Bacterial biofertilizers are:
Rhizobium:
1. Rhizobium, a soil bacterium, forms a symbiotic relationship with leguminous plants.
2. Through root attachment, Rhizobium induces the formation of nodules on the plant roots.
3. These nodules play a crucial role in converting atmospheric nitrogen into ammonia, aiding the plant’s growth.
Azotobacter:
1. Azotobacter comprises Gram-negative, soil-dwelling bacteria that are aerobic and capable of nitrogen fixation.
2. These bacteria exhibit an oval or spherical shape and produce resilient cysts in adverse environmental conditions.
Azospirillum:
1. Azospirillum, a gram-negative bacteria, functions as a plant growth-promoting diazotroph and has an oblong-rod shape without spore production.
2. Being microaerophilic, Azospirillum is aerobic yet capable of surviving in low oxygen environments.