As plant roots grow through soil they release water
soluble compounds such as amino acids, sugars and
organic acids that supply food for the
microorganisms. The food supply means
microbiological activity in the rhizosphere is much
greater than in soil away from plant roots. In return,
the microorganisms provide nutrients for the plants.
All this activity makes the rhizosphere the most
dynamic environment in the soil. Because roots are
underground, rhizosphere activity has been largely
overlooked, and it is only now that we are starting to
unravel the complex interactions that occur. For this
reason, the rhizosphere has been called the last
frontier in agricultural science.