LOCATION LAFITTE            LA+AL

LAFITTE SERIES

TAXONOMIC CLASS: Euic, hyperthermic Typic Haplosaprists

TYPICAL PEDON: Lafitte muck--coastal marsh.
(Colors are for broken face of moist soil unless otherwise stated.)

Oa1--0 to 6 inches; very dark brown (10YR 2/2) muck, same color pressed and rubbed; about 5 percent fiber, less than 1 percent rubbed; massive; slightly fluid, flows with difficulty between fingers when squeezed leaving small residue in hand; many fine live roots; dominantly herbaceous fiber; about 50 percent mineral; few very dark reddish brown (5YR 3/4) fragments of woody fiber; moderately alkaline; gradual smooth boundary.

Oa2--6 to 16 inches; black (10YR 2/1) muck, same color pressed and rubbed; about 6 percent fiber, 1 to 2 percent rubbed; massive; moderately fluid, flows with slight difficulty between fingers when squeezed leaving a small residue in hand; dominantly herbaceous fiber; about 20 percent mineral; moderately alkaline; gradual smooth boundary.

Oa3--16 to 30 inches; black (10YR 2/1) muck, same color pressed and rubbed; about 3 percent fiber, less than 1 percent rubbed; massive; very fluid, flows easily between fingers when squeezed leaving a very small residue in hand; dominantly herbaceous fiber; about 20 percent mineral; moderately alkaline; gradual smooth boundary.

Oa4--30 to 48 inches; black (10YR 2/1) muck, same color pressed and rubbed; about 5 percent fiber, 1 percent rubbed; massive; slightly fluid, flows with difficulty between fingers when squeezed leaving large residue in hand; about 25 percent mineral; moderately alkaline; clear smooth boundary.

Oa5--48 to 52 inches; black (10YR 2/1) muck, same color pressed and rubbed; about 8 percent fiber, 2 percent rubbed; massive; slightly fluid, flows with difficulty through fingers when squeezed leaving large residue in hand; dominantly herbaceous fiber; about 30 percent mineral; moderately alkaline; clear smooth boundary.

Oa6--52 to 75 inches; very dark brown (10YR 2/2) muck, same color pressed, dark reddish brown (5YR 3/2) rubbed; about 20 percent fiber, 5 percent rubbed; massive; moderately fluid, flows easily between fingers when squeezed leaving a large residue in hand; dominantly herbaceous fiber; about 55 percent mineral; moderately alkaline; abrupt smooth boundary. (combined thickness of the Oa horizons is more than 51 inches)

Ag--75 to 90 inches; dark grayish brown (2.5Y 4/2) clay; massive; very fluid, flows between fingers with slight difficulty when squeezed leaving hand empty; moderately alkaline; abrupt smooth boundary. (0 to 50 inches thick)

Cg--90 to 100 inches; gray (N 6/0) clay; massive; very fluid, flows easily through fingers when squeezed leaving hand empty; moderately alkaline.

TYPE LOCATION: Orleans Parish, Louisiana; three and four-tenths miles east of junction of Louisiana Highway 47 and Interstate 10, T. 11 S., R. 13 E.

RANGE IN CHARACTERISTICS: Depth to mineral layers range from 51 inches to over 100 inches. The conductivity of the saturation extract varies seasonally and with the salt content of preceding flood waters but averages 4 to 8 dS/m in at least part of the upper or middle tiers during most of the year.

The organic materials in the surface tier (0 to 12 inches) have color with hue 7.5YR or 10YR, value 2 to 4, and chroma 1 to 3. Fiber content, after rubbing, ranges from 1 to 35 percent. Reaction of the surface tier ranges from slightly acid to moderately alkaline, and from extremely acid to moderately acid where drained. Some pedons have mineral over-wash layers 2 to 10 inches thick in this tier or have a thin Oe horizon of muck or mucky loam.

The organic materials in the subsurface tier (12 to 36 inches) and the bottom tier (36 to 51 inches) have color with hue 7.5YR or 10YR, value 2 or 3, and chroma 1 or 2. Rubbed fiber content averages between 1 to 10 percent of the organic volume. Reaction of the subsurface and bottom tiers are slightly acid to moderately alkaline, and extremely acid to moderately acid where drained. The sodium adsorption ratio is more than 13; the exchangeable sodium percentage is more than 15 and the salinity is moderate or high in some or all layers within these tiers.

The Ag horizon, where present, and Cg horizon have hue of 5Y, 2.5Y, 5GY, or 5BG, value of 3 to 5, and chroma of 1 or 2 or are neutral with value of 4 or 5. Textures are clayey, loamy, or sandy. Reaction is neutral to moderately alkaline.

COMPETING SERIES: These are the Maurepas and Timbalier series in the same family and the Kenner and Terra Ceia series. Maurepas soils have redder hues and are less saline. Terra Ceia soils are nonsaline. Kenner soils have strata of clayey material less than 12 inches thick between depths of 12 and 51 inches. Timbalier soils are more saline.

GEOGRAPHIC SETTING: Lafitte soils are in large areas of intermediate to brackish marshes in the extreme lower Mississippi River delta and coastal areas. They commonly adjoin large brackish water lakes. Elevation is typically one foot above mean sea level to about 3 feet below. Lafitte soils formed in herbaceous plant remains that overlie mineral sediments. Mean annual precipitation is about 65 inches and the mean annual temperature is about 70 degrees F.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Kenner, Maurepas, and Timbalier series and the Allemands and Gentilly series. The Gentilly series is a mineral soil. Allemands soils have mineral layers within 51 inches of the surface. Both of these soils are on the landward side of the Lafitte series, and are less saline.

DRAINAGE AND PERMEABILITY: Very poorly drained; the water table ranges 1 foot above to 0.5 foot below the surface unless protected and pumped. Internal drainage is very slow to none. Permeability is moderately rapid.

USE AND VEGETATION: The main use of these soils is wildlife habitat. Some areas are protected by dikes and pumps and used for urban development. The vegetation is mainly marshhay cordgrass, seashore saltgrass, olney bulrush, coastal water hyssop, saltmarsh bulrush, and seashore paspalum in brackish marsh. In addition to these, widgeongrass, sawgrass, giant bulrush, alligatorweed, common duckweed, roseau, smartweed, bulltongue, and cattail are found in intermediate marshes.

DISTRIBUTION AND EXTENT: Coastal areas of Louisiana (MLRA 151) and possibly Mississippi and Alabama. Extent is large.

MLRA OFFICE RESPONSIBLE: Temple, Texas.

SERIES ESTABLISHED: Orleans Parish, Louisiana; 1972.

REMARKS: Where protected from flooding and drained, these soils subside until organic layers are oxidized and become extremely to strongly acid.

Diagnostic horizons and features recognized in this pedon are:

Sapric soil materials -- 0 to 75 inches (Oa horizons).

Ecological Site: Intermediate Organic Marsh or Brackish Organic Marsh.

ADDITIONAL DATA: Louisiana State University lab data (S94LA-109-016) from Terrebonne Parish.

TAXONOMIC VERSION: Soil Taxonomy, Second Edition, 1999.