LOCATION DANGULCH ID

Established Series
Rev. ALH/RWL
07/2012

DANGULCH SERIES

The Dangulch series consists of deep, well drained soils with slow permeability that formed in colluvium from lacustrine deposits. Slopes range from 25 to 50 percent in foothills. The average annual precipitation is about 15 inches and the average annual temperature is about 47 degrees F.

TAXONOMIC CLASS: Fine, smectitic, mesic Calcic Argixerolls

TYPICAL PEDON: Dangulch silt loam -- on a slightly convex northeast-facing slope of 35 percent, in rangeland at 3,060 feet elevation. When described on August 30, 1995, the soil was dry throughout. (Colors are for air-dry soil unless otherwise stated.)

A--0 to 5 inches; dark grayish brown (10YR 4/2) silt loam, very dark brown (10YR 2/2) moist; moderate fine and medium platy structure parting to moderate fine granular; slightly hard, very friable, moderately sticky and moderately plastic; many very fine and fine, few medium and coarse roots; many very fine and fine, few medium irregular, few coarse tubular pores; neutral (pH 7.2); abrupt smooth boundary. (5 to 12 inches thick)

Bt1--5 to 7 inches; dark grayish brown (10YR 4/2) silty clay loam, very dark grayish brown (10YR 3/2) moist; moderate fine and medium subangular blocky structure; very hard, firm, moderately sticky and moderately plastic; many very fine and fine, few medium and coarse roots; few very fine, fine and medium tubular pores; many distinct clay films on faces of peds and in pores; neutral (pH 7.1); abrupt smooth boundary. (2 to 8 inches thick)

Bt2--7 to 15 inches; brown (10YR 5/3) clay, brown (10YR 4/3) moist; moderate coarse prismatic structure parting to strong fine and medium angular blocky; very hard, firm, very sticky and very plastic; common very fine and fine, few medium roots; few very fine and fine tubular pores; many prominent clay films on faces of peds and in pores; neutral (pH 7.1); clear smooth boundary. (8 to 20 inches thick)

Btk--15 to 21 inches; very pale brown (10YR 7/3) silty clay loam, pale brown (10YR 6/3) moist; moderate fine and medium subangular blocky structure; hard, friable, moderately sticky and moderately plastic; few very fine, fine and medium roots; common very fine and fine tubular pores; common faint clay films on faces of peds and in pores; violently effervescent, common fine and medium masses of calcium carbonates; slightly alkaline (pH 7.8); clear wavy boundary. (5 to 12 inches thick)

Bk1--21 to 29 inches; very pale brown (10YR 8/3) silt loam, pale brown (10YR 6/3) moist; weak fine and medium subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; few very fine and fine roots; common very fine and fine tubular pores; violently effervescent; moderately alkaline (pH 8.1); clear wavy boundary.

Bk2--29 to 48 inches; very pale brown (10YR 8/2) loam, light brownish gray (10YR 6/2) moist; weak fine and medium subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; few very fine and fine roots; common very fine and fine tubular pores; 5 percent pararock fragments; violently effervescent; moderately alkaline (pH 8.2); abrupt irregular boundary. (combined Bk - 10 to 30 inches thick)

Cr--48 to 58 inches; moderately fractured very fine sand lacustrine deposits.

TYPE LOCATION: Ada County, Idaho; about 2 1/2 miles north of the Camelsback Park in Boise; 2,150 feet east and 2,150 feet south of the northwest corner of section 22, T.4 N., R.2 E.; USGS Boise North Quadrangle; (Latitude 43 degrees, 40 minutes, 15 seconds N. and Longitude 116 degrees, 12 minutes, 15 seconds W.)

RANGE IN CHARACTERISTICS:
Mollic epipedon thickness - 7 to 20 inches
Depth to calcium carbonates - 15 to 36 inches
Depth to base of argillic horizon - 20 to 48 inches
Depth to paralithic contact - 40 to 60 inches
Moisture control section - dry 60 to 90 consecutive days following the summer solstice
Average annual soil temperature - 48 to 50 degrees F.

A horizon
Value - 4 or 5 dry, 2 or 3 moist
Chroma - 2 or 3 dry or moist
Bt1 horizon
Value - 4 or 5 dry, 2 or 3 moist
Chroma - 2 or 3 dry or moist
Texture - SIL or SICL
Clay content - 25 to 40 percent
Reaction (pH) - neutral or slightly alkaline

Bt2 horizon
Value - 5 or 6 dry, 3 or 4 moist
Chroma - 3 or 4 dry or moist
Texture - C, SIC or SICL
Clay content - 35 to 45 percent
Reaction (pH) - neutral or slightly alkaline

Btk horizon
Hue - 10YR or 2.5Y
Value - 5 through 7 dry, 4 through 6 moist
Chroma - 3 or 4 dry or moist
Texture - SICL, CL or SIL
Clay content - 25 to 35 percent
Rock fragment content - 0 to 5 percent
Calcium carbonate equivalent - 1 to 5 percent

Bk horizon
Hue - 10YR or 2.5Y
Value - 6 through 8 dry, 4 through 6 moist
Chroma - 2 through 4 dry or moist
Texture - L or SIL
Clay content - 18 to 27 percent
Rock fragment content - 0 to 10 percent
Pararock fragment content - 5 to 25 percent
Effervescence - strong or violent
Calcium carbonate equivalent - 3 to 15 percent
Salinity - nonsaline or very slightly saline
Reaction (pH) - slightly or moderately alkaline

COMPETING SERIES: These are the Banner, Flowell, Gem, Gemson and Kanarra series. Banner soils are very deep. Flowell soils have Ck horizons of strong lime cementation above 40 inches and Bt horizons with color hue of 5YR or 7.5YR. Gem soils are 20 to 40 inches deep to bedrock. Gemson soils have Bt horizons that extend to depths of 40 inches or more. Kanarra soils are very deep and have Bk horizons with over 15 percent calcium carbonate equivalent.

GEOGRAPHIC SETTING: Dangulch soils are steep on hill backslopes at elevations of 2,750 to 3,900 feet. Slopes range from 25 to 50 percent. These soils formed in colluvium from lacustrine deposits. The climate is cool and moist in the winter and warm and dry in the summer. Average annual precipitation ranges from 14 to 18 inches. Average annual temperature ranges from 46 to 48 degrees F. Frost-free period is 100 to 120 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Ada, Pawtoot, Polecat and Shadoval soils. Ada soils are skeletal. Pawtoot and Shadoval soils have an abrupte textural change. Polecat soils are fine-silty. All these soils have an aridic soil moisture regime and are on southerly landscape positions.

DRAINAGE AND PERMEABILITY: Well drained; very rapid runoff; slow permeability.

USE AND VEGETATION: Dangulch soils are used mainly for rangeland and wildlife habitat. The dominant natural vegetation is basin big sagebrush, bluebunch wheatgrass and Idaho fescue.

DISTRIBUTION AND EXTENT: Southwestern Idaho. MLRA 10. Dangulch soils are not extensive.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon

SERIES ESTABLISHED: Ada County, Idaho, 2012

REMARKS: Diagnostic horizons and features recognized in this pedon:
Mollic epipedon - zone 0 to 7 inches (A and Bt1 horizons)
Argillic horizon - zone 5 to 21 inches (Bt1, Bt2 and Btk horizons)
Calcareous horizon - zone 15 to 48 inches (Btk, Bk1 and Bk2 horizons)
Paralithic contact - at 48 inches (Cr)
Particle-size control section - zone 5 to 21 inches
Linear extensibility - 4.5 to 6.0 cm (assumed)
Soil moisture regime - xeric

National Cooperative Soil Survey
U.S.A.