Response of Haricot Bean (<i>Phaseolus vulgaris L.</i>) Varieties to NPSB Fertilizer Rates in Buno Bedele Zone, Southwestern Oromia, Ethiopia

Haricot bean (<i>Phaseolus vulgaris</i> L) is one of the most important pulse crops contributing to food security and livelihoods for the majority of farmers in Ethiopia. However, low soil fertility and absence of recovering package practices are major constraints that limit the production and productivity of haricot bean in the study area. Therefore, the study was conducted to determine the optimum NPSB rates and identify the best performing haricot bean varieties that reply successfully to a specific application rate of NPSB fertilizers and select economically viable treatment/s that can increase the productivity of haricot bean. Factorial combination of five levels of NPSB (0, 50, 100, 150 and 200 kg ha<sup>-1</sup>) and two Haricot bean varieties (SER-119 and SER-125) were laid out in a Randomized Complete Block Design (RCBD) with three replications. The results shown that plant height, number of pods per plant, number of seed per pod, 100 seed weight and grain yield were significantly affected by main effect of varieties. Likewise, number of pod per plant, plant height, and grain yield (1574.9 kg ha<sup>-1</sup>) were significantly affected by the main effects of NPSB fertilizer rates. The highest net benefit (55357.2 Birr ha<sup>-1</sup>) and Marginal Rate of Return (358.61%) were obtained from SER-125 variety applied with the combination of 100 kg NPSB ha<sup>-1</sup>. Therefore, producing haricot bean with the application of 100 kg NPSB ha<sup>-1</sup> was most productive for economical production. Furthermore, emphasis and consideration are required to the issue in future research studies; since the soil is dominantly acidic, there the limiting macro and micro nutrients in the study area, and therefore, more attention must be given to treating the soil by lime.