'Biofertilizer' is a substance which contains living microorganism which, when applied to seed, plant surfaces, or soil, colonizes the rhizosphere or the interior of the plant and promotes growth by increasing the supply or availability of primary nutrients to the host plant.


Biofertilizers add nutrients through the natural processes of fixing atmospheric nitrogen, solubilizing Phosphorus, and stimulating plant growth through the synthesis of growth promoting substances.


Types of Biofertilizers 


The following types of biofertilizers are available to the farmers in India. 


• Nitrogen fixing biofertilizers eg.Rhizobium, Bradyrhizobium, Azo-spirillum and Azotobacter. 

• Phosphorous solubilising biofertilizers (PSB) eg.Bacillus,Pseudomonas and Aspergillus 

• Phosphate mobilizing biofertilizer eg. Mycorrhiza 

• Plant growth promoting biofertilizers eg. Pseudomonas sp. 


Advantages of biofertilizers:


• They help to get high yield of crops by making the soil rich with nutrients and useful microorganisms necessary for the growth of the plants.

• Biofertilizers have replaced the chemical fertilizers as chemical fertilizers are not beneficial for the plants. They decrease the growth of the plants and make the environment polluted by releasing harmful chemicals.

• Plant growth can be increased if biofertilizers are used, because they contain natural components which do not harm the plants but do the vice versa.

• If the soil will be free of chemicals, it will retain its fertility which will be beneficial for the plants as well as the environment, because plants will be protected from getting any diseases and environment will be free of pollutants.

• Biofertilizers destroy those harmful components from the soil which cause diseases in the plants. Plants can also be protected against drought and other strict conditions using biofertilizers.

• Biofertilizers are not costly and even poor farmers can make use of them.

• They are environment friendly and protect the environment against pollutants.