LOCATION SWEITING WA+ID OR
Established Series
Rev. HRG/RJE/TLA/CLM
03/2013
SWEITING SERIES
The Sweiting series consists of moderately deep, well drained soils formed in loess and slope alluvium from weathered basalt. They are on mountain plateaus, hills and benches and have slopes of 2 to 30 percent. The average annual precipitation ranges from 17 to 35 inches and the average annual air temperature is about 43 degrees F.
TAXONOMIC CLASS: Fine, smectitic, frigid Pachic Ultic Argixerolls
TYPICAL PEDON: Sweiting silt loam, open coniferous forest on a 5 percent northeast facing slope at an elevation of 4,080 feet. (Colors are for dry soil unless otherwise noted)
Oi and Oe--2 to 0 inches; partially decomposed needles and twigs.
A1--0 to 3 inches; dark grayish brown (10YR 4/2) silt loam, very dark brown (10YR 2/2) moist; moderate medium granular structure; hard, friable, sticky and plastic; many very fine, fine and few medium roots; many very fine irregular pores; slightly acid (pH 6.5); clear smooth boundary. (3 to 6 inches thick).
A2--3 to 9 inches; dark grayish brown (10YR 4/2) silt loam, very dark grayish brown (10YR 3/2) moist; moderate medium subangular blocky structure; hard, friable, sticky and plastic; common very fine and fine, and few medium roots; common very fine irregular pores; slightly acid (pH 6.3); clear wavy boundary. (5 to 9 inches thick)
Bt1--9 to 15 inches; brown (10YR 4/3) silty clay loam, very dark grayish brown (10YR 3/2) moist; moderate medium prismatic parting to moderate medium angular blocky structure; very hard, firm, sticky and plastic; common very fine, fine and medium, and few coarse roots; common very fine irregular and few very fine tubular pores; common moderately thick stress cutans on faces of peds; 5 percent pebbles; slightly acid (pH 6.2); clear smooth boundary. (4 to 12 inches thick)
Bt2--15 to 18 inches; brown (10YR 4/3) silty clay loam, dark brown (10YR 3/3) moist; moderate medium prismatic parting, parting to moderate medium angular blocky structure; very hard, firm, sticky and plastic; common very fine and fine, and few medium roots; common very fine tubular pores; many moderately thick stress cutans on faces of peds; 10 percent pebbles; slightly acid (pH 6.2); clear smooth boundary. (3 to 7 inches thick)
2Bt3--18 to 22 inches; brown (10YR 4/3) very cobbly silty clay loam, dark brown (10YR 3/3) moist, ped faces dark brown (7.5YR 3/3) moist; strong medium and fine angular blocky structure; very hard, very firm, stocky and plastic; common very fine, fine and medium roots; few fine tubular pores; continuous moderately thick stress cutans on faces of peds and few clay films in pores; 15 percent pebbles and 25 percent cobbles; moderately acid (pH 6.0); abrupt irregular boundary. (3 to 7 inches)
3R--22 inches; basalt.
TYPE LOCATION: Asotin County, Washington; about 8 miles west of Anatone; 700 feet north and 2,500 feet east of southwest corner of sec. 16 T., 8 N., R. 44 E.
RANGE IN CHARACTERISTICS: The mean annual soil temperature is about 45 degrees F. The soils are usually moist, but are dry in all parts between depths of 4 and 12 inches for 45 to 60 consecutive days during summer and fall. The solum thickness and depth to a lithic contact is 20 to 40 inches. The particle-size control section averages 35 to 45 percent clay in the fine earth fraction and is 10 to 35 percent rock fragments. The mollic epipedon is 20 to 36 inches thick and includes all or part of the argillic horizo+Ln. It is moderately acid to neutral.
The A horizon has value of 3 to 5 dry, 2 or 3 moist, and chroma of 1 to 3 dry or moist. It is silt loam with 20 to 27 percent clay. It has 0 to 2 percent cobbles and 0 to 10 percent gravel.
The Bt and 2Bt horizon has hue of 7.5YR or 10YR, value of 3 through 6 dry, 2 to 4 moist, and chroma of 2 to 4 dry or moist. The Bt is silty clay loam, clay loam, silty clay or clay with 35 to 45 percent clay. The 2Bt horizon is gravelly, very gravelly, or very cobbly with 35 to 50 percent clay.
COMPETING SERIES: These are the
Bertag and
Top series. Bertag and Top soils are more than 40 inches deep.
GEOGRAPHIC SETTING: Sweiting soils are on mountain plateaus, hills and benches and have slopes of 2 to 30 percent. These soils formed in loess and slope alluvium from weathered basalt. Elevation ranges from 3,200 to 5,000 feet. These soils are in a climate with warm, dry summers and cool, moist winters. The mean annual precipitation is typically 22 to 35 inches but ranges to 17 inches in northeastern Oregon. The mean January temperature is about 28 degrees F, and the mean July temperature is about 64 degrees F. The average annual air temperature is 42 to 45 degrees F. Frost-free season is 70 to 110 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Anatone,
Bocker,
Cloverland,
Harlow,
Snell, and
Tolo soils. Bocker and Harlow soils have basalt at a depth of less than 20 inches. Cloverland and Tolo soils are more than 40 inches deep to basalt. Snell soils are clayey-skeletal.
DRAINAGE AND PERMEABILITY: Well drained; slow or medium runoff; slow permeability.
USE AND VEGETATION: Used for timber production, grazing, cropland and wildlife habitat. The principal crops are small grains, alfalfa and grass. Native vegetation is ponderosa pine and understory mainly of pinegrass, potential, big bluegrass, and prairie junegrass.
DISTRIBUTION AND EXTENT: Mountainous area of southeastern Washington and northeastern Oregon; MLRA 9. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Asotin County, Washington, 1984.
REMARKS: Partial laboratory data are available - S79WA-003-003. Diagnostic horizons and features recognized in this pedon are a mollic epipedon from the surface to 22 inches, an argillic horizon from 9 to 22 inches, and a lithic contact at 22 inches.
National Cooperative Soil Survey
U.S.A.