Agronomic performance of two intercropped soybean cultivars

Broader environmental tolerance associated with mixed population of soybean (Glycine max Merr.) cultivars may increase soybean yield potential and play a significant role in yield stability. A field study was carried out to assess whether intercropping of two commonly used cultivars of soybean with different morphological characteristics may increase seed yield in Iran. A split-plot design was used with three replications. The main plots were 3 densities; 23.8, 33.3, and 55.5 plants m-2. Sub-plots consisted of intercropping ratios row by row of 100:0 (pure stand of Harcor), 75:25, 50:50, 25:75, and 0:100 (pure stand of Bonus) of Harcor and Bonus cultivars, respectively. The results indicated that the highest seed yield was obtained from 50:50 ratios of the cultivars which had land equivalent ratio (LER) above 1.11. Calculation of LER revealed that seed yield in treatment HBHB was 11% higher than the pure stand. The superiority of intercropping over pure stands occurred only in the highest plant density. Intercropping ratio showed no significant effect on any of yield components. However, pod number per plant was decreased with increasing plant density.