Evaluation of Carrier- and Liquid-Based Bioinoculant as a Promising Approach to Sustain Black Gram (Vigna mungo L.) Productivity.

The use of rhizobia and phosphorus solubilizing bacteria (PSB) as an alternative source to improve soil nutrition is necessary to promote sustainable gram production. In this study, the efficacy of rhizobia (Bradyrhizobium japonicum- BR3267) and PSB (Pseudomonas striata) in liquid form and on carrier material was investigated in a Randomized Complete Block Design. Their effects on root nodulation, nutrient uptake, growth phenology, and yield of black gram were evaluated. Recommended fertilizer dose (RDF)- 200 kg ha−1 N P K (12:30:17) + 0.4 Zn was set as the control and common factor. Integration of Rhizobia + RDF increased plant height, dry matter, leaf chlorophyll, and leaf area index compared to PSB + RDF. The liquid inoculants influenced root nodulation, N and P uptake, growth phenology, and yield more than the carrier-based. Root nodule number plant−1 was highest with Rhizobia + RDF, but root nodule volume and weight increased when PSB was integrated. Nitrogen uptake correlated positively with nodule number (R2 = 0.64) and dry weight (R2 = 0.75). The integrated liquid-based Rhizobia + PSB + RDF produced the highest yield (1268.31 kg ha−1) and was 35% higher than the non-inoculated plot. The higher RDF + Rhizobium + PSB (LB) + RDF trend resulted in a significant aggregate mean of 21.5%, and protein yield (272.77 kg ha−1). The study addressed the hypothesis that rhizobia and PSB in liquid form have a stronger effect on nodulation, which positively affects nutrient uptake capacity and overall crop productivity, so their dual inclusion with RDF in cropping systems is recommended. [ABSTRACT FROM AUTHOR]