EFFECT OF RHIZOBIUM INOCULATION (MB003) AND NPSB FERTI LIZER RATES ON GROWTH YIELD AND YIELD COMPONENTS OF MUNG BEAN (Vigna radiate (L.) WILCZEK) VARIETIES IN MISRAK MESKAN DISTRICT EASTERN GURAGE ZON

Abstract

Lack of adequate information on the use of Rhizobium strain and nitrogen-phosphorus-sulfurboron(NPSB) fertilizer rates are the major yield limiting factors for producing mung bean in the study area. Thereforethe study was conducted with the objective of evaluating the nodulation, growth and yield responses oftwo varieties of mung bean (Vigna radiate (L.) Wilczek) at differ ent rates of NPSB fertilizer andRhizobiuminoculates. A field experiment was carried out during the main cropping season of 2021/22 at Misirak Meskan District in Farmers Training Center (FTC). The treatments combinations were two levels of Rhizobium inoculation (with and with out), twomung bean varieties N-26 (Rassa) and NVL-1(Nassa) and four levels of NPSB fertilizer (0, 50, 100, 150 kg ha-1). The experiment was arranged in a 2×2×4 factorial combination in randomized complete block design with three replications. Soil samples were collected from the experimental field at (0-30cm depth) before planting and after harvest to determine selected soil physicochemical properties. Data on growth, nodulation, yield and yield components were rec ordedand subjected to Analysis of Variance (ANOVA). Results on soil physicochemical proper ties analyzed before planting and after harvest showed significant differences due to the com bined effects of NPSB fertilizers and Rhizobium inoculation. Crop phenology (days to 50% flow ering and days to physiological maturity), growth (plant height, number of primary and second ary branches, shoot fresh and dry weight, root dry weight), and nodulation (number of nodules, nodule fresh and dry) weight of mung bean varieties were significantly affected by NPSB fertiliz er rates and Rhizobium inoculation. Moreover, theinteraction effects of NPSB fertilizer rates, Rhizobium inoculation and mung bean varieties showed significant effects on number of pods per plant, number of seeds per pod, a hundred seed weight, harvest index, grain yield and above ground biomass. The highest mean value of grain yield(2105.77 kg ha-1) was obtained from a combined effect of 150 kg NPSB ha-1and Rhizobium inoculation from variety N-26 which result ed in 61.28% followed by (2078.90 kg ha-1) which was increased by 62.07% at the rate of 100 kg NPSB ha-1increase over the control (1290.37 kg ha-1). Furthermore, the number of seeds per plant, a hundred seeds weight, above ground dry biomass and HI of mung bean were recorded the highest mean values (607.33), (7.50 g), (4241.67 kg ha-1) and 0.483, respectively at the rate of 150 kg NPSB ha-1fertilizer with a Rhizobium inoculation. The partial budget analysis re vealed that the maximum(ETB108600.6 ha-1) net benefit was obtained from combined applica tion of rhizobium inoculation and 100 kg NPSB ha-1from variety N-26 with MRR of 10130%And minimum (ETB 68572.8 ha-1) net benefit was obtained from the control. A net benefit ad vantage of 63.14% (ETB 68572.8 ha-1) when compared with the maximum and minimum net benefit. Hence, Rhizobium inoculation with application of 100 kg NPSB ha-1could be tentatively recommended for mung bean production in Misirak Meskan area. However, the experiment should be repeated over years and locations to provide valid recommendations appropriate for the study site.