Abstract
Fertiliser application and planting densities are among the main factors which affect the growth, development and grain productivity per unit area for faba bean. The current trial was done to determine the effect of bio-fertiliser and inter-row spacing on the yield and yield related traits of faba bean (Vicia faba L.) in south western Ethiopia. Treatments consisted of four rates of rhizobium strain bio-fertiliser (0, 0.25, 0.5 and 0.75 kg/ha) and three inter-row spacings (30, 40, and 50 cm), were laid out as a randomised complete block replicated three times. Analysis of variance showed that the main and interaction effects of rhizobium strain bio-fertiliser and inter-row spacing were significant for days to 50% flowering, number of effective nodules, leaf area index and grain yield. The main effects of rhizobium inoculation and inter-row spacing were significant for plant height, number of leaves per plant, pods per plant, dry weight, above ground dry biomass yield and harvest index. The highest grain yield (2540 kg/ha) was obtained from the application of 0.75 kg/ha bio-fertiliser and 50 cm inter-row spacing while the lowest (1083 kg ha) was obtained from the control of no bio-fertiliser and the narrowest inter-row spacing (30 cm). Generally, significantly higher yields were obtained from the application of the highest rate (0.75 kg/ha) of bio-fertiliser and the widest (50 cm) inter-row spacing. Maximum net return, (ETB53, 850 or US$1843/ha) was obtained by inoculation with a bio-fertiliser rate of 0.75 kg ha and an inter-row spacing of 50 cm. Therefore, inoculation of bio-fertiliser at rate of 0.75 kg ha with inter-row spacing of 50 cm, was found to optimise the yield of faba bean in south western Ethiopia.