Understanding the Role of Bacterial Fertilizers in Stressed Agriculture: Actions, Mechanisms and Future Prospects

Environmental stresses are among the major problems which are decreasing crop productivity at an alarming rate. Several biotic and abiotic stresses such as salt stress, water shortage, high temperature, waterlogging and metal toxicity are dominant in arid and semi-arid areas. Drought occurs as secondary stress during the salt stress conditions which is the most critical factor in arid and semi-arid regions and adversely affecting the crop growth and yield. Soil salinity and Na+ toxicity are also the most critical factors for soil degradation that are affecting the cropping system and ultimately agriculture. Chemical fertilizers are being used as fast food for plants to grow efficiently, but the imbalance and excessive use of such conventional chemical fertilizers are degrading the soil fertility, disturbing the environment, causing eutrophication, showing the hazardous effects on human health and contaminating the underground water. However, the bacterial fertilizers being cheaper and eco-friendly are gaining success in the agricultural community for improving crop production without disturbing the soil’s natural fertility and also saving it against biotic and abiotic stresses. Biofertilizer contains free-living bacteria that can increase plant growth via direct and indirect pathways and are known as effective microbes (EM). Thus, the use of effective microbes as bacterial fertilizers has become the most significant for sustainable agriculture.