EFFECT OF BLENDED NPSB FERTILIZER RATES ON GROWTH, YIELD COMPONENTS AND YIELD OF COMMON BEAN (Phaseolus vulgaris L.) VARIETIES IN BAKADAWULA ARI DISTRICT, SOUTH OMO ZONE, SOUTHERN ETHIOPIA

Common bean is among the most important food and cash legume crops cultivated in southern Ethiopia. But, its productivity in the country remains far below the genetic potential to be attained. This is partly due to low soil fertility management and a lack of improved varieties. Therefore, the study was conducted to evaluate the effect of blended NPSB fertilizer rates on growth, yield components and yield of common bean varieties and to assess economic feasibility of common bean varieties in response to blended NPSB fertilizer rates at Baka Dawula Ari District, South Omo Zone of Southern Ethiopia during the 2022 main cropping season. Treatments consisted of factorial arrangements of three common bean varieties (SER 125, SCR-26 and Hawassa Dume) with five NPSB fertilizer rates (0, 50, 100, 150 and 200 kg ha-1 ) laid out in a randomized complete block design with three replications. The result showed that the highest days to 50% flowering (49.4 days) and days to 90% physiological maturity (82.4 days) were recorded from variety Hawassa Dume, whereas the highest above ground biomass yield (7601.2 kg ha-1 ) and plant height (64.67cm) were recorded from variety SCR-26. The highest total number of nodules (68.32), effective number of nodules (34.21), number of primary branches per plant (4.78), number of seeds per pod (4.7), and hundred seed weight (32.30 g) recorded from SER-125 variety. The highest days to 50% flowering (51.8 days), days to 90% physiological maturity (84.88 days), total number of nodules (83.24), effective number of nodules (41.48), number of primary branches per plant (5.23), plant height (66.53 cm), number of seed per pod (5.38), hundred seed weight (35.02 g) and above ground biomass yield (7767.9 kg ha-1 ) were recorded from the maximum NPSB blended fertilizer rate of 200 kg ha-1 . The maximum numbers of pods per plant (34.13) were recorded from SER-125 with 200 kg ha-1 and grain yield (3,020.8 kg ha-1 ), and harvest index (39.7%) were recorded from SER-125 with 150 kg ha-1 . The partial budget analysis revealed that the highest net benefit of (102,310.8 ETB ha-1 ) with acceptable MRR of (1,247.9 %) was achieved from the treatment combination of 150 kg NPSB ha-1 application rate with SER-125 variety. Therefore, the production of SER-125 variety with 150 kg ha-1 NPSB fertilizer rate. Thus, it can be concluded that SER-125 with 150kg NPSB ha-1 application proved to superior in grain yield as well as economically profitable and temporarily recommended for use. However, this done for one season at single location, the experiment has to be repeated over year and location study need to be evaluated and reconfirmed in different agro-ecology and seasons to reach a conclusive recommendation.