Initiatives (MBFI) at Brandon, Man., are also exploring how to get the most out of forage intercropping.

“We’re interested in intercropping really to put some data behind some of the regenerative agriculture practices,” says Mary-Jane Orr, MBFI’s general manager. These practices include minimizing tillage, increasing plant diversity, incorporating livestock grazing and having living plants as cover on the ground as long as possible, both between growing seasons and in between the rows.

The benefits of growing a cover crop between rows of corn is something Orr and her team are currently studying. “Will that cover crop grow enough to provide an additional forage during corn grazing?” she says. “Is there a role for that cover crop to provide some additional fertility to the corn while it’s growing when we have legumes in the mix?”

In 2019, MBFI ran a trial with corn at 30-inch row spacing and a forage intercrop mixture of yellow sweet clover, Italian ryegrass, hairy vetch and forage rape. However, an early snowstorm in October flattened the intercrop mixture when it was more vulnerable.

“We did see a trend and an increase in the crude protein of the corn forage, so that was an interesting trend that maybe we’re improving the forage quality of the corn, even though the livestock didn’t have access under the snow to the actual intercrop,” says Orr.

This year, they followed up with a similar trial, using a forage mixture of winter triticale, two types of Italian ryegrass, hairy vetch, Berseem clover, yellow sweet clover, plantain, chicory and forage rape. In addition to the test and control plots having 30-inch row spacing, they seeded a plot with 60-inch row spacing to increase the crop density within each row, allowing for more light to reach the plants.

“There’s a very visually noticeable difference in the productivity of that 60-inch row spacing just because it has so much more access to light to grow,” she says. “In the 30-inch row spacing we’re seeing a good establishment of the intercrop, but they’re just not growing as vigorously as in the 60-inch row spacing.”

Yield and forage quality testing had yet to take place at the time of writing, and MBFI will also observe whether the intercrop withstands the fall weather and is accessible for winter grazing.

Orr would also like to examine the hybrid variety differences in corn. “It would be interesting to see if different varieties are more compatible with intercropping than others when it comes to basically sharing the light and the water and the nutrients in the soil,” she says.

“We aren’t currently doing any silage, but I think it would be also interesting for producers to see if you choose to take your corn off as grain or silage, how well those intercrops grow back for an aftermath grazing as opposed to a standing corn grazing.”

Emerging trends in complex mixes, annual forages

At SERF, Shaw oversees trials on both grain and forage intercropping to determine the most beneficial crop combinations. Currently, SERF is running a trial on soybeans and flowery silage corn, with both crops grown on their own as controls. Results on protein and relative feed value are expected in early 2021.

“We picked a type of soybean that’s quite tall and late with the idea that it would be (intended) for forage. So by intercropping, we may be able to increase the protein level in that silage product,” says Shaw. As this was their first attempt at this particular combination and conditions were dry this year, she would like to run this trial again.

Other ongoing trials at SERF include intercropping barley with fall rye, in hopes of using the latter for grazing later in the year, and mixtures of forage brassica with peas and oats.

“Some of the research is starting to dabble in the more complex mixes, and I think that’s a trend among demand from farmers and with regenerative agriculture and soil health becoming a notable trend,” Shaw says. “There’s a push towards more diversity in forage mixes, and also a trend toward using annual forages instead of just relying on perennial forages.”

By including annual forages in a rotation on grain crops, Shaw explains, producers can disrupt disease and pest cycles, as well as weed production. “There’s opportunities for cattle farmers to partner with grain farmers… on something where the grain farmers get a cash benefit from growing forage but don’t actually need to make it into silage or make it into a bale to sell if they don’t want forage.”

Shaw is also interested in running variety trials on forage peas, as the different varieties available haven’t been compared in this manner the way other crops are compared in small plot trials.

“I would like to try seeding some forages into marginal saline land on grain cropland and do some trials on how to most effectively establish those and what kind of mixes are suitable or providing a lot of benefits.”

Know your objectives and have a backup plan

For producers interested in forage intercropping, Orr recommends starting small and understanding your goals for using this method. This can include considering the nutritional needs of your herd, how you want to use this feed and if you need to rest or extend perennial pastures.

It’s also important to measure your own results to help understand what works best for your fields. “One of the messages that came out of some of the work done by Practical Farmers of Iowa, which is another kind of farm research group, is that depending on the year and the variety, the results can really shift and change,” Orr explains.

“Until we get a consistent dataset with reproducible results, it’s really hard to say, ‘Yes, this one thing will work all the time.’ And so I think just taking the time to take yield measurements and track some information on your own farm is really valuable to help you make decisions in that planning as to how to diversify your forage options.”

Having a contingency plan for your feed supply in the event of unfavourable conditions is also something to consider. “At MBFI we’ve also experienced some wrecks when we haven’t had good moisture, when we haven’t had good conditions for getting establishment or if we have untimely weather events,” she says. “When we had that early fall snowstorm, it can really kind of wipe out your best intentions.”