LOCATION TRUCE              TX

TRUCE SERIES

The Truce series consists of soils that are deep over claystone bedrock. These well drained, slowly permeable soils formed in residuum from claystone. These soils are on gently sloping to steep, convex ridges. Slopes are typically 1 to 5 percent, but range from 1 to 40 percent.

TAXONOMIC CLASS: Fine, mixed, active, thermic Udic Paleustalfs

TYPICAL PEDON: Truce fine sandy loam, stony on a 2 percent convex slope in rangeland. (Colors are for dry soil unless otherwise stated.)

A--0 to 3 inches; brown (10YR 4/3) fine sandy loam, dark brown (10YR 3/3) moist; weak fine subangular blocky structure when moist; hard and massive when dry; hard, friable; common fine roots; slightly acid; abrupt smooth boundary. (2 to 10 inches thick)

E--3 to 8 inches; pale brown (10YR 6/3) fine sandy loam, brown (10YR 5/3) moist; weak fine subangular blocky structure; hard, friable; common fine roots; slightly acid; abrupt smooth boundary. (0 to 7 inches thick with combined A and E horizon thickness of 2 to 12 inches)

Bt1--8 to 22 inches; reddish brown (5YR 4/4) clay, dark reddish brown (5YR 3/4) moist; moderate fine and medium blocky structure; extremely hard, very firm; few fine roots; common clay films on surfaces of peds; slightly alkaline; gradual wavy boundary. (8 to 18 inches thick)

Bt2--22 to 30 inches; brown (7.5YR 5/4) clay, brown (7.5YR 4/4) moist, few fine distinct yellowish red and yellowish brown mottles; moderate fine and medium blocky structure; extremely hard, very firm; few fine roots; common clay films on surfaces of peds; slightly alkaline; gradual wavy boundary. (4 to 20 inches thick)

BCt--30 to 45 inches; light yellowish brown (10YR 6/4) clay, yellowish brown (10YR 5/4) moist; weak medium blocky structure; extremely hard, very firm; few fine roots; few clay films; strongly effervescent; moderately alkaline; clear wavy boundary. (4 to 20 inches thick)

Cd--45 to 60 inches; pale olive (5Y 6/3) claystone bedrock, olive (5Y 5/3) moist; weak fine and medium platy structure; few fine roots between plates; few films and threads of calcium carbonate; moderately alkaline.

TYPE LOCATION: Erath County, Texas; from the junction of Interstate 20 and Texas Highway 108, 0.95 mile south on Texas Highway 108, then 75 feet east of highway right-of-way in native range, this point being about 22 miles north-northwest of Stephenville, Texas.

RANGE IN CHARACTERISTICS: Solum thickness ranges from 40 to 60 inchesover dense clay or claystone bedrock. Fragments of sandstone and ironstone mainly 3 to 24 inches across cover 0 to 20 percent of the soil surface. The argillic horizon is clay, sandy clay, or clay loam with clay content of 35 to about 55 percent. Fragments of sandstone and ironstone mainly less than 10 inches across comprise 0 to 5 percent by volume.

The A horizon has hue of 7.5YR or 10YR, value of 4 to 6, chroma of 2 to 4. The E horizon is 1 or 2 units of value lighter in color than the A horizon. Texture is fine sandy loam, with stony, very stony or extremely stony surfaces. The A horizon is hard and massive when dry. Reaction of the A horizon is moderately acid to neutral. Fragments of sandstone and ironstone range from 0 to 25 percent and are less than an inch to 24 inches across the long axis.

The Bt1 horizon has hue of 2.5YR or 5YR, value of 3 to 5, chroma of 3 to 8. Reaction is slightly acid to slightly alkaline. The Bt2 horizon has hue of 5YR, 7.5YR, or 10YR, value of 4 to 6, chroma of 3 to 6. Some pedons have redoximorphic features in shades of brown, olive or red. Reaction is neutral to moderately alkaline.

The BCt horizon is in shades of brown or olive and some pedons contain redoximorphic features in shades of red, brown, or olive. Reaction is neutral to moderately alkaline and is calcareous in most pedons. Some pedons have a BCk horizon.

The Cd horizon is claystone bedrock or dense clay and some pedons are interbedded with thin discontinuous layers of sandstone. It is in shades of olive, brown, yellow, and gray. Reaction ranges from neutral to moderately alkaline and is typically calcareous.

COMPETING SERIES: These include the Callisburg (TX), Chigley (OK), Cona (TX), Edge (TX), Minwells (TX), Shiro (TX), and Windthorst (TX) series. Similar soils are the Delwin, Miles and Rochelle soils. Callisburg soils are greater than 60 inches to bedrock or dense shale material. Chigley soils have hard conglomerate bedrock within 80 inches of the surface. Cona and Shiro soils have sola thickness between 20 and 40 inches. Edge soils are underlain by siltstone. Minwells and Rochelle soils are underlain by thick beds of gravelly materials. Windthorst soils are moist in the soil moisture control section for longer periods and are more acid throughout. Delwin soils have sola greater than 80 inches. Miles soils are in the fine-loamy family.

GEOGRAPHIC SETTING: Truce soils usually have convex surfaces. Typically, they are on gently sloping ridges with slopes of 1 to 5 percent. However, slopes range to 40 percent when the soil is sloping to steep along hillsides. These soils formed in residuum from claystone interbedded with thin discontinuous layers of sandstone of Pennsylvanian age. Mean annual precipitation ranges from 24 to 32 inches, and mean annual temperatures range from 63 to 66 degrees F. Frost free days range from 210 to 240 days, and elevation ranges from 1,000 to 1,800 feet. Thornthwaite annual P-E indices range from 36 to 50.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Bonti series and the Exray, Owens, Shatruce, and Thurber series. Bonti soils are above mainly on ridgetops with plane slopes. Exray soils have sola less than 20 inches to sandstone bedrock, and are above mainly on ridgetops. Owens soils are more alkaline, lack argillic horizons, and are in positions similar to Truce soils. Shatruce soils are 20 to 40 inches thick over shaly clay and are above on bouldery escarpments. Thurber soils have clay loam surface layers, secondary carbonates within 28 inches of the surface, and are below on nearly level or gently sloping positions.

DRAINAGE AND PERMEABILITY: Well drained. Permeability is slow. Runoff is medium on 1 to 5 percent slopes, high on 5 to 20 percent slopes, and very high on slopes greater than 20 percent.

USE AND VEGETATION: Mostly used as rangeland. A few small areas are cropped to small grains and sorghums. Climax vegetation is an open post oak savannah with tall and mid grasses such as indiangrass, big and little bluestem, and sideoats grama. Most areas contain other woody plants such as blackjack oak and elm with invading mesquite, cedar, and lotebush. Present herbaceous vegetation consists mainly of sideoats grama, Texas needlegrass, hairy grama, threeawns, sand dropseed, and other low producing perennials and annuals with western ragweed, Engelmann-daisy, bundleflower, prairie clover, primrose, and gayfeather.

DISTRIBUTION AND EXTENT: North Central Prairie and West Cross Timbers of Texas. The series is extensive.

MLRA OFFICE RESPONSIBLE: Temple, Texas

SERIES ESTABLISHED: Erath County, Texas; 1965.

REMARKS: Diagnostic horizons and features are as follows:

Ochric epipedon - 0 to 8 inches. (A and E horizons)

Argillic horizon - 8 to 30 inches. (Bt1 and Bt2 horizons)

Pale feature - abrupt textural change at a depth of 8 inches

Densic material - 45 to 60 inches (Cd layer).

ADDITIONAL DATA: NSSL sample nos. 76P0508 - 76P0513.