Assessment of Reducing Conditions in Soils.

Anaerobiosis or electrochemical reduction is one of the signature properties of hydric soils and wetlands. It is essential to the definition and recognition of these ecosystems and many important wetland functions are driven by anaerobic biogeochemical processes. Therefore, documentation of reducing conditions in wetland soil systems is desirable, but at the same time challenging.  Many approaches have been utilized in approaching the characterization of redox conditions, including use of indicator dyes, measuring activities of important chemical species, and measurement of redox potentials using Pt and reference electrodes. Each of these have benefits and limitations. In the last decade, another approach has been developed known as IRIS (Indicator of Reduction In Soils) technology, that utilizes the induced reduction of iron oxyhydroxides to assess soil reduction. While not without limitations, IRIS technology offers a relatively easy approach to assessing reducing conditions. Strengths and weakness of these various methods will be examined.