Project Overview
Intercropping involves simultaneously growing two or more crops in the same area of land. This practice offers the potential to increase biodiversity, land use efficiency, and crop productivity via greater resource use efficiency. Intercropping may be valuable in water-limited regions, including prairies, and may provide a way to boost crop yield and quality compared to monoculture systems.
A two-year organic legume + non-legume intercropping study was conducted in Saskatchewan, Canada to determine if intercropping affected weed control and crop yield and quality compared to crop monocultures.
Farmer Takeaways
- Intercropping results in lower weed biomass compared to crop monocultures.
- Intercropping a cereal crop (i.e., oats) with a legume (i.e., field peas) enhances cereal grain weight and legume grain protein content.
- Intercropped legumes and cereal crops may provide mutually beneficial structural support, with the cereal crop providing a structure upon which the growing legume can ‘climb,’ and the legume crop reducing lodging in the cereal crop.
Project Objectives and Approach
Evaluate differences in biomass, yield, and quality of organic cereal crops and legumes when intercropped and grown as monocultures
- A two year study was conducted on organic land at the Swift Current Research and Development Centre in Saskatchewan, Canada.
- Crop combinations included lentil (Lens culinaris Medik. ‘CDC Maxim’) and mustard (Sinapis alba L. ‘AC Andante’), intercropped and monocultured; and field pea (Pisum sativum L. ‘CDC Meadow’) and oat (Avena sativa L. ‘AAC Oravena’), intercropped and monocultured.
- Crop biomass was collected from designated sampling areas within plots approximately two weeks after the non-legume crops began flowering (mid- to late-July).
- A small-plot combine was used to harvest the middle four rows in each plot for each treatment. Harvested grain was dried, cleaned, and separated (for intercropped treatments) using a two-level screen separator. After separating, grain was weighed and nitrogen values tested to determine grain crude protein content.
Determine the ability of intercropping to suppress weeds
- Weed densities* were determined by counting all weeds in random sampling areas in each plot in late July.
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- *Weed density refers to the number of individual weed plants present within a specific unit area, such as plants per square meter.
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- Weed biomass* was collected after density counts were done, at the same time as crop biomass sampling (described above).
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- *Weed biomass measures the total mass or weight of a weed population—typically the dry or fresh weight—within the same area sampled for weed density.
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Key Findings
Both intercropping treatments (lentil x mustard, field pea x oat) increased weed control compared to the respective crop monocultures
- Weed density was generally similar between monoculture and intercrop treatments, but in the lentil x mustard intercrop treatment, weed biomass averaged 268 lb/ac compared to 724 lb/ac for monocultures. This suggests that intercropping may be more resource-efficient and competitive against weeds than when either crop is grown individually.
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- There was a moderate negative correlation between weed biomass and total grain yield (r = -0.45; higher weed biomass = lower total grain yield), suggesting that the weed control provided by intercropping may result in tangible yield benefits.
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Intercropping oats with field pea resulted in higher oat grain weight and higher field pea grain protein content compared to their respective monocultures
- Intercropping oats and field pea resulted in 25% greater grain weight for oats and 11% higher grain protein content for field pea, compared to each crop’s respective monoculture.
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- The observed increase in oat grain weight was likely associated with the lower seeding rate in the intercrop treatments, which would have reduced resource competition among the oat plants.
- The observed increase in legume grain protein content may have been driven by resource use efficiency, as supported by other research.
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Legumes had lower “tolerance” to intercropping compared to non-legumes
- Legume biomass in intercrop treatments was, on average, 2-3x lower than the monoculture treatments, likely due to competition and shading of the non-legume species, and this may have been exacerbated by the dry growing conditions. However, this did not affect the intercrop treatment’s ability to provide greater weed control and did not always reduce grain yield or quality at harvest.
Intercropping oats and field pea greatly reduces lodging in oats
- Although not statistically measured, the researchers observed that there was no lodging present in the oat x field pea intercrop treatment, with the pea plants “climbing” the oats. This supports the idea that intercropping a climbing legume with a cereal crop can provide the legume with physical support and reduce lodging in the cereal.
Resources
Fernandez, M.R., P. Lokuruge, L. Abdellatif, N. Waelchli, J.Y. Leeson, M.P. Schellenberg, and S. Chalmers. (2025). Intercropping of oat or mustard with legumes under organic management in the semiarid Canadian Prairie. Agronomy Journal, 117:e70056.
Read MoreLocation
SaskatchewanCollaborators
Prabhath Lokuruge, Swift Current Research and Development Centre
Lobna Abdellatif, Swift Current Research and Development Centre
Noe Waelchli, Swift Current Research and Development Centre
Julia Y. Leeson, Saskatoon Research and Development Centre
Michael P. Schellenberg, Swift Current Research and Development Centre
Scott Chalmers, Westman Agricultural Diversification Organization
Region
Northwest
Topic
Soil Health, Crop Nutrient Management, Weed Management, Cropping Systems
Category
Grain and Field Crops
Year Published
2025
