What do you mean by biofertilizers?

Biofertilizers:

1. Biofertilizers are substances that contain microorganisms, which when added to the soil increase its fertility and promote plant growth.
2. Biofertilizers increase the supply of essential nutrients to plants.
3. It comprises living organisms which include mycorrhizal fungi, blue-green algae, and bacteria.
4. Mycorrhizal fungi preferentially withdraw minerals from organic matter for the plant whereas cyanobacteria are characterized by the property of nitrogen fixation.
5. They are eco-friendly in nature.
6. They do not cause any harm to the soil or to the environment.