LOCATION TWICHELL OK+KS TX

Tentative Series
SLM
12/2017

TWICHELL SERIES

The Twichell series consists of very deep, well drained, very slowly permeable soils that formed in calcareous loess of late Pleistocene to early Holocene age. These nearly level to very gently sloping soils occur on plains on tablelands. Slope ranges from 0 to 3 percent. Mean annual air temperature is about 13.3 degrees C (56 degrees F), and mean annual precipitation is about 508 mm (20 in).

TAXONOMIC CLASS: Fine, mixed, superactive, mesic Aridic Haplusterts

TYPICAL PEDON: Twichell silty clay loam - on a 0.5 percent linear slope, in cropland at an elevation of 867 m (2844 ft).
(Colors are for dry soil unless otherwise stated.)

Ap--0 to 15 cm (0 to 6 in); grayish brown (10YR 5/2) silty clay loam, very dark grayish brown (10YR 3/2), moist; weak fine and medium granular structure; hard, friable; few very fine and fine roots; noneffervescent; neutral, pH 7.0; abrupt smooth boundary.

A--15 to 28 cm (6 to 11 in); grayish brown (10YR 5/2) silty clay loam, very dark brown (10YR 2/2), moist; weak fine and medium subangular blocky structure; very hard, firm; few very fine and fine roots; noneffervescent; slightly alkaline, pH 7.4; clear smooth boundary. (Combined thickness of the A horizons: 20 to 35 cm [8 to 14 in])

Btss--28 to 51 cm (11 to 20 in); grayish brown (10YR 5/2) silty clay, very dark grayish brown (10YR 3/2), moist; strong medium and coarse prismatic parting to moderate fine and medium angular blocky structure; extremely hard, very firm; few very fine and fine roots; common prominent slickensides (pedogenic); common distinct clay films and common distinct very dark brown (10YR 2/2) organoargillans on faces of peds; reversible trans-horizon cracks filled with very dark brown (10YR 2/2) silty clay loam; slightly effervescent; moderately alkaline, pH 7.9; clear wavy boundary.

Btkss1--51 to 76 cm (20 to 30 in); brown (7.5YR 5/2) silty clay, dark brown (7.5YR 3/2), moist; strong medium and coarse prismatic parting to moderate medium angular blocky structure; extremely hard, very firm; few very fine and fine roots; common prominent slickensides (pedogenic); common distinct clay films and common distinct very dark brown (10YR 2/2) organoargillans on vertical faces of peds, few faint calcium carbonate coats on vertical faces of peds; few fine irregular concretions of calcium carbonate; reversible trans-horizon cracks filled with very dark brown (10YR 2/2) silty clay loam; strongly effervescent; (2 percent calcium carbonate equivalent); moderately alkaline, pH 8.2; gradual smooth boundary.

Btkss2--76 to 102 cm (30 to 40 in); brown (7.5YR 5/2) silty clay loam, dark brown (7.5YR 3/2), moist; moderate medium and coarse prismatic parting to moderate medium subangular blocky structure; very hard, firm; few very fine and fine roots; few distinct slickensides; common distinct clay films on faces of peds and common prominent very dark brown (10YR 2/2) organoargillans on vertical faces of peds; few fine threadlike masses and common fine and medium irregular concretions of calcium carbonate; strongly effervescent (2 percent calcium carbonate equivalent); moderately alkaline, pH 8.3; gradual smooth boundary. (Combined thickness of Btss and Btkss horizons: 56 to 99 cm [22 to 39 in])

2Btk1--102 to 137 cm (40 to 54 in); light brown (7.5YR 6/4) clay loam, brown (7.5YR 4/4), moist; moderate medium and coarse prismatic parting to moderate medium subangular blocky structure; hard, firm; few very fine roots; many prominent clay films on faces of peds and few distinct very dark brown (10YR 2/2) organoargillans on vertical faces of peds; many medium threadlike masses and few fine and medium irregular concretions of calcium carbonate; strongly effervescent (1 percent calcium carbonate equivalent); slightly alkaline, pH 7.5; gradual smooth boundary.

2Btk2--137 to 160 cm (54 to 63 in); brown (7.5YR 5/2) silty clay loam, dark brown (7.5YR 3/2), moist; moderate medium prismatic parting to moderate medium subangular blocky structure; hard, friable; many prominent clay films on faces of peds and few distinct very dark brown (10YR 2/2) organoargillans on vertical faces of peds; few patchy faint calcium carbonate coats on vertical faces of peds; few fine and medium threadlike masses and few fine and medium irregular concretions and masses of calcium carbonate; strongly effervescent (1 percent calcium carbonate equivalent); slightly alkaline, pH 7.7; clear smooth boundary.

2Btk3--160 to 183 cm (63 to 72 in); brown (7.5YR 5/4) silty clay loam, brown (7.5YR 5/4), moist; moderate medium prismatic parting to moderate medium subangular blocky structure; hard, friable; few distinct clay films on faces of peds and few distinct very dark brown (10YR 2/2) organoargillans on vertical faces of peds; many distinct calcium carbonate coats on faces of peds and in pores and root channels; few threadlike masses of calcium carbonate; strongly effervescent; slightly alkaline, pH 7.7; gradual smooth boundary.

2Btk4--183 to 203 cm (72 to 80 in); reddish brown (5YR 5/4) silty clay loam, reddish brown (5YR 4/3), moist; moderate medium prismatic parting to moderate medium subangular blocky structure; hard, friable; few distinct clay films on faces of peds and few faint organic stains on vertical faces of peds; few distinct calcium carbonate coats on vertical faces of peds; few fine threadlike masses of calcium carbonate; noneffervescent; slightly alkaline, pH 7.7. (Combined thickness of 2Btk horizons: 48 to 76 cm [19 to 30 in])

TYPE LOCATION:
Beaver County, Oklahoma; 7 miles south and 5 miles west of Elmwood, OK; then 600 ft north and 180 ft east of the southwest corner of Section 29, Township 1N, Range 23E (Cimarron meridian).

USGS topographic quadrangle: Elmwood, Oklahoma
Latitude: 36 degrees 30 minutes 59.00 seconds N
Longitude: 100 degrees 36 minutes 42.00 seconds W
Datum: WGS84

Decimal Degrees
Std Latitude: 36.5163879
Std Longitude: -100.6116638

UTM Northing: 4042434
UTM Easting: 355692
UTM zone 14S

RANGE IN CHARACTERISTICS:
Soil moisture: An ustic moisture regime bordering on aridic. The soil moisture control section is dry in some or all parts for more than 180 but less than 220 days, cumulative, in normal years.
Solum thickness: More than 200 cm (more than 80 in)
Thickness of mollic epipedon: 35 to 112 cm (14 to 44 in)
Depth to slickensides: 10 to 40 cm (4 to 16 in)
Thickness of slickensides: 35 to 84 cm (14 to 33 in)
Depth to identifiable secondary carbonates: 50 to 76 cm (20 to 30 in)
Depth to calcic horizon: Greater than 150 cm (greater than 60 in)
Linear extensibility: Average of 6.5 to 9.0 cm to a depth of 100 cm
Surface cracks: trans-horizon cracks (reversible) 7 to 64 mm (0.25 to 2.5 in) wide extend from the soil surface to a depth of 76 cm (30 in) or more when the soil is dry.

Particle-size control section (weighted average):
Silicate clay content: 37 to 48 percent
Carbonate clay content: 0 to 1 percent
Coarse fragments: none

A or Ap horizons:
Hue: 10YR
Value: 3 or 4, 2 or 3 moist
Chroma: 2 or 3 moist or dry
Texture: clay loam, silty clay loam
Silicate clay content: more than 30 percent
Coarse fragments: none
Identifiable secondary carbonate: none
Calcium carbonate equivalent: 0 percent
Effervescence: none to very slight
Reaction (pH): neutral to slightly alkaline (6.6-7.4)

Btss horizon (where present):
Hue: 7.5YR, 10YR
Value: 3 or 4, 2 or 3 moist
Chroma: 2 or 3 moist or dry
Texture: Clay loam, silty clay loam, clay, silty clay
Silicate clay content: 35 to 50 percent
Coarse fragments: none
Identifiable secondary carbonate: none
Calcium carbonate equivalent: 0 percent
Effervescence: none to very slight
Reaction (pH): neutral to slightly alkaline (6.6-7.4)

Btkss horizons:
Hue: 7.5YR, 10YR
Value: 3 to 5, 2 to 4 moist
Chroma: 2 to 4 moist or dry
Texture: Clay loam, silty clay loam, silty clay.
Silicate clay content: 35 to 50 percent
Coarse fragments: none
Identifiable secondary carbonate: 1 to 5 percent; fine to medium; masses, nodules, and films
Calcium carbonate equivalent: 0 to 5 percent
Effervescence: none to slight
Reaction (pH): slightly alkaline to moderately alkaline (7.4-8.)

2Btk horizons and 3Btk horizons (where present):
Hue: 5YR, 7.5YR, 10YR
Value: 4 to 7, 3 to 6 moist
Chroma: 2 to 4 moist or dry
Texture: Clay loam, silty clay loam, silt loam, loam.
Coarse fragments: 0 to 2 percent, fine gravel; strongly to very strongly cemented carbonate nodules and concretions
Identifiable secondary carbonate: 2 to 10 percent; fine to coarse; finely disseminated, masses, nodules, and concretions
Calcium carbonate equivalent: 1 to 5 percent
Effervescence: slight to strong
Reaction (pH): slightly alkaline to moderately alkaline (7.4-8.4)

2Bkk and 2BCk horizons (where present):
Hue: 7.5YR, 10YR
Value: 6 to 8 moist or dry
Chroma: 2 to 4 moist or dry
Texture: silt loam, loam, clay loam, and their gravelly or very gravelly counterparts
Coarse Fragments: 0 to 45 percent; fine to coarse gravel; strongly to very strongly cemented carbonate nodules, concretions, and caliche fragments
Identifiable secondary carbonates: 25 to 60 percent; fine to very coarse; finely disseminated, masses, nodules, and concretions
Calcium carbonate equivalent: 40 to 65 percent
Effervescence: violent
Reaction (pH): slightly alkaline to moderately alkaline (7.4-8.4)

COMPETING SERIES:
These are the Moriartche, Silcat, and Tsaile series in the same family. Similar soils include the Sherm series.
Moriartche soils: formed in alluvium derived from shale of Triassic Age on alluvial flats and valley floors and occur at higher elevations with a cooler and drier climate
Silcat soils: formed in alluvium derived from shale of Cretaceous age on stream terraces and occur at higher elevations with a cooler and drier climate
Tsaile soils: formed from alluvium derived from sandstone shale of Triassic Age on stream terraces and fan remnants and occur at higher elevations with a cooler and drier climate
Sherm soils: do not have slickensides and have a calcic horizon within 150 cm (60 in)

GEOGRAPHIC SETTING:
Parent Material: calcareous loess of late Pleistocene to early Holocene age
Landscape: tableland
Landform: plains and interfluves
Slope: 0 to 3 percent
Precipitation Pattern: These soils are intermittently moist in September through November and March through June. July through August and December through February are the driest months.
Mean annual precipitation: 406 to 584 mm (16 to 23 in)
Thornthwaite annual P-E Index Vales: 25 to 36
Mean annual air temperature: 12.2 to 14 degrees C (54 to 57 degrees F)
Frost-free period: 170 to 200 days
Elevation: 750 to 1250 m (2460 to 4100 ft)

GEOGRAPHICALLY ASSOCIATED SOILS:
These are the Balko(T), Belfon, Bigbow, Canina, Conlen, Dalhart, Eva, Forgan, Hansford, Hugoton, Knoblaw, Lautz, Optima, Oslo, Plack, and Waka(T) soils.

Balko, Forgan, Hugoton, and Oslo soils occur on similar landscape positions.
Balko soils: have surface textures with less than 30 percent silicate clay, have a calcic horizon from 100 to 150 cm (40 to 60 in) from the soil surface, and do not have slickensides
Forgan soils: have a fine-loamy particle-size class
Hugoton soils: have a fine-silty particle-size class
Oslo soils: have a fine-silty particle-size class, and a calcic horizon within 100 cm (40 in) of the soil surface

Belfon, Bigbow, and Dalhart occur on slightly higher landscape positions.
Belfon soils: have a fine-loamy particle-size class with a fine or fine-silty discontinuity within 100 cm (40 in) of the soil surface
Bigbow soils: have an ochric epipedon; have a fine-loamy particle-size class with a fine or fine silty discontinuity within 100 cm (40 in) of the soil surface
Dalhart soils: have an ochric epipedon, and a fine-loamy particle-size class

Canina, Eva, and Optima soils occur on higher landscape positions.
Canina soils: have an ochric epipedon, a fine-silty particle-size class, and a calcic horizon within 50 cm (20 in) of the soil surface
Eva soils: have an ochric epipedon, and a coarse-loamy particle-size class
Optima soils: have an ochric epipedon, and a sandy particle-size class

Conlen and Plack soils occur on lower landscape positions.
Conlen soils: have a coarse-loamy particle-size class, do not have an argillic horizon, have a calcic horizon within 50 cm (20 in) of the soil surface, and have carbonatic mineralogy
Plack soils: have a loamy skeletal particle-size class, and a petrocalcic horizon within 10 to 50 cm (4 to 20 in) of the soil surface

Hansford, Knoblaw, and Lautz soils occur in lower playa landscape positions subject to ponding water.
Hansford and Lautz soils: have redox features within 50 cm (20 in) of the soil surface
Knoblaw soils: have redox features within 50 cm (20 in) of the soil surface, and a calcic horizon within 150 cm (60 in) of the soil surface

Waka soils: occur in lower drainageway positions, have an irregular decrease in organic carbon with increasing depth, and a fine-silty particle-size class

DRAINAGE AND PERMEABILITY:
Drainage class: well drained
Permeability: very slow
Runoff: high on 0 to 1 percent slopes, and very high on 1 to 3 percent slopes

USE AND VEGETATION:
Used predominantly for dryland and irrigated cropland. Principal crops grown are corn, grain sorghum, and wheat. Native vegetation is predominantly short grasses including blue grama and buffalograss with lesser amounts of silver bluestem, sideoats grama, and vine-mesquite.

DISTRIBUTION AND EXTENT:
General area: Oklahoma panhandle, northern Texas panhandle, and southwestern Kansas
Land Resource Region: H - Central Great Plains Winter Wheat and Range Region
MLRA 77A - Southern High Plains, Northern Part
Extent: moderate

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas

SERIES PROPOSED: 2010 Beaver County, Oklahoma. The name comes from a community in nearby Ochiltree County, Texas.

REMARKS:
These soils were formerly included in the Pullman and Sherm series.

Diagnostic horizons and features in this pedon:
Particle-size control section: 28 to 78 cm (11 to 31 in)
Mollic epipedon: 0 to 102 cm (0 to 40 in) (Ap, A, Btss, Btkss1, and Btkss2 horizons)
Identifiable secondary carbonates: 51 to 203 cm (20 to 80 in) (all Btk horizons)
Slickensides: 28 to 102 cm (11 to 40 in) (Btss and Btkss horizons)
Cracks: Reversible trans-horizon cracks extend from 28 to 76 cm (11 to 30 in) (Btss and Btkss1 horizons)
Linear extensibility: 8.3 cm to 100 cm
Lithologic discontinuity: 102 to 203 cm (40 to 80 in) (2Btk horizons)

ADDITIONAL DATA: KSSL data available. S1987OK007006(TL), S1987OK007007 (Beaver County, Oklahoma); S1984OK139005 (Texas County, Oklahoma); S1984TX357001, S1994TX357002 (Ochiltree County, Texas); S1984TX341001 (Moore County, Texas).

Taxonomic Version: Keys to Soil Taxonomy, Twelfth Edition, 2014.

National Cooperative Soil Survey
U.S.A.