A review of intercropping systems in Western Canada

Intercropping is gaining interest from Western Canadian producers who are looking for information on how to incorporate intercrops into their production systems. This review summarizes agronomic research on intercropping from the last 40 years in Western Canada and discusses the potential challenges of integrating intercropping into existing crop rotations while identifying challenges and possible solutions. Reviewed literature indicates that several intercrop combinations have been tested in small plots involving up to four crops simultaneously grown, with over 60% comprising pulse–oilseed combinations followed by pulse–cereal combinations at ∼30%. The land equivalent ratio (LER) for pulse–oilseed and pulse–cereal averaged 1.11 and 1.13, respectively. Key agronomic factors that influenced LER in different intercrop combinations have been summarized, and the relationship of N and seeding rate with crop grain LER and partial land equivalent ratio has been assessed. While the relationship between N rate and LER was unclear in pulse–oilseed combinations such as pea (Pisum sativum L.)–canola (Brassica napus L.), LER decreased linearly with increasing N rate (p < 0.004) in pea–barley (Hordeum vulgare L.) intercrop. We highlighted that incorporating intercrops into current rotations will decrease crop rotation lengths with possible implications for disease management. There are many logistical challenges to intercropping but new technology may help producers to adapt.