Biofertilisers harbouring living organisms hold allure due to their prospective favourable
influence on plant growth, coupled with a diminished environmental footprint and cost-effectiveness
in contrast to conventional mineral fertilisers. The purpose of the present study
was to evaluate the capacity of a specific microalga (MACC-612, Nostoc linckia ) biomass
and plant growth-promoting bacteria (PGPB) separately and together to improve crop
growth and promote soil health. The research used a factorial design within a completely
randomised block framework, featuring four replications for three consecutive years
across different fields. The experiment utilised three levels of microalga (control,
0.3 g/L of N. linckia , MACC-612, and 1 g/L of N. linckia , MACC-612) and three levels
of bacterial strains (control, Azospirillum lipoferum and Pseudomonas fluorescens
). The result demonstrated that the use of N. linckia and PGPB separately or jointly
as soil treatment resulted in a substantial improvement in chlorophyll, plant biomass,
soil humus, and nitrogen, depending on the environmental conditions of the years.
The combined use of N. linckia and PGPB results in an improvement in dry leaf weight
by 35.6–107.3% at 50 days after sowing (DAS) and 29.6–49.8% at 65 DAS, compared to
the control group. Furthermore, the studies show that the synergistic application
of N. linckia at 0.3 g/L, in conjunction with A. lipoferum , significantly improved
total nitrogen and (NO 3 − + NO 2 − )-nitrogen, registering increases of 20.7–40%
and 27.1–59.2%, respectively, during the study period. The most effective synergistic
combination was identified through the application of 0.3 g/L of N. linckia along
with A. lipoferum . Hence, application of biofertilisers through synergistic combinations
of two or more microorganisms, such as microalgae and bacteria, holds promise in improving
crop chlorophyll, growth, and soil nitrogen.