LOCATION STEMBER WA+IDEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, mesic Typic Calcixerolls
TYPICAL PEDON: Stember silt loam - cultivated on a 3 percent west facing slope at an elevation of 2,820 feet. (Colors are for dry soil unless otherwise noted).
Ap--0 to 7 inches; dark grayish brown (10YR 4/2) silt loam, very dark brown (10YR 2/2) moist; weak fine and medium granular structure; hard, friable, sticky and plastic; many very fine roots; many very fine irregular pores; 5 percent pebbles, slightly effervescent; moderately alkaline (pH 8.0); abrupt smooth boundary. (6 to 9 inches thick)
A--7 to 11 inches; dark grayish brown (10YR 4/2) gravelly silt loam, very dark brown (10YR 2/2) moist; moderate medium subangular blocky structure; hard, friable, sticky and plastic; many very fine roots; many very fine irregular pores; 20 percent pebbles and 5 percent cobbles, strongly effervescent; moderately alkaline (pH 8.2); clear wavy boundary. (3 to 6 inches thick)
2Bqk1--11 to 15 inches; brown (10YR 5/3) very cobbly silt loam, very dark grayish brown (10YR 3/2) moist; moderate medium and coarse subangular blocky structure; hard, friable, sticky and plastic; many very fine roots; many very fine irregular and common very fine tubular pores; few aggregates of secondary lime; 25 percent pebbles size indurated durinodes and lime-silica coated basalt pebbles and 20 percent lime-silica coated basalt cobbles; violently effervescent; moderately alkaline (pH 8.2); abrupt wavy boundary. (3 to 6 inches thick)
2Bqk1--15 to 18 inches; white (10YR 8/2) very cobbly loam, very pale brown (10YR 7/3) moist; massive hard, firm, slightly sticky and slightly plastic; few very fine roots; many very fine irregular and tubular pores; discontinuous 1/16 to 1 inch thick lenses that are weakly cemented with silica and lime; 25 percent indurated pebble-size durinodes and lime-silica coated basalt pebbles and 30 percent lime- silica coated basalt cobbles; violently effervescent, strongly alkaline (pH 8.6); abrupt wavy boundary. (0 to 4 inches thick)
2Bqk2--18 to 24 inches; white (10YR 8/2) very cobble loam, very pale brown (10YR 7/3) moist; massive; hard, firm, slightly sticky and slightly plastic; few very fine roots; many very fine irregular and tubular pores; 30 percent pebble-size durinodes and lime-silica coated basalt pebbles and 20 percent lime-silica coated basalt cobbles; violently effervescent; strongly alkaline (pH 8.6) abrupt wavy boundary. (3 to 16 inches thick)
3R--24 inches; basalt.
TYPE LOCATION: Asotin County, Washington; about 6 miles north of Anatone; 300 feet east and 1,100 feet north of the southwest corner of sec. 30, T. 9 N., R. 46 E.
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 49 to 54 degrees F. These soils are usually moist, but are dry in all parts between 4 and 12 inches for 75 to 90 consecutive days during summer and fall. After the upper 7 inches are mixed, the entire soil is calcareous. A calcic horizon is at a depth of 9 to 20 inches and a lithic contact with basalt is at a depth of 20 to 35 inches. The particle-size control section averages 19 to 24 percent clay in the fine earth fraction and is 35 to 65 percent rock fragments. The mollic epipedon is 12 to 20 inches thick and includes the A and Bk horizons.
The A horizon has value of 4 or 5 dry and 2 or 3 moist. It is gravelly silt loam or silt loam.
The Bk horizon, when present, has chroma of 2 or 3 dry or moist. It is very cobbly silt loam, very gravelly silt loam or gravelly silt loam.
The 2Bqk horizon has value of 5 through 8 dry, 4 through 7 moist, and chroma of 1 through 3 dry or moist. It is very gravelly loam, extremely cobbly loam, or very cobbly loam. The coarse fragments include 20 to 50 percent lime-silica cemented fragments and 15 to 30 percent lime-silica coated basalt fragments.
COMPETING SERIES: These are the Munk and Sterling series. Munk soils have a paralithic contact at 24 to 40 inches. Sterling soils are more than 40 inches deep.
GEOGRAPHIC SETTING: Stember soils are on basalt plateaus. Slopes are 3 to 30 percent. These soils formed in loess and slope alluvium from weathered basalt. Elevations range from 1,400 to 3,400 feet. Summers are warm and dry and winters are cool and moist. The average annual precipitation ranges from 14 to 18 inches. Mean annual temperature is about 47 degrees F. Frost-free season is 125 to 135 days and up to 180 days in Idaho.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Laufer, Limekiln, Pataha, Rockly, and Thiessen soils. Laufer, Limekiln, and Rockly soils have a lithic contact at a depth of less than 20 inches. Pataha soils are in a fine-loamy family. Theissen soils are clayey-skeletal.
DRAINAGE AND PERMEABILITY: Well drained; slow to medium runoff; moderate permeability.
USE AND VEGETATION: Used for cropland and range. Native vegetation is mainly bluebunch wheatgrass, Idaho fescue, Sandberg bluegrass, arrowleaf balsamroot, and western yarrow.
DISTRIBUTION AND EXTENT: Southeastern Washington and northcentral Idaho. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Asotin County, Washington, 1984.
REMARKS: Diagnostic horizons and features recognized in this pedon are a mollic epipedon from the surface to 15 inches, a calcic horizon from 15 to 24 inches, and a lithic contact at 24 inches.