Response of common bean cultivars to phosphorus application in Boloso Sore and Sodo Zuria Districts, Southern Ethiopia

Abstract

Common bean (Phaseolus vulgaris L.) is an important food crop in Southern Ethiopia. However, the productivity of the crop is constrained by low soil fertility, particularly, phosphorus deficiency due to soil acidity. Therefore, field experiments were conducted to study the response of the crop to phosphorus application on Nitisols at Areka Agricultural Research Centre and Kokate research station in southern Ethiopia. The treatments consisted of three common bean cultivars (Hawassa-Dume, Nasir, and Red-Wolaita) and five phosphorus fertilizer rates (0, 23, 46, 69, and 92 kg P₂O₅ ha^-1). The experiments were laid out as a randomized complete block design in a factorial arrangement and replicated three times per treatment. Analysis of the data indicated that the main effects of cultivar and phosphorus significantly (P < 0.05) influenced grain yield, number of pods per plant, seed weight, leaf area index, and above-ground dry biomass yield. The interaction effects of cultivar and phosphorus rate also significantly (P < 0.05) influenced the number of pods produced per plant at one location (Areka). At Areka, Nasir produced a significantly higher grain yield (2504.8 kg ha^-1) than Hawassa-Dume (1951 kg ha^-1) and Red-Wolita (2198 kg ha^-1). However, at Kokate, the grain yields of the three common bean cultivars were in statistical parity. Application of 69 and 23 kg P₂O₅ ha^-1 resulted in the optimum grain yields of the crop at Areka (2498 kg ha^-1) and Kokate (2219 kg ha^-1), respectively. The results of the economic analysis indicated that cultivar Nasir produced the highest net benefit (15903 Birr ha^-1). It could, thus, be concluded that cultivating Nasir at the rates of 69 P₂O₅ ha^-1 at Areka and 23 kg P₂O₅ ha^-1 at Kokate is most economical for smallholder farmers in the study area.

Keywords: Biomass yield; Economic analysis; Grain yield; Phaseolus vulgaris L.