Asian Journal of Soil Science and Plant Nutrition

Indigenous fermented biological formulations are increasingly used in natural, organic and low-external-input farming, particularly in South Asia. Preparations such as Jeevamrit, Ghanjeevamrit, Beejamrit and Panchagavya contain complex mixtures of microorganisms, organic substrates, nutrients and fermentation-derived metabolites, and are commonly proposed to stimulate soil biological activity and improve crop performance. Yet the central ecological question remains unresolved: whether these preparations reproducibly restructure the rhizosphere microbiome through direct microbial inoculation, indirect biostimulation of resident communities, plant-mediated recruitment, or combinations of these processes. This critical narrative review evaluates the evidence linking indigenous biological formulations with rhizosphere microbial abundance, diversity, community assembly, functional potential, nutrient cycling and soil-plant feedbacks. Particular attention is given to recent culture-independent studies, multi-omics characterisation of formulations, field comparisons of natural and conventional management, and mechanistic evidence from broader soil microbial ecology. The evidence consistently indicates that preparation methods strongly influence the microbial and metabolite composition of fermented inputs. Field studies frequently report higher culturable microbial populations, microbial biomass and enzyme activities under formulation-based or natural-farming treatments, whereas sequencing studies show context-dependent shifts in bacterial and fungal communities. Evidence for durable transfer or engraftment of formulation-derived taxa into the rhizosphere is much weaker; ecological filtering by soil conditions, plant genotype, root exudation, crop stage and co-management practices appears to be decisive. General organic-amendment literature supports a strong biostimulatory role for added carbon and nutrients, complicating attribution of observed responses to introduced microorganisms. Methodological limitations include bundled treatment packages, limited source tracking, reliance on relative-abundance sequencing, sparse longitudinal sampling and inadequate nutrient mass balances. A more defensible interpretation is therefore that indigenous formulations function as variable ecological inputs whose effects emerge from interactions among their microbial consortia, metabolites, substrates and the receiving soil-plant system. Future progress requires factorial multi-site trials, strain-resolved source tracking, absolute microbial quantification, integrated metagenomic-metatranscriptomic-metabolomic measurements, nutrient-budget assessment and explicit biosafety quality control.