LOCATION COLYELL LA

Established Series
Rev. JLD
03/2019

COLYELL SERIES

The Colyell series consists of somewhat poorly drained slowly permeable soils that formed on low terraces in a thin mantle of loess over Late Pleistocene Age sediments. Slopes range from 1 to 3 percent.

TAXONOMIC CLASS: Fine, smectitic, thermic Glossaquic Hapludalfs

TYPICAL PEDON: Colyell silt loam - on a 1.5 percent slope under pine woodland at an elevation of 10 feet. (Colors are for moist soil unless otherwise stated.)

A--0 to 3 inches; dark grayish brown (10YR 4/2) silt loam; weak fine granular structure; friable; many fine and common medium and coarse roots; very strongly acid; clear smooth boundary. (2 to 6 inches thick)

E--3 to 8 inches; yellowish brown (10YR 5/4) silt; few medium distinct strong brown (7.5YR 5/6) mottles; weak fine subangular blocky structure; friable; common fine, medium and coarse roots; few fine pores; many medium black and brown concretions; very strongly acid; clear smooth boundary.

EB--8 to 12 inches; yellowish brown (10YR 5/4) silt loam; few medium distinct strong brown (7.5YR 5/6) mottles; weak medium subangular blocky structure; friable; common fine, medium and coarse roots; very strongly acid; clear wavy boundary. (Combined thickness of the E and EB horizon is 5 to 15 inches.)

2B/E--12 to 15 inches; mottled light brownish gray (10YR 6/2), yellowish brown (10YR 5/4) and yellowish red (5YR 4/6) silty clay (B); weak medium subangular blocky structure; firm; common fine and medium roots; many hard black and brown concretions; thick discontinuous clay films on the vertical faces of peds; few fine pores; interfingers of light brownish gray (10YR 6/2) silt loam (E) are between peds and make up about 15 percent by volume; very strongly acid; clear wavy boundary. (3 to 12 inches thick)

2Bt1--15 to 23 inches; mottled yellowish brown (10YR 5/4) and light brownish gray (10YR 6/2) silty clay; many medium prominent yellowish red (5YR 4/6) mottles; moderate medium subangular blocky structure; firm; few fine and medium roots; few thin light gray (10YR 7/2) silt coats between peds; thick continuous clay films on faces of peds; very strongly acid; clear wavy boundary. (6 to 15 inches thick)

2Bt2--23 to 39 inches; yellowish brown (10YR 5/6) silty clay loam; common medium distinct light brownish gray (10YR 6/2) and few fine distinct strong brown (7.5YR 4/6) mottles; moderate medium subangular blocky structure; firm; few fine roots; thin patchy clay films on faces of peds; strongly acid; clear wavy boundary. (6 to 20 inches thick)

3Btn1--39 to 48 inches; light olive brown (2.5Y 5/6) silty clay loam; common medium distinct light brownish gray (2.5Y 6/2) mottles; moderate coarse prismatic structure; firm; few black stains; common shiny pressure faces on surfaces of peds; few thin clay films on faces of peds; strongly acid; clear wavy boundary. (8 to 18 inches thick)

3Btn2--48 to 60 inches; light olive brown (2.5Y 5/6) silty clay loam; common medium distinct light brownish gray (2.5Y 6/2) mottles; weak coarse prismatic structure; firm; few thin clay films on faces of peds; medium acid.

TYPE LOCATION: Livingston Parish, Louisiana; about 1.25 miles southeast of Verdun, 3,000 feet east of Bayou LaGlaise, 200 feet west of dirt road; sec. 29, T. 8 S., R. 5 E.; lat. 30 degrees 19 minutes 27.01 seconds N. and long. 90 degrees 43 minutes 39.39 seconds W., WGS84.

RANGE IN CHARACTERISTICS: The thickness of the solum ranges from 30 to 70 inches. Loess thickness ranges from 1 to 3 feet. Depth to horizons with 5 to 15 percent exchangeable sodium ranges from 30 to 50 inches.

The Ap or A horizon has hue of 10YR, value of 3 to 5, and chroma of 1 to 3. Reaction ranges from very strongly acid to medium acid, except in areas that have been limed.

The EB or BE horizon has hue of 10YR, value of 5 or 6, and chroma of 4 to 8. Texture is silt loam or silt and reaction ranges from very strongly acid to medium acid. Mottles in shades of brown or gray range from few to many.

The E part of the 2B/E horizon has hue of 10YR, value of 5 to 7, and chroma of 2 or 3. Texture is silt loam and reaction ranges from very strongly acid to medium acid.

The 2Bt horizon and the B part of the 2B/E horizon have hue of 10YR, value of 5 or 6, and chroma of 3 to 8, or they are mottled with shades of brown, gray, or red. Texture is silty clay loam, silty clay, or clay. Reaction ranges from very strongly acid to neutral.

The 3Btn horizon has hue of 10YR or 2.5Y, value of 5 or 6, and chroma of 2 to 8. Mottles in shades of brown and gray range from few to many. Reaction ranges from strongly acid to moderately alkaline. Texture is silty clay loam or silt loam and exchangeable sodium ranges from 5 to 15 percent.

COMPETING SERIES: There are no other series in this family. Abita, Bude, Coteau, Fluker, Longview, Olivier, Providence, and Vidrine soils are in related families. Abita, Coteau, Longview, and Vidrine soils do not have horizons with 5 to 15 percent exchangeable sodium within depths of 30 to 50 inches and have less than 35 percent clay in the particle size control section. Bude, Fluker, Olivier, and Providence soils have fragipans and have less than 35 percent clay in the particle size control section.

GEOGRAPHIC SETTING: Colyell soils are on broad nearly level to gently sloping, convex stream divides and side slopes along drainageways. Slopes range from 1 to 3 percent. These soils formed in thin loess over clayey deposits of Late Pleistocene Age. Near the type location, the mean annual temperature is 67 degrees, and the mean annual precipitation is 64 inches.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Abita and Olivier soils and the Deerford, Springfield, and Verdun soils. The competing Abita and Olivier soils are on higher convex ridges. The Deerford, Springfield, and Verdun soils are at slightly higher elevations on nearly level flats. Deerford and Verdun soils have natric horizons. Springfield soils have an abrupt textural change.

DRAINAGE AND PERMEABILITY: Somewhat poorly drained. Runoff is medium. The permeability is moderate in the upper part of the subsoil and slow in the lower part of the subsoil. Depth to a perched water table is 1.0 to 2.5 feet during the months of December through April.

USE AND VEGETATION: Most of the Colyell soils are in pine woodland, pasture, or homesites. A few areas are cultivated.

DISTRIBUTION AND EXTENT: Louisiana. The series is of moderate extent.

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

SERIES ESTABLISHED: Livingston Parish, Louisiana; 1987.

REMARKS: Laboratory data for the typifying pedon by the Louisiana Agricultural Experiment Station Soil Characterization Lab, sample number S86LA63-38.

Diagnostic horizons and features:
Ochric epipedon - 0 to 12 inches.
Argillic horizon - 12 to 39 inches.
Interfingering - 12 to 15 inches.
Lithologic discontinuity - 12 inches and at 39 inches. Sodium accumulation - 39 to 60 inches (5 to 15 percent exchangeable sodium).

National Cooperative Soil Survey
U.S.A.