Bio fertilizers are preferred to chemical fertilizers due to following advantages :
(i) Decomposition products of bio fertilizers help to bring mineral constituents of soil into solution.
(ii) They improve physio chemical properties of soil such as cation exchange and buffering action.
(iii) They modify the physical properties like granulation of the soil and increases permeability and moisture-holding capacity of soil.
(iv) They are economically cheaper than chemical fertilizers.
(v) Bio fertilizers do not cause any harm to environment while many chemical fertilizers are non-degradable and cause soil and water pollution.
(vi) They provide food for soil microbes and thus enhance microbial activities.