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 5 inches; 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 (3 to 7 inches thick).
E--5 to 10 inches; 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 (3 to 18 inches thick).
Bt/E1--10 to 30 inches; 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--30 to 80 inches; 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 30 to more than 70 inches).
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:
Solum thickness: More than 80 inches
Clay content in the Control Section: 18 to 25 percent
Redoximorphic features: Iron concentrations in shades of red, yellow, or brown, and iron depletions in shades of gray in the subsurface and subsoil
Other distinctive soil features: Silt content in the particle-size control section ranges from 25 to 45 percent
Concentrated minerals: None
A horizon:
Color--Hue of 10YR, value of 3 to 5, and chroma of 1 to 3
Redoximorphic features--None
Texture--Very fine sandy loam, fine sandy loam or loam
Other features--None to few quartzite pebbles are in some pedons
Reaction--Very strongly acid to moderately acid
E horizon:
Color--Hue of 10YR, value of 5 to 7, and chroma of 2 to 4
Redoximorphic features--Iron concentrations in shades of brown,or red, and iron depletions in shades of gray range from none to common
Texture--Very fine sandy loam, fine sandy loam or loam
Other features--None to few quartzite pebbles are in some pedons
Reaction--Very strongly acid or strongly acid
Bt horizon: (where present)
Color--Hue of 7.5YR or 10YR, value of 5 or 6, and chroma of 4 to 8
Redoximorphic features--Iron concentrations in shades of red, yellow, or brown, and iron depletions in shades of gray range from few to many.
Texture--Loam or sandy clay loam
Other features--Thickness ranges up to 26 inches
Reaction--Very strongly acid or strongly acid
Bt/E horizon:
Color--Hue of 7.5YR or 10YR, value of 5 or 6, and chroma of 4 to 8
Redoximorphic features--Iron concentrations in shades of red, yellow, or brown, and iron depletions in shades of gray range from few to many.
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 slightly acid
Btg/E horizon: (where present)
Color--Hue of 7.5YR or 10YR, value of 5 or 6, and chroma of 2
Redoximorphic features--Iron concentrations in shades of red, yellow, or brown, and iron depletions in shades of gray range from common to many.
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 slightly acid
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: Alazan soils are on nearly level Pleistocene terraces. Slopes range from 0 to 2 percent. They are along small drainageways and on stream terrace positions about 2 to 10 feet above flood plains of large streams or rivers, or they are on higher Pleistocene age marine terraces associated with uplands. They formed in thick loamy sediments. Mean annual rainfall ranges from 40 to 55 inches and is evenly distributed throughout the year. Mean annual temperature ranges from 65 to 70 degrees F. Frost free days are 235 to 250. The elevation is 230 to 260 feet above sea level. The Thornthwaite annual P-E indices exceed 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: Alazan soils are moderately well drained. Permeability is moderate. Runoff is very low. An apparent water table is at a depth of 1.5 to 2.5 feet 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 OFFICE RESPONSIBLE: Little Rock, Arkansas
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 10 inches (A and E horizons)
Argillic horizon---- 10 to 80 inches (Bt/E horizons)
Glossic horizon ---- 10 to 80 inches (Bt/E horizons)
Aquic conditions --- 18 to 30 inches (Bt/E1 horizon).