Response of barley cultivars to different combinations and loading systems with Broad bean: growth, yield, and competitive indicators

• Saad Muhsen Barzan Taha Salah Hameed Jumaa

  Author

A field experiment was conducted during the 2024–2025 season in a farmer's field in Al-Jurnaf sub-district, Al-Shirqat district, Salah Al-Din province, Iraq. The site is located at 35.52°N latitude and 43.23°E longitude, 135 .The aim was to evaluate the effect of barley and broad bean loading systems on growth, yield, and some competitive indicators, and to identify the most suitable combinations between varieties and row distribution systems. A split-plot design with three replications was used. The study included three barley cultivars: local Iraqi barley, Ukrainian white barley, and Aldebaran, and two broad bean cultivars: local broad bean and the Spanish Vito cultivar. The treatments included six planting systems: broad bean alone, barley alone, broad bean:barley row, broad bean:two barley rows, broad bean:two barley rows, and two barley:two broad bean rows. The results showed that the single planting of barley was excelled in leaf area (14.067 cm²), number of branches per plant (6.06 branches.plant ^-1), number of grains per spike (41.68 grains per spike⁻¹), and total yield (9.01 tons ha⁻¹), while the barley:broad bean row system achieved the highest thousand grain weight (33.68 g). At the varietal level, Ukrainian white barley was excelled in leaf area (647.65 cm²) and number of branches per plant (5.72 branches.plant ^-1), while Aldebaran was superior in number of grains per spike (40.36 grains . spike⁻¹). No significant differences were found between the varieties in number of branches, thousand grain weight, and total yield. The intercropping of Aldebaran with single planting resulted in the highest leaf area (747.57 cm²), number of grains per spike (42.40 grains . spike⁻¹), and total yield (9.43 t ha⁻¹), while the intercropping of local Iraqi barley with a barley:two broad bean row system resulted in the highest thousand-grain weight (35.86 g). The Land Equivalent Ratio (LER) values ​​ranged from 0.63 to 1.05, with the majority being less than 1, indicating no productivity advantage for intercropping in most combinations. One combination, however, recorded a value of 1.05, suggesting a limited productivity advantage for the intercropping system in that case. The aggressiveness index showed that barley was more competitively dominant in the 1:1 and 1:2 systems, while competitive advantage shifted to broad beans in the 2:1 system, and competition approached equilibrium in the 2:2 system. These results confirm the success of intercropping barley and broad beans. The barley yield depends largely on the ratio of rows and the varietal combination, and maximizing barley yield does not necessarily correspond to maximizing land use efficiency at the agricultural system level.

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