LOCATION PLANK TX

Established Series
JKW-KBH-RM
07/2014

PLANK SERIES

The Plank series consists of very deep, poorly drained soils. These nearly level to very gently sloping soils formed in loamy fluviomarine deposits of the Lissie Formation of early to mid-Pleistocene age. Slope ranges from 0 to 1 percent. Mean annual temperature is about 19.4 degrees C (67 degrees F), and mean annual precipitation is about 1295 mm (51 in)..

TAXONOMIC CLASS: Coarse-silty, siliceous, active, thermic Natric Vermaqualfs

TYPICAL PEDON: Plank silt loam--woodland (Colors are for moist soil unless otherwise stated)

A--0 to 8 cm, (0 to 3 in); grayish brown (10YR 5/2) silt loam; 95 percent massive due to crayfish bioturbation, and 5 percent undisturbed with weak medium subangular blocky structure; hard, firm; many very fine to medium, and common coarse roots; 95 percent of the horizon is crayfish tubules and krotovinas; krotovinas are filled with a mixture of grayish brown (10YR 5/2) silt loam and pinkish gray (7.5YR 7/2) very fine sand; few faint very dark gray (10YR 3/1) organic coats on surfaces of peds; many fine cylindrical and common fine rounded grayish brown (10YR 5/2) hard worm casts; many pieces of charcoal 0.5 to 2.5 cm (1/4 to 1 inch) wide; 3 percent streaks and masses of pinkish gray (7.5YR 7/2) very fine sand albic material on vertical surfaces of peds; extremely acid; clear wavy boundary. (8 to 15 cm [3 to 6 in] thick)

Bg1--8 to 61 cm, (3 to 24 in); light brownish gray (10YR 6/2) silt loam; 95 percent massive due to crayfish bioturbation, and 5 percent undisturbed with weak coarse subangular blocky structure; hard, firm; many very fine to medium, and common coarse roots; many very fine to medium, and common coarse pores; 95 percent by volume of this horizon is crayfish tubules and krotovinas; krotovinas are filled with light brownish gray (10YR 6/2) and grayish brown (10YR 5/2) silt loam, and pink (7.5YR 7/3) and pinkish gray (7.5YR 7/2) very fine sand; few tubules and krotovinas are lined with grayish brown (10YR 5/2) silty clay loam; common fine cylindrical and few fine rounded grayish brown (10YR 5/2) hard worm casts; very few patchy very dark gray (10YR 3/1) organic coats on surfaces of peds, root channels, and in pores; many pieces of charcoal 0.5 to 2.5 cm (1/4 to 1 in) wide; 1 percent fine prominent yellowish red (5YR 5/8), 1 percent fine and medium prominent brown (7.5YR 5/4), 5 percent fine prominent strong brown (7.5YR 5/6), and 12 percent fine and medium distinct yellow (10YR 7/6) iron concentrations with diffuse boundaries on surfaces of peds; 1 percent fine and medium prominent brown (7.5YR 5/4), and brown (7.5YR 4/4), and 1 percent fine prominent yellowish red (5YR 5/6) and light red (2.5YR 6/6) iron concentrations with sharp boundaries lining root channels and pores; 2 percent of the horizon is interfingering of pink (7.5YR 7/3) and pinkish gray (7.5YR 7/2) very fine sand albic material on vertical surfaces of peds; extremely acid; gradual wavy boundary.

Bg2--61 to 90 cm, (24 to 35 in); light gray (10YR 7/2) silt loam; 70 percent massive due to crayfish bioturbation, and 30 percent undisturbed with weak very coarse prismatic structure; very hard, very firm; common fine roots between peds in nonbrittle material; many fine and medium, and common coarse pores; 70 percent of this horizon is crayfish tubules and krotovinas; krotovinas filled with grayish brown (10YR 5/2) silt loam, and pink (7.5YR 7/3), pinkish gray (7.5YR 7/2), light brown (7.5YR 6/3) very fine sand; few tubules and krotovinas are lined with very dark gray (10YR 3/1) and grayish brown (10YR 5/2) silty clay loam; 2 percent fine and medium prominent light red (2.5YR 7/6), 3 percent fine prominent reddish yellow (7.5YR 6/8), 3 percent fine and medium prominent brown (7.5YR 5/4), and 8 percent fine and medium distinct yellow (10YR 7/6), and brownish yellow (10YR 6/6) redox concentrations with diffuse boundaries on surfaces of peds; 1 percent fine prominent brown (7.5YR 5/4), and yellowish red (5YR 4/6) iron concentrations with sharp boundaries lining root channels and pores; 5 percent of the horizon is interfingering of pink (7.5YR 7/3) and pinkish gray (7.5YR 7/2) very fine sand albic material on vertical surfaces of prisms; few pieces of charcoal 0.5 to 2.5 cm (1/4 to 1 in) in diameter; 22 percent is brittle material that is 5 to 15 cm (2 to 6 in) wide with nonbrittle material in between; extremely acid; gradual wavy boundary. (Combined thickness of the Bg subhorizons is 46 to 122 cm [18 to 48 in])

Btg1--90 to 164 cm, (35 to 64 in); grayish brown (10YR 5/2) silt loam; 50 percent massive due to bioturbation, and 50 percent undisturbed with weak very coarse prismatic structure; very hard, very firm; very few very fine, many fine and medium, and common coarse pores; common faint continuous grayish brown (10YR 5/2) clay films lining pores and on prism surfaces of undisturbed material; 50 percent by of this horizon is crayfish krotovinas; krotovinas are filled with grayish brown (10YR 5/2), light gray (10YR 7/2), and light brownish gray (10YR 6/2) silt loam, and pink (7.5YR 7/3), pinkish gray (7.5YR 7/2) and pale brown (10YR 6/3) very fine sand; common fine and medium distinct brown (7.5YR 5/2) organic coats on surfaces of peds; 8 percent fine and medium distinct brownish yellow (10YR 6/6), 20 percent fine and medium prominent strong brown (7.5YR 5/8), and 5 percent fine prominent yellowish brown (10YR 5/8) iron concentrations with diffuse boundaries, 1 percent fine prominent brown (7.5YR 5/4) and yellowish red (5YR 4/6) iron concentrations with sharp boundaries lining root channels and pores; 3 percent fine faint light brownish gray (10YR 6/2) iron depletions with diffuse boundaries 5 percent is interfingering of pink (7.5YR 7/3) very fine sand albic material with pinkish gray (7.5YR 7/2) and pinkish white (7.5YR 8/2) clay depletions in the interior; 26 percent is brittle material that is 5 to 20 cm (2 to 8 in) wide with nonbrittle material in between; extremely acid; gradual wavy boundary.

Btg2--164 to 203 cm, (64 to 80 in); light brownish gray (10YR 6/2) silt loam; weak very coarse prismatic structure; very hard, very firm; common fine to coarse vesicular pores; common distinct grayish brown (10YR 5/2) clay films on pore linings and on surfaces of prisms; 30 percent of this horizon is crayfish krotovinas; krotovinas are filled with light brownish gray (10YR 6/2), light gray (10YR 7/2), and grayish brown (10YR 5/2) silt loam, and pink (7.5YR 7/3), pinkish gray (7.5YR 7/2), and pale brown (10YR 6/3) very fine sand; 12 percent fine and medium distinct brownish yellow (10YR 6/6), 5 percent fine prominent strong brown (7.5YR 5/8), 5 percent fine prominent yellow (2.5Y 7/6), and 1 percent fine prominent light olive brown (2.5Y 5/3) iron concentrations with diffuse boundaries; 3 percent fine and medium distinct pinkish brown (7.5YR 5/2), and 2 percent fine faint grayish brown (10YR 5/2) redox depletions with diffuse boundaries; 5 percent is interfingering of pink (7.5YR 7/3) very fine sand albic material with pinkish gray (7.5YR 7/2) and pinkish white (7.5YR 8/2) clay depletions in the interior; 36 percent is brittle material that is 10 to 25 cm (4 to 10 in) wide with nonbrittle material in between; extremely acid; gradual wavy boundary. (Combined thickness of the Btg subhorizons is 71 to 142 cm [28 to 56 in])

Btg3--203 to 274 cm, (80 to 108 in); pale green (5G 6/2) loam; weak very coarse prismatic structure; 10 percent of the volume of this horizon is crayfish krotovinas; common fine threads of barite; exchangeable sodium percentage is 19; 8 percent fine and medium prominent dark brown (7.5YR 3/2) iron concentrations with diffuse boundaries; 5 percent fine and medium prominent olive (5Y 5/3) iron concentrations with diffuse boundaries; 2 percent by volume is interfingering of pinkish gray (7.5YR 7/2) albic material on surfaces of peds; extremely acid; gradual wavy boundary.

2CBg--274 to 457 cm, (108 to 180 in); pale green (5G 6/2) clay; weak very coarse prismatic structure; 1 percent of this horizon is crayfish krotovinas; common fine threads of barite; exchangeable sodium percentage is 13; few fine rounded hard pitted concretions of calcium carbonate; 1 percent fine prominent dark brown (7.5YR 3/2), and 5 percent fine and medium prominent olive (5Y 5/3) iron concentrations with diffuse boundaries; very strongly acid.

TYPE LOCATION: Hardin County, Texas; from the intersection of U.S. Highway 69 and Farm Road 326 in Kountze, Texas; 7.3 miles north on U.S. Highway 69; 200 feet east in pine plantation. Village Mills topographic quad; Latitude: 30 degrees, 27 minutes, 02 seconds N; Longitude: 94 degrees, 23 minutes, 03 seconds W. NAD 83; UTM Easting 367102 m, UTM Northing 3369528 m, UTM Zone 15.

RANGE IN CHARACTERISTICS:
Soil Moisture: An aquic soil moisture regime.
Mean annual soil temperature: 20.6 to 21.7 degrees C (69 to 71 degrees F).
Depth to albic materials: 6 to 28 cm (2 to 71 in)
Depth to argillic horizon: 43 to 140 cm (17 to 55 in)
Particle-size control section (weighted average)
Clay content: 6 to 15 percent
Sand larger than very fine sand content: 5 to 15 percent
CEC/clay ratio: 0.45 to .60
Aluminum saturation percent: 60 to 90
Exchangeable sodium percentage: 7 to 11

A Horizon
Hue: 7.5YR or 10YR
Value: 4 to 7
Chroma: 1 or 2
Texture: very fine sandy loam or silt loam
Albic material: 0 to 5 percent
Crawfish bioturbation: 50 to 95 percent
Exchangeable sodium percentage (mmhos/cm): 0 to 6
Reaction: extremely acid

Bg Horizon
Hue: 7.5YR or 10YR
Value: 5 to 7
Chroma: 1 or 2
Texture: very fine sandy loam, loam, or silt loam
Redox concentrations: amount-5 to 30 percent, size-fine or medium, color-shades of yellow, brown, or red, contrast-faint to prominent, boundary-sharp to diffuse, location-throughout
Albic material: 0 to 5 percent
Crawfish bioturbation: 50 to 95 percent
Exchangeable sodium percentage(mmhos/cm): 4 to 11
Brittleness: 0 to 5 percent
Reaction: extremely acid or very strongly acid

Btg Horizons
Hue: 7.5YR or 10YR
Value: 6 or 7
Chroma: 1 or 2
Texture: loam or silt loam
Redox concentrations: amount-5 to 40 percent, size-fine to coarse, color-shades of yellow, brown, or red, contrast-faint to prominent, boundary-sharp to diffuse, location-throughout
Redox depletions: amount-1 to 10 percent, size-fine or medium, color-shades of gray, contrast-faint or distinct, boundary-clear or diffuse, location-throughout
Albic material: 0 to 15 percent
Crawfish bioturbation: 30 to 75 percent
Exchangeable sodium percentage(mmhos/cm): 7 to 25
Brittleness: 25 to 50 percent
Reaction: extremely acid or strongly acid
Barite threads or masses: 2 to 15 percent

CBg Horizon (normally below 203 cm (80 in)
Hue: 5Y or 5G
Value: 5 or 6
Chroma: 2
Texture: loam, silty clay loam, or clay
Redox concentrations: amount-1 to 10 percent, size-fine to coarse, color-shades of yellow, brown, or red, contrast-faint to prominent, boundary-sharp to diffuse, location-throughout
Redox depletions: amount-1 to 3 percent, size-fine or medium, color-shades of gray, contrast-faint or distinct, boundary-clear or diffuse, location-throughout
Crawfish bioturbation: 0 to 5 percent
Exchangeable sodium percentage(mmhos/cm): 10 to 25
Brittleness: 1 to 5 percent
Reaction: extremely acid or very strongly acid
Barite threads or masses: 1 to 3 percent

COMPETING SERIES: There are no series in the same family. Similar soils are the Cieno, Jayhawker, Nona, and Sorter series.
Cieno soils: fine-loamy particle-size control section; hyperthermic temperature regime
Jayhawker soils: base saturation less than 35 percent; do not have vermic features; Exchangeable Sodium Percentage less than 6
Nona soils: fine-silty particle-size control section
Sorter soils: coarse-loamy particle-size control section

GEOGRAPHIC SETTING:
Parent material: loamy fluviomarine deposits of the Lissie Formation of early to mid-Pleistocene age
Landscape: coastal plains
Landform: flats
Slope: 0 to 1 percent
Mean annual air temperature: 19.5 to 20.6 degrees C (67 to 69 degrees F).
Mean annual precipitation: 1219 to 1473 mm (48 to 58 in)
Precipitation pattern: Uniform throughout with slight peaks during the spring and fall months.
Frost-free period: 240 to 300 days
Elevation: 22.9 to 46 m (75 to 155 ft)

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Dallardsville (TX), Kirbyville (TX), Kountze (TX), Nona (TX), Otanya (TX), Sorter (TX), and Waller (TX) soils.

Dallardsville, Kirbyville, and Kountze soils: moderately well drained Dallardsville soils are on mounds .6 to 1 m (2 to 3 ft) higher than Plank soils
Kirbyville and Kountze soils are on relict meander belt levees and bars
Otanya soils: well drained; interfluves
Nona soils: fine-silty particle-size control section; similar landform
Sorter soils: coarse-loamy particle-size control section; similar landform
Waller soils: fine-loamy particle-size control section; landform

DRAINAGE AND PERMEABILITY: Poorly drained. Permeability is slow. Runoff is high. These soils remain saturated from late November to May with aquic conditions from December to May in most years.

USE AND VEGETATION: Used primarily for timber production and wildlife habitat. Some areas are used for pasture. Native vegetation is loblolly pine, slash pine, black gum, red maple, yaupon, wax leaf myrtle, Saint John's Cross, sumpweed, bluestems, threeawns, sedges, rushes, and club moss. Pastures are bahiagrass.

DISTRIBUTION AND EXTENT: The Western Gulf Coast Flatwoods of southeast Texas and possibly Louisiana; LRR T; MLRA 152B; moderate extent

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

SERIES ESTABLISHED: Hardin County, Texas, 1998.

REMARKS:
Diagnostic horizons and features recognized in this pedon are:

Particle-size control section: 90 to 140 cm (35 to 55 in). (Btg horizon)
Ochric epipedon: 0 to 8 cm (0 to 3 in). (A horizon)
Argillic horizon: 90 to 274 cm (35 to 108 in). (Btg1, Btg, Btg3 horizons)
Other features:
Vermic feature: more than 50 percent crawfish bioturbation (A, Bg, and Btg horizons)
Aquic conditions: This soil is saturated with aquic conditions to the surface from late November to May in normal years, and redoximorphic features with chroma of 2 or less.

Additional Comments: The classification was changed in April 2000 from Typic Vermaqualfs to Natric Vermaqualfs due to lab data from the series type location from Hardin County, Texas.

The assignment of the cation-exchange activity class is supported by laboratory data number (S94TX-199-005) from series type location in Hardin County, Texas.

ADDITIONAL DATA: National Soil Survey Laboratory data on samples (S94TX-199-005) and Texas A&M University Soil Characterization Lab on samples from the series type location in Hardin County, Texas.

Taxonomic Version: Soil Taxonomy, Eleventh Edition, 2010

National Cooperative Soil Survey
U.S.A.