Importance of Soil Microbes in Nutrient Use Efficiency and Sustainable Food Production

Microorganisms that sustain the fertility of soils, resulting in improved plant nutrition, have continued to magnetize attention because of the increasing cost of agricultural inputs and some of their negative impacts on environmental sustainability. The continuous increase in the world population at an alarming rate requires more food for nutritional security. A doubling in global food demand projected for the next 50 years poses huge challenges for agricultural sustainability. Nowadays, plant growth is enhanced by the increasing input of agrochemicals, which act as plant growth regulators (PGRs) and as nutrients. Excessive/injudicious use of chemicals increases the chances of deteriorating soil and environmental quality. Rhizospheric plant growth–promoting microorganisms (PGPMs) are increasingly and promisingly being distributed in world agriculture. Meanwhile, current use of these efficient PGPMs may offer agronomic, pathogenic, and environmental benefits for intensive agricultural production systems. PGPMs are exhibiting a gradual increase in demand on the world market as sustainable and eco-friendly tools. Possible mechanisms for the effectiveness of biofertilizers are mobilization of the scarcely available plant nutrients nitrogen (N), fixer phosphorus (P), potassium (K), and zinc (Zn) solubilizers; production of plant growth–promoting substances; enhanced and induced resistance to environmental multistress factors; and direct or indirect suppression of harmful microbes. Research activities are currently limited by the lack of standards for production and quality control of different commercially used biofertilizers.