The rhizosphere is that part of the soil ecosystem where plant roots, soil and the soil biota interact with each other. These interactions are often of benefit to plants, improve soil fertility and enhance the degradation of toxic chemicals. Rhizodeposition from plants is the key energy supply for the rhizosphere biota. Mineral nutrients are supplied by the soil matrix, organic residues and biological nitrogen fixation. The interactive biotic community includes microorganisms, protozoa and soil fauna. Some organisms are beneficial whereas others are harmful. Some deleterious organisms can be suppressed in a variety of biological control strategies. The key physical factors governing rhizosphere activity are temperature, water availability, oxygen, pH and soil structure. The rhizosphere has strong influences on agriculture, and the bioremediation of contaminated and degraded land.

Key Concepts:

  • Rhizodeposition from roots generates the energy substrates for rhizosphere organisms.

  • Mineral nutrients are provided by the soil matrix, organic residues and biological nitrogen fixation.

  • Microorganisms interact with protozoa and soil fauna in the rhizosphere.

  • Deleterious organisms can be suppressed by beneficial organisms in biological control.

  • Temperature, water availability, oxygen, pH and soil structure govern biotic activity.

  • The rhizosphere activity can optimise crop production and remediate contaminated and degraded land.

Keywords: roots; soil; microorganisms; biological control; nutrient cycles

Figure 1.

A growing root in soil.

Figure 2.

Factors influencing rhizosphere interactions.

Figure 3.

Bacterial cell on a wheat root surface, surrounded by mucilage (unstructured) and absorbed clay particles. The original resolution of this image is ×50 000.



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Lynch, James M, and de Leij, Frans(May 2012) Rhizosphere. In: eLS. John Wiley & Sons Ltd, Chichester. http://www.els.net [doi: 10.1002/9780470015902.a0000403.pub2]