IRIS tubes are 24 inch pvc tubing that are coated with a specially formulated Fe oxide paint.  When installed in the ground, the paint on the tubes is designed to dissolve under reducing soil conditions (Rabenhorst, 2008).  Results indicate whether or not there is sufficient hydrology and organic matter to support microbial processes for reduction.  This is a good indication of whether the soils are functioning as hydric soils.  In addition, the evidence of functioning microbial processes for reduction also indicate that the microbial processes will support wetland functions such as nutrient transformation.  IRIS tubes are a much less time consuming way to determine soils reduction in the soil than Eh electrodes.  IRIS tubes are a fairly new and under-utilized technology.  Since hydric soils are often slow to develop in wetland mitigation sites, IRIS tubes may be a useful tool to determine if sufficient soil reduction is present.  More detailed information on how MDE utilized IRIS tubes to evaluate a subset of mitigation sites can be found within the MDE Mitigation Report.

* Rabenhorst, M. C. 2008.  Protocol for Using and Interpreting IRIS Tubes.