Agronomic and nutritional performance of lentil-hull-less barley mixtures under temperate Swiss conditions: protein content, protein yield stability, β-glucan content and separation ability.

BACKGROUND

Intercropping of legumes with cereals enhances resilience, resource efficiency, and nutritional quality in food systems, yet few studies have integrated yield stability with grain quantity and post-harvest processability. Lentils (Lens culinaris Medik.) and hull-less barley (Hordeum vulgare L. var. nudum) represent a promising mixture for temperate climates. Here, we provide the first multi-year evaluation of protein content, protein yield stability, β-glucan concentration, and grain separation, across 3 years (2022-2024), two sites, and 22 treatments.

RESULTS

Mixed stands increased barley protein content by 18-26 g kg-1 dry matter (DM) compared with pure unfertilized and fertilized systems, whereas lentil protein content was marginally higher in pure stands. Mixed systems buffered environmental variability (Finlay-Wilkinson bᵢ ≈ 1.1), with variability substantially lower (CV = 38%) than in pure barley stands (63% CV), approaching that of pure lentil stability (29% CV). The lentil cultivar Beluga paired with the barley cultivar AF Cesar achieved the highest protein yield stability, recording a weighted absolute score of 94.5 via the AMMI (additive main effects and multiplicative interaction) yield stability index. β-glucan content (17-76 g kg-1 DM) was highest in fertilized pure AF Cesar and was influenced by year and site. Grain separation showed partially high impurity levels (>1%), due to similar seed sizes, but mixtures with contrasting seed sizes (e.g., Beluga-AF Cesar) improved separation (r = 0.38).

CONCLUSION

Intercropping of lentils with barley increases barley protein content and yield stability under Swiss conditions, providing the first evidence of effects on β-glucan content and seed-size-driven impurity reduction. Selecting cultivar pairs with contrasting seed sizes and optimizing sowing time can improve both agronomic and post-harvest performance in legume-cereal systems. © 2026 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.