Common bean (Phaseolus vulgaris L.) is an important food and cash crop in southwest Ethiopia with multiple uses. Productivity of the crop is, however, low at national as well as regional levels, mainly due to low soil fertility. Phosphorus (P) deficiency is particularly important in acid soils of southwest Ethiopia affecting growth and yield of seed legumes in general and that of common beans in particular. Therefore, a field experiment was conducted to assess the response of common bean cultivars to P application on Nitisols of Jimma in 2016 main cropping season. The treatments consisted of three common bean cultivars (Ibbado, Tatu, and Remeda) and four P fertilizer rates (0, 23, 46, and 69 kg P2O5 ha-1). The experiment was laid out in a Randomized Complete Block Design in a factorial arrangement replicated three times. Results indicated that interaction effects of cultivars and P rates significantly (P < 0.01) influenced phonological parameters, growth parameters, dry biomass yield and seed yield. The highest dry biomass yield (5874 kg ha-1) and seed yield (2821 kg ha-1) were obtained from the treatment combination of cultivar Tatu and 69 kg P2O5 ha-1. The P use efficiency parameters (recovery efficiency, agronomic efficiency) were also significantly affected by the interaction effect of cultivar and P application rate. Cultivar Tatu was found to be more P efficient at P rate of 23 kg P2O5 ha-1. In conclusion, the study pointed out that common bean cultivars responded differently to the various P application rates suggesting the possibility of exploiting cultivar differences to combat P deficiency under acidic conditions. Phosphorus at rate of 23 kg ha-1 will be recommendable for P-efficient cultivar based on phosphorus use efficiency parameters. Accordingly, farmer who has no capacity to buy fertilizer cultivar Tatu was recommended to specific soil of study area. However, since the data is only for one season and location repeating the experiment across location may be helpful to validate the results.
Key words: Common bean, phosphorus use efficiency, seed yield, and soil acidity.
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