LOCATION EDEMAPS OR

Established Series
Rev JVC-JBF
02/2011

EDEMAPS SERIES

The Edemaps series consists of moderately deep to a duripan, well drained soils that formed in alluvium, colluvium, and residuum derived from volcanic rocks. Edemaps soils are on plateaus, hills, and rock pediments. Slopes are 2 to 20 percent. The mean annual precipitation is about 300 mm and the mean annual temperature is about 7 degrees C.

TAXONOMIC CLASS: Fine, smectitic, frigid Argiduridic Durixerolls

TYPICAL PEDON: Edemaps cobbly clay loam--rangeland, on a 6 percent northeast-facing slope at 1,481 meters elevation. (Colors are for dry soil unless otherwise noted.)

A--0 to 18 cm; grayish brown (10YR 5/2) cobbly clay loam, very dark brown (10YR 2/2) moist; weak fine granular structure; slightly hard, very friable, moderately sticky and moderately plastic; many very fine and fine roots; many very fine and fine vesicular and irregular pores; 10 percent gravel, 15 percent cobbles, and 5 percent stones; slightly alkaline (pH 7.8); clear smooth boundary. (18 to 25 cm thick)

Bt1--18 to 25 cm; brown (10YR 4/3) clay, very dark brown (10YR 2/2) moist; weak medium subangular blocky structure; hard, friable, moderately sticky and moderately plastic; common fine roots; common fine and medium irregular pores; few prominent clay films on faces of peds and lining pores; 5 percent gravel; slightly alkaline (pH 7.8); clear smooth boundary. (5 to 23 cm thick)

Bt2--25 to 46 cm; brown (7.5YR 5/4) clay, dark yellowish brown (10YR 4/4) moist; moderate medium subangular blocky structure; hard, friable, moderately sticky and moderately plastic; common medium roots; common fine irregular and tubular pores; common prominent clay films on faces of peds and lining pores; 10 percent gravel; slightly alkaline (pH 7.8); clear smooth boundary. (5 to 25 cm thick)

2Bt3--46 to 64 cm; yellowish brown (10YR 5/6) very cobbly clay loam, dark yellowish brown (10YR 3/4) moist; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common medium roots; common fine irregular and tubular pores; few faint clay films on faces of peds; 25 percent gravel and 20 percent cobbles; slightly alkaline (pH 7.8); clear wavy boundary. (0 to 25 cm thick)

2Bkqm--64 to 76 cm; cemented material; very rigid; indurated by silica and secondary carbonates; violently effervescent; abrupt wavy boundary. (5 to 20 cm thick)

2R--76 cm; fractured basalt.

TYPE LOCATION: Harney County, Oregon; below the Pueblo Mountains about 3 miles southwest of Fields; about 760 feet north and 1,260 feet east of the southwest corner of section 28, T. 38 S., R. 34 E.; USGS Ladycomb Peak 7.5 minute topographic quadrangle; latitude 42 degrees 14 minutes 24 seconds N and longitude 118 degrees 44 minutes 3 seconds W; NAD 83.

RANGE IN CHARACTERISTICS:
Soil moisture: Usually moist from November through May, dry from June through October; aridic moisture regime that borders on xeric.
Mean annual soil temperature: 7 to 8 degrees C.
Mollic epipedon thickness: 18 to 30 cm; typically includes the Bt1 horizon.
Depth to indurated duripan: 50 to 90 cm.
Depth to bedrock: 58 to 100 cm to a lithic contact.

Particle-size control section - Clay content: 35 to 45 percent.
Rock fragments: Averages 5 to 30 percent, mainly gravel and cobbles. Lithology of fragments is volcanic rocks such as tuff, rhyolite, andesite, or basalt.

A horizon
Value: 4 or 5 dry, 2 or 3 moist.
Chroma: 2 or 3, dry or moist..
Organic matter content: 1 to 3 percent.
Reaction: Neutral or slightly alkaline.
Other features: The lower horizon boundary is clear and there is an 8 to 15 percent (absolute) clay increase between the A and Bt1 horizon.

Bt1 and Bt2 horizons
Hue: 7.5YR or 10YR.
Value: 4 through 6 dry, 2 through 4 moist.
Chroma: 3 through 6 dry, 2 through 4 moist.
Texture: Clay, cobbly clay, cobbly clay loam, or gravelly clay loam.
Clay content: 35 to 45 percent.
Rock fragments: 0 to 35 percent.
Organic matter content: 0.5 to 2 percent in the Bt1 horizon.
Reaction: Neutral through moderately alkaline.

2Bt3 horizon (when present)
Hue: 7.5YR or 10YR.
Value: 4 through 6 dry, 2 through 4 moist.
Chroma: 3 through 6 dry, 2 through 4 moist.
Texture: Cobbly clay loam or very cobbly clay loam.
Clay content: 35 to 40 percent.
Rock fragments: 15 to 50 percent.
Reaction: Slightly alkaline or moderately alkaline.

COMPETING SERIES: These are the Hodedo and Tanner series.

Hodedo soils have lithic contacts at depths of 150 cm or more. Tanner soils have calcic horizons above the duripan and have lithic contacts at depths of 100 to more than 150 cm from the soil surface.

GEOGRAPHIC SETTING: Edemaps soils are on plateaus, hills, and rock pediments. These soils formed in alluvium, colluvium, and residuum derived from volcanic rocks such as tuff, andesite, rhyolite, or basalt. Slopes are 2 to 20 percent. Elevation ranges from 1,280 to 1,740 meters. The climate is semiarid and characterized by cold, moist winters and warm, dry summers. The mean annual precipitation is 280 to 360 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 Carryback and Ninemile soils. Carryback soils are moderately deep to lithic contacts and have an absolute clay increase of about 25 percent between the A2 horizon and the 2Bt1 horizon. Ninemile soils are shallow to lithic contacts.

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

USE AND VEGETATION: Edemaps soils are used for rangeland and wildlife habitat. The vegetation commonly is Idaho fescue, Thurber's needlegrass, bluebunch wheatgrass, basin big sagebrush, and Sandberg's bluegrass.

DISTRIBUTION AND EXTENT: Southeastern 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 25 cm (A and Bt1 horizons).
Argillic horizon - The zone from 18 to 64 cm (Bt1, Bt2, and 2Bt3 horizons).
Duripan - The zone from 64 to 76 cm (2Bkqm horizon).
Lithic contact - The boundary at 76 cm to underlying hard, unweathered bedrock (2R layer).
Particle-size control section - The zone from 18 to 64 cm (Bt1, Bt2,and 2Bt3 horizons).

ADDITIONAL DATA: Previous authors and editors include: JAP-TDT-TM.

National Cooperative Soil Survey
U.S.A.