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ARS Home » Pacific West Area » Pullman, Washington » Northwest Sustainable Agroecosystems Research » Research » Publications at this Location » Publication #147020


item Kennedy, Ann
item De Luna, Lilian

Submitted to: Encyclopedia of Soil Science
Publication Type: Book / Chapter
Publication Acceptance Date: 11/1/2003
Publication Date: 3/3/2004
Citation: Kennedy, A. C., de Luna, L. Z. 2004. Rhizosphere. pp. 399-406. In: Hillel, D. editor. Encyclopedia of Soils in the Environment. Oxford, UK. Elsevier LTD.

Interpretive Summary: The rhizosphere, the zone of soil surrounding the root, is a dynamic region governed by complex interactions between plants and the organisms that are in close association with the roots. The composition and pattern of root exudates affect microbial activity and population numbers, which in turn, have an impact on the nematodes and micro-arthropods that share this environment. Beneficial, harmful or neutral relationships exist among different organisms, which ultimately affect root function and plant growth. A better understanding of the soil-root and soil-seed interface is needed to manage microorganisms, increase plant growth and reduce the impact of plant production and agriculture on the environment. This manuscript explored the benefits of studying the rhizosphere, which include the use of plant growth-promoting organisms and the suppression of plant diseases and weeds using biocontrol agents. Rhizosphere organisms can also be used to enhance the formation of stable soil aggregates and as bioremediation agents of contaminated soils. With greater understanding of the ecology and biota in the rhizosphere, scientists, growers and land managers can use processes in this zone of increased nutrients, biotic activity and interactions to improve plant productivity and environmental quality.

Technical Abstract: The rhizosphere is a distinct area of soil surrounding and influenced by the root. This zone is characterized by intense activity due to the release of root exudates, which stimulate or inhibit rhizosphere organisms. The interactions among soil, plants and organisms that comprise the rhizosphere characterize the complexity and the dynamics of this region. Plant/microbe and plant/macrofaunal interactions abound in the rhizosphere. These interactions range from symbiotic relationships of N2 fixation and mycorrhizal associations to pathogenic interactions. Management strategies, such as bioremediation and biological control, will be successful when rhizosphere ecology is considered. A greater understanding of the rhizosphere and its effects on organisms that inhabit this area will allow for manipulations that benefit plant production and the environment.