ARS | Publication request: SOIL BIOTA IN THE RHIZOSPHERE

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: November 3, 2003
Publication Date: March 1, 2004
Citation: Kennedy, A.C. 2004. Soil biota in the rhizosphere. In: Sylvia,D.M.,Fuuhrman,J.J.,Hartel P.G., Zuberer, D.A., editors. Principles and Applications of Soil Microbiology. Upper Sadle River, NJ: Prentice Hall. p. 242-262.

Interpretive Summary: The rhizosphere is that volume of soil that is influenced by the root. In this area organic materials are released from the root or seed that result in altered microbial diversity and increased numbers of organisms, microbial activity and interactions among microorganisms, the seed or root and the soil. Our understanding of the rhizosphere and the many interactions within this zone has increased greatly since the term was first introduced in 1904. Yet the rhizosphere and spermosphere still hold much unknown territory. We investigated the various interactions that influence the health, vigor and productivity of the plant. The microbial community in the rhizosphere can influence plant growth in ways that are beneficial, neutral or detrimental. The challenge is to understand these regions of soil-root and soil-seed interfaces to manage microorganisms, increase plant growth and reduce the impact of crop cultivation on the environment. To successfully use the rhizosphere in agriculture, scientists need to work toward a number of goals, including: 1)identifying the characteristics of microorganisms and plants that control root colonization; 2) understanding microbial ecology to develop more effective strategies for managing the rhizosphere microflora; 3)expanding the view of the rhizosphere from a single root to overlapping rhizospheres; and 4) developing better methods to measure microbial populations and their competitive ability in the rhizosphere.

Technical Abstract: The rhizosphere is that volume of soil that is influenced by the root. In this area organic materials are released from the root or seed that result in altered microbial diversity and increased numbers of organisms, microbial activity and interactions among microorganisms, the seed or root and the soil. In comparison to the near-starvation conditions of the bulk soil, the rhizosphere is the place where nutrients are plentiful, life is good and microorganisms flourish. The rhizosphere is the zone of altered microbial diversity, increased activity and number of organisms, and complex interactions of microorganisms and the root. The significance of the rhizosphere arises from the release of organic material from the root and the subsequent effect of increased microbial activity on nutrient cycling and plant growth. The microbial community in the rhizosphere can influence plant growth in ways that are beneficial, neutral, variable or harmful. These interactions will influence the health, vigor and productivity of the plant.