LOCATION OUACHITA AR+LA MSEstablished Series
TAXONOMIC CLASS: Fine-silty, siliceous, active, thermic Fluventic Dystrudepts
TYPICAL PEDON: Ouachita silt loam, 3 percent slope, forested. (Colors are for moist soil unless otherwise stated.)
A1--0 to 13 cm (0 to 5 in); brown (10YR 4/3) silt loam; weak medium granular structure; friable; many fine roots; moderately acid; clear smooth boundary. (3 to 15 cm (1 to 6 in) thick)
A2--13 to 48 cm (5 to 19 in); dark yellowish brown (10YR 4/4) silt loam; many medium faint pale brown (10YR 6/3) and common fine distinct strong brown mottles; weak medium subangular blocky structure; friable; common fine roots; strongly acid; clear smooth boundary. (15 to 38 cm (6 to 15 in) thick)
Bw1--48 to 86 cm (19 to 34 in); dark yellowish brown (10YR 4/4) silty clay loam; common fine faint pale brown mottles; weak medium subangular blocky structure: firm; few fine roots; very strongly acid; abrupt smooth boundary.
Bw2--86 to 107 cm (34 to 42 in); dark grayish brown (10YR 4/2) silty clay loam; weak medium subangular blocky structure; firm; few fine roots; common fine pores; strongly acid; gradual smooth boundary.
Bw3--107 to 175 cm (42 to 69 in); yellowish brown (10YR 5/4) silty clay loam; moderate medium subangular blocky structure; firm; common fine pores; strongly acid; gradual smooth boundary. (Combined thickness of the Bw horizon ranges from 33 to 60 inches.)
2C--175 to 196 cm (69 to 77 in); yellowish brown (10YR 5/8) loam; massive; friable; common fine pores; very strongly acid.
TYPE LOCATION: Ouachita County, Arkansas; 1 mile north of U.S. Highway 79 on Arkansas Highway 7; 1-3/4 miles northwest on unimproved road; 75 feet from river bank; NW1/4SW1/4NE1/4 sec. 10, T. 13 S., R. 17 W.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 102 to 203 cm (40 to more than 80 in). Reaction ranges from very strongly acid to moderately acid in the A and is very strongly acid or strongly acid in the Bw and C horizons.
A horizon:
Hue: 10YR
Value: 4
Chroma: 2 to 4
or
Value: 5
Chroma: 3
Texture: silt loam, loam or very fine sandy loam.
Reaction: ranges from slightly acid to very strongly acid.
AB, BA or BE horizon (where present):
Hue: 10YR
Value: 4 or 5
Chroma: 3 or 4
Texture: silt loam, loam or very fine sandy loam
Reaction: strongly acid to very strongly acid.
Bw horizon(s):
Hue: 7.5YR or 10YR
Value: 3 to 5
Chroma: 3 to 8
or Hue: 10YR
Value: 4
Chroma: 2
Redoximorphic features: none to common in shades of brown. Some pedons have iron depletions of chroma of 3 or less below 24 inches from the surface.
Texture: silt loam, very fine sandy loam, fine sandy loam, loam, or silty clay loam. The 10 to 40 inch control section has 18 to 30 percent clay.
Reaction: strongly acid to very strongly acid.
BC horizon (where present)
Colors similar to the Bw.
Redoximorphic features: none to common in shades of gray or brown.
Texture is silt loam, loam, or fine sandy loam.
C horizon:
Hue: 7.5YR or 10YR
Value: 4 or 5
Chroma: 3 or 4
Redoximorphic features: none to common in various shades of gray.
Texture: silty loam, fine sandy loam, very fine sandy loam, loamy fine sand or loamy sand.
Reaction: strongly acid to very strongly acid.
COMPETING SERIES: There are no other series in this family. Series in closely related families include:
Cascilla,
Ennis,
Pruitton,
Sardis,
Shellbluff, and
Velda.
Cascilla and Shellbluff soils are in a mixed mineralogy class.
Ennis and Pruitton soils are in a fine-loamy particle-size class.
Sardis soils have gray mottles within 24 inches of the soil surface.
Velda soils are in a coarse-silty particle size class.
GEOGRAPHIC SETTING: Ouachita soils occur on level to nearly level flood plains and natural levees along streams. These soils formed in loamy alluvial sediments mainly from Coastal Plains uplands. Slopes range from 0 to 3 percent. The mean annual temperature is about
63 degrees F and the mean annual precipitation is about 50 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These include the competing
Sardis series and
Amy,
Guyton and
Ochlockonee.
Amy soils, which occur on low terraces, have an argillic horizon and are poorly drained.
Guyton soils, which occur on lower flood plains, have an argillic horizon and are poorly drained.
Ochlockonee soils, which occur on similar landscape positions, are in a coarse-loamy particle size class.
DRAINAGE AND PERMEABILITY: Well drained; slow runoff; moderately slow internal drainage; moderately slow permeability. Most areas of these soils commonly flood a few times each year, usually during winter and early spring.
USE AND VEGETATION: Cleared areas are used for growing soybeans, corn, and pasture. Native vegetation is forests of gum, oak, maple, ash, and pine.
DISTRIBUTION AND EXTENT: Coastal Plain of Alabama, Arkansas, Louisiana, Mississippi, Oklahoma, and Texas. The series is of large extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Morgantown, West Virginia
SERIES ESTABLISHED: Ouachita County, Arkansas; 1969.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from the surface to a depth of 48 cm (0 to 19 in).
Cambic horizon - The zone from a depth of 48 to 175 cm (19 inches to 69 in).
ADDITIONAL DATA: Characterization of the type location by the University of Arkansas Soil Characterization Laboratory. Pedon No. S67AR-103-006.
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