Allelopathic Influence of Medicago sativa Residues on Germination and Early Growth of Chenopodium album

Abstract

Allelopathic effects of Medicago sativa residues were evaluated on germination and early seedling growth of Chenopodium album to assess their potential role in natural weed suppression within agroecosystems. Laboratory bioassays were conducted using varying concentrations of aqueous and residue-based extracts incorporated into germination media, and key parameters including germination percentage, mean germination time, radicle length, plumule elongation, and seedling vigor index were recorded. Results demonstrated a concentration-dependent inhibitory effect of M. sativa residues on all measured growth parameters of C. album. Germination percentage declined significantly with increasing residue concentration, while mean germination time was prolonged, indicating delayed seed metabolic activation. Radicle growth was more strongly suppressed than shoot growth, suggesting higher sensitivity of root tissues to allelochemical exposure. The reduction in seedling vigor index reflected cumulative physiological stress induced by bioactive compounds released during residue decomposition. Aqueous extracts exhibited stronger inhibitory effects compared to partially decomposed residues, indicating higher availability of soluble phytotoxic compounds in fresh plant material. Observed allelopathic activity is likely associated with secondary metabolites such as phenolics, flavonoids, and saponins released during residue degradation. Statistical analysis confirmed significant treatment effects across all growth parameters, supporting the phytotoxic potential of M. sativa residues. The study highlights the dual role of M. sativa as both a forage crop and a potential source of natural weed suppression in integrated cropping systems. These findings suggest that incorporation of M. sativa residues into soil may contribute to reduced weed establishment and improved sustainability in agroecosystems. Further field-based studies are recommended to validate residue-mediated suppression under variable environmental conditions.