EFFECT OF BIO-FERTILIZER AND NPSBZn FERTILIZER APPLICATION RATES ON NODULATION AND PRODUCTIVITY OF COMMON BEAN (Phaseolus vulgaris L.) IN BURJI ZONE, SOUTH ETHIOPIA

Abstract

Low nitrogen and phosphorus availability, coupled with low knowledge of rhizobium inoculants and NPSBZn fertilizer application, reduced common bean productivity in the study region. Hence, the trial was conducted at Soyama Zuriya woreda from March to June. A randomized complete block design in a factorial arrangement was used by researchers, where four rates of NPSBZn mixed fertilizer (0, 50, 100, and 150 kg ha−1) were applied and Rhizobium strain (TAL 379) was used with and without control (no inoculation). Data recorded were analyzed using SAS 9.4 software. Plant height, seeds per pod, and harvest index were found to be significantly increased by Rhizobium inoculation, and NPSBZn levels independently affected these traits. Besides, NPSBZn fertilizer dose and Rhizobium strain interaction had an effect on days to 50% flowering, days to 90% maturity, primary branches plant-¹, total nodules, leaf area, leaf area index, pods plant-¹, hundred-seed weight, biomass yield, and grain yield. The highest grain yield (4052.4583 kg ha-¹) was obtained with 150 kg NPSBZn ha-¹ + Rhizobium inoculation, with higher productivity compared to other treatments. Apart from this, the partial budget analysis also revealed the maximum net benefit of Birr 7222.2 ha-1, % marginal rate of return obtained from combined application of 150 kg blended NPSBZn ha-1 with inoculated strain. Thus, based on these findings, the study recommends the use of 150 kg NPSBZn ha-1 with Rhizobium inoculation for enhancing common bean productivity in the study area.