Starch-based nanoformulation of rhizobium enhancing growth, nodulation, and yield in black gram

Black gram (Vigna mungo (L.) Hepper) is a significant pulse crop due to its nutritional value and productivity within the Indian subcontinent. Pulses possess the inherent ability to fix atmospheric nitrogen into the soil through a symbiotic association with the Rhizobium, a genus of essential soil microorganisms that facilitate nitrogen fixation in legumes. However, conventional biofertilizers encounter challenges related to limited shelf life, reduced cellular viability, and inefficacy of carriers. This research investigates the encapsulation of Rhizobium using starch nanoparticles and sodium alginate to mitigate these drawbacks. The nanoformulations was assessed, with a mean droplet size and polydispersity index of 292 nm and 0.056, respectively. FTIR analysis confirmed the successful incorporation of all functional components. SEM imaging illustrated a uniform distribution of the formulation over the seed coat. Release kinetics displayed an initial burst release, followed by controlled and sustained release phases. The nanoformulations effectively protects the cells from adverse conditions in soil with different pH levels. A pot culture experiment with Black gram was conducted to evaluate the efficacy of the nanoformulations. The findings indicated significant enhancements in growth parameters, nodulation, and yield characteristics compared to the control and conventional treatments. The highest dosage of nanoformulation at the rate of 15ml/8Kg (T6) consistently surpassed other treatments, demonstrating improved shoot and root lengths, chlorophyll content, soluble protein, and enzyme activities. Treatment T6 gains the highest nodule count (approx. 100/plant) and maximized yield parameters. This investigation highlights the potential of Rhizobium nanoformulations in promoting plant growth, nodulation, and yield in black gram. It offers a promising strategy for sustainable agricultural practices and addresses the limitations of traditional biofertilizers.