Proposed Amendments to Soil Taxonomy to Accommodate Subaqueous Soils.
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December 2008
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The following is a draft copy of a proposed amendment to Soil Taxonomy to better classify subaqueous and submerged soils. The proposed amendments were developed by Dr. Mark Stolt, Professor of Pedology and the University of Rhode Island and are currently under review by the National Cooperative Soil Survey. Please send comments to Mark Stolt - mstolt@uri.edu
Jump to Wassists - are subaqueous Histosols. Defined as Histosols that have a positive water potential at the soil surface for 90% of each day. These soils are the second suborder to classify out under Histosols after Folists. The formative element Wass is derived from the German (Swiss) word “wasser” for water.
Wassents - are subaqueous Entisols. Defined as Entisols that have a positive water potential at the soil surface for 90% of each day. These soils are the first suborder to classify out under Entisols. The formative element Wass is derived from the German (Swiss) word “wasser” for water.
Key to Great Groups
LAA. Wassents that have, in all horizons within 100 cm of the mineral soil surface, an electrical conductivity of <0.2 dS/m in a 5/1 by volume mixture of water and soil. Frasiwassents
LAB. Other Wassents that have less than 35 percent (by volume) rock fragments and a texture of loamy fine sand or coarser in all layers within the particle-size control section. Psammowassents
LAC. Other Wassents that have a horizon or horizons with a combined thickness of at least 15 cm within 50 cm of the mineral soil surface that contains sulfidic materials. Sulfiwassents
LAD. Other Wassents that have, in all horizons at a depth between 20 and 50 cm below the mineral soil surface, both an n value of more than 0.7 and 8 percent or more clay in the fine earth fraction. Hydrowassents
LAE. Other Wassents that have either 0.2 percent or more organic carbon of Holocene age at a depth of 125 cm below the mineral soil surface or an irregular decrease in content of organic carbon from a depth of 25 cm to a depth of 125 cm or to a densic, lithic, or paralithic contact if shallower. Fluviwassents
LAF. Other Wassents. Haplowassents
Key to Subgroups
LAEA. Fluviwassents that have a horizon or horizons with a combined thickness of at least 15 cm within 100 cm of the mineral soil surface that contains sulfidic materials. Sulfic Fluviwassents
LAEB. Other Fluviwassents that have a lithic contact within 100 cm of the mineral soil surface. Lithic Fluviwassents
LAEC. Other Fluviwassents that have a buried layer of organic soil materials, 20 cm or more thick, that has its upper boundary within 100 cm of the mineral soil surface. Thapto-Histic Fluviwassents
LAED. Other Fluviwassents that have a chroma of 3 or more in 40% or more of the matrix of one or more horizons between a depth of 15 and 100 cm from the soil surface. Aeric Fluviwassents
LAEE. Other Fluvawassents. Typic Fluviwassents
Key to Subgroups
LAAA. Frasiwassents that have, in all horizons at a depth between 20 and 50 cm below the mineral soil surface, both an n value of more than 0.7 and 8 percent or more clay in the fine earth fraction. Hydric Frasiwassents
LAAB. Other Frasiwassents that have a lithic contact within 100 cm of the mineral soil surface. Lithic Frasiwassents
LAAC. Other Frasiwassents that have less than 35 percent (by volume) rock fragments and a texture of loamy fine sand or coarser in all layers within the particle-size control section. Psammic Frasiwassents
LAAD. Other Frasiwassents that have a buried layer of organic soil materials, 20 cm or more thick, that has its upper boundary within 100 cm of the mineral soil surface. Thapto-Histic Frasiwassents
LAAE. Other Frasiwassents that have either 0.2 percent or more organic carbon of Holocene age at a depth of 125 cm below the mineral soil surface or an irregular decrease in content of organic carbon from a depth of 25 cm to a depth of 125 cm or to a densic, lithic, or paralithic contact if shallower. Fluvic Frasiwassents
LAAF.Other Frasiwassents that have a chroma of 3 or more in 40% or more of the matrix of one or more horizons between a depth of 15 and 100 cm from the soil surface. Aeric Frasiwassents
LAAG. Other Frasiwassents. Typic Frasiwassents
Key to Subgroups
LAFA. Haplowassents that have a horizon or horizons with a combined thickness of at least 15 cm within 100 cm of the mineral soil surface that contains sulfidic materials. Sulfic Haplowassents
LAFB. Haplowassents that have a lithic contact within 100 cm of the mineral soil surface. Lithic Haplowassents
LAFC. Other Haplowassents that have a chroma of 3 or more in 40% or more of the matrix of one or more horizons between a depth of 15 and 100 cm from the soil surface. Aeric Haplowassents
LAFD. Other Haplowassents Typic Haplowassents
Key to Subgroups
LADA. Hydrowassents that have a horizon or horizons with a combined thickness of at least 15 cm within 100 cm of the mineral soil surface that contains sulfidic materials. Sulfic Hydrowassents
LADB. Other Hydrowassents that have, in all horizons at a depth between 20 and 100 cm below the mineral soil surface, both an n value of more than 0.7 and 8 percent or more clay in the fine earth fraction. Grossic Hydrowassents
LADC. Other Hydrowassents that have a lithic contact within 100 cm of the mineral soil surface. Lithic Hydrowassents
LADD. Other Hydrowassents that have a buried layer of organic soil materials, 20 cm or more thick, that has its upper boundary within 100 cm of the mineral soil surface. Thapto-Histic Hydrowassents
LADE. Other Hydrawassents. Typic Hydrowassents
Key to Subgroups
LABA. Psammawassents that have a horizon or horizons with a combined thickness of at least 15 cm within 100 cm of the mineral soil surface that contains sulfidic materials. Sulfic Psammowassents
LABB. Psammawassents that have a lithic contact within 100 cm of the mineral soil surface. Lithic Psammowassents
LABC. Other Psammowassents that have either 0.2 percent or more organic carbon of Holocene age at a depth of 125 cm below the mineral soil surface or an irregular decrease in content of organic carbon from a depth of 25 cm to a depth of 125 cm or to a densic, lithic, or paralithic contact if shallower. Fluventic Psammowassents
LABD. Other Psammowassents that have a chroma of 3 or more in 40% or more of the matrix of one or more horizons between a depth of 15 and 100 cm from the soil surface. Aeric Psammowassents
LABE. Other Psammowassents. Typic Psammowassents
Key to Subgroups
LACA. Sulfiwassents that have a lithic contact within 100 cm of the mineral soil surface. Lithic Sulfiwassents
LACB. Other Sulfiwassents that have, in some horizons at a depth between 20 and 50 cm below the mineral soil surface, either or both: 1. An n value of 0.7 or less; or 2. Less than 8 percent clay in the fine-earth fraction. Haplic Sulfiwassents
LACC. Other Sulfiwassents that have a buried layer of organic soil materials, 20 cm or more thick, that has its upper boundary within 100 cm of the mineral soil surface. Thapto-Histic Sulfiwassents
LACD. Other Sulfiwassents that have either 0.2 percent or more organic carbon of Holocene age at a depth of 125 cm below the mineral soil surface or an irregular decrease in content of organic carbon from a depth of 25 cm to a depth of 125 cm or to a densic, lithic, or paralithic contact if shallower. Fluvic Sulfiwassents
LACE. Other Sulfiwassents that have a chroma of 3 or more in 40% or more of the matrix of one or more horizons between a depth of 15 and 100 cm from the soil surface. Aeric Sulfiwassents
LACF. Other Sulfiwassents. Typic Sulfiwassents
Wassists are subaqueous Histosols. Defined as Histosols that have a positive water potential at the soil surface for 90% of each day. These soils are the second suborder to classify out under Histosols after Folists. The formative element Wass is derived from the German (Swiss) word “wasser” for water.
Key to Great Groups
BBA. Wassists that have, in all horizons within 100 cm of the mineral soil surface, an electrical conductivity of <0.2 dS/m in a 5/1 by volume mixture of water and soil. Frasiwassists
BBB. Other Wassists that have a horizon or horizons with a combined thickness of at least 15 cm within 50 cm of the mineral soil surface that contains sulfidic materials. Sulfiwassists
BBC. Other Wassists. Haplowassists
Key to Subgroups
BBAA. Other Frasiwassists that:
1. Have more thickness of fibric soil materials than any other kind of organic soil material either:
a. In the organic parts of the subsurface tier if there is no continuous mineral layer 40 cm or more thick that has its upper boundary within the subsurface tier; or
b. In the combined thickness of the organic parts of the surface and subsurface tiers if there is a continuous mineral layer 40 cm or more thick that has its upper boundary within the subsurface tier; and
2. Do not have a sulfuric horizon that has its upper boundary within 50 cm of the soil surface; and
3. Do not have sulfidic materials within 100 cm of the soil surface.
Fibric Frasiwassists
BBAB. Other Frasiwassists that have more thickness of sapric soil materials than any other kind of organic soil materials either:
1. In the organic parts of the subsurface tier if there is no continuous mineral layer 40 cm or more thick that has its upper boundary within the subsurface tier; or
2. In the combined thickness of the organic parts of the surface and subsurface tiers if there is a continuous mineral layer 40 cm or more thick that has its upper boundary within the subsurface tier.
Sapric Frasiwassists
BBAC. Other Frasiwassists.
Hemic Frasiwassists
BBBA. Other Sulfiwassists that have more thickness of fibric soil materials than any other kind of organic soil material either:
1. In the organic parts of the subsurface tier if there is no continuous mineral layer 40 cm or more thick that has its upper boundary within the subsurface tier; or
2. In the combined thickness of the organic parts of the surface and subsurface tiers if there is a continuous mineral layer 40 cm or more thick that has its upper boundary within the subsurface tier;
Fibric Sulfiwassists
BBBB. Other Sulfiwassists that have more thickness of sapric soil materials than any other kind of organic soil materials either:
1. In the organic parts of the subsurface tier if there is no continuous mineral layer 40 cm or more thick that has its upper boundary within the subsurface tier; or
2. In the combined thickness of the organic parts of the surface and subsurface tiers if there is a continuous mineral layer 40 cm or more thick that has its upper boundary within the subsurface tier.
Sapric Sulfiwassists
BBBC. Other Sulfiwassists.
Hemic Sulfiwassists
BBCA. Other Haplowassists that have more thickness of fibric soil materials than any other kind of organic soil material either:
1. In the organic parts of the subsurface tier if there is no continuous mineral layer 40 cm or more thick that has its upper boundary within the subsurface tier; or
2. In the combined thickness of the organic parts of the surface and subsurface tiers if there is a continuous mineral layer 40 cm or more thick that has its upper boundary within the subsurface tier;
Fibric Haplowassists
BBCB. Other Haplowassists that have more thickness of sapric soil materials than any other kind of organic soil materials either:
1. In the organic parts of the subsurface tier if there is no continuous mineral layer 40 cm or more thick that has its upper boundary within the subsurface tier; or
2. In the combined thickness of the organic parts of the surface and subsurface tiers if there is a continuous mineral layer 40 cm or more thick that has its upper boundary within the subsurface tier.
Sapric Haplowassists
BBCC. Other Haplowassists.
Hemic Haplowassists
