Species choice and spatial arrangement in soybean-based intercropping: Levers that drive yield and weed control

Abstract

Abstract Soybean is prone to weed infestations and yield variability. With the proposition of using intercropping to overcome these problems, this study explored the effects of combinations of different associated crop species and spatial arrangements on grain production and weed control. In a two-year field experiment in western France, soybean was intercropped with buckwheat, lentil, sorghum and sunflower in two spatial arrangements: within-row intercropping and alternate-row intercropping, to investigate their effects on weed control and soybean production. The results showed that the highest soybean yield occurred in the intercropping with lentil, followed by sorghum and sunflower, and finally buckwheat, but this effect varied by year. The opposite species order was obtained for weed control, revealing a trade-off between soybean production and weed control. We also demonstrated that associated species height was related to soybean yield and weed control. Alternate-row intercropping helped to increase soybean production without compromising weed control for sorghum and buckwheat, which have small height difference with soybean. Finally, our paper showed that combining associated species choice and spatial arrangement allows farmers to manage the trade-off between soybean yield and weed control.