LOCATION CAMPTANK                OR

Established Series
Rev. EGH-MPK-JVC-JBF
12/2022

CAMPTANK SERIES

The Camptank series consists of deep, well drained soils that formed in colluvium and residuum derived from volcanic rocks. Camptank soils are on escarpments of plateaus. Slopes are 15 to 45 percent. The mean annual precipitation is about 280 mm and the mean annual temperature is about 7 degrees C.

TAXONOMIC CLASS: Clayey over loamy-skeletal, smectitic over mixed, superactive, frigid Xeric Paleargids

TYPICAL PEDON: Camptank extremely gravelly fine sandy loam--on a 24 percent northeast-facing slope of an escarpment at an elevation of 1,535 meters--rangeland. (Colors are for dry soil unless otherwise noted.)

A1--0 to 8 cm; light brownish gray (10YR 6/2) extremely gravelly fine sandy loam, dark brown (10YR 3/3) moist; moderate medium platy structure parting to weak fine granular; soft, very friable, slightly sticky and slightly plastic; common very fine roots; common fine vesicular pores; 45 percent gravel, 15 percent cobbles, and 3 percent stones; moderately alkaline (pH 8.0); clear smooth boundary. (5 to 13 cm thick)

A2--8 to 15 cm; light brownish gray (10YR 6/2) sandy loam, brown (10YR 4/3) moist, moderate thin platy structure parting to weak fine granular; slightly hard, very friable, slightly sticky and slightly plastic; common fine and few medium roots; few fine tubular pores; 12 percent gravel; slightly alkaline (pH 7.8); abrupt smooth boundary. (0 to 13 cm thick)

Bt1--15 to 25 cm; brown (10YR 4/3) clay, dark yellowish brown (10YR 4/4) moist; moderate fine prismatic structure parting to weak fine angular blocky; very hard, very firm, very sticky and very plastic; few very fine and few fine roots; few fine tubular pores; common distinct clay films on faces of peds; moderately alkaline (pH 8.0); gradual smooth boundary. (10 to 25 cm thick)

Bt2--25 to 43 cm; yellowish brown (10YR 5/4) clay loam, brown (10YR 4/3) moist; moderate medium platy structure parting to moderate fine angular blocky; hard, friable, moderately sticky and moderately plastic; common distinct clay films on faces of peds; 5 percent gravel; moderately alkaline (pH 8.2) clear smooth boundary. (0 to 25 cm thick)

2Bk--43 to 86 cm; brown (10YR 5/3) very stony fine sandy loam, dark yellowish brown (10YR 4/4) moist; weak medium platy structure; hard, friable, slightly sticky and slightly plastic; few fine and few medium roots; few fine tubular pores; 15 percent gravel, 10 percent cobbles, and 15 percent stones; secondary carbonates segregated as common medium coats on faces of peds and bottoms of rock fragments; strongly effervescent; moderately alkaline (pH 8.4); clear smooth boundary. (15 to 50 cm thick)

2C--86 to 104; pale brown (10YR 6/3) very gravelly fine sandy loam, brown (10YR 5/3) moist; massive; slightly hard, very friable, slightly sticky and slightly plastic; few fine roots; few fine tubular pores; 50 percent gravel; strongly effervescent; moderately alkaline (pH 8.2); abrupt wavy boundary. (0 to 50 cm thick)

3R--104 cm; welded tuff.

TYPE LOCATION: Lake County, Oregon; about 20 miles north of Lake Abert; approximately 900 feet north 1,250 feet west of the southeast corner of section 28, T. 30 S., R. 20 E.; USGS Diatomite Reservoir 7.5 minute topographic quadrangle; latitude 42 degrees 56 minutes 06 seconds N and longitude 120 degrees 21 minutes 04 seconds W NAD 83.

RANGE IN CHARACTERISTICS:
Soil moisture: Usually dry in the moisture control section, moist in winter and spring, dry in summer and fall; aridic moisture regime that borders on xeric.
Mean annual soil temperature: 7 to 8 degrees C.
Ochric epipedon thickness: 5 to 20 cm.
Depth to base of argillic horizon: 25 to 64 cm.
Depth to horizons with skeletal material and identifiable secondary carbonates: 25 to 64 cm.
Depth to bedrock :100 to 150 cm to a lithic contact.
Abrupt textural change: An abrupt horizon boundary is normally present between the A2 horizon and the Bt1 horizon accompanied by an increase in clay content of more than 20 percent.
Other features: A strongly contrasting particle-size class is within a depth of 100 cm.

Particle-size control section - Clay content: 35 to 50 percent in the upper part and 10 to 18 percent in the contrasting lower part;
Rock fragment content: 0 to 15 percent, mainly gravel, in the upper part and 35 to 60 percent in the contrasting lower part. Lithology of fragments are volcanic rocks such as basalt and welded tuff.

A horizons
Value: 5 through 7 dry, 3 or 4 moist.
Chroma: 2 or 3, dry or moist.
Reaction: Slightly alkaline or moderately alkaline.

Bt horizons
Value: 4 or 5 dry
Chroma: 3 or 4, dry or moist
Texture: Clay or clay loam.
Clay content: 35 to 50 percent
Rock fragment content: 0 to 15 percent gravel

2Bk horizon
Value: 5 or 6 dry, 4 or 5 moist.
Chroma: 3 or 4, dry or moist.
Texture: Very stony fine sandy loam or very stony sandy loam.
Clay content: 10 to 18 percent.
Rock fragment content: 35 to 60 percent total with 10 to 35 percent gravel, 3 to 20 percent cobbles, and 5 to 20 percent stones
Calcium carbonate equivalent: 2 to 5 percent.
Salinity(EC): 0 to 4 mmhos/cm
Sodium adsorption ration (SAR): 5 to 12

2C horizon (when present)
Value: 5 or 6 dry, 4 or 5 moist.
Chroma: 3 or 4, dry or moist.
Texture: Very gravelly fine sandy loam, very gravelly sandy loam, or very cobbly sandy loam
Clay content: 7 to 15 percent.
Rock fragment content: 35 to 60 percent total with 25 to 55 percent gravel, 0 to 15 percent cobbles, and 0 to 10 percent stones

COMPETING SERIES: There are currently no other series in this family.

GEOGRAPHIC SETTING: Camptank soils are on escarpments of plateaus. These soils formed in colluvium and residuum derived from volcanic rocks such as welded tuff or basalt. Slopes are 15 to 45 percent. Elevations range from 1,465 to 1,650 meters. The climate is semiarid with 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 Brace, Lonegrave, and Reallis soils. Brace soils are fine-loamy, moderately deep to duripans, and are on plateaus and hills. Lonegrave soils are loamy-skeletal, moderately deep to lithic contacts, and are on escarpments. Reallis soils are coarse-loamy, very deep, have cambic horizons and horizons with durinodes, and are on lake terraces.

DRAINAGE AND PERMEABILITY: Well drained; very high surface runoff; slow permeability; moderately low saturated hydraulic conductivity in the upper part over moderately rapid permeability; high saturated hydraulic conductivity in the strongly contrasting lower part.

USE AND VEGETATION: Camptank soils are used for livestock grazing and wildlife habitat. The vegetation is mainly black sagebrush, bottlebrush squirreltail, and Sandberg's bluegrass.

DISTRIBUTION AND EXTENT: South-central Oregon. These soils are not extensive with about 250 acres of the series mapped to date. MLRA 23.

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

SERIES ESTABLISHED: Lake County (Northern Part), Oregon, 2006. The name is coined.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from the soil surface to 15 cm (A1 and A2 horizons).
Argillic horizon - The zone from 15 to 43 cm (Bt1 and Bt2 horizons).
Paleargid great group feature - The abrupt clay content increase of more than 15 percent at 15 cm (between the A2 and the Bt1 horizons).
Identifiable secondary carbonates - The zone from 43 to 86 cm (2Bk horizon).
Major lithologic discontinuity - The change to loamy-skeletal material at 43 cm (between the Bt2 and 2Bk horizons).
Lithic contact - The boundary at 104 cm to underlying hard unweathered bedrock (3R layer).
Particle-size control section - The zone from 15 to 100 cm (Bt1, Bt2, and 2Bk horizons and part of the 2C horizon).

---

National Cooperative Soil Survey
U.S.A.