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 P 2 O 5 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 P 2 O 5 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 P 2 O 5 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.

Maize is highly responsive to nitrogen fertilizer rates and plant spacing. Continuous efforts have been carried out to improve the yield potential of maize by modifying their architecture through breeding methods with aim of increasing maize yield through increasing number of plants ha-1. Hybrid BH-546 is the recently released variety for this purpose but its optimum nitrogen rate and spacing has not been determined yet. Thus, a field experiment was conducted at Bako research farm in the year 2017 to determine the optimum rate of nitrogen fertilization and intra-row spacing. The experiment was laid out in a randomized complete block design in factorial arrangement with three replications. Three intra-row spacing viz., 75 cm × 40 cm, 75 cm × 30 cm and 75 cm × 20 cm accommodating 33,333, 44,444 and 66,666 plants ha-1 , respectively, with six nitrogen levels viz., 0, 23, 46, 69, 92 and 115 kg ha-1 , were assigned to the experimental plot by factorial combinations. Based on the results, the maximum grain yield (10,208 kgha-1) was obtained when the hybrid was sown at the closest intra-row spacing (20 cm) with application of the highest rate of nitrogen (115 kg ha-1). This result showed 8.9% yield advantages compared to the standard check. However, statistically similar grain yield (9887 kgha-1) was also obtained under application of 92 kg N ha-1 in the same intra-spacing (20 cm). Moreover, since this experiment was conducted for one season and in one location, the comprehensive recommendation could be drawn by investigating more locations over years for this maize hybrid.