LOCATION ALAZAN TXEstablished Series
TAXONOMIC CLASS: Fine-loamy, siliceous, semiactive, thermic Aquic Glossudalfs
TYPICAL PEDON: Alazan loam--an intermound area in native pasture. (colors are for moist soil conditions)
A--0 to 13 cm (0 to 5 in); brown (10YR 4/3) loam; weak fine subangular blocky structure; hard, very friable; common fine and medium roots; few fine pores; strong brown and reddish stains along some root channels; moderately acid; clear smooth boundary (Thickness is 8 to 18 cm [3 to 7 in]).
E--13 to 25 cm (5 to 10 in); pale brown (10YR 6/3) loam; common fine distinct brownish yellow (10YR 6/6) and few fine prominent yellowish red (5YR 5/6) redox concentrations; weak fine subangular blocky structure; hard, very friable; few fine and medium roots; few fine pores; few faint grayish brown worm casts; strongly acid; clear smooth boundary (Thickness is 8 to 26 cm [3 to 18 in]).
Bt/E1--25 to 76 cm (10 to 30 in); strong brown (7.5YR 5/6) sandy clay loam; few medium distinct grayish brown (10YR 5/2) redox depeletions and few fine distinct yellowish red (5YR 4/6) redox concentrations; moderate medium subangular blocky structure; hard, firm; few fine roots; few fine pores; few thin clay films on surfaces of peds; streaks, coatings, and pockets of albic material make up about 15 percent by volume (E); few fine iron-manganese concretions; about 5 percent of matrix is brittle; strongly acid; gradual irregular boundary.
Bt/E2--76 to 203 cm (30 to 80 in); reddish yellow (7.5YR 6/8) sandy clay loam; few medium distinct yellowish red (5YR 4/6) redox concentrations and few fine prominent light brownish gray redox depletions; weak coarse prismatic structure parting to moderate medium subangular blocky; hard, firm; few fine roots; few fine pores; few thin clay films on surfaces of prisms; streaks, coatings, and pockets of albic material make up about 30 percent by volume (E); few fine iron-manganese concretions; about 10 percent of the matrix is brittle; strongly acid (Combined thickness of the Bt/E and Btg/E horizons is 76 to more than 178 cm [30 to more than 70 in]).
TYPE LOCATION: Rusk County, Texas; From Tatum at the intersection of Texas Highway 149 and Texas Highway 43; 2.0 miles northwest on Texas Highway 149; 0.1 mile east on county road 2187; 0.1 mile north on county road 2144; 0.1 mile west on county road 2196; site is 250 feet north in an intermound area of native pasture.
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 70 degrees F)
Thickness of thickness: more than 203 cm (80 in)
Particle-size control section (weighted average)
Clay content: 18 to 25 percent
Silt content: 25 to 45 percent
CEC/clay ratio: 0.24 to 0.40
A horizon
Hue: 10YR
Value: 3 to 5
Chroma: 1 to 3
Texture: very fine sandy loam, fine sandy loam or loam
Rock fragments: none to few quartzite pebbles are in some pedons
Reaction: very strongly acid to moderately acid (4.5 to 6.0)
E horizon
Hue: 10YR
Value: 5 to 7
Chroma: 2 to 4
Redox concentrations: amount-none to common, size-fine to medium, contrast-distinct to prominent, boundary-clear to diffuse, shades-red or brown
Redox depletions: amount-none to common, size-fine to medium, contrast-distinct to prominent, boundary-clear to diffuse, shades-gray
Texture: very fine sandy loam, fine sandy loam or loam
Rock fragments: none to few quartzite pebbles are in some pedons
Reaction: very strongly acid or strongly acid (4.5 to 5.5)
Bt horizon where present
Hue: 7.5YR or 10YR
Value: 5 or 6
Chroma: 4 to 8
Redox concentrations: amount-few to many, size-fine to medium, contrast-distinct to prominent, boundary-clear to diffuse, shades-red or brown
Redox depletions: amount-few to many, size-fine to medium, contrast-distinct to prominent, boundary-clear to diffuse, shades-gray
Texture: loam, sandy clay loam or clay loam
Other features: thickness ranges up to 66 cm (26 in)
Reaction: very strongly acid or strongly acid (4.5 to 5.5)
Bt/E horizon
Hue: 7.5YR or 10YR
Value: 5 or 6
Chroma: 4 to 8
Redox concentrations: amount-few to many, size-fine to medium, contrast-distinct to prominent, boundary-clear to diffuse, shades-red or brown
Redox depletions: amount-few to many, size-fine to medium, contrast-distinct to prominent, boundary-clear to diffuse, shades-gray
Texture: loam, clay loam or sandy clay loam in the Bt part, and loam, fine sandy loam, or sandy loam in the E part
Other features: Intrusions of albic materials (E parts) make up 5 to 50 percent of the horizon, however, the glossic horizon (with more than 15 percent albic material) is more than 20 inches thick. In most pedons, 5 to 20 percent of the matrix is brittle
Reaction: very strongly acid to lightly acid (4.5 to 6.5)
Btg/E horizon where present
Hue: 7.5YR or 10YR
Value: 5 or 6
Chroma: 2
Redox concentrations: amount-common to many, size-fine to medium, contrast-distinct to prominent, boundary-clear to diffuse, shades-red or brown
Redox depletions: amount-common to many, size-fine to medium, contrast-distinct to prominent, boundary-clear to diffuse, shades-gray
Texture: loam, clay loam or sandy clay loam in the Bt part, and loam, fine sandy loam, or sandy loam in the E part
Other features: Intrusions of albic materials (E parts) make up 5 to 50 percent of the horizon
Reaction: very strongly acid to lightly acid (4.5 to 6.5)
COMPETING SERIES: There are no other series in the same family. The
Bernaldo,
Freestone,
Kurth.
Keithville,
Metcalf,
Penning,
Raino, and
Sawlit series are in closely related families. Kurth and Penning soils: have sola 40 and 60 inches thick.
Sawlit soils: have a clayey 2Bt horizon at a depth of 26 to 40 inches.
Bernaldo and Freestone soils: do not have a glossic horizon.
Keithville and Metcalf soils: have a fine-silty particle-size control section.
Raino soils: have a fine-loamy over clayey particle-size control section.
GEOGRAPHIC SETTING:
Parent material: Pleistocene terraces derived from alluvium
Landscape: Coastal Plain
Landform: Small drainageways, stream terraces above flood plains of large streams or rivers , or higher Pleistocene age marine terraces associated with uplands
Slope: Slopes range from 0 to 2 percent.
Mean annual air temperature range: 19 to 21 degrees C (67 to 70 degrees F)
Mean annual Precipitation range: 1016 to 1397 mm (40 to 55 in)
Frost-free period: 235 to 250 days
Elevation: 70 to 79 m (230 to 260 ft)
Thornthwaite annual P-E indices: Exceeds 64
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing
Bernaldo series, and the
Attoyac,
Besner,
Gallime, and
Mollville series.
Bernaldo and Gallime soils: are on slightly higher terrace positions, are well drained and do not have a glossic horizon.
Attoyac soils: have a reddish subsoil, and are on slightly higher positions or on side slopes below areas of Alazan soils.
Besner soils: have a coarse-loamy control section and are on slightly higher positions, typically on mounds.
Mollville soils: are on lower, wetter depressions and are poorly drained.
DRAINAGE AND PERMEABILITY: Moderately well drained. Permeability is moderate. Runoff is very low. An apparent water table is at a depth of 46 to 76 cm (18 to 30 in) during the winter and spring seasons for long to very long durations. The water table is present for a cumulative period of 1 to 3 months during normal years.
USE AND VEGETATION: Used mainly for timber with some areas of improved pasture. A few areas have been cleared and are used for cropland or pasture. Native vegetation is loblolly and shortleaf pine with mixed hardwoods. The understory is dogwood, waxmyrtle, longleaf uniola, pinehill bluestem, and other grasses. Improved pastures include bermudagrass and bahiagrass.
DISTRIBUTION AND EXTENT: Eastern Texas and Louisiana. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Angelina County, Texas; 1984.
REMARKS: The series was updated in 2002 to allow a Bt horizon to occur in some pedons above the glossic horizon. The series was updated in 2004 to add fine sandy loam texture to the range in characteristics for the A and E horizons, allow value 5 in the range in characteristics for the E horizon, allow none to few quartzite pebbles in the epipedon in some pedons, allow clay loam texture in the Glossic horizon, allow the Bt/E horizon to range up to slightly acid, and allow the Btg/E horizon to range down to very strongly acid.
This soil was formerly included in the Caddo or Thage series.
Diagnostic horizons and features in this pedon include:
Ochric epipedon ---- 0 to 25 cm (0 to 10 in). (A and E horizons)
Argillic horizon---- 25 to 203 cm (10 to 80 in). (Bt/E horizons)
Glossic horizon ---- 25 to 203 cm (10 to 80 in). (Bt/E horizons)
Aquic conditions --- 46 to 76 cm (18 to 30 in). (Bt/E1 horizon).
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