Effect of sowing date and variety on yield and weed populations in a lentil-barley mixture

The present study examined variation in sowing date on lentils (Lens culinaris) in a standard lentil-barley (Hordeum vulgare) mixed cropping system in the temperate climate of central Europe to determine the effect on crop yield and weed control. A 2-year (2009/10) field experiment was carried out at the organic research station Kleinhohenheim (KH) and at the conventional research station Oberer Lindenhof (OLI) of the University Hohenheim, southwest Germany. The crop was sown at three dates in the period from March to May. Grain yield was significantly higher at the earliest sowing both for lentils (3.0 t/ha at KH, 2.4 t/ha at OLI) and barley (1.2 t/ha at KH, 2.6 t/ha at OLI). Weed biomass at KH increased significantly with delayed sowing and was independent of lentil genotype, whereas sowing date had no significant effect on overall weed biomass production at OLI. Unlike weed biomass, weed density generally decreased significantly with delayed sowing at OLI. The results indicate that early sowing can increase the yield of lentils, and can be used as an indirect method of weed control in some organic farming systems.