Cereal allelopathy as a natural herbicide: A review of mechanisms and weed control potential

Weed infestation remains one of the primary challenges in global crop production, causing substantial yield losses. Conventional reliance on synthetic herbicides raises concerns regarding environmental safety, herbicide resistance and long-term soil health. Therefore, there is an urgent need for sustainable and eco-friendly weed control alternatives. Allelopathy, defined as the biochemical interaction among plants via secondary metabolites, has emerged as a promising natural mechanism for suppressing weed growth. Among various crops, cereals such as rice (Oryza sativa L.), wheat (Triticum aestivum L.), maize (Zea mays L.) and rye (Secale cereale L.) have demonstrated significant allelopathic potential. This review analyses and synthesises recent findings on the allelopathic properties of cereal crops. It evaluates literature describing the types of allelochemicals released by cereals and the plant parts involved, including roots, stems, leaves and decomposing residues. The study also emphasises the mechanisms through which these allelochemicals influence weed suppression and the role of cereal cover crops, root exudates and leaf litter in natural weed control. Evidence shows that cereal crops release a wide range of allelochemicals capable of inhibiting weed seed germination and seedling growth. These compounds are exuded through roots, volatilized from leaves or released during the decomposition of crop residues. The integration of allelopathic cereals into crop rotation and cover cropping systems can reduce weed pressure, minimise chemical herbicide dependency and enhance soil health. Particularly, root exudates and surface residues of rye and wheat have demonstrated consistent weed-suppressive effects. Allelopathy in cereal crops represents a natural and sustainable strategy for weed suppression. By reducing reliance on chemical herbicides, cereal-based allelopathy supports eco-friendly and resilient agricultural systems. To maximise its practical application, further research is required to elucidate allelochemical modes of action, optimise management practices and integrate allelopathy into holistic weed management programs.