LOCATION TIMBALIER LA

Established Series
Rev. WLC-SDM-CLN
11/2018

TIMBALIER SERIES

The Timbalier series consist of very deep, very poorly drained, rapidly permeable soils that formed in thick herbaceous, highly decomposed organic material. These soils are on saline Gulf Coast marshes and are very frequently flooded by saltwater during high tides. Slopes range from 0 to 0.2 percent.

TAXONOMIC CLASS: Euic, hyperthermic Typic Haplosaprists

TYPICAL PEDON: Timbalier muck--saltwater marsh. (Colors are for wet soil.)

Oa1--0 to 6 inches; very dark grayish brown (10YR 3/2) muck, same color pressed and rubbed; about 10 percent fiber, 5 percent rubbed; massive; moderately fluid, flows easily between fingers when squeezed leaving a small residue in hand; few fine live roots; about 60 percent mineral material; moderately alkaline; clear smooth boundary.

Oa2--6 to 28 inches; very dark brown (10YR 2/2) muck, same color pressed and rubbed; about 10 percent fiber, 5 percent rubbed; massive; very fluid, flows easily between fingers when squeezed leaving hand empty; few fine live roots; dominantly herbaceous material; about 55 percent mineral; moderately alkaline; clear smooth boundary.

Oa3--28 to 48 inches; very dark grayish brown (10YR 3/2) muck, very dark gray (10YR 3/1) pressed and rubbed; about 20 percent fiber, 8 percent rubbed; massive; very fluid, flows easily between fingers when squeezed leaving hand empty; dominantly herbaceous material; about 60 percent mineral; moderately alkaline; clear smooth boundary.

Oa4--48 to 72 inches; dark brown (7.5YR 3/2) muck, very dark gray (10YR 3/1) pressed and rubbed; about 10 percent fiber, 5 percent rubbed; massive; very fluid, flows easily between fingers when squeezed leaving hand empty; dominantly herbaceous material; about 65 percent mineral; moderately alkaline; abrupt smooth boundary. (Combined thickness of the Oa horizons is more than 51 inches)

Cg1--72 to 78 inches; dark gray (5Y 4/1) mucky clay; massive; very fluid, flows easily between fingers when squeezed leaving hand empty; moderately alkaline; abrupt smooth boundary. (0 to 20 inches thick)

Cg2--78 to 84 inches; dark greenish gray (5GY 4/1) clay; massive; very fluid, flows easily between fingers when squeezed leaving hand empty; moderately alkaline.

TYPE LOCATION: Lafourche Parish, Louisiana; 5 miles south of Golden Meadow; 4 miles east of Bayou Lafourche.

RANGE IN CHARACTERISTICS: Depth to clayey mineral layers ranges from 51 inches to more than 100 inches. Salinity is high or very high. Conductivity of the saturation extract ranges from 8 to more than 16 dS/m in some layer within a depth of 40 inches. Reaction ranges from neutral to moderately alkaline in the surface tier and slightly acid to moderately alkaline in the lower tiers. The n-value is more than 1 throughout. The organic fraction is dominantly herbaceous material but some pedons have thin strata of woody peat and/or wood fragments. Mineral content of the organic layers ranges from 30 to 70 percent.

The surface tier (0 to 12 inches) has hue of 7.5YR or 10YR, value of 2 to 4, and chroma of 1 to 3. Fiber content after rubbing ranges from 1 to 35 percent. Some pedons have a mineral over-wash surface layer 2 to 16 inches thick.

The subsurface tier (12 to 36 inches) and bottom tier (36 to 48 inches) have hue of 7.5YR or 10YR, value of 2 or 3, and chroma of 1 to 3. Rubbed fiber content averages between 1 and 10 percent of the organic volume.

The Cg horizon has hue of 10YR to 5G, or is neutral, value of 4 to 6, and chroma of 2 or less. Texture is moderately fluid or very fluid clay, mucky clay, or silty clay. Some pedons have an Ag horizon with value of 3 or 4, and chroma of 0 to 2.

COMPETING SERIES: These are Lafitte and Maurepas series in the same family, and the Allemands, Terra Ceia, and Kenner series. Allemands, Kenner, and Maurepas soils have low salt content. Lafitte soils have less salinity in the control section and are in brackish marshes. Terra Ceia soils are nonsaline.

GEOGRAPHIC SETTING: Timbalier soils are on low Gulf coastal saline marshes at elevations of less than 1 foot. They commonly adjoin the open Gulf or saltwater bays and are flooded very frequently or frequently with saltwater. Slopes range from 0 to 0.2 percent. Mean annual rainfall is about 67 inches and the mean annual temperature is about 70 degrees F.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Lafitte series and the Bellpass, Clovelly, and Scatlake series. Bellpass and Clovelly soils have mineral layers 30 cm or more thick that have the upper boundary within the control section below the surface tier. Lafitte and Clovelly soils are in brackish marshes. Scatlake soils are on slightly higher elevations and are fluid mineral soils.

DRAINAGE AND PERMEABILITY: Timbalier soils are very poorly drained. Runoff is negligible or ponded. Permeability is rapid in the organic layers. Water is at a depth of 0.5 foot below the soil surface to 1 foot above most of the time. During tropical storms, tidal floodwater is as deep as 4 feet or more.

USE AND VEGETATION: Used mostly for wildlife habitat and recreation. This soil has many small areas of open water. The vegetation at the type location is 80 percent smooth cordgrass, 10 percent saltgrass, and 5 percent marshhay cordgrass. Other plants common to this soil are needlegrass rush, bushy sea-oxeye, woody glasswort, and maritime saltwort. Black mangrove grows on this soil only in a belt adjacent to the coastline of the Gulf.

DISTRIBUTION AND EXTENT: On the Gulf Coast Marshes (MLRA 151) of Louisiana and possibly Texas and Mississippi. The extent is moderate.

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

SERIES ESTABLISHED: Lafourche Parish, Louisiana, May 1981.

REMARKS: Timbalier soils have been previously mapped as miscellaneous land types.

Diagnostic horizons and features recognized in this pedon are:

Sapric soil materials -- 0 to 72 inches (Oa horizons).

n-value -- more than 1 in all horizons.

Ecological Site: Saline Organic Marsh.

ADDITIONAL DATA: Louisiana State University data on pedon (S94LA-109-015) from Terrebonne Parish.

TAXONOMIC VERSION: Soil Taxonomy, Second Edition, 1999.

National Cooperative Soil Survey
U.S.A.