Components of Soil
One gram of soil contains approximately one million
microorganisms. The soil has organic matter, soil solution and soil air. All
these components are affected by the activities of microorganisms. Soil is a
constantly changing medium. The soil solution in agricultural soil has ions
like K+, Na++, Mg++, Ca++, Fe+,
S-, NO3, SO4, PO4 and others.
These ions are very essential in culture media. In a fertile
soil, these elements in mineral form are supplemented by organic compound,
derived from the decomposition of animal and plant
residues.Thusthesoilisanexcellentnatural medium for growth of microorganisms.