This document discusses biofertilizers, which are substances that contain living or dormant microorganisms. Biofertilizers help increase nutrients in plants by colonizing their rhizosphere. They are more cost-effective than chemical fertilizers. The document discusses different types of microbes used as biofertilizers, including bacteria, fungi, and cyanobacteria. It provides examples like nitrogen-fixing bacteria in legume roots and mycorrhizal fungi that absorb phosphorus for plants. Biofertilizers are prepared from biological wastes and enrich soil nutrients without chemicals, making them environmentally friendly options for organic farming.