Biofertilizers in Sustainable Agriculture:

• Environmental concerns linked to chemical fertilizers prompt a shift to organic farming.
• Biofertilizers, derived from bacteria, fungi, and cyanobacteria, enhance soil nutrient quality.

Nitrogen-Fixing Bacteria:

• Rhizobium bacteria form symbiotic nodules on leguminous plant roots, fixing atmospheric nitrogen for plant nutrient use.
• Free-living bacteria like Azospirillum and Azotobacter enrich soil nitrogen content.

Mycorrhizal Fungi Associations:

• Fungi, especially Glomus, form mycorrhizal associations with plants, facilitating phosphorus absorption.
• Benefits include resistance to root-borne pathogens, tolerance to salinity and drought, and overall enhanced plant growth.

Cyanobacteria as Biofertilizers:

• Cyanobacteria like Anabaena, Nostoc, and Oscillatoria, widely distributed in aquatic and terrestrial environments, fix atmospheric nitrogen.
• In paddy fields, cyanobacteria serve as vital biofertilizers, contributing to soil fertility.

Role of Blue-Green Algae:

• Blue-green algae add organic matter to the soil, increasing its fertility.

Commercial Biofertilizers:

• Several biofertilizers available commercially in the market.
• Farmers use these to regularly replenish soil nutrients, reducing dependence on chemical fertilizers.