LOCATION BONTI TXEstablished Series
The Bonti series consists of well drained, moderately slowly permeable moderately deep soils over sandstone bedrock that formed in residuum from interbedded sandstone and clayey materials. These soils are on ridges and plains and have slopes ranging from 1 to 40 percent.
TAXONOMIC CLASS: Fine, mixed, active, thermic Ultic Paleustalfs
TYPICAL PEDON: Bonti very fine sandy loam, very stony--in rangeland. (Colors are for dry soil unless otherwise stated.)
A--0 to 4 inches; brown (10YR 4/3) very fine sandy loam, dark brown (10YR 3/3) moist; weak fine subangular blocky structure; slightly hard, friable; many fine and few medium roots; sandstone fragments 10 to 18 inches across cover about 15 percent of surface; sandstone fragments 1 to 10 inches across comprise about 3 percent by volume; slightly acid; clear smooth boundary. (2 to 6 inches thick)
E--4 to 8 inches; light brown (7.5YR 6/4) very fine sandy loam, brown (7.5YR 4/4) moist; weak fine subangular blocky structure; hard, friable; many fine roots; sandstone pebbles less than 3 inches across comprise about 5 percent by volume; moderately acid; clear smooth boundary. (0 to 6 inches thick)
Bt1--8 to 20 inches; red (2.5YR 4/6) clay, dark red (2.5YR 3/6) moist; moderate very fine and fine blocky structure; very hard, firm; many fine roots; thin continuous clay films on faces of peds; moderately acid; gradual smooth boundary. (8 to 14 inches thick)
Bt2--20 to 30 inches; yellowish red (5YR 5/6) clay loam; yellowish red (5YR 4/6) moist; few fine distinct dark red and few fine faint reddish yellow mottles; moderate fine blocky structure; very hard, firm; few fine roots; thin continuous clay films on faces of peds; moderately acid; abrupt boundary. (8 to 20 inches thick)
Cr--30 to 32 inches; brownish yellow weakly and moderately cemented sandstone.
TYPE LOCATION: Erath County, Texas; 14.5 miles northwest of Stephenville on Texas Highway 108, 4.5 miles northeast on Farm Road 1715, 4.4 miles north on county road (1.4 mile north of Russel Chapel Cemetery), 100 feet west in wooded pasture.
RANGE IN CHARACTERISTICS: Solum thickness and depth to bedrock is 20 to 40 inches. Fragments of sandstone and ironstone cover from 0 to 50 percent of the surface. The fragments range from less than 3 to 48 inches across. Fragments in the solum range from 0 to 25 percent by volume and are mainly less than 10 inches across.
The A horizon has hue of 7.5YR to 10YR, value of 4 or 5, and chroma of 2 to 4. The E horizon has hue of 7.5YR to 10YR, value of 5 to 7, and chroma of 2 to 6. Texture is fine sandy loam, very fine sandy loam and less commonly loamy fine sand. Reaction ranges from moderately acid to neutral.
The Bt horizon has hue of 2.5YR or 5YR, value of 4 to 6, and chroma of 4 to 8. Typically, there are a few mottles in shades of red, yellow, or brown in the lower part. The texture is clay, sandy clay, or clay loam with clay content of 35 to 50 percent. Reaction is strongly acid or moderately acid. The base saturation ranges from 50 to 75 percent. The underlying material is weakly to moderately cemented sandstone bedrock with some thin interbeds of strongly cemented, and some interbedded with thin discontinuous layers of claystone.
COMPETING SERIES: These include the Birome, Castell, Darst, Gause, Jedd, Rosanky, Shatruce, Spiller and Travis series in the same family and Bowser, Truce, and Windthorst series. Birome, Darst, Jedd, and Shatruce soils lack a lithic contact of sandstone within 40 inches of soil surface. Bowser soils are skeletal. Castell soils are formed in residuum from gneiss. Gause, Rosanky, Spiller, Travis, Truce, and Windthorst soils have a solum thicker than 40 inches. Truce and Windthorst soils also have base saturation of more than 75 percent in the Bt horizon.
GEOGRAPHIC SETTING: Bonti soils are gently sloping to steep with plane or slightly convex surfaces. They are on ridges and plains over sandstone bedrock mainly of Pennsylvania age. Slopes are usually 1 to 5 percent on ridgetops but range to 40 percent along hillsides. Mean annual temperature is 64 to 67 degrees F., mean annual precipitation is 26 to 32 inches. Frost free period is 215 to 230 days, and elevation ranges form 1200 to 1700 feet. Thornthwaite annual P-E index ranges from 38 to 50.
GEOGRAPHICALLY ASSOCIATED SOILS: These include the competing Shatruce and Truce series and the Exray, Owens, and Vashti series. Shatruce soils are on bouldery escarpments. Truce soils are on lower, convex slopes. Exray soils are less than 20 inches deep to sandstone bedrock and are intermingled with Bonti soils. Owens soils are clayey throughout, are less than 20 inches deep over shale, and mainly are on convex knolls and south-facing escarpments. Vashti soils have fine-loamy control sections and are above stream divides.
DRAINAGE AND PERMEABILITY: Well drained, runoff is medium on 1 to 5 percent slopes, high on 5 to 20 percent slopes, very high on 20 to 40 percent slopes; moderately slow permeability and internal drainage.
USE AND VEGETATION: Used mainly as rangeland. Native vegetation is mainly little and big bluestem, indiangrass, sideoats grama, Arizona cottontop, sand lovegrass, switchgrass, ragweed, blackjack, and post oak.
DISTRIBUTION AND EXTENT: North-central Texas. The series is of moderate extent.
MLRA OFFICE RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Erath County, Texas; 1970.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the zone from 0 to 8 inches.
Argillic horizon - the zone from 8 to 30 inches.
Paralithic material-strongly cemented sandstone 30 to 32 inches.
Ultic feature - base saturation of the Bt horizons is less than 75 percent.
Paleustalf feature - abrupt textural change at 8 inches.
ADDITIONAL DATA: NSSL data from Erath County, Texas (S79TX-143-003); SDHPT data from Eastland County, Texas (S69TX-067-001) and Parker
County, Texas (S70TX-184-005).