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Soil Biology

Soil Health Biology Image


The creatures living in the soil are critical to soil health. They affect soil structure and therefore soil erosion and water availability. They can protect crops from pests and diseases. They are central to decomposition and nutrient cycling and therefore affect plant growth and amounts of pollutants in the environment. Finally, the soil is home to a large proportion of the world's genetic diversity.

Soil Biology Primer

Soil Biology PrimerThe online Soil Biology Primer is an introduction to the living component of soil and how it contributes to agricultural productivity and air and water quality. The Primer includes chapters describing the soil food web and its relationship to soil health and chapters about soil bacteria, fungi, protozoa, nematodes, arthropods, and earthworms.

The online Primer includes all of the text of the printed original, but not all of the images of the soil organisms. The full story of the soil food web is more easily understood with the help of the illustrations in the printed version.

Printed copies of the Soil Biology Primer may be purchased from the Soil and Water Conservation Society. Go to

  • Copyright restrictions: Many photographs in the online Soil Biology Primer cannot be used on other Web sites or for other purposes without explicit permission from the copyright owners. Please contact the Soil and Water Conservation Society at for assistance with copyrighted (credited) images tagged throughout the online Primer.
  • The text, graphs, tables, non-credited photos, and graphics from USDA sources may be used freely; however, please credit the Soil Biology Primer or this Web site.

Soil Biology Primer Chapters


The Natural Resources Conservation Service, with assistance from the Conservation Technology Information Center, provided leadership for this project. The Natural Resources Conservation Service and the Soil and Water Conservation Society thank many individuals, including the following, for their contributions.

Suggested Citation

  • Printed booklet: Tugel, A.J., A.M. Lewandowski, and D. Happe-vonArb, eds. 2000. Soil Biology Primer. Ankeny, IA: Soil and Water Conservation Society.
  • Online primer: Soil Biology Primer [online]. Available: [access date].


  • Elaine R. Ingham
  • Andrew R. Moldenke, Oregon State University
  • Clive A. Edwards, The Ohio State University



  • Arlene J. Tugel, Natural Resources Conservation Service
  • Ann M. Lewandowski, Natural Resources Conservation Service
  • Deb Happe-vonArb, Soil and Water Conservation Society


  • Nancy K. Marshall, Marshall Designs