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https://hdl.handle.net/11681/6517| Title: | Factors controlling the formation of oxidized root channels : a review and annotated bibliography |
| Authors: | Mendelssohn, I. A. |
| Keywords: | Iron plaque Root oxygen loss Root concretions Root deposits Water logging Wetlands Wetland delineation Wetland hydrologic indicators Hydrology Wetland ecology Aquatic plants Roots |
| Publisher: | U.S. Army Engineer Waterways Experiment Station |
| Series/Report no.: | Technical Report (Wetlands Research Program (U.S.)) ; no. Technical Report WRP-DE-5 |
| Abstract: | Although root plaques and associated oxidized root channels are used for wetland identification as field indicators of wetland hydrology, little information is available concerning their reliability and the environmental and biotic factors controlling their formation. Therefore, the objectives of this study were to (A.) provide an annotated bibliography of literature concerning root iron plaques, (B.) describe and evaluate the current state of knowledge of the factors controlling the formation of iron plaques, and (C.) recommend research to address information gaps. Both abiotic and biotic factors control the presence and degree of iron plaque formation. The most important abiotic factor is the availability of soil iron. However, the effect of site-variation in soil physico-chemical characteristics, e.g., texture, organic matter, pH, Eh, and soil fertility, on iron availability and the formation and persistence of root plaque and oxidized root channels have not been adequately investigated. Although the oxidizing capacity of the plant root is the most important biotic factor controlling plaque formation, only a limited number of wetland species have been evaluated for this ability; therefore, species-specific differences are generally unknown. Unlike some of the other hydrologic indicators used in wetland delineation (e.g., water marks on trees or sediment deposits), root plaques and oxidized root channels indicate soil saturation for a sufficient period to produce anaerobic soil conditions. Additionally, when found in conjunction with a living root, oxidized root channels indicate that the anaerobic conditions occurred within the life span of the plant root. Therefore, the presence of oxidized root channels and iron plaque surrounding living roots is a relatively good indicator of wetland hydrologic conditions. However, until more is known about the relative abilities of different plant species to produce oxidized root channels, the temporal persistence of the root iron plaque, and the role soil chemistry plays in controlling plaque formation, the absence of oxidized root channels, in itself, should not be used to indicate the absence of a wetland. |
| Description: | Technical Report |
| Gov't Doc #: | Technical Report WRP-DE-5 |
| Rights: | Approved for public release; distribution is unlimited. |
| URI: | http://hdl.handle.net/11681/6517 |
| Size: | 39 pages |
| Types of Materials: | |
| Appears in Collections: | Technical Report |
Files in This Item:
| File | Description | Size | Format | |
|---|---|---|---|---|
| TR-WRP-DE-5.pdf | 8.94 MB | Adobe PDF |  View/Open |