LOCATION CLAMP                   OR

Established Series
Rev. CFL/TDT/JVC/JBF
02/2011

CLAMP SERIES

The Clamp series consists of very shallow and shallow, well drained soils that formed in colluvium derived from igneous rocks. Clamp soils are on mountains. Slopes are 5 to 70 percent. The mean annual precipitation is about 460 mm and the mean annual temperature is about 5 degrees C.

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive Lithic Haplocryolls

TYPICAL PEDON: Clamp very stony clay loam--on a 40 percent slope--rangeland. (Colors are for dry soil unless otherwise noted.)

A1--0 to 8 cm; grayish brown (10YR 5/2) very stony clay loam, very dark grayish brown (10YR 3/2) moist; weak fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine and fine roots; many very fine and fine irregular pores; 20 percent stones, 15 percent cobbles, and 20 percent gravel; slightly alkaline (pH 7.5); clear smooth boundary (3 to 10 cmthick)

A2--8 to 20 cm; grayish brown (10YR 5/2) very cobbly clay loam, dark brown (10YR 3/3) moist; weak fine subangular blocky structure; slightly hard, firm, slightly sticky and slightly plastic; many very fine and many fine roots; many very fine and many fine irregularly shaped pores; 5 percent stones, 15 percent cobbles, and 20 percent gravel; slightly alkaline (pH 7.5); gradual wavy boundary. (0 to 18 cm thick)

A3--20 to 30 cm; grayish brown (10YR 5/2) very cobbly clay loam, dark brown (10YR 3/3) moist; massive; slightly hard, firm, slightly sticky and slightly plastic; many very fine and many fine roots; many very fine and many fine irregularly shaped pores; 5 percent stones, 15 percent cobbles, and 20 percent gravel; slightly alkaline (pH 7.5); abrupt irregular boundary. (8 to 18 cm thick)

2R--30 cm; fractured igneous bedrock.

TYPE LOCATION: Harney County, Oregon; about 5.7 miles south of Willow Butte and 1.3 miles west of Willow Creek in the SW1/4 of the NE1/4 of section 3, T. 40 S., R. 38 E.; latitude 42 degrees 7 minutes 47 seconds N and 118 degrees 14 minutes 37 seconds W; NAD 83.

RANGE IN CHARACTERISTICS:
Soil moisture: Moist in winter and spring, dry from about mid or late July through mid or late October, (60 to 90 consecutive days); The soil temperature is above 5 degrees C. from early June through late October; xeric moisture regime that borders on aridic.
Mean annual soil temperature: 6 to 8 degrees C.
Mean summer soil temperature: 13 to 15 degrees C.
Mollic epipedon thickness: 10 to 36 cm.
Depth to bedrock: 10 to 36 cm to a lithic contact.
Reaction - Neutral or slightly alkaline.

Particle-size control section - Clay content: 27 to 35 percent.
Rock fragments: averages 35 to 60 percent. Lithology of fragments are igneous rocks such as andesite or basalt.

A horizon
Value: 4 or 5 dry, 2 or 3 moist.
Chroma: 2 or 3, dry or moist.
Organic matter content: 2 to 4 percent.

A2 and A3 horizons
Value: 4 or 5 dry, 2 or 3 moist.
Chroma: 2 or 3, dry or moist.
Rock fragments:, 35 to 60 percent, mainly cobbles.
Organic matter content: 1 to 3 percent .

COMPETING SERIES: These are the Arrowpeak, Betemer, Cheadle, Chokecherry, Dalys, Dollarhide, Eyre, Irigul, Irson, Jonlake, Labshaft, Mccadden , Milling, Poin, Rogert, Schwacheim, Starley, Topeki and Udel series.

Arrowpeak, Betemer, Cheadle, Chokecherry, Dalys, Dollarhide, Eyre, Irson, Jonlake, McCadden, Milling, Poin, Rogert, Topeki ,and Udel soils have less than 27 percent clay in the particle size-control section. Irigul soils have anustic soil moisture regime and the particle-size control section dominated by channer and flagstone shaped rock fragments. Labshaft soils have a particle-size control section dominated by gravel size rock fragmentsand a Bw horizon. Schwacheim soils have an udic bordering ustic soil moisture regime. Starley soils have a particle-size control section dominated by rock fragments of limestone origin and secondary carbonates (Bk horizon) at depths of 13 to 38 cm.

GEOGRAPHIC SETTING: Clamp soils are on mountains. They typically occur on shoulder, backslope, and footslope positions. These soils formed in colluvium derived from fractured igneous rocks such as basalt. Slopes are 5 to 70 percent. Elevations range from 1,590 to 2,625 meters. The climate is semiarid with cold, moist winters and cool, dry summers. The mean annual precipitation is 300 to 600 mm, mean annual temperature is 4 to 6 degrees C, and the frost-free period is 30 to 70 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Baconcamp and Duff soils. Baconcamp and Duff soils have mollic epipedons over 50 cm thick.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; very high surface runoff; moderately slow permeability; moderately high saturated hydraulic conductivity.

USE AND VEGETATION: Clamp soils are used for livestock grazing and wildlife habitat. The present vegetation is mainly low sagebrush, Idaho fescue, Sandberg bluegrass, and bluebunch wheatgrass.

DISTRIBUTION AND EXTENT: South-central Oregon. These soils are moderately extensive. MLRA 23.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California.

SERIES ESTABLISHED: Harney County, Oregon; 1997.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to 30 cm (A1, A2, and A3 horizons).
Lithic contact - The boundary at 30 cm to underlying hard bedrock (2R layer).
Particle-size control section - The zone from the soil surface to 30 cm (A1, A2, and A3 horizons).

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National Cooperative Soil Survey
U.S.A.