Field Indicators of Hydric Soils in the United States - ITC

Field Indicators of Hydric SoilsContentsForeword ........................................................................................ iLocation of Indicators by page ................................................... ivIntroduction ....................................................................................1Concept ...........................................................................................1Cautions ..........................................................................................3Procedure .......................................................................................3To Comment on the Indicators .....................................................4Field Indicators of Hydric Soils .............................................5All soils ...................................................................................5Sandy soils .............................................................................9Loamy and clayey soils ......................................................13Test Indicators of Hydric Soils .............................................20All soils .................................................................................20Sandy soils .......................................................................... 21Loamy and clayey soils ..................................................... 21References ....................................................................................24Glossary ........................................................................................25AppendixesAppendix A: Indicators by Land Resource Region ................31Appendix B: Indicator Correlations ....................................... 32(430, FIHS, Ver. 5.01, March 2003) iii

Field Indicators of Hydric SoilsLocation of Indicators by pageAll soilsA1 Histosol ...................................................... 5A2 Histic Epipedon ........................................ 5A3 Black Histic ...............................................5A4 Hydrogen Sulfide ......................................6A5 Stratified Layers ....................................... 6A6 Organic Bodies. ........................................ 7A7 5 cm Mucky Mineral .................................8A8 Muck Presence. ........................................ 8A9 1 cm Muck .................................................9A10 2 cm Muck .................................................9TA1 Playa Rim Stratified Layers ................... 20TA2 Structureless Muck ................................ 20TA3 Coast Prairie Redox ............................... 20Sandy soilsS1 Sandy Mucky Mineral .............................. 9S2 2.5 cm Mucky Peat or Peat ......................9S3 5 cm Mucky Peat or Peat ....................... 10S4 Sandy Gleyed Matrix .............................. 10S5 Sandy Redox ........................................... 10S6 Stripped Matrix ....................................... 10S7 Dark Surface ........................................... 12S8 Polyvalue Below Surface ....................... 12S9 Thin Dark Surface .................................. 13S10 Alaska Gleyed ......................................... 13TS1 Iron Staining ............................................ 21TS2 Thick Sandy Dark Surface ..................... 21TS3 Dark Surface 2 ........................................ 21TS4 Sandy Neutral Surface ........................... 21TS5 Chroma 3 Sandy Redox ......................... 21Loamy and clayey soilsF1 Loamy Mucky Mineral ........................... 13F2 Loamy Gleyed Matrix ............................. 14F3 Depleted Matrix ...................................... 14F4 Depleted Below Dark Surface ............... 15F5 Thick Dark Surface ................................ 15F6 Redox Dark Surface ............................... 16F7 Depleted Dark Surface ........................... 17F8 Redox Depressions ................................ 17F9 Vernal Pools ............................................ 17F10 Marl .......................................................... 18F11 Depleted Ochric ...................................... 18F12 Iron/Manganese Masses ......................... 18F13 Umbric Surface ....................................... 19F14 Alaska Redox Gleyed ............................. 19F15 Alaska Gleyed Pores .............................. 19F16 High Plains Depressions ........................ 20TF1 ? cm Mucky Peat or Peat ....................... 21TF2 Red Parent Material ............................... 21TF3 Alaska Concretions ................................ 22TF4 2.5Y/5Y Below Dark Surface ................. 22TF5 2.5Y/5Y Below Thick Dark Surface ...... 22TF6 Calcic Dark Surface ............................... 22TF7 Thick Dark Surface 2/1 .......................... 22TF8 Redox Spring Seeps. .............................. 23TF9 Delta Ochric ............................................ 23TF10 Alluvial Depleted Matrix ........................ 23TF11 Reduced Vertic ........................................ 23iv (430, FIHS, Ver. 5.01, March 2003)

Field Indicators of Hydric Soils inthe United StatesIntroductionField Indicators of Hydric Soils in the UnitedStates (hereafter referred to as Indicators) is a guideto help identify and delineate hydric soils in the field(fig. 1). Indicators are not intended to replace orrelieve the requirements contained in the definitionof a hydric soil. The list of Indicators is considered tobe dynamic; changes and additions are anticipatedannually. The section To Comment on the Indicatorsprovides guidance to recommend changes, deletions,and additions. Any modifications to the Indicatorsmust be approved by NRCS and the National TechnicalCommittee for Hydric Soils. To properly use theIndicators, a basic knowledge of soil landscaperelationships and soil survey procedures is necessary.The indicators are designed to be regionally specific.Each indicator provides the Land Resource Regions(LRRs) or the Major Land Resource Areas (MLRAs)in which it can be used. The geographic extent ofLRRs (fig. 2) and MLRAs are defined in USDA AgricultureHandbook 296 (USDA, SCS, 1981). LRR specificIndicators are listed in appendix A and describedin section Field Indicators of Hydric Soils.The indicators are used to identify the hydric soilcomponent of wetlands; however, some hydric soilsdo not have any of the currently listed indicators.Therefore, the absence of any listed indicator doesnot exclude the soil from being classed as hydric.Such soils should be studied and their characteristicmorphologies identified for inclusion in this guide.days. Saturation or inundation when combined withmicrobial activity in the soil causes a depletion ofoxygen. This anaerobiosis promotes biogeochemicalprocesses, such as the accumulation of organicmatter and the reduction, translocation, and/oraccumulation of iron and other reducible elements.These processes result in characteristic morphologiesthat persist in the soil during both wet and dryperiods, making them particularly useful for identifyinghydric soils.Figure 1.The field indicators are to be used to delineatehydric soils. The soil on the right is hydric thathas the Indicator S6 Stripped Matrix starting ata depth of about 14 cm, and the soil on the leftis nonhydric with the Stripped Matrix starting ata depth of about 18 cm.ConceptHydric soils are defined as soils that formed underconditions of saturation, flooding, or ponding longenough during the growing season to develop anaerobicconditions in the upper part of the soil (FederalRegister, July 13, 1994).Nearly all hydric soils exhibit characteristic morphologiesthat result from repeated periods of saturationor inundation, or both, for more than a few(430, FIHS, Ver. 5.01, March 2003) 1

CautionsSome hydric soils have morphologies that are difficultto interpret or seem inconsistent with the landscape,vegetation, or hydrology. Such soils includethose formed in grayish or reddish parent materials;soils that have high pH or low organic matter content;Mollisols and Vertisols; soils that have relictredoximorphic features; and disturbed soils, such ascultivated soils and filled areas.Field Indicators of Hydric Soilsoften contain no visible redoximorphic features. Inmany sites making exploratory observations to ameter or more is necessary. These observationsshould be made with the intent of documenting andunderstanding the variability in soil properties andhydrologic relationships on the site.Depths used in the Indicators are measured from themuck or mineral soil surface unless otherwise indicated.All colors refer to moist Munsell colors (fig. 3).Soil that is artificially drained or protected, for instance,by levees, is hydric if the soil in its undisturbedstate would meet the definition of a hydric soil. This soilshould also have at least one of the Indicators.Morphological features of hydric soils indicate thatsaturation and anaerobic conditions have existedunder either contemporary or former (recent) hydrologicregimes. Features that do not reflect contemporaryor recent hydrologic conditions of saturation andanaerobiosis are relict features. Typically, contemporaryand recent hydric soil morphologies have diffuseboundaries; relict hydric soil features have sharpboundaries. When soil morphology seems inconsistentwith the landscape, vegetation, or observable hydrology,the assistance of an experienced soil or wetlandscientist may be needed to determine whether the soilis hydric.Soil colors specified in the Indicators do not havedecimal points listed; however, colors do occur betweenMunsell chips. Soil colors should not berounded to qualify as meeting an indicator. For example,a soil matrix that has a chroma between 2 and3 should be listed as having a chroma of 2+. This soilmaterial does not have a chroma 2 and would notmeet any indicator that requires a chroma 2 or less.Particular attention should be paid to changes intopography over short distances (microtopography).Small changes in elevation may result in repetitivesequences of hydric/nonhydric soils. The delineationof individual areas of hydric and nonhydric soils maybe difficult.Often the dominant condition (hydric/nonhydric) isthe only reliable interpretation. The shape of thelocal landform can greatly affect the movement ofProcedureTo document a hydric soil, first remove all loose leafmatter, needles, bark, and other easily identifiedplant parts to expose the surface. Dig a hole anddescribe the soil profile to a depth of at least 50 cm(20 in). Using the completed soil description specifywhich Indicators have been matched.Deeper examination of soil may be required wherefield indicators are not easily seen within 50 cm(20 in) of the surface. It is always recommended thatsoils be excavated and described as deep as necessaryto make reliable interpretations. For example,examination to less than 50 cm (20 in) may suffice insoils that have a surface horizon of organic materialor mucky mineral material because these shalloworganic accumulations only occur in hydric soils.Conversely, depth of excavation is often greater than50 cm (20 in) in Mollisols because the upper horizonsof these soils mask the effect of organic material andFigure 3.Indicator F6 Redox Dark Surface. The left ismoist and the right is dry. Most commonlymoist soil colors are to be used when identifyingand delineating hydric soils.(430, FIHS, Ver. 5.01, March 2003) 3

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)

Field Indicators of Hydric SoilsField Indicators of Hydric Soils in the UnitedStates is structured as follows:1. Alpha-numeric listing2. Short name3. Applicable Land Resource Regions (LRRs)4. Description of the field indicator5. User notesFor example, A1 indicates the first indicator for allsoils; Histosol or Histel is the short name; the indicatoris for use in all LRRs; classifies as a Histosolexcept Folists is the field indicator description; andhelpful user notes are added.All soilsAll soils refers to soils that have any USDA soiltexture. Unless otherwise indicated, all minerallayers above any of the Indicators have dominantchroma 2 or less, or the layer(s) with dominantchroma of more than 2 is less than 15 cm (6 in) thick.Also, unless otherwise indicated, nodules and concretionsare not considered to be redox concentrations.Use the following Indicators regardless of texture.Histic Epipedon User Notes: Most histic epipedonsare surface horizons 20 cm (8 in) or more thick oforganic soil material. Aquic conditions or artificialdrainage are required. See Soil Taxonomy, (USDA,NRCS, Soil Survey Staff 1999). Slightly lower organiccarbon contents are allowed in plowed soils (ibid.).See glossary for definitions. See figure 37 (organicsoil material) in the glossary for organic carbonrequirements.A3. Black Histic. For use in all LRRs except W, X,and Y; for testing in LRRs W, X, and Y. A layer ofpeat, mucky peat, or muck 20 cm (8 in) or morethick starting within the upper 15 cm (6 in) ofthe soil surface having hue 10YR or yel-lower,value 3 or less, and chroma 1 or less (fig. 6).Black Histic User Notes: Unlike indicator A2 thisindicator does not require proof of aquic conditionsor artificial drainage. See glossary for definitions ofpeat, mucky peat, and muck. See figure 37 (organicsoil material) in the glossary for organic carbonrequirements.A1. Histosol (for use in all LRRs) or Histel (foruse in LRRs with permafrost). Classifies as aHistosol (except Folist) or as a Histel (exceptFolistel).Histosol User Notes: A Histosol has 40 cm (16 in)or more of the upper 80 cm (32 in) as organic soilmaterial (fig. 5). Organic soil material has an organiccarbon content (by weight) of 12 to 18 percent ormore, depending on the clay content of the soil. Thematerial includes muck (sapric soil material), muckypeat (hemic soil material), or peat (fibric soil material).See glossary for definition of muck, muckypeat, peat, and organic soil material. See figure 37(organic soil material) in the glossary for organiccarbon requirements. Histels are similar to Histosolsexcept they are underlain by permafrost.A2. Histic Epipedon. For use in all LRRs except W,X, and Y; for testing in LRRs W, X, and Y. A histicepipedon.Figure 5.Indicator A1 Histosols. Muck (sapric soilmaterial) is more than 80 cm thick. Scale isfeet (R) and m (L).(430, FIHS, Ver. 5.01, March 2003) 5

Field Indicators of Hydric SoilsFigure 6.Indicator A3 Black Histic. Proof of aquicconditions is not required. Scale is inches (R)and cm (L).observed. Individual strata are dominantly less than2.5 cm (1 in) thick. A hand lens is an excellent tool toaid in the identification of this indicator. Many alluvialsoils have stratified layers at greater depths;these are not hydric soils. Many alluvial soils havestratified layers at the required depths, but lackchroma 2 or less; these do not fit this indicator.Stratified layers occur in any type soil material (figs.7 and 8).Figure 7.Indicator A5 Stratified Layers is sandy. Scale isinches.A4. Hydrogen Sulfide. For use in all LRRs. Ahydrogen sulfide odor within 30 cm (12 in) ofthe soil surface.Hydrogen Sulfide User Notes: The rotten egg smellindicates that sulfate-sulfur has been reduced, andtherefore the soil is anaerobic. In most hydric soilsthe sulfidic odor is only present when the soil issaturated and anaerobic.A5. Stratified Layers. For use in LRRs F, K, L, M,N, O, P, R, S, T, and U; for testing in LRRs V and Z.Several stratified layers starting within theupper 15 cm (6 in) of the soil surface. One ormore of the layers has value 3 or less withchroma 1 or less, and/or it is muck, mucky peat,peat, or mucky modified mineral texture. Theremaining layers have value 4 or more andchroma 2 or less.Stratified Layers User Notes: Use of this indicatormay require assistance from a trained soil scientistthat has local experience. The minimum organiccarbon content of at least one layer of this indicatoris slightly less than required for Indicator A7 MuckyModified Mineral Texture: at least 70 percent of soilmaterial is covered, coated, or similarly masked withorganic matter. An undisturbed sample must beFigure 8.Indicator A5 in loamy material. Scale is inches(R) and cm (L).6 (430, FIHS, Ver. 5.01, March 2003)

Field Indicators of Hydric SoilsA7. 5 cm Mucky Mineral. For use in LRRs P, T, U,and Z. A mucky modified mineral surface layer 5cm (2 in) or more thick starting within 15 cm (6in) of the soil surface (fig. 12).5 cm Mucky Mineral User Notes: Mucky is a USDAtexture modifier for mineral soil. The organic carboncontent is at least 5 percent and ranges to as high as18 percent. The percentage requirement is dependentupon the clay content of the soil; the higher theclay content, the higher the organic carbon requirement.An example is mucky fine sand that has atleast 5 percent organic carbon, but not more thanabout 12 percent organic carbon. Another example ismucky sandy loam that has at least 7 percent organiccarbon, but not more than about 14 percent organiccarbon. See the glossary for the definition of muckymodified mineral texture. See figure 37 (organic soilmaterial) in the glossary for organic carbon requirements.A8. Muck Presence. For use in LRRs U, V, and Z. Alayer of muck that has a value 3 or less andchroma 1 or less within 15 cm (6 in) of the soilsurface (fig. 13).Muck Presence User Notes: The presence of muckof any thickness within 15 cm (6 in) is the only requirement.Normally this expression of anaerobiosisis at the soil surface; however, it may occur at anydepth within 15 cm (6 in). Muck is sapric soil materialwith at least 12 to 18 percent organic carbon.Organic soil material is called muck (sapric soilmaterial) if virtually all of the material has undergonesufficient decomposition such that plant partscannot be identified. Hemic (mucky peat) and fibric(peat) soil materials do not qualify. To determine ifmuck is present, first remove loose leaves, needles,bark, and other easily identified plant remains. Thisis sometimes called a leaf/root mat. Then examinefor decomposed organic soil material. Generally,muck is black and has a greasy feel; sand grainsshould not be evident. Hydric soil indicator determinationsare made below the leaf or root mat; however,root mats that meet the definition of hemic orfibric soil material are included in the decisionmakingprocess for Mucky Peat, Peat, Organic Bodies,or Histic Indicators. See the glossary for thedefinition of muck. See figure 37 (organic soil material)in the glossary for organic carbon requirements.Figure 12. Indicator A7 5 cm Mucky Mineral about 10 cmthick. Indicator S7 Dark Surface is alsopresent. Scale is inches (R) and cm (L).Figure 13. Indicators A8 Muck Presence and S7 DarkSurface. Muck is less than 1 cm thick and thedark surface is 18 cm thick. Scale is inches (R)and cm (L).8 (430, FIHS, Ver. 5.01, March 2003)

Field Indicators of Hydric SoilsA9. 1 cm Muck. For use in LRRs D, F, G, H, P,and T; for testing in LRRs I, J, and O. A layer ofmuck 1 cm (0.5 in) or more thick with value 3or less and chroma 1 or less starting within 15cm (6 in) of the soil surface.1 cm Muck User Notes: Unlike Indicator A8 MuckPresence, there is a minimum thickness requirementof 1 cm. Normally this expression of anaerobiosis isat the soil surface; however, it may occur at anydepth within 15 cm (6 in). Muck is sapric soil materialwith at least 12 to 18 percent organic carbon.Organic soil material is called muck (sapric soilmaterial) if virtually all of the material has undergonesufficient decomposition to limit recognition ofthe plant parts. Hemic (mucky peat) and fibric (peat)soil materials do not qualify. To determine if muck ispresent, first remove loose leaves, needles, bark, andother easily identified plant remains. This is sometimescalled a leaf/root mat. Then examine for decomposedorganic soil material. Generally, muck isblack and has a greasy feel; sand grains should not beevident. Hydric soil indicator determinations aremade below the leaf or root mat; however, root matsthat meet the definition of hemic or fibric soil materialare included in the decisionmaking process forMucky Peat, Peat, Organic Bodies, or Histic Indicators.See the glossary for the definition of muck. Seefigure 37 (organic soil material) in the glossary fororganic carbon requirements.A10. 2 cm Muck. For use in LRRs M and N; fortesting in LRRs A, B, C, E, K, L, S, W, X, Y, and Z. Alayer of muck 2 cm (0.75 in) or more thick withvalue 3 or less and chroma 1 or less startingwithin 15 cm (6 in) of the soil surface.2 cm Muck User Notes: This Indicator requires aminimum muck thickness of 2 cm. Normally thisexpression of anaerobiosis is at the soil surface;however, it may occur at any depth within 15 cm(6 in). Muck is sapric soil material with at least 12 to18 percent organic carbon. Organic soil material iscalled muck (sapric soil material) if virtually all ofthe material has undergone sufficient decompositionto limit recognition of the plant parts. Hemic (muckypeat) and fibric (peat) soil materials do not qualify.To determine if muck is present, first remove looseleaves, needles, bark, and other easily identifiedplant remains. This is sometimes called a leaf/rootmat. Then examine for decomposed organic soilmaterial. Generally, muck is black and has a greasyfeel; sand grains should not be evident. Hydric soilindicator determinations are made below the leaf orroot mat; however, root mats that meet the definitionof hemic or fibric soil material are included in thedecisionmaking process for Mucky Peat, Peat, OrganicBodies, or Histic Indicators. See the glossaryfor the definition of muck. See figure 37 (organic soilmaterial) in the glossary for organic carbon requirements.Sandy soilsSandy soils refers to those soils that have a USDAtexture of loamy fine sand and coarser. Unless otherwiseindicated, all mineral layers above any of theIndicators have dominant chroma 2 or less, or thelayer(s) with dominant chroma of more than 2 is lessthan 15 cm (6 in) thick. In addition, unless otherwiseindicated, nodules and concretions are not consideredto be redox concentrations. Use the following sandyIndicators for sandy mineral soil materials:S1. Sandy Mucky Mineral. For use in all LRRsexcept W, X, and Y. A mucky modified sandy minerallayer 5 cm (2 in) or more thick startingwithin 15 cm (6 in) of the soil surface.Sandy Mucky Mineral User Notes: Mucky is aUSDA texture modifier for mineral soils. The organiccarbon content is at least 5 percent and ranges to ashigh as 14 percent for sandy soils. The percent-agerequirement is dependent upon the clay content ofthe soil; the higher the clay content, the higher theorganic carbon requirement. An example is muckyfine sand that has at least 5 percent organic carbon,but not more than about 12 percent organic carbon.See the glossary for the definition of mucky modifiedmineral texture. See figure 37 (organic soilmaterial) in the glossary for organic carbon requirements.S2. 2.5 cm Mucky Peat or Peat. For use in LRRs Gand H. A layer of mucky peat or peat 2.5 cm (1in) or more thick with value 4 or less andchroma 3 or less starting within 15 cm (6 in) ofthe soil surface underlain by sandy soil material.2.5 cm Mucky Peat and Peat User Notes: Muckypeat (hemic soil material) and peat (fibric soil material)having at least 12 to 18 percent organic carbon.Organic soil material is called peat if virtually all ofthe plant remains are sufficiently intact to permitidentification of plant remains. Mucky peat is an(430, FIHS, Ver. 5.01, March 2003) 9

Field Indicators of Hydric SoilsStripped Matrix User Notes: This indicator includesthe indicator previously named polychromaticmatrix (Florida Soil Survey Staff, 1992) aswell as the term streaking (Environmental Laboratory,1987) (app. B). Common to many (USDA, SoilSurvey Division Staff, 1993) areas of stripped (uncoated)soil materials 1 to 3 cm (0.5 to 1 in) in size isa requirement. Commonly the splotches of color havevalue 5 or more and chroma 1 and/or 2 (stripped) andchroma 3 and/or 4 (unstripped). The matrix may lackthe 3 and/or 4 chroma material. The mobilization andtranslocation of the oxides and/or organic matter isthe important process and should result in splotchycoated and uncoated soil areas (figs. 16, 17, and 18).Figure 16. Indicator S6 Stripped Matrix. The matrixstripped of iron oxides begins below a depth ofabout 10 cm. Scale is inches (R) and cm (L).Figure 15. Indicator S5 Sandy Redox. The redox massesoccur below a depth of about 10 cm. Scale isinches.Figure 17. Indicator S6 Stripped Matrix. The matrix strippedof organic matter begins beneath the surfacelayer. Scale is inches.(430, FIHS, Ver. 5.01, March 2003) 11

Field Indicators of Hydric SoilsS7. Dark Surface. For use in LRRs N, P, R, S, T, U,V, and Z. A layer 10 cm (4 in) or more thickstarting within the upper 15 cm (6 in) of the soilsurface with a matrix value 3 or less and chroma1 or less. At least 70 percent of the visiblesoil particles must be covered, coated, orsimilarly masked with organic material. Thematrix color of the layer immediately belowthe dark layer must have chroma 2 or less(fig. 19).Dark Surface User Notes: The organic carboncontent of this indicator is slightly less than requiredfor mucky. An undisturbed sample must beobserved. A 10X or 15X hand lens is an excellent toolto aid this decision. Many wet soils have a ratio ofabout 50 percent soil particles that are coveredor coated with organic matter and about 50 percentuncoated or uncovered soil particles, giving the soil asalt and pepper appearance. Where the percent ofcoverage is less than 70 percent, a Dark Surfaceindicator is not present.S8. Polyvalue Below Surface. For use in LRRs R,S, and T; for testing in LRRs K and L. A layer withvalue 3 or less and chroma 1 or less startingwithin 15 cm (6 in) of the soil surface underlainby a layer(s) where translocated organic matterunevenly covers the soil material forming adiffuse splotchy pattern. At least 70 percent ofthe visible soil particles in the upper layer mustbe covered, coated, or masked with organicmaterial. Immediately below this layer, the organiccoating occupies 5 percent or more of thesoil volume and has value 3 or less and chroma 1or less. The remainder of the soil volume hasvalue 4 or more and chroma 1 or less.Polyvalue Below Surface User Notes: This indicatordescribes soils with a very dark gray or blacksurface or near-surface layer less than 10 cm (4 in)thick underlain by a layer where organic matter hasbeen differentially distributed within the soil bywater movement (figs. 19 and 20). The mobilizationand translocation of organic matter results insplotchy coated and uncoated soil areas as describedin the Sandy Redox and Stripped Matrix Indicatorsexcept that for S8 the whole soil is in shades of blackand gray. The chroma 1 or less is critical because itlimits application of this indicator to only those soilsthat are depleted of iron. This indicator includes theindicator previously termed streaking (EnvironmentalLaboratory, 1987) (app. B).Figure 18. Indicator S6 Stripped Matrix. Close up of ovalstripped areas showing the associated decomposingroots.Figure 19. Indicator S7 Dark Surface. The dark surface is15 cm thick. The material below 15 cm meetsthe intent of Indicator S8 Polyvalue BelowSurface. Scale is inches.12 (430, FIHS, Ver. 5.01, March 2003)

Field Indicators of Hydric SoilsS9. Thin Dark Surface. For use in LRRs R, S, andT; for testing in LRRs K and L. A layer 5 cm (2 in)or more thick entirely within the upper 15 cm (6in) of the surface, with value 3 or less andchroma 1 or less. At least 70 percent of thevisible soil particles in this layer must be covered,coated, or masked with organic material.This layer is underlain by a layer(s) with value 4or less and chroma 1 or less to a depth of 30 cm(12 in) or to the spodic horizon, whichever isless.Thin Dark Surface User Notes: This indicatordescribes soils with a very dark gray or black nearsurfacelayer at least 5 cm (2 in) thick underlain by alayer where organic matter has been carried downwardby flowing water (fig. 20). The mobilization andtranslocation of organic matter results in an unevendistribution of organic matter in the eluvial (E)Figure 20. Indicator S8 Polyvalue Below Surface (R) andIndicator S9 Thin Dark Surface (L). Organicmatter has been mobilized and translocated. Aspodic horizon is not required but commonlyoccurs in soils with these indicators. Scale isinches.horizon. The chroma 1 or less is critical because itlimits application of this indicator to only those soilsthat are depleted of iron. This indicator commonlyoccurs in hydric Spodosols; however, a spodic horizonis not required.S10. Alaska Gleyed. For use in LRRs W, X, and Y.Dominant hue N, 10Y, 5GY, 10GY, 5G, 10G, 5BG,10BG, 5B, 10B, or 5PB, with value 4 or more inthe matrix, within 30 cm (12 in) of the mineralsurface, and underlain by hue 5Y or redder in thesame type of parent material.Alaska Gleyed User Notes: Gley colors are notsynonymous with gray colors. Gley colors are thosecolors that are on the gley page (Gretag/Macbeth.2000). They have hue N, 10Y, 5GY, 10GY, 5G, 10G,5BG, 10BG, 5B, 10B, or 5PB, with value 4 or more.Color comparison to underlying material must bebased on material of the same type or lithology.Loamy and clayey soilsLoamy and clayey soils refers to those soils withUSDA textures of loamy very fine sand and finer.Unless otherwise indicated, all mineral layers aboveany of the Indicators have dominant chroma 2 orless, or the layer(s) with dominant chroma of morethan 2 is less than 15 cm (6 in) thick. Also, unlessotherwise indicated, nodules and concretions are notconsidered to be redox concentrations. Use thefollowing loamy and clayey Indicators for loamy orclayey mineral soil materials:F1. Loamy Mucky Mineral. For use in all LRRsexcept N, R, S, V, W, X, and Y, those using A7, andMLRA 1 of LRR A. A mucky modified loamy orclayey mineral layer 10 cm (4 in) or more thickstarting within 15 cm (6 in) of the soil surface.Loamy Mucky Mineral User Notes: Mucky is aUSDA texture modifier for mineral soils. The organiccarbon is at least 8 percent, but can range to as highas 18 percent. The percentage requirement is dependentupon the clay content of the soil; the higher theclay content, the higher the organic carbon requirement.An example is mucky sandy loam that has atleast 8 percent organic carbon, but not more thanabout 14 percent organic carbon. See the glossary forthe definition of mucky modified mineral texture. Seefigure 37 (organic soil material) in the glossary fororganic carbon requirements.(430, FIHS, Ver. 5.01, March 2003) 13

Field Indicators of Hydric SoilsF2. Loamy Gleyed Matrix. For use in all LRRsexcept W, X, and Y. A gleyed matrix that occupies60 percent or more of a layer starting within 30cm (12 in) of the soil surface.Loamy Gleyed Matrix User Notes: Gley colors arenot synonymous with gray colors. Gley colors arethose colors that are on the gley pages (Gretag/Macbeth. 2000). They have hue N, 10Y, 5GY, 10GY, 5G,10G, 5BG, 10BG, 5B, 10B, or 5PB, with value 4 ormore. The gleyed matrix only has to be presentwithin 30 cm (12 in) of the surface. Soils with gleyedmatrices are saturated for a significant duration; thisis why no thickness of the layer is required (figs. 21and 22). See glossary for the definition of gleyedmatrix.Figure 21. Indicator F2 Loamy Gleyed Matrix. The gleyedmatrix begins at a depth of about 18 cm.Indicator F3 Depleted Matrix also occursbetween the gleyed matrix and the surfacelayer.F3. Depleted Matrix. For use in all LRRs except W,X, and Y. A layer with a depleted matrix that has60 percent or more chroma 2 or less that has aminimum thickness of either:a. 5 cm (2 in) if 5 cm (2 in) is entirelywithin the upper 15 cm (6 in) of the soil,orb. 15 cm (6 in) and starts within 25 cm(10 in) of the soil surface.Depleted Matrix User Notes: Redox concentrationsincluding iron/manganese soft masses or pore linings,or both, are required in soils with matrix colors of 4/1,4/2, and 5/2 (fig. 23). A, E and calcic horizons mayhave low chromas and high values and may thereforebe mistaken for a depleted matrix; however, they areexcluded from the concept of depleted matrix unlesscommon or many, distinct or prominent redox concentrationsas soft masses or pore linings are present.Redox concentrations are not required for soils withmatrix value 5 or more and chroma 1 or value 6 ormore and chroma 2 or 1 (fig. 24). See glossary for thecomplete definition of depleted matrix. The lowchroma matrix must be caused by wetness and not arelict or parent material feature.Figure 22. Indicator F2 Loamy Gleyed Matrix. The gleyedmatrix starts at the soil surface. Scale isinches.14 (430, FIHS, Ver. 5.01, March 2003)

Field Indicators of Hydric SoilsF4. Depleted Below Dark Surface. For use in allLRRs except W, X, and Y; for testing in LRRs W, X,and Y. A layer with a depleted matrix that has 60percent or more chroma 2 or less starting within30 cm (12 in) of the soil surface that has a minimumthickness of either:a. 15 cm (6 in),b. 5 cm (2 in) if the 5 cm (2 in) consists offragmental soil material (see glossary).The layer(s) above the depleted matrix has value3 or less and chroma 2 or less.Depleted Below Dark Surface User Notes: Thisindicator often occurs in Mollisols, but also applies tosoils that have umbric epipedons and dark coloredochric epipedons. For soils that have dark coloredepipedons greater than 30 cm (12 in) thick, useIndicator F5. Redox concentrations including iron/Figure 23. Indicator F3 Depleted Matrix. The chroma is 2below a depth of about 15 cm. Redox concentrationsare present. Scale is inches.manganese soft masses, pore linings, or both, arerequired in soils that have matrix colors of 4/1, 4/2,and 5/2. A, E, and calcic horizons may have lowchromas depleted matrix; however, they are excludedfrom the concept of depleted matrix unlesscommon or many, distinct or prominent redox concentrationsas soft masses or pore linings arepresent. See glossary for the definition of depletedmatrix.F5. Thick Dark Surface. For use in all LRRs exceptW, X, and, Y; for testing in LRRs W, X, and Y. Alayer at least 15 cm (6 in) thick with a depletedmatrix that has 60 percent or more chroma 2 orless (or a gleyed matrix) starting below 30 cm(12 in) of the surface. The layer(s) above thedepleted or gleyed matrix has hue N and value 3or less to a depth of 30 cm (12 in) and value 3 orless and chroma 1 or less in the remainder of theepipedon.Thick Dark Surface User Notes: The soil has ablack or very dark gray surface layer 30 cm (12 in)or more thick (figs. 25 and 26). The dark subsoil hasvalue 3 or less, and chroma 1 or less. Below the darkcolored epipedon is a depleted matrix or gleyedmatrix. This indicator is most often associated withoverthickened soils in concave landscape positions.Figure 24. Indicator F3 Depleted Matrix. The chroma is 1within a depth of about 10 to 15 cm. Redoxconcentrations are absent. Scale is inches.(430, FIHS, Ver. 5.01, March 2003) 15

Field Indicators of Hydric SoilsFigure 25. Indicator F5 Thick Dark Surface. A depletedmatrix is below the mollic epipedon. Scale isinches.Redox concentrations including iron/manganese softmasses or pore linings, or both, are required in soilsthat have matrix colors of 4/1, 4/2, and 5/2. A, E, andcalcic horizons may have low chromas and highvalues and may be mistaken for a depleted matrix.They are excluded, however, from the concept ofdepleted matrix unless common or many, distinct orprominent redox concentrations as soft masses orpore linings are present. See glossary for the definitionof depleted matrix.F6. Redox Dark Surface. For use in all LRRsexcept W, X, and Y; for testing in LRRs W, X, and Y.A layer at least 10 cm (4 in) thick entirelywithin the upper 30 cm (12 in) of the mineralsoil that has:a. matrix value 3 or less and chroma 1 orless and 2 percent or more distinct orprominent redox concentrations as softmasses or pore linings, orb. matrix value 3 or less and chroma 2 orless and 5 percent or more distinct orprominent redox concentrations as softmasses or pore linings.Figure 26. Indicator F5 Thick Dark Surface. Deep observationis often necessary.Redox Dark Surface User Notes: Redox concentrationsin high organic matter mineral soils with a darksurface are often difficult to see (figs. 27 and 28).The organic matter masks some or all of the concentrationsthat may be present. Careful examination isrequired to see what are often brownish mottles inthe darkened materials. In some instances, drying ofthe samples makes the concentrations (if present)easier to see. Dried colors, if used, need to havematrix chromas of 1 or 2, and the redox concentrationsneed to be distinct or prominent.In soils that are wet because of subsurface saturation,the layer immediately below the dark epipedonshould have a depleted or gleyed matrix. Soils thatare wet because of ponding or shallow, perched layerof saturation may not always have a depleted/gleyedmatrix below the dark surface. This morphology hasbeen observed in soils that have been compacted bytillage and other means. It is recommended thatdelineators evaluate the hydrologic source andexamine and describe the layer below the darkcolored epipedon when applying this indicator. Redoxconcentrations including iron/manganese softmasses or pore linings, or both, are required in soilsthat have matrix colors of 4/1, 4/2, and 5/2. A, E, andcalcic horizons may have low chromas and highvalues and may, therefore, be mistaken for a depletedmatrix; however, they are excluded from the16 (430, FIHS, Ver. 5.01, March 2003)

Field Indicators of Hydric Soilsconcept of depleted matrix unless common or many,distinct or prominent redox concentrations as softmasses or pore linings are present.Figure 27. Indicator F6 Redox Dark Surface. Prominentredox concentrations as soft masses and porelinings are present. Below the dark epipedon isindicator F4 Depleted Dark Surface. Scale iscm.F7. Depleted Dark Surface. For use in all LRRsexcept W, X, and Y; for testing in LRRs W, X, and Y.Redox depletions, with value 5 or more andchroma 2 or less, in a layer at least 10 cm(4 in) thick entirely within the upper 30 cm(12 in) of the mineral soil that has:a. matrix value 3 or less and chroma 1 orless and 10 percent or more redoxdepletions, orb. matrix value 3 or less and chroma 2 orless and 20 percent or more redoxdepletions.Depleted Dark Surface User Notes: Care should betaken not to mistake mixing of an E or calcic horizoninto the surface layer as depletions. The pieces of Eand calcic horizons are not redox depletions. Knowledgeof local conditions is required in areas where Eand/or calcic horizons may be present. In soils thatare wet because of subsurface saturation, the layerimmediately below the dark surface should have adepleted or gleyed matrix. Redox depletions shouldhave associated microsites with redox concentrationsthat occur as Fe pore linings or masses withinthe depletion(s) or surrounding the depletion(s).Figure 28. Indicator F6 Redox Dark Surface. Often, as inthis soil, the redox concentrations are small(fine).F8. Redox Depressions. For use in all LRRs exceptW, X, and Y; for testing in LRRs W, X, and Y. Inclosed depressions subject to ponding, 5 percentor more distinct or prominent redox concentrationsas soft masses or pore linings in a layer 5cm (2 in) or more thick entirely within theupper 15 cm (6 in) of the soil surface (fig. 29).Redox Depressions User Notes: This indicatoroccurs on depressional landforms, such as vernalpools, playa lakes, rainwater basins, grady ponds,and potholes; but not microdepressions on convex orplane landscapes.F9. Vernal Pools. For use in LRRs C and D. Inclosed depressions subject to ponding, presenceof a depleted matrix in a layer 5 cm (2 in) thickentirely within the upper 15 cm (6 in) of the soilsurface.Vernal Pools User Notes: Most often soils pondwater for two reasons: they occur on landscapepositions that collect water and they have a restrictivelayers(s) that prevents water from movingdownward through the soil. Normally this indicatoroccurs at the soil surface. Redox concentrationsincluding iron/manganese soft masses or pore linings,or both, are required in soils that have matrix(430, FIHS, Ver. 5.01, March 2003) 17

Field Indicators of Hydric Soilscolors of 4/1, 4/2, and 5/2. A, E, and calcic horizonsmay have low chromas and high values and may,therefore, be mistaken for a depleted matrix; however,they are excluded from the concept of depletedmartix unless common or many, distinct or prominentredox concentrations as soft masses or pore liningsare present.F10. Marl. For use in LRR U. A layer of marl thathas a value 5 or more starting within 10 cm (4in) of the soil surface (fig. 30).Marl User Notes: Marl is a limnic material depositedin water by precipitation of CaCO 3 by algae asdefined in Soil Taxonomy (USDA, NRCS, Soil SurveyStaff. 1999). It has a Munsell value 5 or more andreacts with dilute HCl to evolve CO 2 . Marl is not thecarbonatic substrate material associated with limestonebedrock. Some soils have materials with all theproperties of marl except they lack the requiredMunsell value. These soils are hydric if the requiredvalue is present within 10 cm (4 in) of the soil surface.Normally this indicator occurs at the soil surface.Figure 29. Indicator F8 Redox Depressions. This soil hasmainly iron redox concentrations in the upperpart and iron/manganese in the lower part.Scale is cm (L) and inches (R).F11. Depleted Ochric. For use in MLRA 151 ofLRR T. A layer(s) 10 cm (4 in) or more thickthat has 60 percent or more of the matrix withvalue 4 or more and chroma 1 or less. The layeris entirely within the upper 25 cm (10 in) of thesoil surface.Depleted Ochric User Notes: This indicator is applicableon accreting deltaic areas of the MississippiRiver.F12. Iron/Manganese Masses. For use in LRRs N,O, P, and T; for testing in LRR M. On flood plains,a layer 10 cm (4 in) or more thick with 40 percentor more chroma 2 or less, and 2 percent ormore distinct or prominent redox concentrationsas soft iron/manganese masses and diffuseboundaries. The layer occurs entirely within 30cm (12 in) of the soil surface. Iron/manganesemasses have value 3 or less and chroma 3 or less;most commonly they are black (fig. 31). Thethickness requirement is waived if the layer isthe mineral surface layer.Iron/Manganese Masses User Notes: These iron/manganese masses are usually small (2 to 5 mm) andhave a value and chroma 3 or less. They can be black.Figure 30. Indicator F10 Marl. This indicator is known tooccur only in south Florida. Scale is feet.18 (430, FIHS, Ver. 5.01, March 2003)

Field Indicators of Hydric SoilsThe low matrix chroma is because of wetness and isnot a relict or parent material feature. Iron/manganesemasses should not be confused with the largerand redder iron nodules associated with plinthite(USDA, NRCS, 2002) or with concretions that havesharp boundaries. This indicator occurs on floodplains of rivers, such as the Apalachicola, Congaree,Mobile, Savannah, and Tennessee Rivers.F13. Umbric Surface. For use in LRRs P and T. Indepressions and other concave landforms, alayer 25 cm (10 in) or more thick starting within15 cm (6 in) of the soil surface in which theupper 15 cm (6 in) must have value 3 or less andchroma 1 or less, and the lower 10 cm (4 in) ofthe layer must have the same colors as above orany other color that has a chroma 2 or less (fig.32).Umbric Surface User Notes: Thickness requirementsmay be slightly less than those required for anumbric epipedon. Microlows are not considered to beconcave landforms. Umbric surfaces on higherlandscape positions, such as side slopes dominatedby Humic Dystrudepts, are excluded.F14. Alaska Redox Gleyed. For use in LRRs W, X,and Y. A layer that has dominant matrix hue 5Ywith chroma 3 or less, or hue N, 10Y, 5GY, 10GY,5G, 10G, 5BG, 10BG, 5B, 10B, or 5PB, with 10percent or more redox concentrations as porelinings with value and chroma 4 or more. Thelayer occurs within 30 cm (12 in) of the soilsurface.Alaska Redox Gleyed User Notes: Presence of 10percent redox concentrations as pore linings in adominantly gleyed matrix (hue N, 10Y, 5GY, 10GY, 5G,10G, 5BG, 10BG, 5B, 10B, or 5PB with value 4 ormore); or hue 5Y with chroma 3 or less is required.Pore linings must have value and chroma 4 or more.F15. Alaska Gleyed Pores. For use in LRRs W, X,and Y. Presence of 10 percent hue N, 10Y, 5GY,10GY, 5G, 10G, 5BG, 10BG, 5B, 10B, or 5PB withvalue 4 or more in the matrix or along channelscontaining dead roots or no roots within 30 cm(12 in) of the soil surface. The matrix has dominantchroma 2 or less.Alaska Gleyed Pores User Notes: Presence of 10percent gleyed root channels within a low chromamatrix is required.Figure 32. Indicator F13 Umbric Surface. This umbricsurface is about 20 cm thick. Scale is inches.Figure 31. Indicator F12 Iron/Manganese Masses in a 40percent depleted matrix. Scale is inches.(430, FIHS, Ver. 5.01, March 2003) 19

Field Indicators of Hydric SoilsF16. High Plains Depressions. For use in MLRAs72 and 73 of LRR H; for testing in other MLRAs ofLRR H. In closed depressions subject to ponding,a mineral soil that has chroma 1 or less to adepth of at least 35 cm (13.5 in) and a layer atleast 10 cm (4 in) thick within the upper 35 cm(13.5 in) of the mineral soil that has either:a. 1 percent or more redox concentrations asnodules or concretions, orb. redox concentrations as nodules orconcretions with distinct or prominentcorona.High Plains Depressions User Notes: This indicatoris for closed depressions (FSA playas) in westernKansas, southwestern Nebraska, eastern Colorado,and southeastern Wyoming. It occurs in soils such asthe Ness and Pleasant series. The matrix color of the35 cm (13.5 in) layer must be a chroma 1 or less;chroma 2 matrix colors are excluded; value is usually3. The nodules/concretions are rounded, hard to veryhard, range in size from less than 1 mm to 3 mm, andmost commonly are black or reddish black. Thecorona usually are reddish brown, strong brown, oryellowish brown. The nodules/concretions can beremoved from the soil, and the corona (halos) willoccur as coatings on the concentration or will remainattached to the soil matrix. Use of 10X to 15X magnificationaids in the identification of these features.Test Indicators of Hydric SoilsThe Indicators listed before this section should betested for use in LRRs other than those listed. OtherIndicators for testing are listed below. This list oftest indicators is not extensive. Users of the Indicatorsare encouraged to submit descriptions of othersoil morphologies they think indicative of hydricsoils along with supporting data for inclusion insubsequent versions of Field Indicators of HydricSoils in the United States.All soilsTA1. Playa Rim Stratified Layers. For testing inLRR D. Stratified layers starting within the upper15 cm (6 in) of the soil surface. At least onelayer has value 3 or less and chroma 1 or less orit has value 2 or more and chroma 2 or less with2 percent or more distinct or prominent redoxconcentrations as soft masses or pore linings.The upper 15 cm (6 in) has dominant chroma 2or less.Playa Rim Stratified Layers User Notes: Unlikethe Indicator A5 Stratified Layers, this indicator doesnot require continuous chroma 2 or less. Thin layersof chroma 3 or higher may occur as long as the upper15 cm (6 in) is dominantly chroma 2 or less. A minimumamount of organic carbon is not required. Alayer that has redox concentrations is substitutionalfor the dark layer. This indicator occurs on sparselyvegetated playas and playa rims adjacent tononvegetated playas.TA2. Structureless Muck. For testing in MLRAs141, 143, 144b, 145, and 146 of LRR R. Startingwithin 15 cm (6 in) of the soil surface on concavepositions or in depressions, a layer of muck2 cm (0.75 in) or more thick that has no soilstructure.Structureless Muck User Notes: Nonhydric muckhorizons have low moisture content and are usuallyfluffy or have weak to moderate structure. Hydricmuck horizons are usually wet and amorphous or, ifdry, then are hard and difficult to rewet.TA3. Coast Prairie Redox. For use in MLRA 150Aof LRR T. A layer starting within 15 cm (6 in) ofthe soil surface that is at least 10 cm (4 in)thick and has a matrix chroma 3 or less with 2percent or more distinct or prominent redoxconcentrations as soft masses or pore linings, orboth.Coast Prairie Redox User Notes: These hydricsoils occur mainly on depressional landforms andportions of the intermound landforms on the LissieFormation. Redox concentrations occur mainly asiron dominated pore linings (Vepraskas, 1994). Commonto many redox concentrations are required.Chroma 3 matrices are allowed because they may be20 (430, FIHS, Ver. 5.01, March 2003)

Field Indicators of Hydric Soilslandscape position this indicator fails. It may benecessary to limit this indicator to concave landscapes.TF8. Redox Spring Seeps. For testing in LRR D. Alayer that has value 5 or more and chroma 3 orless with 2 percent or more distinct or prominentredox concentrations as soft masses or porelinings (fig. 34). The layer is at least 5 cm (2 in)thick and is within the upper 15 cm (6 in) of thesoil surface.Redox Spring Seeps User Notes: This indicator issimilar to Indicator F9 Vernal Pools. However, tomore fully correlate hydric soils to wetland vegetation,chroma 3 is included in this indicator as well asthe redox concentrations portions of the depletedmatrix concept. This indicator is not unique to depressionallandscapes; therefore, that requirement isdropped. As inferred, this indicator may occur inseeps and flow-through areas adjacent to springs andupslope end of drainageways as well as depressionalseeps surrounded by uplands.TF9. Delta Ochric. For testing in LRR O. A layer10 cm (4 in) or more thick that has 60 percentor more of the matrix with value 4 or more andchroma 2 or less, but has no redox concentrations.This layer occurs entirely within the upper30 cm (12 in) of the soil surface.Figure 34. Indicator TF8 Redox Spring Seeps withprominent redox concentrations. Scale is cm.Delta Ochric User Notes: This indicator is applicablein accreting areas of the Mississippi RiverDelta.TF10. Alluvial Depleted Matrix. For testing inLRRs M, N, and S. On frequently flooded floodplains, a layer with a matrix that has 60 percentor more chroma 3 or less with 2 percent redoxconcentrations as soft iron masses, startingwithin 15 cm (6 in) of the soil surface and extendingto a depth of more than 30 cm (12 in).TF11. Reduced Vertic. For testing in all LRRs thathave Vertisols and Vertic intergrades. In Vertisolsand Vertic intergrades, a positive reaction toalpha-alpha-Dipyridyl thata. is the dominant (60%or more) condition ofa layer at least 4 inches thick within theupper 12 inches (or at least 2 in thickwithin the upper 6 in) of the mineral ormuck soil surface,b. occurs for at least 7 continuous days and 28cumulative days, andc. occurs during a normal (within 16–84% ofprobable precipitation) or drier season andmonth.Please follow the procedures and note the considerationsin Hydric Soil Technical Note 8 (useof alpha-alpha-Dipyridyl).Reduced Vertic User Notes: The time requirementsfor this indicator were identified from research inMLRA 150A in LRR T (Gulf Coastal Prairies); these orslightly modified time requirements may be found toidentify wetland Vertisols and Vertic Intergrades inother parts of the Nation. These soils generally havea thick, dark surface horizon, but Indicators F4, F5,and F6 are often lacking; possibly due to masking ofredoximorphic features by organic carbon. Thesesoils are a special case of the Problem Soils withthick, dark A horizons listed in the 1987 Corps ofEngineers Wetlands Delineation Manual (EnvironmentalLaboratory, 1987).(430, FIHS, Ver. 5.01, March 2003) 23

Field Indicators of Hydric SoilsReferencesUnless otherwise noted the following referencesinclude definitions of terms used throughout thisdocument and have additional information concerningthe terms in the glossary of this document.Environmental Laboratory. 1987. Corps of EngineersWetland Delineation Manual, Technical ReportY–87–1. U.S. Army Engineers Waterways ExperimentStation, Vicksburg, MS.Federal Register. 1994. Changes in hydric soils of theUnited States. Washington, DC, July 13 (currentHydric Soil definition)Federal Register. 2002. Hydric soils of the UnitedStates. Washington, DC (current Hydric Soilcriteria).Gretag/Macbeth. 2000. Munsell® color. New Windsor,NY.Mausbach, M.J., and J.L. Richardson. 1994. BiogeochemicalProcesses in hydric soils. CurrentTopics in Wetland Biogeochemistry 1:68-127,Wetlands Biogeochemistry Institute, LouisianaState Univ. Baton Rouge, LA.National Research Council. 1995. Wetlands: characteristicsand boundaries. National AcademyPress, Washington, DC.Richardson, J.L., and M.J. Vepraskas (eds.). 2000.Wetland soils: their genesis, morphology, hydrology,landscapes and classification. CRCPress, Boca Raton, FL.Soil Science Society of America. 1987. Glossary ofSoil Science Terms. Soil Science Society ofAmerica, Madison, WI.Soil Science Society of America. 1993. Proceedingsof the Symposium on Soil Color, October 21–26,1990. San Antonio, TX. J.M. Bigham and E.J.Ciolkosz (eds.), Special Publ. #31, Soil ScienceSociety of America, Madison, WI.United States Department of Agriculture, NaturalResources Conservation Service. 1996. Fieldindicators of hydric soils in the United States,Ver. 3.2. G.W. Hurt, P.M. Whited, and R.F. Pringle(eds.).United States Department of Agriculture, NaturalResources Conservation Service. 1998. Fieldindicators of hydric soils in the United States,Ver. 4.0. G.W. Hurt, P.M. Whited, and R.F. Pringle(eds.).United States Department of Agriculture, NaturalResources Conservation Service. 1999. Soiltaxonomy: A basic system of soil classificationfor making and interpreting soil surveys. U.S.Dep. Agric. Handb. 436,Washington, DC.United States Department of Agriculture, NaturalResources Conservation Service. 2002. Fieldbook for describing and sampling soils. Compiledby P.J. Schoeneberger, D.A. Wysocki, E.C.Benham, and W.D. Broderson. National SoilSurvey Center, Lincoln, NE.United States Department of Agriculture, Soil ConservationService. 1981. Land resource Regionsand major land resource areas of the UnitedStates. Agric. Handb. 296. US Govt. Printing Off.,Washington, DC.United States Department of Agriculture, Soil ConservationService. 1991. Hydric soils of theUnited States. Soil Conservation Service incooperation with the National Technical Committeefor Hydric Soils, Washington, DC.United States Department of Agriculture, Soil ConservationService. 1992. Soil and Water Relationshipsof Florida’s Ecological Communities.G.W. Hurt (ed.). Florida Soil Survey Staff,Gainesville, FL.United States Department of Agriculture, Soil ConservationService. 1993. National Soil SurveyHandbook. Washington, DC.United States Department of Agriculture, Soil ConservationService. 1993. Soil Survey Manual.U.S. Dep. Agric. Handb. 18, Washington, DC.Vepraskas, M.J. 1994. Redoximorphic Features forIdentifying Aquic Conditions. Tech. Bulletin 301.North Carolina Ag. Research Service, NorthCarolina State Univ., Raleigh, NC.24 (430, FIHS, Ver. 5.01, March 2003)

Field Indicators of Hydric SoilsGlossaryMarked with an asterisk (*), these terms, asdefined in this glossary, may have definitionsthat are slightly different from the definitions inthe referenced materials. The definitions are toassist users of this publication and are notintended to add to or replace definitions in thereferenced materials.A Horizon. A mineral horizon that formed at thesurface or below an O horizon where organicmaterial is accumulating. See USDA, NRCS, SoilTaxonomy (1999) for complete definition.Accreting areas. Landscape positions where soilmaterial accumulates through deposition fromhigher elevations or upstream positions morerapidly than is being lost through erosion.Anaerobic. A condition in which molecular oxygen isvirtually absent from the soil.Anaerobiosis. Microbiological activity underanaerobic conditions.Aquic conditions. Conditions in the soil representedby depth of saturation, occurrence of reduction,and redoximorphic features. See USDA, NRCS,Soil Taxonomy (1999) for complete definition.*Artificial drainage. The use of human efforts anddevices to remove free water from the soilsurface or from the soil profile. The hydrologymay also be modified by the use of levees anddams to prevent water from entering a site (fig. 35).Biologic zero. The soil temperature, at a depth of 50cm, below which the growth and function oflocally adapted plants are negligible.Figure 35. The presence of artificial drainage does notalter the hydric status of a soil.Calcic horizon. An illuvial horizon in which carbonateshave accumulated to a significant extent.See USDA, NRCS, Soil Taxonomy (1999) forcomplete definition.Calcium carbonate. Chemical formula of CaCO 3.Calcium carbonate effervesces when treatedwith cold hydrochloric acid.CaCO 3equivalent. This is the acid neutralizingcapacity of a soil expressed as a weight percentageof CaCO 3(molecular weight of CaCO 3equals 100).Closed depressions. A low-lying area surrounded byhigher ground with no natural outlet for surfacedrainage.COE. United States Army Corps of Engineers.Common. When referring to redox concentrations ordepletions, or both, common represents 2 to 20percent of the observed surface.Concave landscapes. A landscape whose surfacecurves downward.*Covered, coated, masked. These terms describeall of the redoximorphic processes by which thecolor of soil particles are hidden by organicmaterial, silicate clay, iron, aluminum, or somecombination of these.*Depleted matrix. A depleted matrix is the volumeof a soil horizon or subhorizon from which ironhas been removed or transformed by processesof reduction and translocation to create colorsof low chroma and high value. A, E and calcichorizons may have low chromas and high valuesand may therefore be mistaken for a depletedmatrix. However, they are excluded from theconcept of depleted matrix unless common ormany, distinct or prominent redox concentrationsas soft masses or pore linings are present.In some places the depleted matrix may changecolor upon exposure to air (reduced matrix),this phenomena is included in the concept ofdepleted matrix. The following combinations ofvalue and chroma identify a depleted matrix:• Matrix value 5 or more and chroma 1 with orwithout redox concentrations as soft massesand/or pore linings, or• Matrix value 6 or more and chroma 2 or 1with or without redox concentrations as softmasses and/or pore linings, or• Matrix value 4 or 5 and chroma 2 and has 2percent or more distinct or prominent redoxconcentrations as soft masses and/or porelinings, or(430, FIHS, Ver. 5.01, March 2003) 25

Field Indicators of Hydric Soils• Matrix value 4 and chroma 1 and has 2 percentor more distinct or prominent redoxconcentrations as soft masses and/or porelinings.Diffuse boundary. Used to describe redoximorphicfeatures that grade gradually from one color toanother (fig. 36). The color grade is commonlymore than 2 mm wide. Clear is used to describeboundary color gradations intermediate betweensharp and diffuse.Distinct 1 . Readily seen, but contrast only moderatelywith the color to which compared. Thecontrast is distinct if the:1. delta hue = 0, anda. delta value 1 to 2 to

Field Indicators of Hydric Soils*Gleyed matrix. Soils that have a gleyed matrixhave the following combinations of hue, value,and chroma and the soils are not glauconitic:1. 10Y, 5GY, 10GY, 10G, 5BG, 10BG, 5B, 10B, or5PB with value 4 or more and chroma 1; or2. 5G with value 4 or more and chroma 1 or 2;or3. N with value 4 or more; or4. (for testing only) 5Y, value 4 or more, andchroma 1.In some places the gleyed matrix may changecolor upon exposure to air (reduced matrix).This phenomenon is included in the concept ofgleyed matrix.*Hemic. See Mucky peat.Histic epipedon. A thick (20–60 cm [8–24 in])organic soil horizon that is saturated with waterat some period of the year unless artificiallydrained and that is at or near the surface of amineral soil.Histels. Organic soils that overly permafrost andshow evidence of cryoturbation. See USDA,NRCS, Soil Taxonomy (1999) for completedefinition.Histosols. Organic soils that have organic soilmaterial in more than half of the upper 80 cm(32 in), or that are of any thickness if overlyingrock or fragmental materials have intersticesfilled with organic soil materials. See USDA,NRCS, Soil Taxonomy (1999) for completedefinition.Horizon. A layer, approximately parallel to thesurface of the soil, distinguishable from adjacentlayers by a distinctive set of propertiesproduced by soil forming processes. See USDA,NRCS, Soil Taxonomy (1999) for completedefinition.Hydric soil criteria.1. All Histels except Folistels and all Histosolsexcept Folists, or2. Soils in Aquic suborders, great groups, orsubgroups, Albolls suborder, Aquisalids,Historthels, and Histoturbels great groups,and Cumulic or Pachic subgroups that are:a. somewhat poorly drained with a watertable equal to 0.0 foot from the surfaceduring the growing season, orb. poorly drained or very poorly drained andhave either:(1) water table equal to 0.0 foot duringthe growing season if textures arecoarse sand, sand, or fine sand in alllayers within 20 inches, or for othersoils; or(2) water table at less than or equal to 0.5foot from the surface during thegrowing season if permeability isequal to or greater than 6 inches perhour in all layers within 20 inches; or(3) water table at less than or equal to 1foot from the surface during thegrowing season, if permeability is lessthan 6 inches per hour in any layerwithin 20 inches; or3. Soils that are frequently ponded for long orvery long duration during the growing seasonor4. Soils that are frequently flooded for long orvery long duration during the growing season.Hydric soil definition (1994). A soil that formedunder conditions of saturation, flooding, orponding long enough during the growing seasonto develop anaerobic conditions in the upperpart.Hydrogen sulfide odor. The odor of H2S, which issimilar to rotten eggs.Hydromorphic. Features in the soil caused orformed by water.Layer(s). A horizon, subhorizon, or combination ofcontiguous horizons or subhorizons that shareproperty(s) referred to in the Indicators.Lithologic discontinuity. Occurs in a soil that hasdeveloped in more than one type of parentmaterial. Commonly determined by a significantchange in particle-size distribution, mineralogy,and other properties that indicate adifference in material from which the horizonsformed.Land Resource Region (LRR). These geographicareas are characterized by a particular patternof soils, climates, water resources, and landuse. Each LRR has a different letter of thealphabet (A–Z). LRRs are defined in USDAAgriculture Handbook 296.Many. When referring to redox concentrations and/or depletions, many represents more than 20percent of the observed surface.Marl. An earthy, unconsolidated deposit consistingchiefly of calcium carbonate mixed with clay inapproximately equal proportions, formed primarilyunder freshwater lacustrine conditions.Complete definition in description USDA NRCS,Soil Taxonomy (1999).Matrix. The dominant soil volume that is continuousin appearance and envelopes microsites. Whenthree colors exist, such as when a matrix,depletions, and concentrations are present, thematrix may represent less than 50 percent ofthe total soil volume.(430, FIHS, Ver. 5.01, March 2003) 27

Field Indicators of Hydric SoilsMLRA. Major Land Resource Areas. Geographicallyassociated divisions of land resource regions.defined in USDA Agriculture Handbook 296.Mollic epipedon. A mineral surface horizon that isrelatively thick, dark colored, humus rich, andhas high base saturation. See USDA, NRCS, SoilTaxonomy (1999) for complete definition.Mollisols. Mineral soils that have a mollic epipedon.See USDA, NRCS, Soil Taxonomy (1999) forcomplete definition.*Muck. A sapric organic soil material in whichvirtually all of the organic material is decomposed,not allowing for identification of plantforms. Bulk density is normally 0.2 g/cm 3 ormore. Muck has

Field Indicators of Hydric SoilsRedox depletions. Bodies of low chroma (2 or less)having value 4 or more where Fe/Mn oxideshave been stripped or where both iron andmanganese oxides and clay have been stripped.Redox deletions contrast distinctly or prominentlywith the matrix. See Vepraskas (1994) forcomplete description.Redoximorphic features. Features formed by theprocesses of reduction, translocation, or oxidationof Fe and Mn oxides. Formerly calledmottles and low chroma colors (fig. 38). SeeVepraskas (1994) for complete description.Reduced matrix. Soil matrices that have low chromaand high value, but whose color changes in hue orchroma when exposed to air. See Vepraskas(1994) for complete description.*Reduction. For the purpose of the Indicators, whenthe redox potential (Eh) is below the ferric/ferrous iron threshold as adjusted for pH. Inhydric soils, this is the point when the transformationof ferric iron (Fe+++) to ferrous iron(Fe++) occurs (fig. 39).Relict features. Soil morphological features that donot reflect recent hydrologic conditions ofsaturation and anaerobiosis (fig. 40). SeeVepraskas (1994) for complete description.*Sapric. See Muck.Saturation. When the soil water pressure is zero orpositive, most all the soil pores are filled withwater.Sharp boundary. Used to describe redoximorphicfeatures that grade sharply from one color toanother. The color grade is commonly less than0.1 millimeter wide (fig. 40).Figure 38. Redoximorphic features as required in many ofthe Indicators. These redox concentrationsoccur as pore linings along root channels andped faces.Soft masses. Redox concentrations that are nothard, frequently within the matrix, and whoseshape is variable.Soil texture. The weight proportion of the soilseparates for particles less than 2 mm.Figure 39. Reduction would probably occur in this saltmarsh throughout the year. The Indicator A4Hydrogen Sulfide would most likely occur here.Figure 40. Sharp boundaries, such as those shown here,may indicate these redoximorphic features arerelict.(430, FIHS, Ver. 5.01, March 2003) 29

Field Indicators of Hydric SoilsSpodic horizon. A mineral soil horizon that is characterizedby the illuvial accumulation of amorphousmaterials composed of aluminum andorganic carbon with or without iron. The spodichorizon has a certain minimum thickness andminimum quantity of oxalate extractable carbonplus aluminum or specific color requirements,or both.Umbric Epipedon. A thick, dark mineral surfacehorizon that has base saturation of less than 50percent. See USDA, NRCS, Soil Taxonomy(1999) for complete definition.Vertisol. A mineral soil with 30 percent or moreclay in all layers. This soil expands and shrinksdepending on moisture content and containsslickensides or wedge-shaped peds. See USDA,NRCS, Soil Taxonomy (1999) for completedefinition.Wetland. An area that has hydrophytic vegetation,hydric soils, and wetland hydrology, per the FSAManual and the U.S. Corps of Engineers, 1987Wetlands Delineation Manual (fig. 41).Within. When referring to specific indicator depthrequirements, within means not beyond indepth, for example, less than or equal to 15 cm.Figure 41. If the area this soil represents has hydrophyticvegetation and wetland hydrology, it would be awetland. This soil has the Indicator F2 LoamyGleyed Matrix.30 (430, FIHS, Ver. 5.01, March 2003)

Field Indicators of Hydric SoilsAppendix AIndicators by Land Resource Region (LRR)LRRIndicatorsAA1, A2, A3, A4, A10, S1, S4, S5, S6, F1 (except MLRA 1), F2, F3, F4, F5, F6, F7, F8, TF2, TF7.BCDEFGHIJKLMNOPRSA1, A2, A3, A4, A10, S1, S4, S5, S6, F1, F2, F3, F4, F5, F6, F7, F8, TF2, TF7.A1, A2, A3, A4, A10, S1, S4, S5, S6, F1, F2, F3, F4, F5, F6, F7, F8, F9, TF2, TF7.A1, A2, A3, A4, A9, S1, S4, S5, S6, F1, F2, F3, F4, F5, F6, F7, F8, F9, TA1, TF2, TF5, TF7, TF8.A1, A2, A3, A4, A10, S1, S4, S5, S6, F1, F2, F3, F4, F5, F6, F7, F8, TF2, TF7.A1, A2, A3, A4, A5, A9, S1, S3, S4, S5, S6, F1, F2, F3, F4, F5, F6, F7, F8, TS2, TS5, TF1, TF2, TF4, TF5,TF6, TF7.A1, A2, A3, A4, A9, S1, S2, S4, S5, S6, F1, F2, F3, F4, F5, F6, F7, F8, TS3, TS5, TF1, TF2, TF6, TF7.A1, A2, A3, A4, A9, S1, S2, S4, S5, S6, F1, F2, F3, F4, F5, F6, F7, F8, F16 (MLRAs 72 & 73 only), TS5,TF1, TF2, TF7.A1, A2, A3, A4, A9, S1, S4, S5, S6, F1, F2, F3, F4, F5, F6, F7, F8, TF2, TF7.A1, A2, A3, A4, A9, S1, S4, S5, S6, F1, F2, F3, F4, F5, F6, F7, F8, TF2, TF7.A1, A2, A3, A4, A5, A10, S1, S4, S5, S6, F1, F2, F3, F4, F5, F6, F7, F8, TS5, TF2, TF7.A1, A2, A3, A4, A5, A10, S1, S4, S5, S6, F1, F2, F3, F4, F5, F6, F7, F8, TS5, TF2, TF7.A1, A2, A3, A4, A5, A10, S1, S3, S4, S5, S6, F1, F2, F3, F4, F5, F6, F7, F8, F12, TS4, TS5, TF1, TF2, TF4, TF5,TF6, TF7, TF10.A1, A2, A3, A4, A5, A10, S1, S4, S5, S6, S7, F2, F3, F4, F5, F6, F7, F8, F12, TF2, TF7, TF10.A1, A2, A3, A4, A5, A9, S1, S4, S5, S6, F1, F2, F3, F4, F5, F6, F7, F8, F12, TF2, TF9.A1, A2, A3, A4, A5, A6, A7, A9, S4, S5, S6, S7, F2, F3, F4, F5, F6, F7, F8, F12, F13, TF2.A1, A2, A3, A4, A5, S1, S3, S4, S5, S6, S7, S8, S9, F2, F3, F4, F5, F6, F7, F8, TA2, TF2, TF7.A1, A2, A3, A4, A5, A10, S1, S4, S5, S6, S7, S8, S9, F2, F3, F4, F5, F6, F7, F8, TF2, TF4, TF10.T A1, A2, A3, A4, A5, A6, A7, A9, S4, S5, S6, S7, S8, S9, F2, F3, F4, F5, F6, F7, F8, F 11 (MLRA 151 Only), F12,F13, TA3 (MLRA 150a 0nly)U A1, A2, A3, A4, A5, A6, A7, A8, S4, S5, S6, S7, F2, F3, F4, F5, F6, F7, F10, F13.VWXYZA1, A2, A3, A4, A5, A8, S4, S5, S6, S7, F2, F3, F4, F5, F6, F7, F8, TF2, TF7.A1, A2, A3, A4, A10, S10, F4, F5, F6, F7, F8, F14, F15, TS1, TF2, TF3, TF7.A1, A2, A3, A4, A10, S10, F4, F5, F6, F7, F8, F14, F15, TS1, TF2, TF3, TF7.A1, A2, A3, A4, A10, S10, F4, F5, F6, F7, F8, F14, F15, TS1, TF2, TF3, TF7.A1, A2, A3, A4, A5, A6, A7, A8, S4, S5, S6, S7, F2, F3, F4, F5, F6, F7, F8, TF2, TF7.(430, FIHS, Ver. 5.01, March 2003) 31

Field Indicators of Hydric SoilsAppendix BIndicator CorrelationsSource: U.S. Corps of Engineers Wetland Delineation Manual 1987. Technical Report, Y–87–1. EnvironmentalLaboratory, U.S. Army Engineers Waterways Experiment Station. Vicksburg. MS.SoilsRegional IndicatorsNon-sandy soils:a. Organic soils (Histosols) A1 Histosolb. Histic Epipedon A2 Histic EpipedonA3 Black Histicc. Sulfidic material A4 Hydrogen Sulfided. Aquic or peraquic moisture regime ——————e. Reducing soil conditions TF11 Reduced Verticf (1). Gleyed soils (gray color)f (2). Soils that have bright mottlesand/or low matrix chromaF2 Loamy Gleyed MatrixF14 Alaska Redox GleyedF15 Alaska Gleyed PoresF3 Depleted MatrixF9 Vernal PoolsF11 Depleted OchricF16 High Plains DepressionsTF8 Redox Spring SeepsTF9 Delta OchricTF10 Alluvial Depleted Matrixg. Soil appearing on the hydric soils list ——————h. Iron and manganese concretions F12 Iron/Manganese MassesTF3 Alaska ConcretionsNot listed in the 1987 manualA5 Stratified LayersA6 Organic BodiesA7 5 cm Mucky MineralA8 Muck PresenceA9 1 cm MuckA10 2 cm MuckF1 Loamy Mucky MineralF4 Depleted Below Dark SurfaceF5 Thick Dark SurfaceF6 Redox Dark SurfaceF7 Depleted Dark SurfaceF10 MarlF13 Umbric Surface32 (430, FIHS, Ver. 5.01, March 2003)

Field Indicators of Hydric SoilsAppendix B: Indicator Correlations—Continued1987 Manual Regional IndicatorsNot listed in 1987 manual—ContinuedTA1 Playa Rim Strat. LayersTA2 Structureless MuckTF1 ? cm Mucky or PeatTF2 Red Parent MaterialTF4 Y Below Dark SurfaceTF5 Y Below Thick Dark SurfaceTF6 Calcic Dark SurfaceTF7 Thick Dark Surface 2/1TS2 Thick Sandy Dark SurfaceTF7 Thick Dark Surface 2/1TF11 Reduced VerticSandy soils:a. Organic soils (Histosols) A1 Histosolb. Histic epipedon A2 Histic EpipedonA3 Black Histicc. Sulfidic material A4 Hydrogen sulfided. Aquic or peraquic moisture regime —————————e. Reducing soil conditions —————————f. Iron and manganese concretions —————————g. High organic matter content in A6 Organic Bodiesthe surface horizonA7 5 cm Mucky MineralA8 Muck PresenceA9 1 cm MuckA10 2 cm MuckS1 Sandy Mucky MineralS2 2.5 cm Mucky or PeatS3 5 cm Mucky Peat or PeatS7 Dark SurfaceTA2 Structureless MuckTS2 Thick Sandy Dark Surfaceh. Streaking of subsurface horizons S6 Stripped Matrixby organic matterS8 Polyvalue Below Surfacei. Organic pan S9 Thin Dark Surfacej. Soils appearing on the hydric soils list —————————(430, FIHS, Ver. 5.01, March 2003) 33

Field Indicators of Hydric SoilsAppendix B: Indicator Correlations—Continued1987 Manual Regional IndicatorsNot listed in the 1987 manualA5 Stratified LayersS4 Sandy Gleyed MatrixS10 Alaska GleyedTA1 Playa Rim Stratified LayersTS1 Iron StainingTS4 Sandy Neutral SurfaceProblem soilsSandy soilsSoils with thick dark A horizonsSoils with red parent materialSoils with low chroma parent materialA5 Stratified LayersS5 Sandy RedoxS6 Stripped MatrixS8 Polyvalue Below SurfaceS9 Thin Dark SurfaceTA1 Playa Rim Stratified LayersTS5 Chroma 3 Sandy RedoxF4 Dep. Below Dark SurfaceF5 Thick Dark SurfaceF6 Redox Dark SurfaceF7 Depleted Dark SurfaceF13 Umbric SurfaceF16 High Plains DepressionsTF4 Y Below Dark SurfaceTF5 Y Below Thick Dark SurfaceTF6 Calcic Dark SurfaceTS2 Tk. Sandy Dark SurfaceTF7 Thick Dark Surface 2/1TF11 Reduced VerticF8 Redox DepressionsF9 Vernal PoolsF12 Iron/Manganese MassesTA3 Coast Prairie RedoxTS1 Iron StainingTF2 Red Parent MaterialTF8 Redox Spring SeepsS4 Sandy Gleyed MatrixS10 Alaska GleyedF10 MarlTS4 Sandy Neutral Surface34 (430, FIHS, Ver. 5.01, March 2003)