Chickpea-Wheat Intercropping Improves Weed Control and Shapes Weed Community Composition but Effects on Community Functional Traits Are Cultivar and Site-Dependent

Chickpea (Cicer arietinum L.) is highly susceptible to weed competition, yet chemical and mechanical control options remain limited. Intercropping with wheat (Triticum aestivum L.) offers a potential agroecological alternative, but its effectiveness across environments and cultivars remains poorly understood. A three-year field experiment was conducted at two Italian sites (Pisa and Udine) comparing six chickpea cultivars grown as mechanically weeded sole crops or intercropped with common wheat. Weed suppression, floristic composition, and taxonomic and functional weed diversity indices were assessed at crop flowering. Eleven functional traits were retrieved from databases; however, as no literature value was available, a novel field-measured Specific Leaf Area (SLA) value for Cyperus rotundus L. was determined. Intercropping reduced weed biomass by 57%–70% in Pisa and performed comparably to mechanical weeding in Udine, where high weed pressure prevailed. Desi-type cultivars (Castor, Nero della Murgia) and Lambada showed better weed control than the other Kabuli cultivars. Weed community composition in intercropped plots closely resembled that of sole-crop wheat, identifying the cereal as the dominant biotic filter. Intercropping preserved weed species richness and exerted only targeted, cultivar-dependent effects on specific functional traits. Chickpea–wheat intercropping can be a viable component of Integrated Weed Management, providing effective weed suppression while maintaining community diversity. Multi-year, long-term studies and breeding programmes targeting competitive cultivars are needed to fully harness the agroecological potential of intercropping systems.