LOCATION CRAWLEY IDEstablished Series
The Crawley series consists of shallow, well drained soils with moderately slow permeability that formed in colluvium and residuum from silty lacustrine deposits. Slopes range from 15 to 65 percent in foothills. The average annual precipitation is about 14 inches and the average annual temperature is about 50 degrees F.
TAXONOMIC CLASS: Loamy, mixed, superactive, mesic, shallow Aridic Argixerolls
TYPICAL PEDON: Crawley silt loam -- on a 15 percent slightly convex northeast-facing slope at 3,540 feet elevation in rangeland. When described on June 23, 1994, the soil was dry throughout. (Colors are for air-dry soil unless otherwise noted.)
A--0 to 4 inches; grayish brown (10YR 5/2) silt loam, very dark grayish brown (10YR 3/2) moist; moderate fine granular structure; soft, very friable, slightly sticky and slightly plastic; many very fine and fine, few medium and coarse roots; many very fine and fine irregular pores; slightly acid (pH 6.4); clear smooth boundary. (2 to 8 inches thick)
Bt1--4 to 7 inches; brown (10YR 5/3) silty clay loam, dark brown (10YR 3/3) moist; moderate fine subangular blocky structure; hard, friable, moderately sticky and moderately plastic; common very fine and fine, few medium and coarse roots; common very fine and fine tubular pores; common distinct clay films on faces of peds and in pores; 10 percent pararock fragments; neutral (pH 7.0); clear wavy boundary. (0 to 10 inches thick)
Bt2--7 to 13 inches; yellowish brown (10YR 5/4) paragravelly silty clay loam, dark yellowish brown (10YR 4/4) moist; strong fine and medium subangular blocky structure; hard, friable, moderately sticky and very plastic; few very fine, fine and medium roots; common very fine and fine tubular pores; common distinct clay films on faces of peds and in pores; 25 percent pararock fragments; neutral (pH 7.0); abrupt smooth boundary. (3 to 14 inches thick)
Crkq--13 to 23 inches; stratified silty lacustrine deposits that have less than 5 percent calcium carbonate on horizontal and vertical faces of deposits; discontinuous, very thin (less than 1mm) silica coatings on horizontal and vertical sediment planes.
TYPE LOCATION: Boise County, Idaho; about 7.5 miles south and 3 miles west of Horseshoe Bend; 550 feet north and 1,000 feet east of the southwest corner of section 31, T.6 N., R.2 E.; USGS Pearl Quadrangle; Latitude - 43 degrees, 48 minutes, 34 seconds N. and Longitude - 116 degrees, 16 minutes, 11 seconds W.; NAD 83.
RANGE IN CHARACTERISTICS:
Mollic epipedon thickness - 7 to 10 inches
Depth to paralithic contact - 10 to 14 inches
Moisture control section - moist less than 90 consecutive days when the soil temperature is greater than 47 degrees F.
Average annual soil temperature - 51 to 53 degrees F.
A horizon
Value - 4 or 5 dry, 2 or 3 moist
Chroma - 2 or 3 dry or moist
Clay content - 18 to 25 percent
Rock fragments - 0 to 10 percent fine gravel
Reaction - slightly acid or neutral
Bt horizon
Value - 5 or 6 dry, 3 or 4 moist
Chroma - 2 through 4 dry or moist
Texture - SICL or CL
Clay content - 27 to 35 percent
Rock fragments - 0 to 5 percent gravel
Pararock fragments - 5 to 30 percent
Reaction - neutral or slightly alkaline
Cr horizon
Some pedons do not have secondary silica or calcium carbonate
COMPETING SERIES: These are the Arclay, Luppino, Siscab and Wedekind series. Arclay soils are 14 to 20 inches deep to a paralithic contact, 40 to 60 inches deep to a lithic contact, and have 15 to 30 percent granitic rock fragments within the Bt horizon. Luppino soils are 20 to 30 inches percent sand coarser than very fine sand within the Bt horizon. Siscab soils have 18 to 27 percent clay and 15 to 35 percent rock fragments in the particle-size control section. Wedekind soils have 18 to 27 percent clay, 5 to 35 percent rock fragments, and more than 15 percent sand coarser than very fine sand within the particle-size control section.
GEOGRAPHIC SETTING: Crawley soils are on convex hill backslopes and shoulders at elevations of 2,650 to 4,100 feet. Slopes range from 15 to 65 percent. The soils formed in colluvium and residuum from silty lacustrine deposits. The average annual precipitation is 13 to 16 inches. The average annual temperature is 49 to 51 degrees F. The frost-free period is 130 to 150 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Ayette, Breadloaf, Hullsgulch and Meclo soils. Ayette soils are deep to a paralithic contact. Breadloaf and Meclo soils are moderately deep to a paralithic contact. Hullsgulch soils are very deep. All of these soils are on similar geomorphic positions.
DRAINAGE AND PERMEABILITY: Well drained; medium to very rapid runoff; moderately slow permeability.
USE AND VEGETATION: Crawley soils are used mainly for rangeland. Native vegetation is basin big sagebrush and bluebunch wheatgrass.
DISTRIBUTION AND EXTENT: West-central Idaho. MLRA 10. Crawley soils are of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Boise County Area, Idaho, Parts of Ada and Boise Counties, 2005.
REMARKS: Diagnostic horizons and features recognized in this pedon:
Mollic epipedon - zone from the surface to 7 inches (A and Bt1 horizons)
Argillic horizon - zone from 7 to 13 inches (Bt1 and Bt2 horizons)
Particle-size control section - zone from 0 to 13 inches
Paralithic contact - at 13 inches (Crkq horizon)
Soil moisture regime - aridic bordering on xeric
These soils are drier than other Xerolls in the region under similar precipitation due to early runoff and extended period of high evapotranspiration.