Simple and Reliable Approach for Quantifying IRIS Tube Data

The recent use of IRIS (indicator of reduction in soils) tubes by wetland scientists and approval of their use by the National Technical Committee for Hydric Soils has required some simple means for quantifying paint removed from the tubes. The cylindrical shape of the tubes has generally made scanning or other automated processes difficult. Visual estimations are commonly made, but recent work has pointed out substantial errors from visual estimations and also a high variation among individuals using this approach. This note describes a simple and reliable method for quantifying paint removed from IRIS tubes by placing a transparent mylar grid around the tube, physically marking the grid, and then counting the marked sectors. This method, which requires approximately 8 min per tube, is much more accurate and the variation between individuals making the same evaluations is far smaller than when making visual estimations.