The term redoximorphic refers to the reduction and oxidation chemical reactions and the resulting appearance or morphology of the soil horizon. While color is often used to indicate the presence of oxidized or reduced zones on soil, it is not the only indicator that can be used. This page provides information to help characterize and identify oxidation-reduction (redox) conditions in a soil. For information and a discussion on redox in soil, link here. Several links are also included at the bottom of this page. These provide information on redox chemistry in soil and how it affects soil and soil processes, including pollutants in soil.

Interpreting soil borings

Characterizing redox status of soil

When logging soil descriptions while taking borings, care should be taken to provide adequate information to interpret the boring log. We recommend the following.

  • Note the color. Grey or blue are associated with reducing conditions, while brown and red are associated with oxidizing conditions.
  • Accurately describe the soil water (moisture) content, using terms such as saturated, wet, moist, and dry.

Potential issues with interpreting boring logs

  • Grey or blue colors above brown or red colors in the soil profile. These conditions should not exist unless the upper soil has been manipulated in some fashion, such as consisting of fill.
  • Wet or saturated soil above soil that has a drier condition. This indicates presence of an impeding layer, such as clay, that retains water relative to the underlying layer.