ABSTRACT

In recent years, the term rhizosphere has appeared more and more frequently as a key word on papers that cover all basic and applied sciences related to soilplant-microbe relationships, such as soil fertility and biotechnology, microbial ecology, and plant nutrition, physiology, and pathology. A literature search with rhizosphere and (carbon or nitrogen) as requests for only the last 4 years would generate more than 500 responses. Any physical, chemical, and biological change occurring within the root sphere or even indirectly mediated by its excretions and organic debris is called a rhizosphere effect. Despite the demonstration of this effect on the basis of either an increase in number (1,2) or changes in the biodiversity (3) of microorganisms, it has been much more difficult to produce experimental evidence for the rhizosphere effect in terms of carbon and nutrient flows specific to the rhizosphere environment (see Chap. 12).