LOCATION CAMPSPASS               MT+CO UT

Established Series
Rev. RER/KLS
08/2022

CAMPSPASS SERIES

The Campspass series consists of deep, well drained soils that formed in alluvium and material derived from sedimentary rock. These soils are on hill slopes, fan terraces, and benches. Slopes are 3 to 75 percent. Mean annual precipitation is about 430 mm and mean annual air temperature is about 5 degrees C.

TAXONOMIC CLASS: Fine, smectitic, frigid Typic Haplustalfs

TYPICAL PEDON: Campspass loam, ponderosa pine open timber (colors are for dry soil unless otherwise noted).

Oi--0 to 4 cm; slightly decomposed pine needles and leaves of shrubs and grass

Oa--4 to 5 cm; decomposed needles and twigs

A--5 to 18 cm; very dark gray (10YR 3/1) loam, black (10YR 2/1) moist; weak medium platy structure parting to medium granules; slightly hard, friable, nonsticky and nonplastic; common medium and many very fine roots; common pores; coating and patches of light gray silt and fine sand grains; less than 1 percent red and yellow sandstone and slate fragments; slightly acid (pH 6.5); clear wavy boundary. (5 to 13 cm thick)

E--18 to 31 cm; light brownish gray (10YR 6/2) at bottom of peds to light gray (10YR 7/2) on tops of peds, loam, brown (10YR 4/3) moist; uncrushed, dark brown (10YR 3/3) moist; weak fine and medium subangular blocky structure; slightly hard, friable, sticky and slightly plastic; common medium roots; common fine pores; thin continuous coating of clear silt and fine sand grains on peds; broken silt films on tops of peds; less than 1 percent red and yellow sandstone and slate fragments; slightly acid (pH 6.5); clear wavy boundary. (15 to 25 cm thick)

B/E--31 to 41 cm; B part (85 percent) brown (10YR 5/3) coated clay loam, brown (10YR 4/3) moist; E part (15 percent) light yellowish brown (10YR 6/4) coated pale brown (10YR 6/3) moist, and grading with depth to yellowish brown (10YR 5/4) loam, weak fine and medium subangular blocky structure; hard, friable, sticky and plastic; common medium roots; common fine pores; broken silt films on tops of peds and interfingering of silt film between peds; less than 1 percent red and yellow sandstone and slate fragments; neutral (pH 7.0); gradual boundary. (10 to 25 cm thick)

Bt--41 to 69 cm; very pale brown (10YR 7/3) clay loam, yellowish brown (10YR 5/4) moist; moderate fine and medium subangular blocky structure; slightly hard, friable, sticky and plastic; common medium roots; few fine pores; continuous distinct yellowish brown (10YR 5/4) clay films in pores extending out onto faces of peds; very dark grayish brown (10YR 3/2); few faint clay films on concave ped faces; less than 1 percent red and yellow sandstone and slate fragments; neutral (pH 7.0); many large krotovinas; abrupt wavy boundary. (25 to 38 cm thick)

Bk--69 to 92 cm; very pale brown (10YR 7/3) gravelly loam, yellowish brown (10YR 5/4) moist; weak fine blocky structure; hard, friable, nonsticky and nonplastic; few fine matted roots; common fine pores; contains 25 percent porcelanite fragments 75 mm and less in diameter; common fine threads of lime; strongly effervescent; moderately alkaline (pH 8.0); clear wavy boundary. (23 to 50 cm thick)

2C--92 to 115 cm; yellowish red (5YR 4/6) silty clay loam, yellowish brown (10YR 5/6) moist; firm, sticky and plastic; strongly effervescent; moderately alkaline (pH 8.0); abrupt boundary. (0 to 40 cm thick)

2R--115 to 158 cm; fractured slate, sandstone, and porcelanite.

TYPE LOCATION: Powder River County, Montana; SW 1/4 of sec. 23, T. 2 S., R. 46 E., on NE facing 35 percent slope under western yellow pine.

RANGE IN CHARACTERISTICS:
Mean annual soil temperature--4 to 8 degrees C
Moisture control section--10 to 30 cm
Depth to bedrock--100 to 150 cm
Depth to Bk horizon--45 to 75 cm

A horizon
Hue--10YR or 2.5Y
Value--3, 4, or 5 dry; 2 or 3 moist
Chroma--1 or 2
Texture--loam, fine sandy loam, or silt loam
Clay content--15 to 27 percent
Rock fragment content--0 to 10 percent channers
Reaction--pH 6.1 to 7.8


E horizon
Hue--10YR or 2.5Y
Value--6 or 7 dry; 4 or 5 moist
Chroma--2 or 3
Texture--loam, fine sandy loam, or silt loam
Clay content--15 to 20 percent
Rock fragment content--0 to 10 percent channers or pebbles
Reaction--pH 6.1 to 7.8


B/E horizon
Hue--10YR or 2.5Y
Value--B part 4 or 5, E part 6 or 7 dry; B part 3, 4, or 5, E part 4 or 5 moist
Chroma--2, 3, or 4
Texture--clay loam, silty clay loam, or clay
Clay content--35 to 45 percent
Rock fragment content--0 to 10 percent channers or pebbles
Reaction--pH 6.6 to 7.8

Bt horizon
Hue--10YR or 2.5Y
Value--5, 6, or 7 dry; 4 or 5 moist
Chroma--2, 3, or 4 moist
Texture--clay loam, silty clay loam, or clay
Clay content--35 to 45 percent
Rock fragment content--0 to 10 percent channers or pebbles
Reaction--pH 6.6 to 7.8

Bk horizon
Hue--10YR or 2.5Y
Value--6 or 7 dry; 4, 5, or 6 moist
Chroma--3 or 4
Texture--loam, silty clay loam, or clay loam
Clay content--20 to 30 percent
Rock fragment content--0 to 35 percent channers or pebbles
Calcium carbonate equivalent--6 to 15 percent
Reaction-pH 7.4 to 8.4

2C horizon
Hue--10YR or 5YR
Value--4, 5, or 6 dry; 4 or 5 moist
Chroma--4 or 6
Texture--loam, silty clay loam, or clay loam
Clay content--25 to 35 percent clay
Rock fragment content--0 to 35 percent channers or pebbles
Reaction--pH 7.4 to 8.4

COMPETING SERIES: These are the Citadel (SD), Fortwingate (NM), Goldvale (CO), Kelvin (ND), Larkson (CO), McVickers (AZ), Osoridge (NM), Pylon (MT), and Zuni (NM) series. The Citadel soils do not have a horizon of secondary carbonate accumulation and are mainly strongly acid above a depth of 58 cm. The Fortwingate, Osoridge, and Pylon soils have lithic or paralithic bedrock at moderate depths. The Fortwingate and Osoridge soils do not have a horizon of secondary carbonate accumulation. Also, the Pylon soils have a very hard or hard and massive surface, and an extremely hard argillic horizon. The Goldvale and Larkson soils do not have a horizon of secondary carbonate accumulation. Kelvin soils do not have a horizon of secondary carbonate accumulation, or a thin dark A horizon. The McVickers soils have the base of the argillic horizon at a depth of 100 cm or deeper, and do not have a horizon of secondary carbonate accumulation. The Zuni soils formed in materials weathered from coarse grained granite and are free of carbonate throughout the soil.

GEOGRAPHIC SETTING:
Landform--hill slopes, fan terraces, and benches
Parent material--colluvium and materials derived from consolidated sedimentary rocks
Elevation--1075 to 1375 meters
Slope--3 to 75 percent
Climate--long, cold winters; moist springs; and early, warm summers
Mean annual precipitation--380 to 480 mm
Mean annual air temperature--3 to 7 degrees C
Frost-free period--90 to 110 days

GEOGRAPHICALLY ASSOCIATED SOILS: None listed

DRAINAGE AND PERMEABILITY: Well drained; moderately slow permeability

USE AND VEGETATION: Campspass soils are used mainly for native range, wildlife habitat, watershed, and for timber production. Potential native vegetation is mainly ponderosa pine, chokecherry, dogwood, hawthorne, serviceberry, Oregon-grape, and pinegrass.

DISTRIBUTION AND EXTENT: Campspass soils are moderately extensive and occur in southeastern Montana, western Colorado, and eastern Utah. MLRAs 34A, 43B, 48A, and 58A.

SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Bozeman, Montana

SERIES ESTABLISHED: Powder River County (Powder River Area), Montana, 1967

REMARKS: Diagnostic horizons and features recognized in this soil are:
Ochric epipedon--5 to 31 cm (A and E horizons)
Albic horizon--18 to 31 cm (E horizon)
Argillic horizon--31 to 69 cm (B/E and Bt horizons)
Secondary carbonate accumulation--69 to 92 cm (Bk horizon)
Lithic contact--115 cm to bedrock (2R horizon)
Particle-size control section--31 to 69 cm (B/E and Bt horizons)

Campspass soils have a frigid temperature regime and an ustic soil moisture regime with a typic subclass.

Converted to metric, updated formatting, and O horizons were updated to start at zero. 8/2022

Soil Interpretations Records: MT0440 and MT1035.

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National Cooperative Soil Survey
U.S.A.