Legume-oilseed intercropping in mechanised broadacre agriculture – a review

Abstract Intercropping aims to exploit complementary and facilitative interactions between species to improve capture and efficiency in the use of resources, and yield and profit per unit land and time. This review uses the ecological theory of intercropping to investigate the agronomic benefits and drawbacks of legume-oilseed intercropping and its place in mechanised broadacre agriculture. Complementary, competitive and facilitative interactions between species are analysed with a focus on nutrients and water in a range of legume oilseed pairings including pea-canola, soybean-sunflower, and chickpea-flax. Of the 41 studies investigated, 35 report yield, nutrient-use efficiency, or economic benefits of legume-oilseed intercropping. Legume-oilseed intercrops appear to negate many of the agronomic and technical issues associated with the more traditional cereal-legume pairings, and offer novel benefits such as the break-crop advantage to cereal dominant systems, and allelopathic pest repellence. While many of the traditional constraints to manage intercrops in broadacre mechanised systems appear to be tractable, this review also identifies priorities for further research and development of legume-oilseed intercrops. We conclude that legume-oilseed species pairings may have potential as commercially viable, large scale intercrops, as an effective means to improve productivity in broadacre mechanised agricultural systems.