EFFECT OF NITROGEN SOURCES ON GROWTH, YIELD AND YIELD COMPONENTS OF COMMON BEAN (Phaseolus vulgaris L.) VARIETIES AT MESKAN, SOUTHERN ETHIOPIA

Abstract

Common beans (Phaseolus vulgaris L.) are an important cash crop and protein source for farmers in many parts of Ethiopia. However, lacks of adequate information on the use of nitrogen source fertilizers are the major yield limiting factors for common bean production in the study area. Thus, the field experiment was conducted at Meskan District in 2018 cropping season to evaluate the effect of nitrogen sources on growth, yield and yield components of common bean varieties; and to identify economically appropriate combination of nitrogen sources that give optimum yield of major common bean varieties. Factors studied includes four common bean varieties (Hawassa Dume, Gegeba, Rori and Ibado) and four level of N sources (T1= Control; T2=Rhizobium inoculated; T3=46 kg N ha -1 , T4= 46 kg N ha -1 + Rhizobium inoculated). The treatments were arranged using randomized complete block design in factorial arrangements with three replications. Results revealed varietal differences on growth, yield and yield components. The highest pod number plant -1 (29.1), seed number pod -1 (5.6) and grain yield (2.7 t ha -1 ) were recorded from variety Hawassa Dume. Similarly, nitrogen sources had significant effect on growth, yield and yield components. Significantly, higher number of pods plant -1 (27.5), seeds pod -1 (5.6), and grain yield (2.7 t ha -1 ) were recorded from combined application of Rhizobium inoculation+46kg N ha -1 . There was significant interaction effect of N sources with varieties on nodule number, root dry weight and straw yield, where by the highest nodule number plant -1 (40), root dry weight (11.6 ) and straw yield (4.5 t ha -1 ) were recorded from combined application of Rhizobium strain HB-429 and 46 kg N ha -1 with variety Hawassa Dume except number of nodule plant -1 . Grain yield was positively and significantly correlated with phenological, growth, nodulation, yield and yield components except maturity date. Partial budget analysis of the study revealed that the highest net return (32,748 ETB ha -1 ) was obtained from Hawassa Dume variety with combined application of inoculation and 46 kg N ha -1 . Based on the results of this study, it can be concluded that combined application of Rhizobium inoculation with 46 kg N ha -1 found to be appropriate for common bean variety Hawassa Dume in the study area. However, the result of the present study need to be evaluated and reconfirmed on farmers field across season and areas in order to reach to a conclusive recommendation.