Harnessing the Efficacy of a Rhizobium Strain in Individual and Consortium Mode to Promote Sustainable Lentil Production and Biofortification under Diverse Soil Conditions

Purpose Supplementing chemical fertilizers with bio-fertilizers is vital for sustaining agricultural productivity while reducing the adverse environmental effects of traditional fertilizers. Present study aimed to assess the effectiveness of Rhizobium inoculation (individual and consortium modes) compared to chemical fertilizers in enhancing lentil growth, yield, and nutrient fortification in lentil grains across different soil systems. MethodsRhizobium and rhizobacteria were isolated from Bihar’s Tal soil and screened for plant growth promoting activities, nodulation, and nutrients solubilization. A pot experiment involving thirteen treatments, each replicated three times, was conducted for evaluation. Out of 28 isolates, four strains- DPR2 (Rhizobium leguminosarum bv. viciae), DPB4 (Bacillus cabrialesii), DPP4 (Pseudomonas synxantha) and DPA1 (Azotobacter salinestris) strains were selected based on their plant growth promoting activities, nutrient solubilization capabilities and harmoniously coexist. Results In a pot experiment, the consortium of DPR2 + DPB4 + DPP4 + DPA1 exhibited the shortest germination time and significantly improved nodule formation, plant growth, yield and yield attributes across all soil types. Moreover, this consortium significantly increased biofortification of macronutrients (N, P and K) and micronutrients (Fe and Zn) in lentil grains compared to other treatments. Irrespective to treatments, the number of root nodules, plant growth, yield and yield attributes, nutrient accumulation in lentil grains were consistently highest in Tal soil and lowest in calcareous soil. Conclusions Consortium of DPR2 + DPB4 + DPP4 + DPA1 can enhance lentil yield and fortification of nutrients in grains. Thus, consortium may hold promise as a bio-fertilizer supplement to chemical fertilizers for sustainable lentil production in diverse soil systems.