Impact of Different Agroecological Practices for Weed Management on Weeds and Crops Development

Cover crops and mulches are widely used techniques for limiting weeds and pests’ effects on crops. This study compared six practices over two growing seasons in two organic farms in Cuneo province, North-West Italy: two bio-based biodegradable mulch sheets (BM01 and BM02), dead mulch (hazelnut shells), living mulch (Trifolium repens L.), mechanical control, and an untreated control. Spring crops included Lactuca sativa L. var. capitata, Allium cepa L. cv. ‘Tropea’, and Brassica oleracea L. var. italica, while autumn crops were Lactuca sativa L. var. capitata, Allium fistulosum L., and Brassica oleracea L. var. italica. Weed infestation was evaluated through density (n/m2), biomass (g/m2), and diversity (Shannon Index), alongside crop yield and quality. Biodegradable mulch sheets provided the greatest weed suppression, followed by hazelnut shells, while living mulch and untreated control showed the highest weed pressure. Crop yield varied significantly among practices and species: BM01 and BM02 resulted in the highest yields, while living mulch consistently produced the lowest. Lettuce displayed the best quality across both farms, whereas onion quality varied by site. The highest quality scores were observed under biodegradable mulches and mechanical control, while living mulch and untreated control yielded the poorest results. Overall, biodegradable mulches emerged as the most effective balance between weed suppression, crop yield, and quality in organic systems.