Biofertilizers: A Nexus between soil fertility and crop productivity under abiotic stress

High food demand for the world's teeming population necessitates the intensification of crop production in modern agriculture, which requires the extensive use of synthetic fertilizers for higher crop yield. The excessive use of chemical fertilizers, despite the high nutrients contents and ability to grow crops faster, discovered to be dangerous to the health and environment besides polluting the groundwater and atmosphere in the future. The alternative to these, biofertilizers arose today due to their attributes towards eco-friendly, cost-effective, and easy to apply in the agricultural field. Biofertilizers are a batch of diverse microorganisms, which can induce plant growth-promotion activities along with soil health, even under abiotic stress conditions. Biofertilizers maybe plant growth-promoting rhizobacteria, arbuscular mycorrhizal fungi, and as well as the consortia of other beneficial microbes. Biofertilizers can sustain plant growth performance, even in a challenging environment. The performance of perfect-candidate-biofertilizer in the agricultural field depends on crop type, properties of inoculants, technical background, and environmental condition. Biofertilizers can, directly or indirectly, help in attaining food security compared to the harmful effect of chemical fertilizers. A direct mechanism of Biofertilizers refers to phyto-stimulation and nutrient mobility, while an indirect mechanism poses bio-control activity. Direct mechanisms involve phytohormone production and phosphate, potassium, zinc, etc. solubilization. While, indirect-mechanism is HCN production, siderophore production, antibiotic production, etc. The present review elucidates the diversity of microbial inoculants (biofertilizers), their impacts on agricultural production through rising soil fertility, and overall crop yield. In line with related literature worked out by different researchers