Field Indicators of Hydric Soils in the United States - ITC

Field Indicators of Hydric Soilswater through the landscape. Significant changes inparent material or lithologic discontinuities in thesoil can affect the hydrologic properties of the soil.After exploratory observations have been madesufficient to understand the soil-hydrologic relationshipsat the site, subsequent excavations may thenbe shallower if identification of appropriate indicatorsallows.To Comment on the IndicatorsThe Indicators are revised and updated as field dataare collected to improve our understanding of hydricsoil processes (fig. 4). Revisions, additions, and othercomments regarding field observations of hydric soilconditions that cannot be documented using thepresently recognized Indicators are welcome; however,any modifications and additions must be approvedby NRCS and NTCHS. Guidelines for requestingchanges to field indicators are as follows:1. Adding indicators or changing existing indicators—Minimally,the following should accompanyall requests for additions and changes to existinghydric soil indicators in Field Indicators of HydricSoils in the United States:(a) Detailed pedon descriptions of at least threepedons that document the addition or changeand detailed pedon descriptions of threeneighboring nonhydric pedons.(b) Detailed vegetative data collected to representthe vegetation of the six pedons.(c) Saturation/inundation data and redox potential(Eh) data for a duration that captures thesaturation cycle (dry-wet-dry) of at least oneof the hydric pedons and one of the nonhydricpedons. Precipitation and in situ soil-water pHdata from the same sites should also be provided.Monitoring instrumentation should beinstalled according to the Hydric Soil TechnicalStandard in Technical Note 11 (http://soils.usda.gov/soil_use/hydric/hstn.htm).2. Adding a test indicator—Minimally, the followingshould accompany all requests for adding atest indicator to Field Indicators of Hydric Soilsin the United States:(a) Detailed pedon descriptions of at least threepedons that document the test indicator anddetailed pedon descriptions of three neighboringnonhydric pedons.(b) Detailed vegetative data collected to representthe vegetation of the six pedons.Figure 4.Proper installation of the right kinds ofmonitoring devices is important to obtainapproval of changes and additions to the hydricsoil indicators.3. All requests involving 1 and 2 above additionallyrequire a short written plan that(a) Identifies the problem,(b) Explains the rationale for the request, and(c) Provides the following:– person responsible and point of contact(e–mail and mail addresses and phonenumber)– timeline for supporting data and final reportto be delivered to NTCHS– timeline needed for final NTCHS decision– partners involved in projectRequests and data should be sent to:Wade Hurt, ChairNTCHS Field Indicator SubcommitteeP.O. Box 110290University of FloridaGainesville, FL 32611-0290e-mail: Wade_Hurt@mail.ifas.ufl.edu4 (430, FIHS, Ver. 5.01, March 2003)