Intercropping and Nitrogen Management: Insights from Lana Shaw

Intercropping is gaining attention across the Canadian prairies as farmers look for new tools to reduce input costs, improve soil health, and increase profitability. At a recent webinar hosted by SaskSoil agronomist Lana Shaw, research manager at the Southeast Research Farm, shared her expertise on nitrogen management in intercrop systems. Drawing from over a decade of research, Shaw explained how properly designed intercrops can reduce – and sometimes eliminate – the need for synthetic nitrogen fertilizer.

Watch the Webinar Here

Why Intercropping Matters

Shaw framed intercropping as a “new play in the farmer’s playbook.” Instead of relying on conventional monocrops, producers can pair a legume with a non-legume crop to unlock synergies:

• Nitrogen fixation: Legumes capture atmospheric nitrogen and feed themselves without synthetic fertilizer.

• Nitrogen transfer: Companion crops like flax, camelina, or mustard can access nitrogen fixed by the legume.

• Soil health benefits: Diverse root systems improve soil biology and resilience.

• Reduced input costs: Less reliance on expensive nitrogen fertilizer.

“Don’t sabotage the nitrogen fixation factory,” Shaw cautioned, emphasizing that applying too much nitrogen fertilizer suppresses the legume’s ability to fix nitrogen.

Key Research Findings

Shaw shared results from multi-year trials across Western Canada:

• Chickpea-Flax Intercrops: Adding nitrogen fertilizer offered no economic advantage. Yields and profitability were stable without it.

• Camelina-Lentil Intercrops: Fertilized plots often produced lower overall value because camelina yield gains came at the expense of lentil yields.

• Pea-Canola and Pea-Mustard Systems: Isotope tracing confirmed direct nitrogen transfer—up to 44% from peas to mustard in one trial.

These results show that intercropping can be productive and profitable without synthetic nitrogen, making it a promising approach for regenerative agriculture.

Designing a Successful Intercrop

Shaw stressed that intercropping isn’t a one-size-fits-all solution. Success requires thoughtful system design:

• Crop compatibility: Match maturities and ensure both crops can be harvested efficiently.

• Seeding strategy: Mixed rows often improve nitrogen transfer through closer root interaction.

• Rotation planning: Ensure intercrops fit into a broader cropping system.

• Start small: Trial new combinations on a limited scale before expanding.

She described the ideal balance as “friendly competition” between crops, where both benefit rather than one outcompeting the other.

Practical Considerations for Farmers

During the Q&A session, Shaw addressed real-world management questions:

• Foliar fertilizers: May not be necessary in most intercrop systems.

• Seeding rates: Adjust to maintain balance between crops.

• Relay cropping: Offers potential but requires careful timing and equipment adjustments.

• Weed suppression: Some intercrop pairings, like camelina-lentil, show promise against herbicide-resistant weeds.

The Bigger Picture

Adopting intercropping could deliver more than just short-term input savings. Long-term benefits include:

• Improved soil structure and microbial diversity

• Reduced fertilizer dependence across rotations

• Lower greenhouse gas emissions

• Opportunities to access new markets, such as camelina for biofuels

“We end up with better problems doing these regenerative approaches instead of the intractable problems of conventional systems,” Shaw reflected.

Conclusion

Intercropping is not a simple recipe—it’s a systems approach. But when managed well, it offers farmers a way to reduce nitrogen inputs, improve soil health, and diversify markets. Shaw’s central takeaway was clear:

👉 Don’t undermine the nitrogen fixation process with excess fertilizer. Instead, design intercrops for synergy and long-term profitability.

For farmers curious about trying intercropping, Shaw recommends starting small, gathering data on your own farm, and building from there.