LOCATION ACTEM                   OR

Established Series
Rev. EGH-TDT-JVC-JBF
11/2010

ACTEM SERIES

The Actem series consists of shallow to a duripan, well drained soils that formed in alluvium and colluvium derived from volcanic rocks. Actem soils are on hills and lava plateaus. Slopes are 2 to 20 percent. The mean annual precipitation is about 250 mm and the mean annual temperature is about 7 degrees C.

TAXONOMIC CLASS: Clayey, smectitic, frigid, shallow Xeric Argidurids

TYPICAL PEDON: Actem cobbly loam--rangeland. (Colors are for dry soil unless otherwise noted.)

A--0 to 5 cm; light gray (10YR 7/2) cobbly loam, brown (10YR 4/3) moist; weak medium platy structure; hard, very friable, slightly sticky and slightly plastic; common fine and common medium roots; many fine and medium vesicular pores; 10 percent gravel and 10 percent cobbles; neutral (pH 7.3); clear wavy boundary. (5 to 18 cm thick)

Bt--5 to 18 cm; brown (10YR 5/3) clay, yellowish brown (10YR 5/4) moist; moderate and strong coarse subangular blocky structure; hard, firm, very sticky and very plastic; common fine and common medium roots; many fine and medium irregular pores; common distinct clay films on faces of peds; slightly alkaline (pH 7.4); clear wavy boundary.

Btk--18 to 38 cm; light yellowish brown (10YR 6/4) clay loam, dark yellowish brown (10YR 4/4) moist; moderate medium subangular blocky structure parting to moderate fine angular blocky; hard, firm, moderately sticky and moderately plastic; common fine and common medium roots; many fine irregular pores; common distinct clay films on faces of peds; secondary carbonates are finely disseminated in the matrix; strongly effervescent; slightly alkaline (pH 7.5); clear wavy boundary. (Combined thickness of the Bt and Btk horizons is 13 to 40 cm)

Bkqm--38 to 51 cm; very pale brown (10YR 8/3) cemented material, pale brown (10YR 6/3) moist; moderate very thick platy structure; very rigid; indurated by secondary silica; few fine roots between plates; secondary carbonates are finely disseminated in the matrix; strongly effervescent; abrupt smooth boundary. (10 to 25 cm thick)

2R--51 inches; basalt.

TYPE LOCATION: Harney County Oregon; in Butcher Flat about 2,500 feet south and 1,800 feet west of the northeast corner of section 25, T. 38 S., R. 30 E.; USGS Acty Mountain NW 7.5 minute topographic quadrangle; latitude 42 degrees 14 minutes 51 seconds N and longitude 119 degrees 07 minutes 54 seconds W; NAD 83.

RANGE IN CHARACTERISTICS:
Soil moisture: Usually moist from late fall through early spring, dry from late spring through early fall; aridic moisture regime that borders on xeric.
Mean annual soil temperature: 7 to 8 degrees C.
Depth to base of argillic horizon: 30 to 50 cm.
Depth to identifiable secondary carbonates: 13 to 33 cm.
Depth to indurated duripan: 30 to 50 cm.
Depth to bedrock: 50 to 75 cm to a lithic contact.

Particle-size control section - Clay content: 35 to 45 percent.
Rock fragments: 0 to 35 percent, mainly gravel. Lithology of fragments are volcanic rocks such as basalt, rhyolite, andesite, or tuff.

A horizon
Value: 6 or 7 dry, 3 through 5 moist.
Chroma: 2 or 3, dry or moist.
Other features: The lower boundary is clear and there is a 10 to 20 percent (absolute) clay increase between the A and Bt horizon.

Bt horizon
Hue: 7.5YR or 10YR.
Value: 5 or 6 dry, 4 or 5 moist
Chroma: 3 or 4 dry or moist
Texture: Clay, gravelly clay loam, or gravelly clay.
Clay content: 35 to 45 percent.
Rock fragments: 0 to 35 percent total; 0 to 25 percent gravel and 0 to 10 percent cobbles.
Reaction: Neutral or slightly alkaline.

Btk horizon
Hue: 7.5YR or 10YR.
Texture: Clay loam, clay, or cobbly clay loam.
Clay content: 35 to 45 percent.
Rock fragments: 0 to 30 percent total; 0 to 20 gravel and 0 to 10 percent cobbles.
Calcium carbonate equivalent: 1 to 3 percent.
Reaction: Neutral or slightly alkaline
Other features: Some pedons have a Bkq horizon above the duripan.

Bkqm horizon
Hue: 7.5YR or 10YR.
Value: 7 or 8 dry, 6 or 7 moist.
Chroma: 3 or 4, dry or moist.

COMPETING SERIES: This is the Ratto series.

Ratto soils - do not have lithic contacts within 150 cm of the soil surface

GEOGRAPHIC SETTING: Actem soils are on hills and plateaus. These soils formed in alluvium and colluvium derived from volcanic rocks such as basalt, rhyolite, andesite, or tuff. Slopes are 2 to 20 percent. Elevations range from 1,280 to 1,830 meters. The climate is semiarid and characterized by cold, moist winters and warm, dry summers. The mean annual precipitation is 200 to 300 mm, the mean annual temperature is 6 to 7 degrees C., and the frost-free period is 50 to 80 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Gradon and Wagontire soils. Gradon soils are fine-loamy are on alluvial fans or fan remnants. Gradon and Wagontire soils have mollic epipedons. Wagontire soils are on fan remnants.

DRAINAGE AND PERMEABILITY: Well drained; very high surface runoff; slow permeability; moderately low saturated hydraulic conductivity.

USE AND VEGETATION: Actem soils are used for livestock grazing and wildlife habitat. The potential native vegetation is Wyoming big sagebrush, Thurber's needlegrass, bluebunch wheatgrass, and Indian ricegrass.

DISTRIBUTION AND EXTENT: South-central Oregon. These soils are extensive with about 227,000 acres of the series mapped to date. 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:
Ochric epipedon - The zone from the soil surface to 5 cm (A horizon).
Argillic horizon - The zone from 5 to 38 cm (Bt and Btk horizons).
Identifiable secondary carbonates - The zone from 18 to 50 cm (Btk and Bkqm horizons).
Duripan - The zone from 38 to 51 cm (Bkqm horizon).
Lithic contact - The boundary at 51 cm to underlying hard, unweathered bedrock (2R layer).
Particle-size control section - The zone from 5 to 38 cm (Bt and Btk horizons).

ADDITIONAL DATA: Partial laboratory data is available for this soil. Sample number S78 OR25-1-1 through 3 from Harney County, Oregon, Oregon Soil Characterization Lab, Oregon State University, Corvallis, OR, 9/78.

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National Cooperative Soil Survey
U.S.A.