Cropping system redesign for allelopathy: A vision for the ‘post‐herbicide era’

Abstract Arable weed management faces an uncertain future. A climate of tightening regulations and widespread herbicide resistance has led to suggestions that we are entering the ‘post herbicide era’, but successful weed management with no, or fewer, herbicides will require a diversification and de‐intensification of management strategies. One underappreciated strategy is to utilise the natural chemical interactions between plants, both antagonistic (allelopathy), and benign (allelobiosis). The prevailing, reductionist approach to allelopathy is as a substitution for synthetic herbicides, which has had the effect of limiting our ecological understanding of these plant–plant interactions. I posit here that allelopathy and allelobiosis will only be effective in regulating arable weeds through ecological redesign, inspired by the ecosystems outside of agricultural land in which these interactions affect plant growth. Increased integration of concepts from studies of these ecosystems should therefore be prioritised in allelopathic weed management. Research should, for instance, consider recognition interactions, the stimuli which can induce allelopathic responses, and the effects of plant community diversity on these interactions. In short, researchers should consider the desired outcome of allelopathic weed management and the context in which it would be required to operate. As such, management of agricultural land should prioritise reductions in disturbance and especially tillage, to foster the development of a benign, self‐regulatory weed community based on low‐level competition and allelopathic inhibition, which does not require intensive management efforts.