LOCATION CARVILLE                LA

Established Series
Rev. JDS/BM/CG
02/2013

CARVILLE SERIES

The Carville series consists of very deep, somewhat poorly drained, moderately permeable soils that formed in recent loamy alluvium. These soils are on nearly level to very gently sloping natural levee positions on flood plains, mainly along the Mississippi River and its distributaries. Slopes range from 0 to 2 percent.

TAXONOMIC CLASS: Coarse-silty, mixed, superactive, calcareous, hyperthermic Fluventic Endoaquepts

TYPICAL PEDON: Carville very fine sandy loam on a 1 percent slope in tame pasture. (Colors are for moist soil unless otherwise stated.)

Ap1--0 to 15 cm (0 to 6 inches); dark grayish brown (10YR 4/2), silt loam; weak medium granular structure; very friable, slightly sticky, nonplastic; many fine roots throughout; very slight effervescence, by HCl, 1 normal; moderately alkaline; clear smooth boundary. (10 to 20 cm (4 to 8 in) thick))

Ap2--15 to 33 cm (6 to 13 inches); grayish brown (10YR 5/2) silt loam; weak fine subangular blocky structure; very friable, slightly sticky, nonplastic; many fine roots throughout; common fine high continuity tubular pores; 5 percent faint organic stains throughout; 15 percent fine distinct dark yellowish brown (10YR 4/4) and dark yellowish brown (10YR 3/4) irregular masses of oxidized iron on faces of peds; slight effervescence, by HCl, 1 normal; strongly alkaline; abrupt smooth boundary. (0 to 20 cm thick (0 to 8 in))

C1--33 to 48 cm (13 to 19 inches); grayish brown (10YR 5/2) and brown (10YR 5/3), stratified silt loam; weak fine platy structure; very friable, slightly sticky, nonplastic; many fine roots throughout; common fine high continuity tubular pores; 8 percent fine distinct dark yellowish brown (10YR 4/4) irregular masses of oxidized iron throughout; 2 percent fine prominent brown (7.5YR 4/4) dendritic masses of oxidized iron lining pores; 2 percent medium distinct irregular dark gray (2.5Y 4/1) iron depletions throughout; 1 percent fine worm casts; slight effervescence by HCl, 1 normal; moderately alkaline; abrupt smooth boundary.

C2--48 to 71 cm (19 to 28 inches); brown (10YR 5/3) silt loam; weak fine platy structure; very friable, slightly sticky, nonplastic; common fine roots throughout; common fine high continuity tubular and few medium high continuity tubular pores; 15 percent fine and medium faint light brownish gray (10YR 6/2) platy iron depletions along lamina or strata faces; 5 percent fine distinct brown (7.5YR 4/4) dendritic masses of oxidized iron lining pores; very slight effervescence, by HCl, 1 normal; moderately alkaline; abrupt wavy boundary.

C3--71 to 84 cm (28 to 33 inches); grayish brown (10YR 5/2) silt loam; structureless massive; very friable, slightly sticky, nonplastic; common fine roots throughout; common fine high continuity tubular and few medium high continuity tubular pores; 20 percent fine prominent strong brown (7.5YR 4/6) cylindrical masses of oxidized iron lining pores; 5 percent medium distinct yellowish red (5YR 4/6) irregular masses of oxidized iron lining pores; 2 percent fine distinct dendritic iron depletions on surfaces along root channels; moderately alkaline; abrupt smooth boundary.

C4--84 to 99 cm (33 to 39 inches); dark yellowish brown (10YR 4/4) silt loam; weak fine subangular blocky structure; very friable, slightly sticky, nonplastic; common fine roots throughout; few fine high continuity tubular and few medium high continuity tubular pores; 15 percent fine and medium distinct gray (10YR 5/1) dendritic iron depletions lining pores; 5 percent fine distinct strong brown (7.5YR 4/6) cylindrical masses of oxidized iron throughout; moderately alkaline; clear smooth boundary.

Cg1--99 to 114 cm (39 to 45 inches); grayish brown (10YR 5/2) silt loam; structureless massive; very friable, slightly sticky, nonplastic; few fine roots throughout; common fine high continuity tubular pores; 15 percent fine and medium prominent strong brown (7.5YR 5/6) cylindrical masses of oxidized iron lining pores; 3 percent fine and medium prominent strong brown (7.5YR 4/6) cylindrical masses of oxidized iron lining pores; moderately alkaline; clear smooth boundary.

Cg2--114 to 137 cm (45 to 54 inches); dark greenish gray (5GY 4/1) silt loam; structureless massive; very friable, slightly sticky, nonplastic; few very fine roots throughout; few very fine high continuity tubular pores; 5 percent fine prominent irregular yellowish brown (10YR 5/4) masses of oxidized iron throughout; 3 percent fine and medium prominent brown (7.5YR 4/4) irregular masses of oxidized iron lining pores; moderately alkaline; diffuse wavy boundary.

Cg3--137 to 191 cm (54 to 75 inches); dark greenish gray (5GY 4/1) silt loam; structureless massive; very friable, slightly sticky, nonplastic; 10 percent faint organic stains throughout; 3 percent fine prominent reddish brown (5YR 4/4) cylindrical masses of oxidized iron lining pores; 2 percent fine and medium prominent dark yellowish brown (10YR 4/4) irregular masses of oxidized iron throughout; 1 percent nonflat 5 to 20 cm wood fragments; moderately alkaline.

TYPE LOCATION: St. John the Baptist Parish, Louisiana; located from the intersection of U.S. Highways 51 and 61 in LaPlace, Louisiana, 0.97 kilometers (0.6 mile) southeast on U.S. Highway 61, then 1.6 kilometers (1 mile) northeast on Oswald Avenue, then 137 meters (450 feet) northwest through tree line, then 402 meters (0.25 mile) southwest along tree line, and 76 meters (250 feet) due north into pasture; Latitude 30 degrees, 4 minutes, 7.25 seconds N.; Longitude 90 degrees, 27 minutes, 50.04 seconds W., Laplace, Louisiana USGS 7.5 Minute Quadrangle, NAD-27.

RANGE IN CHARACTERISTICS:
Solum thickness: 25 to 127 cm (10 to 50 in)
Clay content in the Control Section: 6 to 18 percent

A or Ap horizon:
Color--Hue of 10YR, value of 4 or 5, and chroma of 2 or 3; or hue of 7.5YR, value of 4 and chroma of 2.
Redoximorphic features--Iron accumulations in shades of brown and iron depletions in shades of gray are present in some pedons.
Texture--Silt loam, very fine sandy loam, or fine sandy loam.
Other features--None to slight effervescence in dilute HCl in the parts within a depth of 10 inches; and very slight to slight effervescence in dilute HCl in the parts below that.
Reaction--Moderately acid through moderately alkaline.
Thickness--10 to 36 cm (4 to 14 in). If a Bg or Bw horizon is not present, an Ap2 horizon that has weak to moderate structural development has its lower boundary at more than 15 cm (6 in) deep.

Bg or Bw horizon: (where present)
Color--Hue of 10YR or 2.5Y, value of 4 or 5, and chroma of 1 to 3, however the range also includes value 6 in the lower part; or hue of 7.5YR, value of 4, and chroma of 2 to 4. Some layer or strata with chroma of 4 has its upper boundary within a depth of 76 cm (30 in). In many pedons, the entire Bg horizon has been truncated by bedding for sugarcane cultivation and is part of the Ap horizon.
Redoximorphic features--Iron accumulations in shades of brown and iron depletions in shades of gray range from few to many.
Texture--Dominantly silt loam, loam, or very fine sandy loam, but some pedons have thin strata of finer or coarser material.
Other features--Very slight to slight effervescence in dilute HCl in the parts within a depth of 51 cm (20 in); and none to slight effervescence in dilute HCl in the parts below that.
Reaction--Neutral through moderately alkaline in the parts within a depth of 51 cm (20 in) and moderately acid through moderately alkaline in the parts below that.
Thickness--0 to 117 cm (0 to 46 in)

C horizon:
Color--Hue of 10YR or 2.5Y, value of 4 or 5, and chroma of 2, however the range also includes value 6 in the lower part, or subhorizons with chroma of 3 or 4. Some subhorizon of the Bg or C horizon within a depth of 51 cm (20 in) must have chroma of 2 or less in the matrix however.
Redoximorphic features--Iron accumulations in shades of brown and iron depletions in shades of gray range from few to many.
Texture--Dominantly is silt loam, loam, or very fine sandy loam, but some pedons have thin strata of finer or coarser material.
Other features--Very slight to slight effervescence in dilute HCl in the parts within a depth of 51 cm (20 in); and none to slight effervescence in dilute HCl in the parts below that.
Reaction--Moderately acid through moderately alkaline
Ab horizon: (where present)
Color--Hue of 10YR, value of 4 or 5, and chroma of 1 or 2. .
Redoximorphic features--Iron accumulations in shades of brown and iron depletions in shades of gray range from few to many.
Texture--Fine sandy loam, loamy very fine sand, very fine sandy loam, loam, silt loam, silty clay loam, clay loam, silty clay, or clay.
Other features--Depth to a buried A horizon is more than 102 cm (40 in).
Reaction--Moderately acid through moderately alkaline
Thickness=0 to 25 cm (0 to 10 in)

Cg horizon:
Color--Hue of 10YR to 5GY, value of 4 to 6, and chroma of 1 or 2.
Redoximorphic features--Iron accumulations in shades of brown and iron depletions in shades of gray range from few to many.
Texture--Dominantly is silt loam, loam, or very fine sandy loam, but some pedons have thin strata of silty clay loam or silty clay below a depth of 102 cm (40 in).
Other features--Many pedons have wood fragments in the Cg horizon.
Reaction--Moderately acid through moderately alkaline

COMPETING SERIES: There are no other series in the same family.

GEOGRAPHIC SETTING: Carville soils are on nearly level to very gently sloping natural levee positions on flood plains along the Mississippi River and its distributaries. The soil formed in recent loamy alluvium. Most areas are protected from flooding by levees. The climate is humid temperate. Elevation ranges from 1 to 8 meters (3 to 25 ft) above mean sea level. Mean annual air temperature ranges from 18 to 24 degrees C (65 to 75 degrees F), and mean annual precipitation is 1397 to 1778 mm (55 to 70 in). Annual frost free days range from 235 to 350.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cancienne, Vacherie and Gramercy series. Cancienne soils have a fine-silty control section. Gramercy soils have a fine control section. Vacherie soils have a clayey discontinuity beginning at a depth of 51 to 102 cm (20 to 40 in) deep.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Somewhat poorly drained; low to negligible runoff; moderate saturated hydraulic conductivity. The soil is saturated in all layers below depths of 30 to 76 cm (12 to 30 in) from December through June in normal years. It stays saturated within a depth of 76 cm (30in) for periods of up to 1 month duration in normal years. Flooding frequency ranges from none to common.

USE AND VEGETATION: Most areas have been cleared and are primarily used for sugarcane, small grain, soybeans, corn, truck crops, pasture, and hay crops. The native forest vegetation in uncultivated areas is predominantly oaks, cottonwood, hickories, and sweetgum with an undergrowth of vines and canes.

DISTRIBUTION AND EXTENT: Southern Mississippi River Alluvium in south-central Louisiana. The series is of small extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: AUBURN, ALABAMA

SERIES ESTABLISHED: The series was proposed for the update of St. John the Baptist Parish, Louisiana in 2001. The series was established by an Amendment to the Correlation of St. Mary Parish, Louisiana in 8/2002. Carville soils were formerly included in the Convent series.

REMARKS: The classification was changed from a Fluvaquentic subgroup to a Fluventic subgroup in 2004 according to 9th ed. Keys to Soil Taxonomy. The reaction class was also changed from nonacid to calcareous based on data from the type location and supporting pedons, and a study of other supporting sites in St. John the Baptist Parish. The type location pedon was sampled for full characterization analyses by NSSL, Lincoln, Ne. (S02-LA095-003).

Diagnostic horizons and features recognized in this pedon include:
Ochric epipedon...... 0 to 33 cm (0 to 13 in) (Ap horizons)
Cambic horizon........ 15 to 33 cm (6 to 13 in) (Ap2 horizon)
Irregular organic carbon decrease... 0 to 127 cm (0 to 50 in)(C and Cg horizons)
Free carbonates.......0 to 71 cm (0 to 28 in) (Ap, C1, and C2 horizons)
Aquic conditions......saturation, reduction and redoximorphic features (including chroma 2 matrix) within a depth of 51 cm (20 in).

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National Cooperative Soil Survey
U.S.A.