LOCATION DOUGAL                  ID

Established Series
Rev. ALH-CLM-JVC
12/2022

DOUGAL SERIES

The Dougal series consists of very shallow and shallow, well drained soils that formed in residuum derived from welded rhyolitic tuff or andesite. Dougal soils are on hills and structural benches. Slopes are 2 to 20 percent. The mean annual precipitation is about 12 inches and the mean annual temperature is about 47 degrees F.

TAXONOMIC CLASS: Loamy, mixed, superactive, mesic Lithic Xeric Haplargids

TYPICAL PEDON: Dougal stony sandy loam--on a slope of 3 percent at 5,380 feet elevation--rangeland. (Colors are for dry soil unless otherwise noted. When described on September 16, 1980, the soil was slightly moist to 8 inches and dry below.) The soil surface has about 2 percent stone cover.

A--0 to 4 inches; pale brown (10YR 6/3) stony sandy loam, dark brown (10YR 3/3) moist; weak medium subangular blocky structure parting to weak fine platy; slightly hard, very friable, slightly sticky and slightly plastic; many very fine, many fine, and few medium roots; common very fine and common fine vesicular and irregular pores; 5 percent gravel and 1 percent stones; neutral (pH 6.9); clear smooth boundary. (2 to 6 inches thick)

AB--4 to 8 inches; pale brown (10YR 6/3) sandy loam, brown (10YR 4/3) moist; moderate medium subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine, common fine, and common medium roots; common very fine and common fine irregular and tubular pores; 5 percent gravel; slightly acid (pH 6.5); clear smooth boundary. (0 to 5 inches thick)

Bt--8 to 16 inches; light yellowish brown (10YR 6/4) sandy clay loam, yellowish brown (10YR 5/4) moist; strong medium subangular blocky structure; hard, friable, slightly sticky and slightly plastic; common very fine, common fine, and few medium roots; many very fine and many fine tubular and irregular pores; common faint and distinct clay films on faces of peds and bridging sand grains; 10 percent gravel; slightly acid (pH 6.3); abrupt wavy boundary. (5 to 8 inches thick)

R--16 inches; fractured, welded rhyolitic tuff.

TYPE LOCATION: Owyhee County, Idaho; about 28.5 miles west of Grasmere; 2,200 feet west and 1,250 feet north of the southeast corner of section 22, T. 12 S., R. 1 W.; USGS Battle Creek Lakes 7.5 minute topographic quadrangle; 42 degrees 21 minutes 45 seconds north latitude and 116 degrees 26 minutes 23 seconds west longitude, NAD27.

RANGE IN CHARACTERISTICS:

Soil moisture - Usually moist in winter and spring; dry in summer and fall; aridic moisture regime that borders on xeric.

Mean annual soil temperature - 47 to 51 degrees F.

Ochric epipedon thickness - 2 to 8 inches.

Depth to bedrock - 7 to 16 inches to a lithic contact.

Particle-size control section - Clay content: Averages 19 to 30 percent; Sand content: 30 to 60 percent; Rock fragments: Averages 10 to 35 percent, mainly pebbles. Lithology of fragments are volcanic rocks such as tuff and andesite.


A and AB horizons - Value: 5 through 7 dry, 3 or 4 moist.
Chroma: 2 or 3, dry or moist
Clay content: 10 to 24 percent.
Reaction: Slightly acid or neutral.


Bt horizon - Hue: 7.5YR or 10YR.
Value: 5 or 6 dry, 4 or 5 moist.
Chroma: 3 through 6, dry or moist.
Texture: Sandy clay loam, gravelly sandy clay loam, or gravelly clay loam.
Clay content: 20 to 30 percent.
Rock fragments: 10 to 35 percent, mainly pebbles.

COMPETING SERIES: These are the Banbury, Bombadil, Fubble, Jaybee, Kreza, and Meninik (T) series.

Banbury and Kreza soils have slightly alkaline or moderately alkaline reaction classes. Bombadil soils have neutral or slightly alkaline reaction classes. Fubble soils have identifiable secondary carbonates below the argillic horizon. Jaybee soils have 35 to 45 percent clay in the argillic horizon. Meninik soils have 15 to 30 percent sand in the particle-size control section.

GEOGRAPHIC SETTING: Dougal soils are on hills and structural benches. These soils formed in residuum derived from welded rhyolitic tuff, andesite, or related volcanic rocks. Slopes are 2 to 20 percent. Elevations range from 4,000 to 5,450 feet. The climate is semiarid with cool, moist winters and warm, dry summers. The mean annual precipitation is 11 to 13 inches, mean annual temperature is 45 to 49 degrees F., and the frost-free period is 85 to 115 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bruncan, Duco, and Chinabutte soils. Bruncan soils have calcic horizons, are shallow to duripans over lithic contacts, and are on similar slope positions. Duco and Chinabutte soils are loamy-skeletal, have mollic epipedons, and occur on adjacent slopes.

DRAINAGE AND PERMEABILITY: Well drained; very high surface runoff; moderate permeability.

USE AND VEGETATION: Dougal soils are used mainly for rangeland and wildlife habitat. The dominant natural vegetation is low sagebrush, bluebunch wheatgrass, and Sandberg's bluegrass.

DISTRIBUTION AND EXTENT: Southwestern Idaho. These soils are moderately extensive. MLRA 25.

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

SERIES ESTABLISHED: Owyhee County Area, Idaho, l992.

REMARKS: Diagnostic horizons and features recognized in this pedon are:

Ochric epipedon - The zone from the soil surface to 8 inches (A and AB horizons).

Argillic horizon - The zone from 8 to 16 inches (Bt horizon).

Lithic contact - The boundary at 16 inches to underlying hard bedrock (R layer).

Particle-size control section - The zone from 8 to 16 inches (Bt horizon).

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National Cooperative Soil Survey
U.S.A.