LOCATION KAPLAN LAEstablished Series
TAXONOMIC CLASS: Fine, smectitic, thermic Aeric Chromic Vertic Epiaqualfs
TYPICAL PEDON: Kaplan silt loam--cropland, on a nearly level ridge. (Colors are for moist soil unless otherwise stated)
Ap1--0 to 4 inches; dark grayish brown (10YR 4/2) silt loam; weak fine granular structure; friable; common fine and medium roots; slightly acid; abrupt smooth boundary. (4 to 8 inches thick)
Ap2--4 to 10 inches; dark grayish brown (10YR 4/2) silt loam; weak medium granular structure; friable; few fine roots; few fine distinct dark yellowish brown (10YR 4/4) iron concentrations; few prominent reddish brown (5YR 4/4) stains along root channels; neutral; abrupt smooth boundary. (0 to 7 inches thick)
Btg1--10 to 16 inches; dark gray (10YR 4/1) silty clay loam; moderate medium subangular blocky structure; firm; few fine roots; few faint dark gray clay films on surfaces of peds; common medium iron-manganese concretions; few fine faint grayish brown (10YR 5/2) iron depletions; many yellowish brown (10YR 5/4) stains along root channels; neutral; clear smooth boundary. (0 to 12 inches thick)
Btg2--16 to 22 inches; dark grayish brown (10YR 4/2) silty clay; moderate medium subangular blocky structure; firm; few fine roots; common distinct dark gray (10YR 4/1) clay films on surfaces of peds; few fine black iron-manganese concretions; common medium prominent red (2.5YR 4/8) iron concentrations; neutral; gradual wavy boundary. (0 to 14 inches thick)
Btkg1--22 to 27 inches; light yellowish brown (2.5Y 6/4) silty clay ped interiors with gray (10YR 5/1) and dark gray (10YR 4/1) ped surfaces; moderate medium subangular blocky structure; firm; few fine roots; few fine vesicular pores; common faint gray (10YR 5/1) and dark gray (10YR 4/1) clay films on surfaces of peds; few fine black iron-manganese concretions; many medium distinct light brownish gray (2.5Y 6/2) iron depletions; many yellowish brown (10YR 5/6) and common fine prominent red (2.5YR 4/6) iron concentrations; few medium calcium carbonate concretions; moderately alkaline; gradual wavy boundary. (5 to 15 inches thick)
Btkg2--27 to 44 inches; light brownish gray (2.5Y 6/2) silty clay; moderate coarse prismatic structure parting to moderate medium subangular blocky; firm; few fine roots; common fine vesicular pores; common distinct gray (10YR 5/1) and dark gray (10YR 4/1) clay films on surfaces of peds; common fine black iron-manganese concretions; common medium prominent olive yellow (2.5Y 6/8) iron concentrations; common medium and coarse calcium carbonate concretions; moderately alkaline; gradual wavy boundary. (10 to 20 inches thick)
Btkssg1--44 to 53 inches; light brownish gray (2.5Y 6/2) silty clay loam; moderate coarse prismatic structure parting to weak medium subangular blocky; firm; common fine vesicular pores; common distinct gray (10YR 5/1) clay films on vertical surfaces of peds; few medium and coarse black iron-manganese concretions; common fine prominent yellowish red (5YR 5/8) iron concentrations; common medium and coarse calcium carbonate concretions; few distinct slickensides; moderately alkaline; gradual wavy boundary. (5 to 15 inches thick)
Btkssg2--53 to 65 inches; gray (5Y 6/1) silty clay loam; moderate coarse subangular blocky structure; firm; common fine vesicular pores; few faint clay films on vertical surfaces of peds; common medium black iron-manganese concretions; many coarse prominent yellowish red (5YR 5/6) iron concentrations; common medium and coarse calcium carbonate concretions; few distinct slickensides; moderately alkaline.
TYPE LOCATION: Cameron Parish, Louisiana; 2.1 miles south of intersection of LA Highway 14 and LA Highway 98 on gravel road; 200 feet east of gravel road in cropland; northeast corner of T. 12 S., R. 5 W.; USGS Thronwell, La. topoquad; (Latitude 30N, 02, 11; Longitude 92W, 49, 47).
RANGE IN CHARACTERISTICS: The solum is more than 80 inches thick. Linear extensibility ranges from 6.0 to 7.5 cm in the upper 40 inches.
The A, or Ap horizon, has hue of 10YR, value of 4, and chroma of 1 to 3. Reaction is slightly acid or neutral, but ranges to moderately alkaline. Redox features are in shades of brown.
The Btg horizon has hue of 10YR or 2.5Y, value of 4 or 5, and chroma of 1 or 2. Iron concentrations are in shades of red or brown. Coatings on surfaces of peds are very dark gray or dark gray. Texture is silty clay loam or silty clay. Reaction ranges from neutral to moderately alkaline.
The Btkg and Btkssg horizons have hue of 10YR to 5Y, value of 5 or 6, and chroma of 1 or 2. Subhorizons of the Btk horizon have ped interiors with chroma of 2 to 4. Iron concentrations are in shades of brown or red. Coatings on surfaces of peds are gray or dark gray. Reaction is slightly alkaline or moderately alkaline. Carbonate concretions range from few to many. Texture is silty clay loam or silty clay.
COMPETING SERIES: There are no other series in the same family. Similar soils are the Crowley, Forestdale, Gaylesville, Midland, and Okeetee series. Crowley, Forestdale, Gaylesville, and Okeetee soils do not have calcium carbonate concretions. Also, Crowley soils have an albic horizon and an abrupt textural change. Midland soils do not have subhorizons with 2 or 3 chroma ped interiors and are poorly drained.
GEOGRAPHIC SETTING: Kaplan soils are on broad ridges on the Gulf Coast Prairies. These nearly level to very gently sloping soils formed in loamy and clayey sediments on terraces of late Pleistocene age. Slopes are dominantly less than 1 percent, but range to 3 percent. Mean annual air temperature ranges from 67 to 70 degrees F. Mean annual precipitation ranges from 54 to 62 inches. Frost free days range from 280 to 350. Elevation ranges from 5 to 50 feet. Thornthwaite P-E index ranges from 60 to 80.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the similar Crowley and Midland soils and the Morey and Mowata soils. Crowley and Midland soils are on about the same to slightly lower landscape positions. Morey soils are on slightly lower landscape positions and have a mollic epipedon. Mowata soils are on lower landscape positions and are poorly drained.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained. Permeability is slow. Runoff is medium on 0 to 1 percent slopes and high on 1 to 3 percent slopes. An apparent water table fluctuates between a depth of 1.5 to 2.5 feet below the surface during the months of December through April.
USE AND VEGETATION: Used mainly for cropland or pasture. Some areas are used for homesites. Native vegetation is dominantly tall grasses and sedges.
DISTRIBUTION AND EXTENT: Gulf Coastal Prairie of Louisiana and possibly southeast Texas (MLRA 150A, LRR T). The series is of moderate extent.
MLRA OFFICE RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Cameron Parish, Louisiana; 1984.
REMARKS: These soils were formerly included with the Crowley series. Classification changed 7/99 based on Keys to Soil Taxonomy, Eighth Edition, 1998. Also, mineralogy changed from mixed to smectitic based on LSU soil lab data and mineralogy of associated soils.
Diagnostic Horizons and features recognized in this pedon are:
Ochric epipedon--0 to 10 inches (Ap1 and Ap2 horizons.)
Argillic horizon--10 to 65 inches (Btg1, Btg2, Btkg1, Btkg2, Btkg3, Btkg4 horizons.)
Aquic moisture regime and episaturation in upper argillic horizon.
Chromic feature--Value of 4 or more in the ochric epipedon (Ap1 an d Ap2 horizons).
Vertic subgroup--linear extensibility more than 6.0 cm in upper 40 inches and slickensides in argillic horizon.
ADDITIONAL DATA: LSU lab data on pedons from Vermilion Parish (S84LA-113-002), Cameron Parish (S85LA-023-004), and Acadia Parish (S96LA-001-006).
TAXONOMIC VERSION: Keys to Soil Taxonomy, Ninth Edition, 2003.