LOCATION TREP               TX+LA
Established Series


The Trep series consists of very deep, moderately well drained, moderately slowly permeable soils on uplands. These nearly level to strongly sloping soils formed in sandy and loamy Coastal Plain sediments. Slopes range from 0 to 12 percent.

TAXONOMIC CLASS: Loamy, siliceous, semiactive, thermic Arenic Paleudults

TYPICAL PEDON: Trep loamy fine sand--pastureland. (Colors are for moist soil unless otherwise stated.)

Ap--0 to 5 inches; dark grayish brown (10YR 4/2) loamy fine sand, grayish brown (10YR 5/2) dry; weak fine granular structure; slightly hard, very friable; few fine roots; medium acid; clear smooth boundary. (4 to 10 inches thick)

E--5 to 24 inches; pale brown (10YR 6/3) loamy fine sand, very pale brown (10YR 7/3) dry; single grained; loose; few fine roots; medium acid; gradual smooth boundary. (14 to 30 inches thick)

Bt1--24 to 40 inches; brownish yellow (10YR 6/6) sandy clay loam, yellow (10YR 7/6) dry; few fine prominent pale red mottles; weak coarse and medium subangular blocky structure; hard, friable; few fine roots; few fine pores; few clay films on faces of peds; strongly acid; gradual smooth boundary. (6 to 20 inches thick)

Bt2--40 to 48 inches; mottled light brownish gray (10YR 6/2), yellowish brown (10YR 5/6), and dark red (2.5YR 3/6) sandy clay loam; moderate medium subangular blocky structure; hard, firm; few brittle red mottles; few fine roots; few fine pores; patchy clay films on faces of peds; strongly acid; diffuse wavy boundary. (8 to 15 inches thick)

Bt3--48 to 74 inches; mottled yellowish brown (10YR 5/8), dark red (10R 3/6), and light brownish gray (10YR 6/2) sandy clay; weak medium subangular blocky structure; very hard, very firm; few fine roots; few fine pores; patchy clay films on faces of peds; very strongly acid.

TYPE LOCATION: Anderson County, Texas; about 1.75 miles south of Neches; from U. S. Highway 79, 1.5 miles south on county road and 100 feet east.

RANGE IN CHARACTERISTICS: Solum thickness ranges from 60 to more than 80 inches. The clay content of the control section ranges from 22 to 35 percent.

The A1 or Ap horizon has hue of 7.5YR or 10YR, value of 4 or 5, chroma of 2 to 4. The E horizon has colors with one or two units of value greater than the A horizon. The A and E horizons are loamy fine sand or fine sand. The reaction of the A & E horizons ranges from strongly acid to slightly acid unless limed.

The upper part of the Bt horizon has hue of 10YR or 2.5Y, value of 5 or 6, chroma of 4 to 8. Mottles in shades of red or brown, range from few to common. Mottles with chroma of 2 or less are below a depth of 30 inches. Texture is sandy clay loam or loam. Reaction ranges from very strongly acid to medium acid.

The lower part of the Bt horizon is typically mottled in shades of gray, brown, or red. Some pedons have a grayish or brownish matrix with yellow or red mottles. Texture is clay or sandy clay. The reaction is very strongly acid or strongly acid.

COMPETING SERIES: These are the Autryville, Bonneau, Boykin, Briley, Letney, Lovett, Lowndes, Lucy, Rosalie, and Wagram series. Autryville and Lowndes series are bisequal soils. In addition, Lowndes soils have hue redder than 10YR in the upper Bt horizon. Bonneau, Letney, Rosalie and Wagram soils lack clayey lower Bt horizons. Boykin, Briley, and Lucy soils have hue redder than 10YR throughout the Bt horizon. Lovett soils are in a wetter climatic and receive more than 50 inches of precipitation annually.

GEOGRAPHIC SETTING: Trep soils are on nearly level to strongly sloping uplands of the Coastal Plain. Slope gradients are predominately 1 to 4 percent but range up to 12 percent. The soils formed in stratified acid sediments of marine origin. The mean annual precipitation is 40 to 50 inches and the Thornthwaite annual P-E indices are 66 to 82. Average annual air temperature ranges from 65 to 67 degrees F.

GEOGRAPHICALLY ASSOCIATED SOILS: These are mainly the Bowie, Darco, Kirvin, Kullit, Lilbert, and Sacul series. Bowie, Kirvin, Kullit, and Sacul soils have loamy surface layers less than 20 inches thick. Darco soils have a sandy surface layer more than 40 inches thick. Lilbert soils have more than 5 percent plinthite. Darco, Kirvin, Lilbert, and Sacul soils are typically on positions higher in the landscape. Bowie and Kullit soils are on similar positions.

DRAINAGE AND PERMEABILITY: Moderately well drained. Internal drainage is moderate through the upper Bt horizon and slow through the lower Bt horizon. Runoff is slow. Permeability is moderately slow.

USE AND VEGETATION: Most of these soils were formerly cultivated but are now in pasture or woodland. Native vegetation is loblolly and short leaf pine, sweetgum, red oak, hickory, and blackjack oak with an understory of American Beauty berry, sassafras, sumac, hawthorn, native grasses, forbs, and vines. A few areas are cropped to corn, peas, or oats.

DISTRIBUTION AND EXTENT: Southern Coastal Plain of Texas and possibly adjoining states. The series is of moderate extent.


SERIES ESTABLISHED: Anderson County, Texas; 1970.

Diagnostic horizons and features:

Ochric epipedon 0 to 24 inches.

Arenic feature - sandy textures to 24 inches.

Argillic horizon - 24 to 74 inches.

Pale feature - Clay content does not decrease by 20 percent of maximum within 60 inches and red mottles are present.

National Cooperative Soil Survey