EFFECTS OF INOCULANT AND NPS FERTILIZER ON NODULATION, GROWTH AND YIELDS OF COMMON BEAN (Phaseolus vulgaris L.) VARIETIES AT BILATE ZURIA DISTRICT, SIDAMA REGIONAL STATE, ETHIOPIA

Abstract

Common bean (Phaseolus vulgaris L.) is a major grain legume grown and consumed in subSaharan Africa, including Ethiopia. It is the most important food legume, fodder and cover crop. However, its cultivation is globally constrained mainly by low soil fertility and lack of improved agronomic practices. Four common bean varieties (Ibaddo, Hawassa Dume, Omo95 and Nasir were studied under three nutrient conditions (0kg ha-1 ,100 kg ha-1 NPS, Inoculation by strain HB-429) in three replication of randomized complete block design (RCBD) during the 2019 main cropping season (June to September). The objectives of the study were investigating the response these varieties to the three nutrient statuses in nodulation, growth, yield and yield components and investigating the variety X inoculant/fertilizer interaction in the same traits. There were significant differences between the four varieties in all traits (nodulation, growth, yield and yield components). Ibaddo had the highest grain yield (2.81 t ha-1 ) while Hawassa Dume had the highest mean in yield (2.53 t ha-1 ). The three fertilizer levels also differed significantly in all traits, 100 kg ha-1 NPS giving the highest means in all traits, while the control (no fertilizer application) had the lowest mean in all traits. Inoculation by rhizobium strain had intermediate mean of all traits. The variety X inoculant/fertilizer interaction was also significant for all traits except for nodule dry weight, leaf area index, shoot dry weight, grain yield, above biological yield and harvest index. Omo95 variety had the lowest means in all traits except leaf area index, plant height, number of primary branches where ranks first, second and third. The highest net return (48325 ETB ha-1 ) with acceptable marginal rate return (5993%) was obtained from Hawassa Dume variety with 100 kg NPS ha-1 followed by Hawassa Dume variety with strain HB-429 inoculation had net return of 41337 ETB ha-1 with 4895% marginal rate of return. This implies that the grower on the study area can gate additional benefit of 59.93 and 48.95 ETB for every 1 ETB expense by growing Hawassa Dume with the application of 100 kg NPS ha-1 and strain HB-429 inoculation, in that order. Moreover, the highest net benefits (37763.5) with MRR (%) of 3084 ETB and net benefits of 3935ETB with MRR (%) obtained from variety Ibaddo and Nasir grown with strain HB-429 and 100 kg NPS ha-1 fertilizer application. Therefore, use of both Hawassa Dume and Nasir varieties with 100 kg NPS ha-1 and Hawassa Dume and Ibaddo grown with strain HB-429 found to be economically feasible at the study area. However, verification of the result on farmers’ fields across season and similar areas could be required before wide use of this study to put the recommendation in firm ground.