Effect of Vetch and Grass Pea Intercropping with Barley on Yield, Seed Multiplication Ratio, Broad-Leaved Weed Suppression

Background and Objective: Intercropping cereals with legumes can improve crop productivity, suppress weeds, and enhance the efficient use of soil resources. This study aimed to evaluate the effects of different mixture rates of vetch and grass pea with barley on grain yield, biomass yield, seed multiplication ratio, and broadleaf weed suppression. Materials and Methods: Four mixture ratios of legume and barley were evaluated: 100:0, 75:25, 50:50, and 25:75. The effects of increasing seeding rates and different crop mixtures on grain and biomass yields, seed multiplication ratio, and broadleaf weed biomass and stem density were assessed. The trial followed a randomized complete block design with two treatment factors: Biomass yield potential (2 levels: High biomass and low biomass) and [barley:legume] mixture ratio (4 levels: 100:0, 75:25, 50:50, and 25:75), replicated 3 times in 2019 and 4 times in 2020 and 2021. The effects of increasing seeding rates and different crop mixtures was evaluated against 5 parameters: Grain yield, biomass yield, seed multiplication ratio, broadleaf weed biomass yield and broadleaf weed stem density. Results: Increasing the seeding rate significantly increased the relative grain and biomass yields of the three crops. Mixed cropping produced significantly higher total forage yields than the respective pure stands. The seed multiplication ratio was highest under the 25:75 mixture ratio. Intercropping also significantly reduced broadleaf weed biomass and the number of weed stems. However, no significant differences in weed suppression were observed among the different mixture ratios. Conclusion: The findings demonstrate beneficial interactions between barley and legume crops in mixed cropping systems. Barley may contribute to weed suppression and provide physical support to the legume crops, while vetch and grass pea may improve soil fertility through biological nitrogen fixation. Appropriate barley-legume mixtures may therefore provide a promising strategy for improving forage productivity and weed management.