Hydric Soils Technical Note 10
Additional changes to "Field Indicators of Hydric Soils in the United States" (Version 4.0, March 1998).
Send comments to Wade Hurt.
The NTCHS met in Houston (Stafford), Texas in May 2000 and made the following changes and corrections.
Change 1: On page 14, F3, column 1, definition of Depleted Matrix, insert the following sentence: The minimum thickness requirement is 5 cm (2 in.) if the depleted matrix is entirely within the upper 15 cm (6 in.) of the mineral soil.
On page 20, column 1, add the following test indicator:
TA3. Coast Prairie Redox. For use in MLRA 150A of LRR T. A layer starting within 15 cm (6 in.) of the soil surface that is at least 10 cm (4 in.) thick and has a matrix chroma 3 or less with 2% or more distinct or prominent redox concentrations as soft masses and/or pore linings.
Coast Prairie Redox User Notes: These hydric soils occur mainly on depressional landforms and portions of the intermound landforms on the Lissie Formation. Redox concentrations occur mainly as iron dominated pore linings (Vepraskas, 1994). Common to many redox concentrations are required. Chroma 3 matrices are allowed because they may be the color of stripped sand grains or because few to common sand size reddish chert particles occur and may prevent obtaining chroma 2 or less.
Change 3: On page 22, TF7, column 1, last sentence in Definition of the indicator should read as follows: The layer(s) above the depleted or gleyed matrix have hue 10YR or yellower, value 2.5 or less and chroma of 1 or less to a depth of 30 cm (12 in.) and value 3 or less and chroma 1 or less in the remainder of the epipedon.
Change 4: On page 30, the following reference is added: U.S. Department of Agriculture, Soil Survey Staff, 1999. Soil Taxonomy: A basic system of soil classification for making and interpreting soil surveys. USDA Agricultural Handbook 436. U.S. Govt. Printing Off., Washington, DC.