LOCATION TIMPSON TX+LA AREstablished Series
TAXONOMIC CLASS: Coarse-silty, siliceous, semiactive, thermic Oxyaquic Glossudalfs
TYPICAL PEDON: Timpson silt loam, on a mound, 1 percent slope in timber; elevation is 58 m (190 ft) (Colors are for moist soil unless otherwise stated.)
A--0 to 18 cm (0 to 7 in); dark grayish brown (10YR 4/2) silt loam; weak fine subangular blocky structure; soft, friable; many fine, medium and coarse roots; strongly acid; clear smooth boundary. (Thickness is 8 to 20 cm [3 to 8 in].)
E--18 to 36 cm (7 to 14 in); yellowish brown (10YR 5/4) very fine sandy loam; weak medium subangular blocky structure; soft; very friable; many fine, medium and coarse roots; very strongly acid; clear smooth boundary.
BE--36 to 53 cm (14 to 21 in); strong brown (7.5YR 5/6) very fine sandy loam; moderate fine and medium subangular blocky structure; soft; very friable; many fine, medium and coarse roots; few fine distinct yellow (10YR 7/6) and few fine faint reddish yellow masses of iron accumulation; extremely acid; clear smooth boundary. (Combined thickness of E and BE horizons is 25 to 76 cm [10 to 30 in].)
Bt1--53 to 71 cm (21 to 28 in); strong brown (7.5YR 5/8) loam; weak coarse prismatic structure parting to weak fine subangular blocky; slightly hard, friable; common fine, medium and coarse roots; many very fine and common fine and medium pores; few fine distinct red (2.5YR 4/6) masses of iron accumulation; few faint clay films on faces of peds; very strongly acid; clear smooth boundary.
Bt2--71 to 86 cm (28 to 34 in); strong brown (7.5YR 5/6) loam; weak coarse prismatic structure parting to weak fine subangular blocky; slightly hard, friable; few fine, medium and coarse roots; many very fine and common fine and medium pores; few fine faint reddish yellow (7.5YR 6/8) iron accumulations; few faint clay films on faces of peds; few fine black iron-manganese concretions; very strongly acid; clear smooth boundary.
Bt3--86 to 112 cm (34 to 44 in); yellowish brown (10YR 5/6) loam; weak coarse prismatic structure parting to moderate medium subangular blocky; slightly hard, friable; few fine, medium and coarse roots; many fine and common medium pores; few coarse pores; common medium distinct yellowish red (5YR 5/6) and few medium faint reddish yellow (7.5YR 6/6) masses of iron accumulation; few faint clay films on faces of peds; few thin light gray (10YR 7/2) skeletans and clay depletions; few fine and medium black iron-manganese concretions; about 20 percent of matrix is brittle; very strongly acid; clear smooth boundary. (Combined thickness of Bt horizon is 25 to 102 cm [10 to 40 in].)
Bt/E--112 to 135 cm (44 to 53 in); light yellowish brown (10YR 6/4) loam in the Bt part; weak fine prismatic structure parting to moderate fine subangular blocky; hard, friable; few fine, medium and coarse roots; common fine and medium pores; common medium prominent red (2.5YR 5/8) masses of iron accumulation; common fine prominent yellowish red (5YR 4/6) masses of iron accumulation; few fine prominent red (2.5YR 4/8) masses of iron accumulation; grayish brown clay films mainly on vertical faces of prisms; faint clay films throughout; light gray (10YR 7/2) intrusions of albic materials (E parts) make up about 33 percent of the volume, and about 20 percent are tongues 10 to 15 mm wide that extend through the horizon; about 10 percent of matrix is brittle; very strongly acid; abrupt irregular boundary. (Thickness is 0 to 36 cm [0 to 14 in].)
2Btg/E--135 to 145 cm (53 to 57 in); light brownish gray (10YR 6/2) clay loam in the Btg part; weak coarse prismatic structure parting to weak fine subangular blocky; extremely hard, very firm; few fine and medium roots; few fine pores; common medium and coarse prominent red (2.5YR 4/6) masses of iron accumulation; few fine distinct brownish yellow (10YR 6/6) masses of iron accumulation; few clay films on faces of prisms; light gray (10YR 7/2) intrusions of albic materials (E parts) make up about 40 percent of the volume, and about 33 percent are tongues 5 to 12 mm wide and 5 to 7 cm long; very strongly acid; clear smooth boundary. (Thickness is 0 to 31 cm [0 to 12 in].)
2Btg1--145 to 158 cm (57 to 62 in); gray (10YR 6/1) clay loam; weak coarse prismatic structure parting to moderate fine subangular blocky; extremely hard, very firm; few fine and medium roots; few fine pores; common medium and coarse red (2.5YR 4/6) masses of iron accumulation; few fine distinct strong brown (7.5YR 5/6) masses of iron accumulation; few pressure faces up to 10 cm across; very strongly acid; gradual wavy boundary.
2Btg2--158 to 188 cm (62 to 74 in); light brownish gray (10YR 6/2) clay loam; weak coarse prismatic structure parting to moderate fine subangular blocky; extremely hard, very firm; few fine and medium roots; few fine pores; many medium and coarse distinct yellowish brown (10YR 5/6) masses of iron accumulation; few fine distinct strong brown (7.5YR 5/8) masses of iron accumulation; few pressure faces; common faint grayish clay films on faces of prisms; very strongly acid; gradual smooth boundary.
2B't3--188 to 203 cm (74 to 80 in); strong brown (7.5YR 5/8) sandy clay loam; weak medium prismatic structure parting to weak fine subangular blocky; very hard, firm; few fine and medium roots; few fine and medium pores; many medium and coarse yellowish brown (10YR 5/6) and light brownish gray (10YR 6/2) iron depletions; common faint dark yellowish brown clay films on faces of prisms; very strongly acid.
TYPE LOCATION: Shelby County, Texas; from the intersection of Farm Road 417 and Texas Highway 87 in Shelbyville; approximately 11 miles northeast on Farm Road 417 to Farm Road 139; 1.4 miles north on Farm Road 139; 0.6 mile west on logging road; 500 feet northwest on skid trail in compartment #8 of the Sabine National Forest. (Latitude: 31 degrees, 50 minutes, 9.1 seconds N; Longitude: 93 degrees, 56 minutes, 58.8 seconds W. Huxley, Texas, Louisiana topographic quadrangle; NAD 1927)
RANGE IN CHARACTERISTICS:
Soil Moisture: An udic soil moisture regime. The soil moisture control section is not dry in any part for more than 90 days in normal years.
Mean annual soil temperature: 19 to 21 degrees C (67 to 69 degrees F)
Depth to abrupt lithologic discontinuity: 114 to 152 cm (45 to 60 in)
Depth to albic materials: 58 to 152 cm (23 to 60 in)
Depth to albic horizon: 8 to 20 cm (3 to 8 in)
Depth to argillic horizon: 46 to 86 cm (18 to 34 in)
Depth to glossic horizon: 76 to 127 cm (30 to 50 in)
Depth to redox depletions: 46 to 100 cm (18 to 40 in)
Depth to episaturation: 76 to 100 cm (30 to 39 in)
Thickness of solum: more than 200 cm (80 in)
Particle-size control section (weighted average)
Clay content: 10 to 18 percent
Rock fragments: 0 to 5 percent
CEC/clay ratio: 0.24 to 0.40
A or Ap Horizon
Hue: 10YR
Value: 3 to 5
Chroma: 2 or 3
Texture: loam, silt loam, very fine sandy loam or fine sandy loam
Clay content: 2 to 12 percent
Redox concentrations: amount-none to few, size-fine to coarse, contrast-faint to prominent, boundary-sharp to diffuse, location-throughout, shades-brown
Rock fragments: rounded ironstone or quartzite range from 0 to 5 percent
Reaction: very strongly to slightly acid (4.5 to 6.5)
E Horizon
Hue: 7.5 YR or 10YR
Value: 5 to 7
Chroma: 3 or 4
Texture: loam, silt loam, very fine sandy loam or fine sandy loam
Clay content: 2 to 12 percent
Redox concentrations: amount-none to common, size-fine to coarse, contrast-faint to prominent, boundary-sharp to diffuse, location-throughout, shades-brown or yellow
Rock fragments: rounded ironstone or quartzite range from 0 to 5 percent
Reaction: very strongly to moderately acid (4.5 to 6.0)
BE Horizon, where present
Hue: 7.5YR or 10YR
Value: 4 to 7
Chroma: 6 or 8
Texture: loam, silt loam, very fine sandy loam or fine sandy loam
Clay content: 4 to 10 percent
Redox concentrations: amount-none to common, size-fine to coarse, contrast-faint to prominent, boundary-sharp to diffuse, location-throughout, shades-brown or yellow
Rock fragments: rounded ironstone or quartzite range from 0 to 5 percent
Reaction: extremely to moderately acid (3.6 to 6.0)
Bt Horizon
Hue: 7.5YR or 10YR
Value: 5 or 6
Chroma: 4 to 8
Texture: loam or silt loam. Silty clay loam may occur below the control section of some pedons
Clay content: 10 to 30 percent
Clay films: location throughout, contrast faint to prominent
Redox concentrations: amount-none to common, size-fine to coarse, contrast-faint to prominent, boundary-clear to diffuse, location-throughout, shades-red, brown or yellow
Redox depletions: amount-0 to 5 percent, size-fine to coarse, contrast-faint to prominent, boundary-clear to diffuse, location-throughout, shades-gray
Rock fragments: rounded ironstone or quartzite range from 0 to 5 percent
Brittleness: 0 to 20 percent
Albic materials: 0 to 5 percent in shades of gray
Reaction: extremely to strongly acid (3.6 to 5.5)
Bt/E Horizon
Hue: 7.5YR or 10YR
Value: 5 or 6
Chroma: 4 to 8
Variegated: Horizon may be variegated in shades of red, brown, yellow or gray
Texture: loam or silt loam. Silty clay loam may occur below the control section
Clay content: 10 to 30 percent
Clay films: location throughout, contrast faint to prominent
Redox concentrations: amount-few to common, size-fine to coarse, contrast-faint to prominent, boundary-clear to diffuse, location-in matrix, shades-red, yellow or brown
Redox depletions: amount-none to common, size-fine to coarse, contrast-faint to prominent, boundary-clear to diffuse, location-in matrix, shades-gray
Albic materials: 8 to 35 percent
Rock fragments: rounded ironstone or quartzite range from 0 to 5 percent
Brittleness: 0 to 10 percent
Albic materials: 8 to 35 percent
Reaction: extremely to strongly acid (3.6 to 5.5)
2Bt/E or 2Btg/E Horizon
Colors: Shades of red, brown or gray
Texture: clay loam, clay, silty clay or silty clay loam?
Clay content: 30 to 50 percent
Clay films: location throughout, contrast faint to prominent
Redox concentrations: amount-few to many, size-fine to coarse, contrast-faint to prominent, boundary-clear to diffuse, location-in matrix, shades-red, brown or yellow
Redox depletions: amount-few to many, size-fine to coarse, contrast-faint to prominent, boundary-clear to diffuse, location-in matrix, shades-gray
Brittleness: 0 to 5 percent
Albic materials: 15 to 45 percent
Reaction: extremely or very strongly acid (3.6 to 5.0)
2Bt Horizon where present
Hue: 10YR to 5YR
Value: 4 or 5
Chroma: 6 or 8
Variegated: horizon may be variegated in shades of red, brown, yellow or gray
Texture: clay loam, clay, silty clay or silty clay loam
Clay content: 30 to 50 percent
Clay films: location throughout, contrast faint to prominent
Redox concentrations: amount-few to many, size-fine to coarse, contrast-faint to prominent, boundary-clear to diffuse, location-in matrix, shades-red, brown or yellow
Redox depletions: amount-few to many, size-fine to coarse, contrast-faint to prominent, boundary-clear to diffuse, location-in matrix, shades-gray
Reaction: extremely or very strongly acid (3.6 to 5.0)
2B't or 2BC Horizon
Hue: 5YR to 7.5YR
Value: 5 or 6
Chroma: 6 or 8
Variegated: horizon may be variegated in shades of yellow, brown, red, gray or olive
Texture: silty clay loam, clay loam, loam or sandy clay loam
Clay content: 20 to 40 percent
Clay films: location throughout, contrast faint to prominent
Redox concentrations: amount-few to many, size-fine to medium, contrast-faint to prominent, boundary-clear to diffuse, location-in matrix, shades-yellow, brown or red
Redox depletions: amount-few to many, size-fine to coarse, contrast-faint to prominent, boundary-clear to diffuse, location-in matrix, shades-gray or olive
Reaction: extremely or very strongly (3.6 to 5.0)
COMPETING SERIES: There are no other series in the same family. Similar soils are the
Gist,
Glenmora,
Keithville,
Leverett,
Messer and
Tippo series.
Gist soils: have a CEC:clay ratio of more than 0.6.
Messer soils: lack a clayey lithologic discontinuity.
Leverett and Tippo soils: have mixed mineralogy.
Keithville and Glenmora soils: lack a glossic horizon
GEOGRAPHIC SETTING:
Parent material: loamy and clayey alluvium over the residuum of the Wilcox geologic formation
Landscape: Coastal plain
Landform: fluvatile or marine terrace
Slope: 0 to 2 percent
Mean annual air temperature range: 18 to 19 degrees C (65 to 66 degrees F)
Mean annual precipitation range: 1220 to 1320 mm (48 to 52 in)
Frost-free period: 235 to 240 days
Elevation: 31 to 122 m (100 to 400 ft)
Thornthwaite annual P-E indices: 78 to 84
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Metcalf (LA),
Latex (TX),
Guyton (LA), and
Eastwood (TX) series.
Metcalf soils: are on lower intermound positions and have aquic conditions in the upper part of the argillic horizon.
Latex soils: are on ridges and do not have a glossic horizon.
Guyton soils: are on lower positions and have a gray matrix throughout.
Eastwood soils: are on ridges and sideslopes and have a fine particle size family.
DRAINAGE AND PERMEABILITY: Moderately well drained. Permeability is moderately slow. Runoff is low to medium. A perched water table is at a depth of 76 to 107 cm (2.5 to 3.5 feet) for brief to long durations during January through March.
USE AND VEGETATION: Used for pasture or woodland. Native vegetation consists of loblolly pine, shortleaf pine, sweetgum and red oak. Bermudagrass and bahiagrass are used in most improved pastures.
DISTRIBUTION AND EXTENT: Eastern Texas and Louisiana; Land Resource Region (P); MLRA 133B; the series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Shelby County, Texas, 2002, Shelby County soil survey area, Texas, 2002. The name is from a nearby community.
REMARKS: The series was formerly included in the Sawtown, Cart and Messer series. The series was separated based on particle size control section and presence of a clayey lithologic discontinuity.
Diagnostic horizons and features recognized in this pedon are:
Particle size control section: 53 to 104 cm (21 to 41 in.) (Bt1, Bt2, Bt3 horizon)
Ochric epipedon: 0 to 36 cm (0 to 14 in). (A and E horizons)
Argillic horizon: 53 to 203 cm (21 to 80 in). (Bt, Bt/E, 2Bt/E, 2Btg, 2Bt'3 horizons)
Glossic horizon: 112 to 145 cm (44 to 57 in). (Bt/E, 2Bt/E horizons)
Redoximorphic concentrations: 36 to 188 cm (21 to 74 in). (BE, Bt, Bt/E, 2Btg/E, 2Btg1 horizons)
Redoximorphic depletions: 86 to 203 cm (34 to 80 in). (Bt3, Bt/E, 2Btg/E, 2Btg, 2Bt'3 horizons)
Episaturation: The zone of saturation at 86 to 145 cm (34 to 57 in). (Bt3, Bt/E, 2Btg/E horizons)
Lithologic discontinuity: At the upper boundary of the 2Btg/E horizon.
The assignment of the cation-exchange activity class is supported by laboratory data number S86TX-419-001 from Shelby County, Texas.
ADDITIONAL DATA: TAMU Data from type location S86TX-419-001. Particle-size analysis tests were performed at the project office on six pedons. Piezometer data available from the type location for the period of October 1993 through October 2001.
TAXONOMIC VERSION: Keys to Soil Taxonomy, 10th Edition, 2006