LOCATION MAUREPAS LA

Established Series
Rev. JDS
01/2018

MAUREPAS SERIES

The Maurepas series consists of very deep, very poorly drained, rapidly permeable organic soils that formed in woody plant remains. These soils are in large backswamps of the lower Mississippi River Delta and associated coastal areas. Slopes are less than 1.0 percent.

TAXONOMIC CLASS: Euic, hyperthermic Typic Haplosaprists

TYPICAL PEDON: Maurepas muck--cypress swamp. (Colors are for moist soil unless otherwise stated.)

Oa1--0 to 10 inches; dark brown (7.5YR 3/2) and very dark grayish brown (10YR 3/2) muck; structureless massive; 15 percent fiber, unrubbed; 5 percent fiber, rubbed; moderately alkaline; clear smooth boundary. (6 to 12 inches thick).

Oa2--10 to 23 inches; dark brown (7.5YR 3/2) and very dark grayish brown (10YR 3/2) muck; structureless massive; 30 percent fiber, unrubbed; 3 percent fiber, rubbed; moderately alkaline; clear smooth boundary.

Oa3--23 to 64 inches; brown (7.5YR 4/4) and very dark grayish brown (10YR 3/2) muck; structureless massive; wood fragments; moderately alkaline; clear smooth boundary (combined thickness of the O horizons is more than 51 inches).

Cg--64 to 80 inches; dark gray (N 4/) mucky clay; structureless massive; wood fragments; moderately alkaline.

TYPE LOCATION: St. John the Baptist Parish, Louisiana; located from LaPlace, Louisiana, 7.43 miles north of the intersection of I-10 and I-55 on I-55 to exit ramp for Peuine Road, then 3.58 miles north on Peuine Road to Bayou Black, then 350 feet east on Bayou Black, and 300 feet northeast of Bayou into swamp; Sec. 28, T. 9 S., R. 8 E.; Latitude 30 degrees, 14 minutes, 7.26 seconds N., Longitude 90 degrees, 24 minutes, 24.46 seconds W., Ruddock, Louisiana USGS 7.5 Minute Quadrangle, NAD-83.

RANGE IN CHARACTERISTICS:
Solum thickness: Thickness of the organic material ranges from 51 to 80 or more inches
Redoximorphic features: Gleyed matrix in the mineral layers
Other distinctive soil features: Wood fragments in the lower part of the organic layers.
Concentrated minerals: Salinity is nonsaline to slightly saline in more than half of the subsurface and bottom tiers.

Surface tier of the Oa horizon:
Color--Hue of 5YR through 10YR, value of 3 or less, and chroma of 2 or less.
Texture--Muck
Other features--Rubbed fiber content is 2 to 40 percent
Reaction--Moderately acid to moderately alkaline under natural conditions; and extremely acid to strongly acid in drained and protected areas.
Thickness--12 inches

Subsurface tier of the Oa horizon:
Color--Hue of 5YR through 10YR, value of 2 or 3, and chroma of 4 or less.
Texture--Muck
Other features=Unrubbed fiber content is as much as 60 percent. Rubbed fiber content is less than 10 percent. Salinity is nonsaline to slightly saline.
Reaction--Moderately acid to moderately alkaline
Thickness--24 inches

Bottom tier of the Oa horizon:
Color--Hue of 7.5YR through 10YR, value of 2 or 3, and chroma of 4 or less.
Texture--Muck; thin lenses or layers of very fluid gleyed clay are within the bottom tier below a depth of 51 inches in some pedons.
Other features--Less than 10 percent fibers after rubbing, but some pedons have thin layers that contain more fibers. Fibers are dominantly woody, but some pedons have as much as 45 percent herbaceous fiber in the 0 to 51 inch control section. The organic layers contain between 15 and 45 percent mineral matter. Logs, dominantly cypress, and wood fragments in varying states of decomposition, are commonly throughout the organic material. Salinity is nonsaline to slightly saline.
Reaction--Moderately acid to moderately alkaline
Thickness--15 to more than 40 inches

Cg horizon: (where present)
Color--Hue of 10YR to 5BG, value of 4 or 5, and chroma of 1, or it is neutral with value of 4 to 6.
Redoximorphic features--Gleyed matrix; iron accumulations in shades of brown or olive range from none to common in the upper part.
Texture--Clay or mucky clay
Other features--Slightly fluid to very fluid manner of failure. Thin layers of peat or muck and/or layers of wood, logs, and stumps are present in some pedons.
Reaction--Neutral to moderately alkaline

COMPETING SERIES: These are the Lafitte, Terra Ceia, Timbalier, and Torry series in the same family, and the Hobonny series in a closely related family. Lafitte soils contain dominantly herbaceous fiber and have SAR more than 13 or ESP more than 15 in more than half of the subsurface tier. Terra Ceia soils contain dominantly herbaceous fiber, and the organic layers typically are underlain by more sandy or loamy mineral soil materials, shell fragments, or limestone. Timbalier soils are on areas of tidal marsh, contain mainly herbaceous fiber, and are more saline. Torry soils contain dominantly herbaceous fiber, and the organic layers are underlain by limestone within a depth of 80 inches. Hobonny soils are in a thermic temperature regime.

GEOGRAPHIC SETTING: Maurepas soils are in large backswamps of the lower Mississippi River Delta and associated coastal areas at elevations of less than 5 feet above sea level. The soils formed mainly in woody plant remains mixed with a small amount of mineral soil matter. The climate is humid and subtropical. Mean annual precipitation is about 64 inches and the mean annual temperature is about 68 degrees F. near the type location.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Allemands, Barbary, Carlin, Everglades, Gentilly, Kenner, and Okeechobee series. Allemands soils are on the landward side of coastal freshwater marshes and have less than 51 inches of organic material over mineral layers. Barbary and Gentilly soils are clayey mineral soils with an organic surface layer less than 16 inches thick. Carlin soils are on freshwater coastal marshes and have a water layer more than 6 inches thick within the control section. Everglades and Okeechobee soils formed mainly in herbaceous material and are more fibrous. Kenner soils are on freshwater to saline marshes and have thin mineral strata within 51 inches of the surface.

DRAINAGE AND PERMEABILITY: Very poorly drained. The soil is ponded for very long durations in normal years. The soil is saturated in all layers throughout the year, unless artificially drained. Internal drainage is very slow to none. Runoff is negligible. Permeability is rapid. The soils are frequently to very frequently flooded for long to very long durations.

USE AND VEGETATION: All of these soils are used as habitat for wetland wildlife. A very small acreage is used for timber production. Most areas of these soils have a sparse, diminishing stand of baldcypress trees and encroaching marsh grasses or open water.

DISTRIBUTION AND EXTENT: Southern Mississippi Valley Alluvium (MLRA 131) in South Louisiana. The series is of moderate extent.

SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: AUBURN, ALABAMA

SERIES ESTABLISHED: Livingston Parish, Louisiana; 1931.

REMARKS: The series type location was moved to a new site in St. John Parish in 2002 because the previous type location was uncertain.
Diagnostic horizons and features recognized in this pedon include:
Histic Epipedon .........0 to 72 inches (Oa horizons)

National Cooperative Soil Survey
U.S.A.