Lentil–Cereal Intercropping in a Mediterranean Area: Yield, Pests and Weeds

Introducing grain legumes into cereal-based cropping systems can enhance crop diversification and related factors (e.g., farm N-self-sufficiency). Lentil (Lens culinaris Medik.) is a minor grain legume species that offers nutritional and other benefits when incorporated into diets. However, lentil production is often characterized by low and unstable yields due to drought, pests, and high yield losses during mechanical harvest. Intercropping is a promising agroecological-based strategy that may overcome these drawbacks. Our objective was to determine if intercropping (i) enhanced crop productivity and resource use efficiency, and (ii) suppressed weeds and bruchid insect pest dynamics. To do this, two lentil–cereal intercropping mixtures were compared in central Italy during 2020 and 2021 as follows: (i) lentil + triticale (× Triticosecale Wittm., Forricale) and (ii) lentil + barley (Hordeum vulgare L., ‘Cometa’). Weed biomass was reduced by 97% because of the competitive ability of the grass component in intercrops compared to a lentil monocrop (p ≤ 0.05). Both intercrops reduced bruchid grain loss by 16% and showed higher efficiency than single pure stand crops (land equivalent ratio >1). Unfortunately, the highly competitive effect of the cereal reduced lentil yield in intercrops by 59% (−40.3 g m−2, on average). Our results indicate that cereals should be planted at low densities, or the spatial arrangement of both species should be modified, to prevent suppression of lentils in intercrops with barley, triticale, and other small-grain crops.