Effects of Mulching on Weed Density, Biomass and Diversity in Faba Bean Under Field Conditions in the Meknes Region of Morocco

<p>Reducing reliance on synthetic herbicides is essential to protect health, preserve ecosystems and limit resistant weeds. A two-season field experiment in Meknes, Morocco, assessed the effects of plane tree leaves, oat straw and black plastic mulches on faba bean growth, weed control and diversity. Weed infestation was highest in unweeded plots. All mulches reduced weed density and biomass, with control rates of 80.37%, 69.51% and 84.50%, respectively. Yields rose by 43.46% with plane leaves, 41.53% with oat straw and 50.84% with black plastic. Mulching lowered species number and the Margalef index at flowering. The Shannon–Wiener index remained unchanged at maturity, indicating no loss of overall diversity. Although black plastic was most effective, organic mulches gave similar results. Given the risk of soil microplastic contamination, plant-based options offer a safer, more sustainable alternative. Mulching is a practical and eco-friendly method for weed control and yield improvement in faba bean cultivation.</p>