LOCATION IOTA LA

Established Series
DRM-JKW-RM
10/2013

IOTA SERIES

The Iota series consists of very deep, well drained soils. These soils formed in loamy and clayey sediments of Pleistocene age. These gently sloping to moderately sloping soils are on terraces. Slopes range from 3 to 8 percent. Mean annual air temperature is about 19.5 degrees C (67 degrees F), and mean annual precipitation is about 1549 mm (61in).

TAXONOMIC CLASS: Fine, smectitic, thermic Vertic Hapludalfs

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

A--0 to 8 cm (0 to 3 in); brown (10YR 4/3) silt loam; weak fine granular structure; slightly hard, friable; many fine and medium roots; strongly acid; abrupt smooth boundary. (8 to 15 cm [3 to 6 in] thick)

E--8 to 18 cm (3 to 7 in); pale brown (10YR 6/3) silt loam; weak medium platy structure parting to weak fine granular; slightly hard, friable; many fine and medium roots; very strongly acid; abrupt smooth boundary. (0 to 13 cm [0 to 5 in] thick)

Bt--18 to 41 cm (7 to 16 in); red (2.5YR 4/8) silty clay; moderate medium subangular blocky structure; slightly hard, firm; common fine and medium roots; common very fine and fine tubular pores; few distinct clay films on surface of peds and in pores; very strongly acid; clear wavy boundary.

Btss--41 to 71 cm (16 to 28 in); yellowish red (5YR 4/6) silty clay; moderate medium subangular blocky structure; hard, firm; few fine and medium roots; common very fine and fine tubular pores; common distinct slickensides with wedge shaped aggregates; common distinct clay films on surface of peds and in pores; common coarse prominent strong brown (7.5YR 5/6) masses of iron accumulation and common medium prominent pale brown (10YR 6/3) iron depletions in matrix; very strongly acid; gradual wavy boundary. (Combined thickness of the Bt horizons range from 41 to 119 cm [16 to 47 in])

BC--71 to 109 cm (28 to 43 in); variegated matrix of reddish brown (5YR 5/4) and yellowish red (5YR 5/8) silty clay loam; moderate medium subangular blocky structure; hard, firm; few medium distinct yellowish red (5YR 4/6) masses in matrix; stratified pockets of pale brown (10YR 6/3) silt loam; very strongly acid; gradual wavy boundary. (0 to 61 cm [0 to 24 in] thick)

C1--109 to 152 cm (43 to 60 in); pale brown (10YR 6/3) silty clay loam; massive; firm; many fine and medium round iron-manganese concretions; slightly acid; gradual wavy boundary.

C2--152 to 203 cm (60 to 80 in) ; pale brown (10YR 6/3) silt loam; massive; friable; neutral.

TYPE LOCATION: Acadia Parish, Louisiana; about 3 miles north-northeast of Iota to end of Parish Road 436; 0.9 mile northwest on woodland road; 300 feet south of drain and 200 feet northeast in woodland. (Evangeline USGS quad; 1550 feet north and 2800 feet west of the southeast corner of section 12, T. 8 S., R. 2 W.; Latitude 30 degrees, 22 minutes, 2 seconds N; Longitude 92 degrees, 32 minutes, 2 seconds W; WGS 84).

RANGE IN CHARACTERISTICS:
Solum thickness: 102 to 152 cm (40 to 60 in).

Particle-size control section (weighted average)
Clay content: 40 to 60 percent
Linear extensibility is 6 cm or more between the soil surface and a depth of 100 cm (39.4 in). Slickensides or wedge shaped peds are within 125 cm (49.2 in) of the soil surface.

A (Ap where present) Horizon
Hue: 10YR
Value: 3 to 5 (where value is 3, the thickness is less than 15 cm (6 in)
Chroma: 1 to 3
Texture: very fine sandy loam or silt loam
Reaction: very strongly acid to moderately acid.

E (where present) Horizon
Hue: 10YR
Value: 5 to 7
Chroma: 1 to 3
Texture: very fine sandy loam or silt loam
Reaction: very strongly acid to moderately acid.

Bt and Btss Horizons
Hue: 2.5YR or 5YR
Value: 3 to 5
Chroma: 4 to 8
Texture: clay or silty clay
Redox concentrations: amount-none to many, shades- red or brown
Redox depletions: amount-none to many, shades- gray
Reaction: very strongly acid to neutral

BC Horizon
Variegated matrix in shades of red, brown, or gray
Texture: silty clay loam, clay, or silty clay
Identifiable secondary carbonate: amount-none to few, kind-concretions
Reaction: very strongly acid to neutral.

C (Ck where present) Horizon
Hue: 10YR (Some pedons have a variegated matrix in shades of red, brown, or gray)
Value: 5 to 7
Chroma: 2 or 3
Texture: very fine sandy loam, silt loam, silty clay loam, clay, or silty clay or stratified with these textures
Identifiable secondary carbonate: amount-none to common, kind-concretions
Reaction: upper part ranges from slightly acid to slightly alkaline. In the lower part reaction ranges from neutral to moderately alkaline.

COMPETING SERIES: These are the Chickasaw (TN), Colbert (AL), Etoile (TX), Kellison (TX), Oakhurst (TX), Oula (LA), Rayburn (TX), Telogia (FL), and Woodtell (TX) series in the same family.

Similiar soils are Boswell, Gore, Forbing, Kolin, and McKamie series.
Chickasaw and Rayburn soils: 102 to 152 cm (40 to 60 in) to a paralithic contact.
Colbert soils: 102 to 152 cm (40 to 60 in) to a lithic contact with limestone bedrock.
Etoile and Kellison soils: 102 to 152 cm (40 to 60 in) to Tertiary age claystone.
Oakhurst and Oula soils: 102 to 152 cm (40 to 60 in) to Catahoula Formation of Tertiary age tuffaceous siltstones or claystones.
Telogia soils: underlain with limestone that ranges from 102 to 152 cm (40 to 60) from the surface
Woodtell soils: 102 to 152 cm (40 to 60 in) to stratified or thinly bedded loamy and clayey sediments of Tertiary age.
Boswell, Forbing, and Gore soils: do not have a clay decrease of 20 percent or more from the maximum clay content within 152 cm (60 in) of the soil surface.
Gore soils: moderately well drained.
Kolin soils: siliceous mineralogy, and have a yellowish matrix.
McKamie soils: mixed mineralogy.

GEOGRAPHIC SETTING:
Parent material: red alluvium presumed to be derived originally from Permian age redbeds and associated sediments.
Landscape: river valleys on flat coastal plains
Landform: stream terraces
Slope: 3 to 8 percent
Soil Moisture: An udic soil moisture regime. The soil moisture control section is dry in some or all parts for less than 90 days in normal years.
Mean annual soil temperature: 19.9 to 21.7 degrees C (68 to 71 degrees F)
Mean annual air temperature range: 19.3 to 20.1 degrees C (67 to 69 degrees F)
Mean annual precipitation range: 1397 to 1651 mm (55 to 65 in)
Precipitation Pattern: Rainfall is fairly uniform throughout the year with slight peaks during the spring and fall months
Frost-free period: 250 to 300 days
Elevation: 15 to 61 m (49 to 200 ft)

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Acadiana LA), Barbary (LA), Basile (LA), Kinder (LA), and Vidrine (LA) soils.

Acadiana soils: on less sloping areas above drainageways.
Vidrine soils: on circular mounded positions usually mapped in a complex with Kinder soils.
Kinder and Vidrine soils: on broad, nearly level, higher stream divide landscape positions.
Acadiana, Basile, and Kinder soils: glossic horizons.
Basile soils: on flood plains of drainageways.
Barbary soils: very poorly drained, fluid clays in swamps at lower elevations.

DRAINAGE AND PERMEABILITY: Well drained. Permeability is very slow. Runoff is very high on 3 to 5 and 5 to 8 percent slopes.

USE AND VEGETATION: Most of the acreage is in woodland, mainly loblolly pine with mixed hardwoods that have encroached onto the native prairie. A small acreage is used for crops and pasture. Main crop grown is soybeans.

DISTRIBUTION AND EXTENT: Southwest Louisiana and possibly southeast Texas; LRR T; MLRA 150A. The series is of moderate extent.

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

SERIES ESTABLISHED: Acadia Parish, Louisiana; 2000.

REMARKS: The Iota soils were formerly included with the Acadia, Gore, Muskogee, or McKamie series. The series description was updated during the Soil Data Join and Recorrelation initiative.
Diagnostic horizons and features in this pedon include:

Ochric epipedon-0 to 18 cm (0 to 7 inches) (A and E horizons).
Albic horizon-8 to 18 cm (3 to 7 inches) (E horizon).
Argillic horizon-18 to 71 cm (7 to 28 inches) (Bt and Btss horizons).
Vertic properties/slickensides-41 to 71 cm (16 to 28 inches) (Btss horizon).
Clay decreases with depth- the clay content of the control section decreases by 20 percent (relative) or more from the top of the argillic horizon within a depth of 60 inches.

ADDITIONAL DATA: Laboratory data from Louisiana Agricultural Experiment Station (S94LA-001-4) Acadia Parish, LA.

Taxonomic Version: Keys to Soil Taxonomy, Eleventh Edition, 2010.

National Cooperative Soil Survey
U.S.A.