Durum wheat-vetch intercropping in Mediterranean agroecological systems: Effects on yield, nitrogen balance, and farm profitability

Cereal–legume intercropping offers a viable pathway for advancing the agroecological transition of Mediterranean farming systems from conventional monocultures to more diversified and sustainable agroecosystems. However, field-based evaluations, particularly involving underutilized species and contrasting input levels, remain limited. This study assessed the performance of a low-input intercropping system combining durum wheat and common vetch ( Vicia sativa L.), compared to fertilized and unfertilized sole crops, over two growing seasons (2022–2024) in Southern Italy. Compared to the input-intensive monoculture, the intercropping system matched or exceeded grain yield in 2022–2023 (3.31 vs. 3.03 t ha⁻¹) and was comparable in 2023–2024 (2.67 vs. 2.79 t ha⁻¹), despite a sharp decline in rainfall (314.6 mm vs. 673.6 mm) and a rise in mean temperature (15.47 °C vs. 13.58 °C)), which increased drought stress.Protein content was comparable or higher (13.9% vs. 12.3% in 2022–2023; 12.4% vs. 12.3% in 2023–2024), and nitrogen uptake increased by 15.2 kg ha⁻¹ (91.3 vs. 76.1 kg ha⁻¹) in 2022–2023 and 11.9 kg ha⁻¹ in 2023–2024 (66.6 vs. 54.7 kg ha⁻¹). Common vetch demonstrated the highest nitrogen accumulation and contributed up to 124.6 kg N ha⁻¹ via crop residues, enhancing nutrient cycling. Land Equivalent Ratios (1.62 and 1.35) confirmed superior land-use efficiency. Economically, intercropping achieved the highest contribution margin (€280.6 ha⁻¹), outperforming the fertilized wheat monoculture (€47.5 ha⁻¹), despite additional seed separation costs. While absolute performance declined under drought, intercropping remained competitive or superior to monocultures across all metrics, reinforcing its potential as a resilient, low-input solution for Mediterranean agriculture. Further research, supported by long-term field trials, should aim to validate these benefits, improve legume drought tolerance, and refine species combinations to enhance resilience and adaptability in dry Mediterranean environments. • Durum wheat and vetch intercropping was assessed on-farm over two Mediterranean seasons. • Intercropping matched or exceeded yield and protein levels high-input monoculture. • Increased nitrogen uptake by 15–22% and returned 90.1–124.6 kg N ha⁻¹ via residues. • Achieved land-use advantage (LER > 1) and superior economic returns. • Durum–vetch intercropping offers a viable option for agroecological transition.