Blackgram (Vigna mungo L.) is a vital pulse crop for food and nutritional security in the mid-hills of Nepal, but its productivity remains constrained by poor nutrient management and limited use of Rhizobium inoculants. In particular, deficiencies of essential micronutrients such as boron (B) and molybdenum (Mo), together with underutilization of beneficial Rhizobium, restrict nodulation, nitrogen fixation, and yield potential. To address this issue, a field experiment was conducted at the Agronomy Farm, Lamjung Campus, to assess the combined effects of Rhizobium inoculation and micronutrient supplementation on local blackgram. A split-plot design with three replications was used, where Rhizobium inoculation (inoculated vs. non-inoculated) formed the main plot factor, and seven nutrient treatments were assigned to subplots: control, 250 ppm B, 500 ppm B, 250 ppm Mo, 500 ppm Mo, 250 ppm B + 250 ppm Mo, and 500 ppm B + 500 ppm Mo. Results showed that Rhizobium inoculation significantly improved nodulation, biomass, and yield attributes compared with non-inoculated plots. The combined application of 500 ppm B and 500 ppm Mo with Rhizobium inoculation achieved the highest nodulation, biomass, and seed yield (120.73 g per 2.1 m2). These findings suggest that integrated nutrient management using Rhizobium inoculation with balanced B and Mo supplementation can substantially enhance blackgram productivity, reduce dependence on chemical fertilizers, and contribute to sustainable pulse-based farming systems in Nepal’s mid-hills.
Bhandari et al. (Tue,) studied this question.