LOCATION MCLENNAN                TX

Established Series
Rev. CLN-RMR-RM
02/2018

MCLENNAN SERIES

The McLennan series consists of very deep to loamy shale, siltstone, and flaggy limestone. These well drained soils formed in residuum derived from shale, claystone, or siltstone interbedded with flaggy limestone of Upper Cretaceous Age. These gently sloping to moderately steep soils are on steep ridges on dissected plains. Slopes range from 3 to 20 percent. Mean annual precipitation is about 892 mm (35.1 in) and the mean annual air temperature is about 18.6 degrees C (65.5 degrees F).

TAXONOMIC CLASS: Fine-silty, carbonatic, thermic Udic Haplustepts

TYPICAL PEDON: McLennan clay loam--in a cultivated field. (Colors are for dry soil unless otherwise stated.)

A--0 to 18 cm (0 to 7 in); grayish brown (2.5Y 5/2) clay loam, dark grayish brown (2.5Y 4/2) moist; moderate fine subangular blocky structure; hard, friable; common very fine and fine roots; common wormcasts; common channers 5 to 15 cm (2 to 6 in) across, few flaggy limestone fragments that are 3 cm (1 in) thick and 15 to 25 cm (6 to 10 in) across; calcium carbonate equivalent is 50 percent; violently effervescent; moderately alkaline; clear smooth boundary. (8 to 20 cm [3 to 8 in] thick)

Bw--18 to 36 cm (7 to 14 in); light olive brown (2.5Y 5/4) clay loam, olive brown (2.5Y 4/4) moist; moderate medium prismatic structure parting to moderate subangular blocky; hard, firm; common very fine and fine roots; calcium carbonate equivalent is 70 percent; few medium calcium carbonate concretions; violently effervescent; moderately alkaline; clear smooth boundary. (0 to 46 cm [0 to 18 in] thick)

Bk1--36 to 61 cm (14 to 24 in); light yellowish brown (2.5Y 6/4) clay loam, yellowish brown (10YR 5/4) moist; moderate medium prismatic structure parting to moderate very fine subangular blocky; hard, firm; few very fine and fine roots; calcium carbonate equivalent is 70 percent; few medium soft masses of calcium carbonate; common medium calcium carbonate concretions; violently effervescent; moderately alkaline; clear smooth boundary. (20 to 51 cm [8 to 20 in] thick)

Bk2--61 to 81 cm (24 to 32 in); light yellowish brown (2.5Y 6/4) clay loam, yellowish brown (10YR 5/4) moist; moderate medium prismatic structure parting to moderate very fine subangular blocky; hard, firm; few very fine and fine roots; calcium carbonate equivalent is 70 percent; common medium soft masses of calcium carbonate; common medium calcium carbonate concretions; violently effervescent; moderately alkaline; clear smooth boundary. (0 to 51 cm [0 to 20 in] thick)

Bk/C--81 to 203 cm (32 to 80 in); olive yellow (2.5Y 6/6) silty clay loam, light olive brown (2.5Y 5/6) moist; few strata of brownish yellow (10YR 6/6) loam up to 8 cm (3 in) thick interbedded throughout; moderate medium subangular blocky structure; very hard, firm; few fine roots; about 5 to 10 percent medium distinct light brownish gray (2.5Y 6/2) shale fragments (C); calcium carbonate equivalent is 70 percent; common medium masses and concretions of calcium carbonate; few thin discontinuous quartzite limestone layers about 3 cm (1 in) thick interbedded throughout; violently effervescent; moderately alkaline.

TYPE LOCATION: McLennan County, Texas; from the intersection of Texas Highway 317 and Farm to Market Road 107 in Moody, Texas; 2.8 miles northwest on Texas Highway 317 to County Road 119; 1.9 miles north on County Road 119; 150 ft west of road in rangeland.
USGS Topographic Quadrangle: Moody, TX;
Latitude: 31 degrees, 22 minutes, 12 seconds North;
Longitude: 97 degrees, 21 minutes, 35 seconds West.
Datum: WGS84

RANGE IN CHARACTERISTICS:

Solum depth: from 152 to 203 cm (60 to 80 in)
Soil Moisture: An ustic soil moisture regime that borders on udic. The soil moisture control section is dry in some or all parts for 90 or more cumulative days and moist, in some part, either for more than 180 cumulative days per year, or for 90 or more consecutive days in normal years.
Soil temperature: 15 to 22 degrees C (59 to 72 degrees F)
Thickness of ochric epipedon: 8 to 20 cm (3 to 8 in) thick
Thickness of cambic horizon: 132 to 195 cm (52 to 77 in)

Particle-size control section:
Silicate clay content: 25 to 35 percent
Rock fragments: amount-0 to 13 percent; kind-limestone; shape-flat; size-gravels
Calcium carbonate equivalent: 40 to 80 percent
Identifiable secondary carbonates: amount-0 to 5 percent; kind-carbonate masses and concretions; size-fine or medium

A horizon
Hue: 10YR or 2.5Y
Value: 5 or 6, dry or moist
Chroma: 2 to 4, dry or moist
Rock Fragments: amount- 1 to 13 percent; size-gravels which are 5 to 51 cm (2 to 20 in) across the long axis and 1.5 to 8 cm (0.5 to 3 in) thick; kind-limestone; shape-flat
Texture: clay loam or silty clay loam
Reaction: moderately alkaline

Bw horizon
Hue: 10YR or 2.5Y
Value: 5 to 7, dry or moist
Chroma: 2 to 6, dry or moist
Texture: clay loam or silty clay loam
Rock Fragments: amount- 1 to 13 percent; size-gravels which are 5 to 51 cm (2 to 20 in) across the long axis and 1.5 to 8 cm (0.5 to 3 in) thick; kind-limestone; shape-flat
Calcium carbonates: amount-0 to 10 percent; kind-carbonate masses and concretions; size-fine or medium
Reaction: moderately alkaline
Other Features: mottles of gray that are inherited from the parent material present in some pedons

Bk horizon
Hue: 10YR or 2.5Y
Value: 5 to 7, dry or moist
Chroma: 2 to 6, dry or moist
Texture: clay loam or silty clay loam
Rock Fragments: amount- 1 to 13 percent; size-gravels which are 5 to 51 cm (2 to 20 in) across the long axis and 1.5 to 8 cm (0.5 to 3 in) thick; kind-limestone; shape-flat
Calcium carbonates: amount-5 to 25 percent; kind-carbonate masses and concretions; size-fine or medium
Reaction: moderately alkaline
Other Features: mottles of gray that are inherited from the parent material present in some pedons

Bk/C horizon
Hue: 10YR to 5Y
Value: 5 to 7, dry or moist
Chroma: 4, dry or moist
Texture: It contains strata of limestone 3 to 10 cm (1 to 4 in) thick interbedded with shale, clay, claystone, siltstone, silty clay loam, clay loam or loam.
Calcium carbonates: amount- 2 to 20 percent, kind-carbonate masses or concretions, size-fine or medium
Reaction: moderately alkaline

COMPETING SERIES: These include the Altoga and Howe series in the same family, and the similar Austin, Brackett, Cranfill, Cuthand, Ellis, Kerrville, Lamar, Lott, Seawillow, and Whitewright series.
Altoga soils: do not contain flaggy fragments of limestone or dense substrata and typically occur on old high terraces, footslopes and alluvial fans.
Howe soils: have a paralithic contact to chalk.
Austin and Lott soils: have mollic epipedons.
Brackett, Cranfill, Lamar, and Seawillow soils: are in a fine-loamy family, in addition, Lamar soils have less than 40 percent calcium carbonate equivalent.
Cuthand soils: are in a coarse-silty family.
Ellis soils: are in a fine family, have vertic properties, and are noncalcareous.
Kerrville soils: contain more than 5 percent fragments in the control section.
Whitewright soils: are shallow over chalk.

GEOGRAPHIC SETTING:
Parent material: residuum weathered from shale, claystone, or siltstone interbedded with flaggy limestone, mainly of the Eagle Ford Group of upper Cretaceous Age
Landscape: Dissected Plains
Landform: backslopes on sideslopes on upland steep ridges
Slope: mainly 8 to 15 percent but range from 3 to 20 percent
Mean annual air temperature: 17.8 to 21.1 degrees C (64 to 68 degrees F)
Mean annual precipitation: 762 to 1016 mm (30 to 40 in)
Frost-free period: 230 to 266 days
Elevation: 137.3 to 244 m (450 to 801 ft)

GEOGRAPHICALLY ASSOCIATED SOILS: These include the similar Austin, Lott, Ferris, and Heiden series.
Austin and Lott soils: have mollic epipedons and typically are on smoother less sloping landscapes. Ferris and Heiden soils: are on similar positions, are in a fine family, and have intersecting slickensides.

DRAINAGE AND PERMEABILITY:
Drainage class: Well;
Permeability class: Moderately slow
Runoff: medium on 3 to 5 percent slopes and high on 5 to 20 percent slopes.

USE AND VEGETATION: Used for pasture as well as cropland. The main grasses are common and improved bermudagrass and K.R. bluestem. Native vegetation includes little bluestem, silver bluestem, sideoats grama, Texas wintergrass and a few scattered elm and oak trees. Small grain and grain sorghum are the main crops grown.

DISTRIBUTION AND EXTENT: Texas. This soil occurs in the North Central Texas Blackland Prairies (MLRA 86A). The soil is of moderate extent.

SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Temple, Texas

SERIES ESTABLISHED: McLennan County, Texas; 1992.

REMARKS: McLennan soils have formerly been included with the Ferris or Sumter Series.

Diagnostic horizons and features recognized in this pedon are:

Ochric epipedon: 0 to 18 cm (0 to 7 in) (A horizon)
Cambic horizon: 18 to 36 cm (7 to 14 in) (Bw horizon)
Calcic horizon: 36 to 203 cm (14 to 80 in) (Bk1, Bk2, Bk/C horizons)

ADDITIONAL DATA: None

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

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National Cooperative Soil Survey
U.S.A.