LOCATION RENCOT                  MT+UT WY

Established Series
Rev. DES-JJU-RJS
06/2011

RENCOT SERIES

The Rencot series consists of shallow, well drained soils that formed in slope alluvium or colluvium over residuum weathered from metamorphic and sedimentary rock. These soils are on hills, strath terraces, mountains and ridges. Slopes are 0 to 75 percent. Mean annual precipitation is about 12 inches, and mean annual air temperature is about 42 degrees F.

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Lithic Calciustepts

TYPICAL PEDON: Rencot channery loam, grassland (colors are for dry soil unless otherwise noted).

A--0 to 4 inches; pale brown (10YR 6/3) channery loam, brown (10YR 5/3) moist; moderate fine granular structure; slightly hard, very friable, slightly sticky and slightly plastic; many fine roots; many fine pores; 20 percent channers; strongly effervescent; moderately alkaline (pH 8.2); clear smooth boundary. (3 to 5 inches thick)

Bk1--4 to 14 inches; pale yellow (2.5Y 8/2) very channery loam, light brownish gray (2.5Y 6/2) moist; weak coarse blocky structure; hard, very friable, slightly sticky and slightly plastic; common fine roots; common fine pores; 40 percent channers; common soft masses of calcium carbonate and calcium carbonate casts on undersides of rock fragments; violently effervescent; moderately alkaline (pH 8.4); clear smooth boundary.

Bk2--14 to 18 inches; pale yellow (2.5Y 7/4) very channery loam, light olive brown (2.5Y 5/4) moist; massive; slightly hard, very friable, slightly sticky and slightly plastic; 60 percent channers; violently effervescent; moderately alkaline (pH 8.4); abrupt wavy boundary. (combined thickness of the Bk1, Bk2 horizons - 7 to 15 inches)

R--18 inches; fractured hard, argillite bedrock.

TYPE LOCATION: Broadwater County, Montana; 1,900 feet east and 1,700 feet north of the southwest corner of sec. 18, T. 8N, R. 3E.

RANGE IN CHARACTERISTICS:
Mean annual soil temperature - 40 to 47 degrees F.
Depth to Bk horizon - 3 to 5 inches
Depth to lithic contact - 10 to 20 inches
Particle-size control section (weighted average) - 18 to 30 percent clay

A horizon
Hue: 7.5YR, 10YR or 2.5Y; dry or moist
Value: 4 to 7 dry; 3 to 5 moist
Chroma: 2 to 4; dry or moist
Texture: loam, fine sandy loam, sandy loam, coarse sandy loam or clay loam
Clay content: 15 to 30 percent
Rock fragments: 10 to 60 percent--10 to 50 percent channers and gravel, 0 to 30 percent flagstones or cobbles
Calcium carbonate equivalent: 0 to 10 percent
Reaction: pH 7.4 to 8.4

Bk1 horizon
Hue: 7.5YR, 10YR or 2.5Y; dry or moist
Value: 6 to 8 dry; 4 to 7 moist
Chroma: 2 to 4; dry or moist
Texture: loam, fine sandy loam, sandy loam, sandy clay loam or clay loam
Clay content: 15 to 30 percent
Rock fragments: 35 to 60 percent--25 to 60 percent gravel and channers, 0 to 35 percent flagstones and cobbles
Calcium carbonate equivalent: 10 to 40 percent
Reaction: pH 7.9 to 8.4

Bk2 horizon
Hue: 7.5YR, 10YR or 2.5Y; dry or moist
Value: 6 to 8 dry; 4 to 7 moist
Chroma: 2 to 4; dry or moist
Texture: loam, sandy loam, fine sandy loam or clay loam
Clay content: 15 to 30 percent
Rock fragments: 35 to 75 percent--35 to 60 percent gravel and channers, 0 to 35 percent flagstones and cobbles
Calcium carbonate equivalent: 15 to 40 percent
Reaction: pH 7.9 to 9.0

COMPETING SERIES:
Cedarknoll (UT) - have a Bw horizon
Culebra (CO) - have less than 18 percent clay in the particle-size control section
Hackling (CO) - have less than 18 percent clay in the particle-size control section
Rentsac (MT) - have less than 18 percent clay in the particle-size control section
Schoonover (CO) - have a calcic horizon at a depth of greater than 5 inches

GEOGRAPHIC SETTING:
Landform - hills, strath terraces, mountains and ridges
Elevation - 3,500 to 6,500 feet
Slope - 0 to 75 percent
Parent material - slope alluvium or colluvium over residuum weathered from metamorphic and sedimentary rock
Climate - long, cold winters; moist springs; and warm summers
Mean annual precipitation - 10 to 15 inches
Mean annual temperature - 38 to 45 degrees F.
Frost-free period - 70 to 120 days
In Wyoming and Utah elevations range to 8,500 feet; and the frost-free period is 60 to 120 days

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Rootel and Tolman soils. Rootel soils are moderately deep. Tolman soils have a mollic epipedon and lack a calcic horizon.

DRAINAGE AND PERMEABILITY: Well drained; moderate permeability.

USE AND VEGETATION: Rencot soils are used as rangeland. Potential native vegetation is mainly bluebunch wheatgrass, western wheatgrass, needleandthread, blue grama, Sandberg bluegrass and fringed sagewort.

DISTRIBUTION AND EXTENT: Rencot soils are of moderate extent in western and central Montana, and in Colorado, Wyoming, and Utah. MLRAs - 34A, 43B, 44B, 46, 47 48A, 49, 52, 58A.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana.

SERIES ESTABLISHED: Broadwater County, Montana, 1971.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - from 0 to 4 inches (A horizon)
Calcic horizon - from 4 to 18 inches (Bk1, Bk2 horizons)
Lithic contact - at 18 inches (R horizon)
Particle-size control section - from 10 to 18 inches (part of Bk1, Bk2 horizons)

Rencot soils have a frigid temperature regime and an ustic moisture regime bordering on aridic.

ADDITIONAL DATA: Soil interpretations records - MT0538 and MT1105.

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National Cooperative Soil Survey
U.S.A.