LOCATION PLEDGER TX+OK

Established Series
WLM-CLN-RM
09/2015

PLEDGER SERIES

The Pledger series consists of very deep, moderately well drained, very slowly permeable soils that formed in clayey alluvium. These nearly level soils are on flood plains. Slope ranges from 0 to 1 percent, but mostly less than 0.5 percent. Mean annual precipitation is about 1245 mm (45 in). Mean annual air temperature is about 20.6 degrees C (69 degrees F).

TAXONOMIC CLASS: Very-fine, smectitic, hyperthermic Typic Hapluderts

TYPICAL PEDON: Pledger clay- taken from a microlow in bottomland hardwood forest, at an elevation about 12.2 m (40 ft). (Colors are for moist soil unless otherwise stated.)

A1--0 to 20 cm (0 to 8 in); black (10YR 2/1) clay, black (10YR 2/1), dry; moderate fine subangular blocky structure; extremely firm, extremely hard, very sticky, very plastic; common fine and medium roots; common fine tubular and many very fine tubular pores; less than 1 percent very fine prominent strong brown (7.5YR 5/6) masses of oxidized iron with sharp boundaries lining pores; neutral, clear smooth boundary. (combined thickness of the A horizons is 30 to 76 cm [12 to 30 in])

A2--20 to 44 cm (8 to 17 in); black (10YR 2/1) clay, black (10YR 2/1), dry; moderate fine and medium subangular blocky structure; extremely firm, extremely hard, very sticky, very plastic; common fine and medium roots; few fine and many very fine pores; less than 1 percent very fine prominent strong brown (7.5YR 5/6) masses of oxidized iron with sharp boundaries lining pores; neutral; clear smooth boundary.

Bss1--44 to 88 cm (17 to 35 in); black (10YR 2/1) clay, very dark gray (10YR 3/1), dry; moderate medium wedge structure parts to moderate medium subangular blocky structure; extremely firm, extremely hard, very sticky, very plastic; common fine roots and few medium roots; few fine tubular and many very fine tubular pores; 15 percent distinct slickensides (pedogenic); 1 percent very fine prominent strong brown (7.5YR 5/6) masses of oxidized iron with sharp boundaries lining pores; wedge-shaped peds tilted at 35 to 45 degrees to the horizontal; neutral; gradual smooth boundary. (Combined thickness of the Bss horizons is 28 to 107 cm [11 to 42 in])

Bss2--88 to 133 cm (35 to 52 in); black (10YR 2/1) clay, very dark gray (10YR 3/1), dry; moderate medium wedge structure parts to moderate medium angular blocky structure; extremely firm, extremely hard, very sticky, very plastic; few fine and medium roots; few fine tubular and common very fine tubular pores; 25 percent distinct pressure faces and 25 percent prominent slickensides (pedogenic); 1 percent very fine prominent strong brown (7.5YR 5/6) masses of oxidized iron with sharp boundaries lining pores; wedge-shaped peds tilted at 40 to 45 degrees to the horizontal; slightly alkaline; gradual wavy boundary.

Bkss1--133 to 171 cm (52 to 67 in); yellowish red (5YR 4/6) silty clay, yellowish red (5YR 5/6), dry; moderate medium wedge structure parts to moderate medium angular blocky structure; extremely firm, extremely hard, very sticky, very plastic; few fine roots; few fine tubular and common very fine tubular pores; 25 percent prominent pressure faces and 50 percent slickensides (pedogenic); 1 percent fine and medium distinct strong brown (7.5YR 5/8) masses of oxidized iron with clear boundaries on faces of peds and 2 percent fine distinct grayish brown (10YR 5/2) iron depletions with clear boundaries on slickensides; 2 percent fine carbonate nodules; wedge shaped peds tilted at 50 to 60 degrees to the horizontal; strong effervescence; slightly alkaline; gradual wavy boundary. (Combined thickness of the Bkss horizons is 61 to 157 cm [24 to 62 in])

Bkss2--171 to 182 cm (67 to 72 in); yellowish red (5YR 4/6) clay, yellowish red (5YR 5/6), dry; moderate medium wedge structure parts to moderate medium angular blocky structure; extremely firm, extremely hard, very sticky, very plastic; few fine roots; few fine tubular and common very fine tubular pores; 10 percent prominent pressure faces and 30 percent prominent slickensides (pedogenic); 1 percent fine and medium prominent gray (10YR 6/1) iron depletions with clear boundaries on slickensides; 1 percent fine and medium black (7.5YR 2.5/1) iron-manganese nodules; 2 percent fine carbonate nodules; wedge-shaped peds tilted at 50 to 60 degrees to the horizontal; strong effervescence; slightly alkaline; gradual wavy boundary.

Bkss3--182 to 220 cm (72 to 87 in); red (2.5YR 4/6) silty clay, red (2.5YR 5/6), dry; moderate medium wedge structure parts to moderate medium angular blocky structure; extremely firm, extremely hard,very sticky, very plastic; few fine roots; few fine tubular and common very fine tubular pores; 10 percent distinct pressure faces and 25 percent prominent slickensides (pedogenic); 1 percent fine and medium prominent gray (10YR 6/1) iron depletions with clear boundaries on slickensides; 1 percent fine and medium black (7.5YR 2.5/1) iron-manganese nodules; 1 percent fine and medium prominent black (10YR 2/1) iron-manganese masses with clear boundaries lining pores; 1 percent fine carbonate nodules; wedge-shaped peds tilted at 50 to 60 degrees to the horizontal; strong effervescence; slightly alkaline; gradual smooth boundary.

TYPE LOCATION: Brazoria County, Texas; from the intersection of Texas Highway 35 and FM 524 in Old Ocean, 3.6 miles west on FM 524 to entrance of the US Fish and Wildlife Service property; 0.25 mile north on dirt road; 0.2 mile east on dirt road; 250 ft south in bottomland hardwood in a nonponded area. Ashwood USGS quadrangle; Latitude: 29 degrees 7 minutes 7 seconds N; Longitude: 95 degrees 46 minutes 54 seconds W; WGS84.

RANGE IN CHARACTERISTICS:
Solum thickness: more than 203 cm (80 in).
When dry, cracks more than 1 cm (0.4 in) wide extend from the surface to depths ranging from 50 to 127 cm (20 to 50 in).
Depth to slickensides and wedge shaped aggregates: 30 to 66 cm (12 to 26 in).
Calcium carbonate segregations: 1 to 5 mm in size, range from less than 1 to 3 percent of some horizon from 100 to 152 cm (40 to 60 in) of the surface.
Undisturbed areas have gilgai, with microhighs 10 to 30 cm (4 to 12 in) higher than microlows. Distance between microhighs and microlows ranges from 1 to 3.7 m (3.5 to 12 ft). Microhighs tend to have the higher chroma subsoil and carbonate segregations closer to the surface than the microlows.
Soil Moisture: An udic soil moisture regime. The soil moisture control section is not dry for more than 300 days in normal years.
Mean annual soil temperature: 21.7 to 22.8 degrees C (71 to 73 degrees F)

Particle size control section (weighted average)
Clay content: 60 to 80 percent.
Sand content: 1 to 5 percent.

A Horizons:
Hue: 5YR to 10YR
Value: 2 or 3
Chroma: 1
Texture: clay or silty clay
Clay content: 55 to 75 percent
Sand content: 1 to 10 percent
Redox concentrations: amount-none to 1 percent, shades-or brown or yellow
Redox depletions: amount-none to 1 percent, shades-gray
Effervescence: none to very slight (effervescence usually occurs only in microhighs)
Reaction(pH): slightly acid to slightly alkaline (6.1 to 7.8)

Bss Horizons:
Hue: 5YR to 10YR
Value: 2 or 3
Chroma: 1 or 2
Texture: clay or silty clay
Clay content: 60 to 75 percent
Sand content: 1 to 10 percent
Slickensides/Pressure faces: amount-few to many; distinctness-distinct or prominent
Redox concentrations: amount-none to 2 percent, shades-brown or yellow
Redox depletions: amount-none to 2 percent, shades-gray
Iron-manganese concentrations: amount-none to 2 percent; size-fine; kind-nodules
Effervescence: none to strong (effervescence usually occurs only in microhighs)
Reaction(pH): neutral to moderately alkaline (6.6 to 8.4)

Bkss Horizons:
Hue: 2.5YR to 7.5YR
Value: 3 to 6
Chroma: 2 to 6
Texture: clay or silty clay
Clay content: 45 to 75 percent
Sand content: less than 1 percent to 10 percent
Slickensides/Pressure faces: amount-few to many; distinctness-distinct or prominent
Redox concentrations: amount-none to 5 percent, shades-brown or yellow
Redox depletions: amount-none to 5 percent, shades-gray
Iron-manganese concentrations: amount-none to 2 percent; size-fine; kind-nodules and masses
Effervescence: slight to strong
Reaction(pH): slightly alkaline or moderately alkaline (7.4 to 8.4)

Some pedons have BC or BCk horizons has about the same colors as the lower Bss horizons. Texture is mainly clay with thin discontinious strata of silt loam, silty clay loam, and silty clay. Buried soils having dark A horizons are common below 102 cm (40 in). Reaction is slightly alkaline or moderately alkaline and strongly effervescent.

COMPETING SERIES: There are no series in the same family. Similiar soils are the Brazoria, Ganado, Laewest, and Lake Charles series.
Brazoria soils: have chroma of 3 or more, or value of 4 or more, in the upper 30 cm (12 in) of the solum.
Ganado, Laewest, and Lake Charles soils: have a particle-size control section with less than 60 percent clay

GEOGRAPHIC SETTING:
Parent material: clayey alluvium derived from granitic sources in Central and North Central Texas
Landscape: river valleys on flat coastal plains
Landform: flood plains
Slope: 0 to 1 percent, but mainly less than 0.5 percent
Mean annual precipitation: 1143 to 1397 mm (45 to 55 in)
Precipitation Pattern: uniform throughout the year with slight peaks in spring and fall months
Thornthwaite P-E Index: 60 to 66
Mean annual air temperature: 20.6 to 21.7 degrees C (69 to 71 degrees F)
Frost-free period: 270 to 335 days
Elevation: 3 to 30.5 m (10 to 100 ft)

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Asa, Brazoria, Churnabog, Lake Charles, and Norwood series.
Asa and Norwood soils: are in a fine-silty family; on a slightly higher position on a similar landform
Brazoria soils are on a similar to slightly higher positions on a similar landform.
Lake Charles soils: formed in fluviomarine deposits; not on flood plains

DRAINAGE AND PERMEABILITY: Moderately well drained. Permeability is very slow. Runoff is medium to high Water enters the soil rapidly when dry and cracked, and very slow when moist. These soils flood rarely to frequently, except where protected, for brief duration.

USE AND VEGETATION: Mainly used as improved pasture, cropland or wildlife habitat. The main crops are corn, cotton, and sorghum. Improved pasture consists of bermudagrass and dallisgrass. Native vegetation is pecan, elm, oak, ash, dwarf palmetto and cottonwood trees. In open areas mid and tall grasses.

DISTRIBUTION AND EXTENT: Mainly along the lower reaches of the Brazos and Colorado Rivers; LRR T; MLRA-150A (Gulf Coast Prairies). The series is of large extent.

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

SERIES ESTABLISHED: Reconnaissance soil survey of Central Gulf Coast Area of Texas; 1910.

REMARKS: Particle size and mineralogy data from the type location and TAMU data on 10 pedons from Matagorda, Wharton, Brazoria and Ft. Bend Counties, Texas, indicate a very-fine, montmorillonitic family. Based on this data, classification changed from fine, mixed, thermic Vertic Hapludolls to very-fine, montmorillonitic, thermic Typic Pelluderts, 8/90. The classification is changed from thermic Typic Pelluderts to hyperthermic Typic Hapluderts based on Amendment 16 to Soil Taxonomy (2/94). The temperature regime change is based on NRCS temperature study. The series type location was moved from Fort Bend County to Brazoria County during the Soil Data Join and Recorrelation initiative in 2015. The Fort Bend site is on the fringe of the series province and was disturbed by nearby urban encroachment.

Diagnostic horizons and features recognized in this pedon are:

Mollic epipedon: 0 to 133 cm (0 to 52 in) (A1, A, Bss1, and Bss2 horizons)
Calcic horizon (more than 20 percent calcium carbonate equivalent):133 to 220 cm (52 to 87 in) Bkss horizons
Cambic horizon: 44 to 220 cm (17 to 87 in) (Bss1, Bss2, Bkss1, Bkss2, Bkss3 horizons).

Vertic features: Slickensides from 44 to 220 cm (17 to 87 in). Deep, wide cracks open less than 90 cumulative days in most years.

ADDITIONAL DATA: KSSL characterization data on type location on pedon number 98TX039003. Engineering test data by TDHPT (Sample No. S76TX039-009, Brazoria County, TX). More information on hydrology, vegetation and characterization can be found in the final report of the bottomland hardwoods soil moisture monitoring study conducted by Wes Miller of the NRCS.

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

National Cooperative Soil Survey
U.S.A.