LOCATION COWCAMP MT

Established Series
Rev. PEM-KTS-RJS
03/2011

COWCAMP SERIES

The Cowcamp series consists of very deep, well-drained soils that formed in mixed alluvium. These soils are on fan remnants, stream terraces, alluvial fans and outwash plains. These soils are subject to prolonged saturation from flood irrigation. Slopes are 0 to 15 percent. Mean annual precipitation is about 16 inches, and mean annual air temperature is about 37 degrees F.

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive Oxyaquic Argicryolls

TYPICAL PEDON: Cowcamp silt loam, in irrigated grass pasture (colors are for dry soil unless otherwise noted).

Oi--0 to 2 inches; undecomposed and partially decomposed matted roots; abrupt smooth boundary. (1 to 3 inches thick)

A1--2 to 6 inches; dark grayish brown (10YR 4/2) silt loam, very dark gray (10YR 3/1) moist; weak very fine and fine subangular blocky structure parting to weak very fine and fine granular; soft, very friable, slightly sticky and slightly plastic; many very fine roots and few fine roots; many very fine and fine dendritic and tubular pores; 5 percent gravel; neutral (pH 6.7); clear wavy boundary.

A2--6 to 13 inches; brown (10YR 5/3) silt loam, dark brown (10YR 3/3) moist; weak very fine and fine subangular blocky structure parting to weak very fine and fine granular; soft, very friable, slightly sticky and slightly plastic; many very fine and few fine roots; many very fine and fine dendritic and tubular pores; 5 percent gravel; neutral (pH 6.8); clear wavy boundary. (Combined thickness of A horizons - 10 to 15 inches)

Bt/E--13 to 18 inches; Bt part (60 percent) light brown (7.5YR 6/3) gravelly silt loam, brown (7.5YR 5/3) moist; E part (40 percent) pinkish gray (7.5YR 7/2) gravelly silt loam, pinkish gray (7.5YR 6/2) moist; common fine and medium faint strong brown (7.5YR 5/6) moist redox concentrations (due to prolonged saturation from flood irrigation); moderate very fine and fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine and few fine roots; common very fine and few fine dendritic tubular pores; few faint patchy clay films on faces of peds; many silt and sand skeletans on faces of peds; 20 percent gravel; slightly acid (pH 6.5); clear wavy boundary. (0 to 10 inches thick)

Bt1--18 to 28 inches; light yellowish brown (10YR 6/4) very cobbly clay loam, yellowish brown (10YR 5/4) moist; few fine faint strong brown (7.5YR 5/6) moist redox concentrations (due to prolonged saturation from flood irrigation); moderate fine and medium subangular blocky structure; slightly hard, friable, moderately sticky and slightly plastic; common very fine and few fine roots; common very fine and few fine dendritic tubular pores; common faint patchy clay films on faces of peds; 25 percent gravel, 20 percent cobbles; neutral (pH 6.7); clear wavy boundary.

Bt2--28 to 35 inches; brownish yellow (10YR 6/6) very gravelly loam, yellowish brown (10YR 5/6) moist; moderate fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few very fine roots; common very fine and few fine dendritic tubular pores; few faint patchy clay films on faces of peds; 40 percent gravel, 10 percent cobbles; slightly acid (pH 6.5); clear wavy boundary. (combined thickness of Bt horizons is 10 to 20 inches)

BC--35 to 60 inches; pink (7.5YR 7/4) very gravelly sandy loam, strong brown (7.5YR 5/6) moist; weak very fine and fine subangular blocky structure; soft, very friable, slightly sticky and nonplastic; few very fine roots; common very fine interstitial pores; 40 percent gravel, 15 percent cobbles; neutral (pH 6.7).

TYPE LOCATION: Beaverhead County, Montana; 750 feet south and 1300 feet east of the NW corner of sec. 32, T. 3 S., R. 16 W. Highland Ranch topographic quadrangle, UTM 12T, 0296202e, 5045687n. NAD 83

RANGE IN CHARACTERISTICS:
Mean annual soil temperature: 35 to 40 degrees F.
Mean summer soil temperature: 53 to 57 degrees F.
Ustic moisture regime
Mollic epipedon thickness: 10 to 15 inches

Note: Some pedons have an E horizon. Redox concentrations due to prolonged saturation from flood irrigation can occur in all horizons above the BC horizon.

A horizons
Hue: 10YR or 7.5YR; dry or moist
Value: 3 to 5 dry; 2 or 3 moist
Chroma: 1 to 3; dry or moist
Texture: loam or silt loam
Clay content: 18 to 27 percent
Content of rock fragments: 5 to 50 percent--5 to 40 percent gravel, 0 to 30 percent cobbles
Reaction: pH 6.1 to 7.3

Bt/E horizon
Hue: 10YR or 7.5YR
Value: Bt part: 5 or 6 dry; 4 or 5 moist;
E part: 6 or 7 dry; 5 or 6 moist;
Chroma: 2 to 4; dry or moist
Texture: loam, silt loam or clay loam
Clay content: 23 to 30 percent
Content of rock fragments: 15 to 60 percent--15 to 45 percent gravel, 0 to 15 percent cobbles
Reaction: pH 6.1 to 7.3

Bt horizons
Hue: 10YR or 7.5YR; dry or moist
Value: 5 to 7 dry; 4 or 5 moist
Chroma: 2 to 6; dry or moist
Texture: sandy clay loam, loam or clay loam
Clay content: 23 to 35 percent
Rock fragments: 35 to 65 percent--20 to 40 percent gravel, 10 to 30 percent cobbles
Reaction: pH 6.1 to 7.3

BC horizon:
Hue: 7.5YR or 10YR; dry or moist
Value: 6 or 7 dry; 5 or 6 moist
Chroma: 2 to 6; dry or moist
Texture: sandy loam, sandy clay loam or loam
Clay content: 15 to 25 percent
Rock fragments: 35 to 70 percent--30 to 45 percent gravel, 5 to 40 percent cobbles
Reaction: pH 6.1 to 7.3

COMPETING SERIES:
Marcel (MT) - have a seasonally high water table at depths of less than or equal to 42 inches

GEOGRAPHIC SETTING:
Landform - fan remnants, stream terraces, alluvial fans and outwash plains
Elevation - 5,900 to 7,300 feet
Slope - 0 to 15 percent
Parent material - mixed alluvium
Climate - long, cold winters; cool, moist springs; short, cool summers
Mean annual precipitation - 14 to 20 inches
Mean annual air temperature - 34 to 39 degrees F.
Frost-free period - 30 to 70 days

GEOGRAPHICALLY ASSOCIATED SOILS:
These are the Beaverslide, Bighole, Mooseflat, Shewag and Wisdom soils. The Beaverslide soils have greater than 35 percent clay in the control section and occur on remnant terraces and fans, Bighole soils are fine-loamy and occur on remnant terraces and fans, Mooseflat soils are very poorly drained and occur on floodplains and drainageways, Shewag soils are 10 to 20 inches to sand and gravel and occur on outwash plains, and Wisdom soils are fine-loamy over sandy skeletal and occur on outwash plains.

DRAINAGE AND PERMEABILITY: Well drained (Oxyaquic moisture subclass due to prolonged saturation from flood irrigation); moderately slow permeability.

USE AND VEGETATION: Cowcamp soils are used for irrigated grass hay and irrigated pasture. The vegetation is mainly Garrison creeping foxtail, meadow foxtail, timothy, tufted hairgrass, and other miscellaneous sedges, rushes and forbs.

DISTRIBUTION AND EXTENT: Cowcamp soils are not extensive in the intermountain valleys of southwestern Montana. MLRAs - 43B, 44B.

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

SERIES ESTABLISHED: Beaverhead County, Montana, Big Hole Valley Area, 2005.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - from 2 to 13 inches (A1 and A2 horizons)
Glossic horizon - from 13 to 18 inches (Bt/E horizon)
Horizons with redox concentrations - from 13 to 28 inches (Bt/E and Bt horizons)
Particle-size control section - from 13 to 33 inches (Bt/E, Bt1 and part of Bt2 horizons)

Cowcamp soils have a cryic temperature regime, an ustic moisture regime, and an oxyaquic moisture subclass.

National Cooperative Soil Survey
U.S.A.