Which microorganisms are used in agriculture and why?

Nitrogen-fixing bacteria, particularly Rhizobium species and free-living bacteria like Azotobacter, are extensively used in agriculture as biofertilizers because they convert atmospheric nitrogen into plant-usable forms, reducing or eliminating the need for expensive and environmentally harmful synthetic fertilizers. Rhizobium bacteria form symbiotic relationships with leguminous crops (beans, peas, clover, soybeans), colonizing root nodules and supplying nitrogen directly to plants while receiving carbohydrates in return. Farmers inoculate legume seeds with Rhizobium cultures before planting to enhance nodulation and maximize nitrogen fixation, improving crop yields and soil fertility sustainably.

Beyond nitrogen fixation, other beneficial microorganisms used in agriculture include Azospirillum and Azotobacter for cereals and vegetables, phosphate-solubilizing bacteria like Bacillus that make soil phosphorus available to plants, and mycorrhizal fungi that enhance nutrient and water uptake through symbiotic root associations. Microbial biopesticides containing Bacillus thuringiensis (Bt) are used to control insect pests organically without chemical pesticides. Decomposer microorganisms in compost and organic matter break down crop residues, releasing nutrients for subsequent crops. These microbial applications support sustainable agriculture by improving soil health, reducing chemical inputs, lowering production costs, minimizing environmental pollution, and promoting long-term agricultural productivity.