Agronomic Performance in Durum Wheat–Vetch Intercropping: An Agroecological Strategy for Resource Use Efficiency.

Crop diversification is a fundamental agroecological strategy to enhance resource use efficiency, improve soil fertility, and increase the resilience of agricultural systems to climatic variability. Intercropping between durum wheat (Triticum durum Desf.) and common vetch (Vicia sativa L.) represents a viable approach to achieving these objectives in Mediterranean organic farming. This study investigates the agronomic interactions between wheat and vetch under simultaneous sowing and harvesting, focusing on yield performance, nitrogen (N) dynamics, and overall system efficiency. A two-year field experiment was conducted in southern Italy, in the Basilicata region, using an additive intercropping model, optimizing species densities to balance complementarity and competition. Results demonstrate that intercropping enhances nitrogen use efficiency and increases total N uptake compared to monocultures. The land equivalent ratio consistently exceeded 1, confirming superior resource utilization. Moreover, intercropping improved wheat grain protein content, indicating enhanced N availability. Despite inter-annual climatic variability, intercropped systems exhibited greater yield stability than wheat monocultures, mitigating the effects of drought stress. Economic assessment revealed that intercropping maintains a competitive gross production value, supporting its feasibility under low-input conditions. However, logistical challenges, particularly post-harvest grain separation, limit broader adoption. These findings underscore the potential of wheat–vetch intercropping to improve agronomic performance, reduce dependence on synthetic fertilizers, and enhance system resilience, contributing to more sustainable Mediterranean cropping systems.