LOCATION WOCKUM WAEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Vitrandic Argixerolls
TYPICAL PEDON: Wockum ashy silt loam- rangeland, on a 31 percent northwest- facing slope at 3,200 feet elevation. (Colors are for dry soil unless otherwise stated. All textures are apparent field textures.)
A--0 to 4 inches; dark grayish brown (10YR 4/2) ashy silt loam, black (10YR 2/1) moist; weak, fine, subangular blocky structure parting to weak fine granular; soft, friable, slightly sticky and slightly plastic; many very fine and few fine roots; common fine irregular pores; neutral (pH 7.2) clear smooth boundary. (2 to 5 inches thick)
AB--4 to 12 inches; dark grayish brown (10YR 4/2) ashy silt loam, black (10YR 2/1) moist; moderate fine to medium subangular blocky structure; soft, friable, slightly sticky and slightly plastic; many very fine, common fine and few medium roots; common fine irregular pores; neutral (pH 7.2); clear smooth boundary. (5 to 10 inches thick)
2Bt1--12 to 17 inches; dark brown (7.5YR 4/4) silt loam, dark brown (10YR 3/3) moist; weak medium prismatic structure parting to moderate medium subangular blocky; slightly hard, friable, slightly sticky and slightly plastic; common very fine and medium roots; common fine and very fine tubular pores; common distinct dark brown (7.5YR 3/2) clay films on faces of peds; neutral (pH 7.2); clear wavy boundary. (4 to 6 inches thick)
2Bt2--17 to 27 inches; yellowish brown (7.5YR 5/4) silt loam, dark brown (10YR 3/3) moist; moderate coarse subangular blocky structure parting to strong medium subangular blocky; hard, friable, slightly sticky and moderately plastic; common very fine and few medium roots; common fine and very fine tubular pores; common distinct dark brown (10YR 3/4) clay films on faces of peds; 5 percent pebbles; neutral (pH 7.2); clear wavy boundary. (6 to 12 inches thick)
2Bt3--27 to 40 inches; light yellowish brown (10YR 6/4) silty clay loam, dark yellowish brown (10YR 4/4); moderate coarse subangular blocky structure, hard, friable, slightly sticky and moderately plastic; few very fine roots; common fine and very fine tubular pores; common distinct dark yellowish brown (10YR 3/4) clay films on faces of peds; 10 percent pebbles; neutral (pH 7.2); clear wavy boundary. (8 to 15 inches thick)
2Bt4--40 to 60 inches; light brown (7.5YR 6/4) gravelly clay loam, dark brown (7.5YR 4/4) moist; moderate coarse subangular blocky structure; hard, firm, slightly sticky and moderately plastic; few very fine roots; common fine and very fine tubular pores; common distinct yellowish brown (10YR 3/4) clay films on faces of peds; 20 percent pebbles; neutral (pH 7.2).
TYPE LOCATION: Kittitas County, Washington, about 1,860 feet east, 1,010 feet south of the NW corner, section 22, T. 14 N., R. 21 E.; USGS Black Rock Springs NW topographic quadrangle; Latitude 46 degrees, 41 minutes, 26 seconds N., Longitude 120 degrees, 11 minutes, 02 seconds W.
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 47 to 52 degrees F. These soils are usually moist but are dry in the moisture control section for 90 to 100 consecutive days following the summer solstice. Thickness of the mollic epipedon is 20 to 30 inches. The upper 7 to 12 inches has estimated bulk density of 1.15 to 1.30 g/cc, volcanic glass content of 5 to 20 percent, acid oxalate extractable aluminum plus one-half extractable iron of 0.4 to 0.7 percent, and 15 bar water retention of 5 to 10 percent for air dried samples. The particle-size control section averages 22 to 35 percent clay in the fine earth fraction and 5 to 15 percent coarse fragments by volume.
The A horizon has a value of 3 or 4 dry, 2 or 3 moist, and a chroma of 1 or 2 dry or moist. Organic matter is 2 to 3 percent.
The Bt horizon has hue of 10YR or 7.5YR and value of 4 through 6 dry, 2 through 4 moist, and chroma of 3 or 4, dry or moist. The upper part is silt loam or silty clay loam. The lower part is gravelly clay loam, very gravelly loam or cobbly silty clay loam. It is neutral or slightly alkaline.
COMPETING SERIES: These are the Georgecreek, Glenrose, Hillcreek (T), Morical, Mozen (T), Pachneum (T), Ralock, Rollinger, Shushuskin (T), Teewee , Tolius, Umperon (T), Volinger (T), and Wenner (T) series. Georgecreek soils have 25 to 50 percent medium, coarse, and very coarse sand, are dry for 75 to 90 days, and have mollic epipedons 8 to 16 inches thick. Glenrose soils have 10 to 25 medium, coarse, and very coarse sand, are dry 60 to 75 days, and have mollic epipedons that are 10 to 20 inches thick. Hillcreek soils are dry for 60 yo 90 days. Morical soils are 20 to 40 inches to weathered bedrock. Mozen and Shushuskin soils are 20 to 40 inches deep to a lithic contact. Pachneum soils are dry for 75 to 90 days and have 5 to 15 percent rock fragments in the PSCS. Ralock soils average 15 to 30 percent coarse fragments by volume and have secondary carbonates at a depth of 24 to 38 inches. Rollinger soils are dry 100 to 120 days and have mollic epipedons more than 40 inches thick. Teewee soils have 10 to 25 percent medium, coarse, and very coarse sand, are dry 60 to 90 days and have mollic epipedons 10 to 20 inches thick. Tolius soils are dry for 60 to 90 consecutive days following the summer solstice. Umperon soils are dry for 75 to 90 consecutive days and have 3 to 5 percent organic matter in the A horizon. Volinger soils have secondary carbonates at a depth of 43 to 60 inches. Wenner soils have mollic epipedons 10 to 18 inches thick and have 20 to 30 percent rock fragments.
GEOGRAPHIC SETTING: Wockum soils are on hillslopes and have slopes of 15 to 65 percent. These soils formed in loess mixed with volcanic ash in the surface and colluvium from basalt. Elevations are 2,500 to 3,300 feet. These soils are in a semiarid climate with warm dry summers and cold moist winters. Average annual precipitation is 12 to 15 inches. Average January temperature is about 25 degrees F., average July temperature is about 69 degrees F., and average annual temperature is about 48 degrees F. The frost-free season is 120 to 135 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Blint and Windry soils. Blint soils are on hillslopes, are loamy-skeletal and 20 to 40 inches to a lithic contact. Windry soils are on hillslopes, are loamy-skeletal and are 12 to 20 inches to a lithic contact.
DRAINAGE AND PERMEABILITY: Well drained, medium to very rapid runoff; moderately slow permeability.
USE AND VEGETATION: Rangeland and wildlife habitat. Vegetation is Idaho fescue, bluebunch wheatgrass, Sandberg bluegrass, Cusick bluegrass, and threetip sagebrush.
DISTRIBUTION AND EXTENT: Kittitas County, Washington. Series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Kittitas County, Washington, 1994.
REMARKS: Diagnostic horizons and features recognized in this pedon are a mollic epipedon from the surface to 27 inches and an argillic horizon from 12 to 60 inches. The particle-size control section is the zone from 12 to 32 inches (upper 20 inches of the argillic horizon).
The classification was changed from Pachic Argixerolls to Vitrandic Argixerolls in 1994.