Response of Faba Bean (Vicia faba L.) Grain Yield to Biofertilizer Rates and Inter Row Spacings at Kaffa Zone, South Western Ethiopia

Purpose: Soil nutrient depletion and crop management practices are the significant factors affecting faba beans production over the world. Biofertilizers can improve soil fertility and health. Moreover, it adds essential nutrients and improves water retention in the soil. Thus, its use is unquestionable to maintain soil fertility and enhance crop production. Hence, biofertilizer rates and inter-spacings were used to enhance faba bean production.Research Method: The Field trials were performed to determine the response of faba bean (Vicia faba L.) grain yield to bio-fertilizer rates and row spacings in the main growing season in 2019 at Kaffa zone, Southwestern Ethiopia. Factorial combinations of four rates of bio-fertilizer (0, 0.25, 0.5, and 0.75kg/ha) and three inter-row spacings (30, 40, and 50cm) were carried out in RCBD with three replications. The LSD test was done at alpha = 0.05 level of probability.Findings: The results of ANOVA presented that the main effect, as well as the interaction effects of biofertilizers and row spacing, have a significant effect on the yield of faba bean. The pods/plants number, hundred seed weight, and HI are mainly affected by biofertilizer rates and row spacings. The combination of 0.75kg/ha of biofertilizer rates and 50cm of space between rows recorded the maximum pods per plant in number, the weight of hundred seeds, grain yield, and harvest index. The highest grain yield (2540 +/- 276kg/ ha) was attained with the application of 0.75kg/ha of bio-fertilizer and 50cm of distance between rows, whereas, the lowest (1083.3 +/- 117.7kg/ha) was observed from the null treatments and the smaller spacing between rows (30cm).Generally, the significantly maximum yield was obtained because of the maximum rate of bio-fertilizer with the widest inter-row spacing in this experiment. Therefore, inoculation of bio-fertilizer at a dosage of 0.75kg/ha with a row distance of 50cm was found to be optimum for the maximum yield of faba bean in Southwestern Ethiopia and other similar agroecologies. It is further recommended that this result is from only one season at one site and hence this study may be repeated in space and time to reach a concrete recommendation. Research Limitation: Additional authentication and trials across similar agroecology would be essential to make conclusive recommendations since the field trials were directed for sole cropping season and a site.Originality/ Value: This is an organic fertilizer that could be used by farmers and investors in the future, to increase the production of faba bean.