2. Soil Biogeochemistry

Soils are a primary determinant of site quality and environmental conditions in terrestrial ecosystems, providing water, nutrients, acid neutralizing capacity, shelter, and anchorage for terrestrial life forms. Beyond these essential functions in terrestrial ecosystems, soils also exert a strong influence on aquatic systems through effects on the chemistry and hydrologic routing of drainage water inputs to lakes and streams. In this chapter, the physical and chemical characteristics of soils are examined, along with key soil biogeochemical processes that influence the belowground cycling of elements in watershed ecosystems. Comparative data are used to illustrate the ranges of soil properties observed across the forest landscape. Results illustrate that soils provide a remarkable system of nutrient supply and storage based on integrated contributions from geologic and organic source materials.