Biofertilizers for Improving Nutrient Use Efficiency in Sustainable Agriculture: Emerging Technologies and Future Perspectives

Abstract

Global application of inorganic fertilizers surpassed 190 million tonnes in 2025; however, crops typically take up less than 50% of the nutrients applied, especially nitrogen, leading to major nutrient losses, deterioration of soil quality, greenhouse gas emissions, eutrophication, and reductions in biodiversity. Consequently, increasing nutrient use efficiency (NUE) without compromising yields has become a central objective for sustainable agriculture. Biofertilizers containing beneficial microorganisms such as nitrogen-fixing bacteria, phosphate- and potassium-solubilizing microbes, arbuscular mycorrhizal fungi (AMF), and plant growth-promoting rhizobacteria (PGPR) have gained attention as environmentally friendly substitutes or supplements to mineral fertilizers because they enhance nutrient availability, nutrient acquisition, and plant tolerance to stress. This review offers a critical synthesis of current understanding of how biofertilizers improve NUE through mechanisms such as biological nitrogen fixation, nutrient solubilization and mobilization, phytohormone synthesis, rhizosphere modification, and regulation of plant–microbe interactions. It also discusses recent progress in microbial consortia, biofilm-based products, nano-biofertilizers, microbiome engineering, and genomics-guided strain improvement that has increased the effectiveness and field performance of microbial inoculants. Nonetheless, issues involving microbial survival, formulation durability, performance across diverse agroecological settings, and scaling up for commercial use still hinder broad adoption. Future work should prioritise the design of climate-smart microbial products via synthetic microbial communities, multi-omics tools, precision agriculture, and artificial intelligence-assisted strain selection to enhance the reliability and effectiveness of biofertilizers. Incorporating biofertilizers into nutrient management strategies can decrease reliance on synthetic fertilizers, restore soil health, improve NUE, and support environmentally resilient and sustainable farming systems. Overall, this review presents a comprehensive and forward-looking analysis of how biofertilizers can contribute to sustainable nutrient management and climate-resilient agriculture.