Rhizosphere
Definition
The area immediately around plant roots, including the roots itself that comprises intense microbial activity, where plants, microorganisms, other soil organisms, and soil structure and chemistry, interact in complex ways.
Source
Glossary. M.S. Ashton et al. (eds.), Managing Forest Carbon in a Changing Climate, DOI 10.1007/978-94-007-2232-3, © Springer Science+ Business Media B.V. 2012
Alternative definition
The soil region in the immediate vicinity of growing plant roots.
Alternative source
FAO Glossary of Biotechnology for Food and Agriculture, 2001 (http://www.fao.org/biotech/index_glossary.asp?lang=en).