Influence of Biofertilisers on Mulberry Productivity: A Review

Organic sources of nutrients, particularly when integrated with beneficial microbes, have shown potential to improve soil fertility and crop productivity while reducing dependency on synthetic inputs. Mulberry (Morus spp.) is the exclusive food plant of the domesticated silkworm (Bombyx mori L.) and constitutes the biological and economic foundation of the global sericulture industry. Intensive cultivation practices dependent on synthetic fertilisers have progressively degraded mulberry garden soils, diminishing leaf yield, nutritive quality, and long-term crop sustainability. Biofertilisers — preparations containing live or dormant beneficial microorganisms — have emerged as eco-friendly, cost-effective alternatives that underpin sustainable mulberry cultivation. This review synthesises research published between 1995 and 2025 on the influence of nitrogen-fixing bacteria (Azotobacter, Azospirillum, Beijerinckia), phosphate-solubilising microorganisms (PSM), arbuscular mycorrhizal fungi (AMF), cyanobacteria, and other plant growth-promoting rhizobacteria (PGPR) on the growth, leaf yield, and biochemical quality of mulberry. Evidence consistently demonstrates that biofertiliser application improves vegetative growth parameters, enhances macronutrient and micronutrient uptake, raises leaf moisture, protein, sugar, and amino acid contents, and reduces dependence on chemical inputs by up to 50–75%. Downstream benefits to silkworm rearing — including improved larval growth, cocoon weight, shell ratio, filament length, and raw silk quality — have been documented across multiple agro-climatic zones. Integrated nutrient management (INM) approaches combining biofertiliser consortia with reduced doses of chemical fertilisers or organic manures consistently outperform either strategy in isolation. Key challenges include inconsistent field performance, limited strain standardisation, inadequate shelf-life formulations, and low farmer awareness. Future research priorities include multi-location field trials, development of stable formulations, and elucidation of the molecular mechanisms governing biofertiliser–mulberry interactions. This review provides a comprehensive reference for researchers and practitioners engaged in sustainable sericulture nutrient management.