LOCATION THUSO WAEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, mesic Vitrandic Haploxerolls
TYPICAL PEDON: Thuso ashy sandy loam, on a west-facing 65 percent slope at 2,900 feet elevation in a meadow. (Colors are for dry soil unless otherwise stated. All textures are apparent field textures.)
A1--0 to 12 inches; brown (10YR 4/3) ashy sandy loam, very dark grayish brown (10YR 3/2) moist; moderate fine and medium granular structure; soft, friable, nonsticky and nonplastic; many very fine and fine roots; many very fine and fine irregular pores; 10 percent pebbles; neutral (pH 6.6); gradual smooth boundary.
A2--12 to 25 inches, brown (10YR 4/3) gravelly ashy sandy loam, dark brown (10YR 3/3) moist; moderate fine subangular blocky structure; slightly hard, friable, nonsticky and nonplastic; many very fine and fine roots; many very fine and fine irregular pores; 25 percent pebbles and 5 percent cobbles; neutral (pH 6.6); gradual smooth boundary. (combined A horizons 10 to 25 inches thick)
2Bw--25 to 37 inches, brown (10YR 5/3) very cobbly sandy loam, brown (10YR 4/3) moist; moderate medium subangular blocky; slightly hard, friable, nonsticky and nonplastic; many very fine and common fine roots; many irregular pores; 25 percent pebbles and 20 percent cobbles; neutral (pH 6.6); gradual wavy boundary. (8 to 18 inches thick)
2C--37 to 60 inches, olive brown (2.5Y 4/4) very cobbly sandy loam, olive brown (2.5Y 4/3) moist; massive; slightly hard, friable, nonsticky and nonplastic; common very fine and few fine roots; common very fine and fine irregular pores; 30 percent pebbles and 20 percent cobbles; neutral (pH 6.6).
TYPE LOCATION: Okanogan County, Washington; about 3 miles northeast of Conconully, Washington; 600 feet west and 1800 feet south of the northeast corner of section 28, T. 36 N., R. 20 E. (Latitude 48 degrees 35' 36"N., Longitude 119 degrees 41' 28"W.)
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 47 to 53 degrees F. These soils are usually moist but are dry in all parts of the moisture control section for 90 to 105 days following the summer solstice. The mollic epipedon is 10 to 25 inches thick, has a base saturation of 50 to 75 percent, an estimated bulk density of 1.10 to 1.30 g/cc, volcanic glass content of 5 to 20 percent, acid-oxalate extractable aluminum plus one-half the acid-oxalate extractable iron of 0.4 to 1.0 percent, and 15-bar water retention of 5 to 10 percent for air dried samples. The particle-size control section averages 35 to 50 percent coarse fragments by volume, and 8 to 18 percent clay. Reaction is slightly acid to neutral throughout.
The A1 horizon has value of 4 or 5 dry, 2 or 3 moist, and chroma of 1 to 3 dry or moist.
The A2 horizon has value of 4 or 5 dry, 2 or 3 moist, and chroma of 1 to 3 dry or moist. The texture is gravelly ashy or very gravelly ashy sandy loam. It is 20 to 40 percent pebbles.
The 2Bw horizon has value of 4 to 6 dry, 3 or 4 moist, chroma of 3 or 4 dry or moist. The texture is very cobbly sandy loam or very gravelly sandy loam. It is 20 to 40 percent pebbles and 5 to 20 percent cobbles.
The 2C horizon has value 4 to 6 dry, 3 to 5 moist, and chroma of 3 or 4 dry or moist. The texture is very cobbly sandy loam or very gravelly sandy loam. It is 25 to 45 percent pebbles and 10 to 30 percent cobbles.
COMPETING SERIES: These are the Borgeau, Eaglespring, Garrison, Louiecreek, Raisio, Wagberg, Whitestone, and Vanbrunt series. Raisio and Vanbrunt soils are 20 to 40 inches deep to a lithic contact. Borgeau soils have a particle-size control section dominated by metamorphic rock fragments and are dry in the moisture control section for 75 to 90 consecutive days. Eaglespring soils are 40 to 60 inches to bedrock. Garrison soils have a sandy-skeletal material in the lower part of the particle-size control section. Louiecreek soils have 8 to 15 percent clay in the particle-size control section, and the base saturation is (by sum) 75 to 100 percent except in the upper part of the A horizon. Wagberg soils have less than 8 percent clay in the particle-size control section. Whitestone soils are dry in the moisture control section for 75 to 90 consecutive days following the summer solstice.
GEOGRAPHIC SETTING: Thuso soils are on backslopes of foothills and mountains. Slopes are 35 to 65 percent. These soils formed from colluvium with minor component of glacial till from metasedimentary rock, and with a component of volcanic ash in the upper part. Elevations range from 2,200 to 3,700 feet. The climate is characterized by hot, dry summers and cold, moist winters. The average annual precipitation ranges from 15 to 18 inches. The average January temperature ranges from 25 to 30 degrees F., the average July temperature ranges from 65 to 70 degrees F., and the average annual temperature ranges from 45 to 52 degrees F. The frost-free season ranges from 100 to 130 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Koepke, Oxerine, Rufus, and Wynhoff soils. Koepke soils are on backslopes and footslopes of mountains, have a thick layer of volcanic ash, and are in a frigid temperature regime. Oxerine soils are on footslopes, backslopes, shoulders, and ridges of mountains. They are 20 to 40 inches to bedrock and in a frigid temperature regime. Rufus soils are found on south-facing hillsides, shoulders and ridgetops. They are 10 to 20 inches to bedrock. Wynhoff soils are on backslopes, footslopes and shoulders of mountains. They are 20 to 40 inches to bedrock.
DRAINAGE AND PERMEABILITY: Well drained, rapid to very rapid runoff; moderately rapid permeability.
USE AND VEGETATION: This soil is used for livestock grazing, recreation, wildlife habitat, and watershed. Native vegetation is bluebunch wheatgrass, Idaho fescue, common yarrow, arrowleaf balsamroot, eriogonum, and Saskatoon serviceberry.
DISTRIBUTION AND EXTENT: Okanogan County, Washington. This series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Okanogan National Forest, Okanogan County, Washington, 2005.
REMARKS: Diagnostic horizons and features in this pedon: Mollic epipedon - 0 to 25 inches (A1 and A2 horizons) Cambic horizon - 25 to 37 inches (2Bw horizon) PSCS: - 10 to 40 inches (A2, 2Bw, and part of the A1, 2C horizons)
Vitrandic properties from 0 to 25 inches.