LOCATION CLEMVILLE               TX

Established Series
GSM- ACT-KBH-JKW
04/2015

CLEMVILLE SERIES

The Clemville series consists of very deep, well drained soils that formed in loamy and clayey calcareous alluvial sediments. These nearly level to gently sloping soils are on flood plains. Slopes range from 0 to 3 percent. Mean annual precipitation is about 1143 mm (45 in), and Mean annual air temperature is about 20.6 degrees C (69 degrees F).

TAXONOMIC CLASS: Fine-silty, mixed, superactive, hyperthermic Fluventic Eutrudepts

TYPICAL PEDON: Clemville silty clay loam--cropland. (Colors are for moist soil unless otherwise stated.)

Ap--0 to 15 cm (0 to 6 in); brown (7.5YR 4/4), silty clay loam, brown (7.5YR 5/4) dry; weak fine granular structure; hard, friable; many fine roots; many very fine pores; few fragments of snail shells; common worm casts; strongly effervescent, moderately alkaline; abrupt smooth boundary. (Thickness of the Ap horizon is 7 to 25 cm [3 to 10 in])

A--15 to 31 cm (6 to 12 in); brown (7.5YR 4/4) silty clay loam, brown (7.5YR 5/4) dry; weak fine granular structure; hard, friable; many fine roots; many fine and very fine pores; few fragments of snail shells; many worm casts; strongly effervescent, moderately alkaline; clear smooth boundary. (Thickness of the the A horizon is 7 to 45 cm [0 to 8 in])

Bw--31 to 76 cm (12 to 30 in); stratified light brown (7.5YR 6/4) silt loam, few thin lenses of reddish brown (5YR 5/4) and brown (7.5YR 5/4) silty clay loam; massive when moist, weak coarse subangular blocky when dry; breaks to platy fragments along some bedding planes; hard, friable, nonsticky and nonplastic; few fine roots; common very fine pores; few fragments of snail shells; common wormcasts; many horizontal bedding planes; strongly effervescent, moderately alkaline; abrupt smooth boundary. (Thickness of the Bw horizon is 30 to 76 cm [12 to 30 in])

Ab--76 to 127 cm (30 to 50 in); dark brown (7.5YR 3/3) silty clay, brown (7.5YR 4/3) dry; moderate medium and fine angular blocky structure; very hard, firm; few fine roots; common wormcasts; few strongly cemented concretions of calcium carbonate, few distinct coats of calcium carbonate on surfaces of peds, strongly effervescent, moderately alkaline; gradual smooth boundary. (Thickness of the Ab horizon is 0 to 76 cm [0 to 30 in])

Bb--127 to 203 cm (50 to 80 in); reddish brown (5YR 4/3) silty clay, reddish brown (5YR 5/3) dry; weak medium angular blocky structure; very hard, firm; few strongly cemented concretions of calcium carbonate; thin distinct calcium carbonate coats on surfaces of peds; strongly effervescent, moderately alkaline.

TYPE LOCATION: Wharton County, TX; from Wharton, Texas, about 15 miles
Northwest on Farm Road 102 to the intersection of Farm Road 102 and Farm Road 26l4, 2.0 miles west on Farm Road 2614, 1.0 mile south on a gravel road, 200 feet west of gravel road in cultivated field. Markham TX USGS quad; Latitude: 29 degrees, 25 minutes, 23.63 seconds N; Longitude: 96 degrees, 18 minutes, 42.39 seconds W. WGS84; UTM Easting 760804 m, UTM Northing 3257884 m, UTM Zone 14.

RANGE IN CHARACTERISTICS:
These soils are in the udic soil moisture regime. The soil moisture control section remains moist in some parts for more than 275 days in normal years.
Mean annual soil temperature: 21.5 to 22 degrees C (70 to 72 degrees F)
Depth to cambic horizon: 23 to 38 cm (9 to 15 in)

Particle-size control section (weighted average)
Clay content: 27 to 35 percent
Sand content: 2 to 20 percent

A horizon
Hue: 5YR or 7.5YR
Value: 3 to 6
Chroma: 2 to 6
Texture: silt loam or silty clay loam
Effervescence: slight to violent
Reaction: neutral to moderately alkaline

Bw horizon
Hue: 5YR or 7.5YR
Value: 4 to 6
Chroma: 3 to 6
Texture: silt loam or silty clay loam
Effervescence: slight to violent
Reaction: neutral to moderately alkaline

Ab horizon
Hue: 5YR to 10YR
Value: 2 to 5
Chroma: 1 to 6
Texture: silty clay loam to clay
Clay content: 35 to 50 percent
Effervescence: slight to violent
Reaction: neutral to moderately alkaline

Bb horizon
Hue: 5YR to 10YR
Value: 4 or 5
Chroma: 2 to 8
Texture: silty clay loam, silty clay, or clay
Effervescence: slight to violent
Reaction: neutral to moderately alkaline

COMPETING SERIES: This is the Norwood series. Similar soils are the Asa,
Brazoria, Highbank, Norwood, Ships, and Weswood series.
Norwood soils: do not have horizons containing more than 35 percent clay within 91 cm (36 in) of the soil surface
Asa, Brazoria, Highbank, Ships, and Weswood soils: are in the thermic temperature
Asa soils: have a mollic epipedon
Brazoria, Highbank, and Ships soils: have more than 35 percent clay in the particle-size control section

GEOGRAPHIC SETTING:
Parent Material: loamy and clayey calcareous alluvium
Landscape: Coastal Plains
Landform: Flood plains
Mean annual air temperature: 20 to 22 degrees C (68 to 72 degrees F)
Mean annual precipitation: 1092 to 1245 mm (43 to 49 in)
Frost-free period: 270 to 300 days
Elevation: 6 to 30.5 m (19 to 100 ft)

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Asa, Brazoria, Norwood, and Pledger series.
Asa, Brazoria, and Norwood soils: are on similar positions
Pledger soils: have a mollic epipedon, are clayey throughout, and have cracks when dry. They are on similar to slightly lower positions.

DRAINAGE AND PERMEABILITY: Well drained. Permeability is slow. Runoff is low on slopes less than 1 percent, and medium on 1 to 3 percent slopes. Flooding occurs at intervals of once each 2 to 10 years, except where protected.

USE AND VEGETATION: Mainly used for pastureland, but also for cropland. Crops include cotton, corn, grain sorghums, and alfalfa. Native vegetation was a dense forest of pecan, cottonwood, elm, oak, and hackberry trees with an understory of coarse bunch grasses.

DISTRIBUTION AND EXTENT: Mainly along the lower Brazos and Colorado Rivers in Texas. Land Resource Region T; MLRA 150A; the series is moderately extensive.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas

SERIES ESTABLISHED: Wharton County, Texas, l975.

REMARKS: Classification change from Typic Udifluvents to Fluventic Eutrudepts (1998 and 2000) based on the presence of a weak cambic horizon evidenced by removal of carbonates, slight color change in the Bw horizon, and landscape position conducive to the development of a cambic horizon. Change from thermic to hyperthermic temperature regime based geographic distribution of the series. Edited 04-2015 (KBH, JKW) by adding effervescence in range of characteristics, and updating competing series section.

Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon: 0 to 31 cm (0 to 12 in) (Ap and A horizons)
Cambic horizon: 31 to 76 cm (12 to 30 in) (Bw horizon)
Fluventic feature: stratification and irregular decrease of organic carbon with depth

ADDITIONAL DATA: Texas Highway Department data on pedons sampled in Brazoria County, TX (S76TX-039-018) and Washington County, TX (S73TX-239-003).

Taxonomic Version: Keys to Soil Taxonomy, Twelfth Edition, 2014.

---

National Cooperative Soil Survey
U.S.A.