LOCATION SAUM OREstablished Series
TAXONOMIC CLASS: Fine, mixed, active, mesic Ultic Palexeralfs
TYPICAL PEDON: Saum silt loam, in an area of Saum silt loam, 12 to 20 percent slopes at an elevation of 810 feet. (Colors are for dry soil unless otherwise noted.)
Ap--0 to 7 inches; brown (7.5YR 4/4) broken face silt loam, dark brown (7.5YR 3/3) broken face, moist; moderate very fine subangular blocky structure; friable, slightly hard, slightly sticky and slightly plastic; many very fine roots; many fine tubular and few medium tubular and many very fine tubular pores; 3 percent medium spherical strongly cemented iron- manganese concretions and 4 percent fine spherical strongly cemented iron-manganese concretions; 4 percent subrounded indurated basalt gravel; moderately acid (pH 5.7); clear smooth boundary.
A--7 to 13 inches; brown (7.5YR 4/4) broken face silt loam, dark brown (7.5YR 3/3) broken face, moist; moderate fine subangular blocky structure; friable, hard, slightly sticky and slightly plastic; common very fine roots; many fine tubular and common medium tubular and few coarse tubular and few very coarse tubular and many very fine tubular pores; 2 percent fine spherical strongly cemented iron-manganese concretions and 2 percent medium spherical strongly cemented iron-manganese concretions; 1 percent nonflat subrounded moderately cemented 2- to 5-millimeter basalt fragments; 3 percent subrounded indurated basalt gravel; moderately acid (pH 5.9); clear smooth boundary.
BA--13 to 22 inches; brown (7.5YR 4/4) broken face silt loam, dark brown (7.5YR 3/4) broken face, moist; moderate fine and medium subangular blocky structure; friable, hard, moderately sticky and moderately plastic; common very fine roots; many fine tubular and common medium tubular and few coarse tubular and many very fine tubular pores; 5 percent faint clay films on faces of peds and 30 percent faint brown (7.5YR 5/3), dry, silt coats on vertical faces of peds; 3 percent fine spherical strongly cemented iron-manganese concretions; 1 percent subrounded indurated basalt gravel; slightly acid (pH 6.1); gradual smooth boundary.
Bw--22 to 35 inches; brown (7.5YR 4/4) broken face silty clay loam, dark brown (7.5YR 3/4) broken face, moist; moderate medium subangular blocky structure; firm, hard, moderately sticky and moderately plastic; common very fine roots between peds; many fine tubular and common medium tubular and many very fine tubular pores; 35 percent faint clay films on surfaces along pores and 35 percent faint clay films on faces of peds and 50 percent faint brown (7.5YR 5/3), dry, silt coats on vertical faces of peds; 1 percent subrounded indurated basalt gravel; slightly acid (pH 6.1); clear smooth boundary.
2Bt2--35 to 50 inches; brown (7.5YR 4/4) broken face silty clay, dark reddish brown (5YR 3/4) broken face, moist; moderate medium subangular blocky structure; firm, hard, moderately sticky and moderately plastic; very few very fine roots between peds; many fine tubular and many very fine tubular pores; 1 percent prominent pale brown (10YR 6/3), dry, silt coats on faces of peds and 65 percent faint clay films on faces of peds and 65 percent faint clay films on surfaces along pores; 10 percent prominent black (10YR 2/1), dry, manganese coatings on vertical faces of peds; 1 percent subrounded indurated basalt gravel; moderately acid (pH 6.0); gradual smooth boundary.
2BCt--50 to 68 inches; reddish brown (5YR 4/4) broken face clay, dark reddish brown (5YR 3/4) broken face, moist; weak medium and coarse subangular blocky structure; firm, hard, moderately sticky and moderately plastic; very few very fine roots between peds; many fine tubular and many very fine tubular pores; 1 percent prominent silt coats on faces of peds and 60 percent faint pale brown (10YR 6/3), dry, clay films on faces of peds and 60 percent faint clay films on surfaces along pores; 30 percent prominent black (10YR 2/1), dry, manganese coatings on vertical faces of peds; 3 percent nonflat subrounded moderately cemented 2- to 5-millimeter basalt fragments; 6 percent subrounded indurated basalt gravel; moderately acid (pH 5.8)
TYPE LOCATION: Yamhill County, Oregon; northeast 1/4 of the northwest 1/4 of the southeast of section 27 T. 2 S., R.3 W. Willamette Meridian. (Latitude 45 degrees, 22 minutes, 5.2 seconds N., Longitude 123 degrees, 2 minutes, 17.8 seconds W. NAD 83). Dundee Oregon USGS topographic quadrangle.
RANGE IN CHARACTERISTICS: The mean annual soil temperature is about 53 to 55 degrees F. The soils are usually moist but are dry for 45 to 60 consecutive days in all parts between depths of 4 and 12 inches following the summer solstice. Depth to basalt is greater than 60 inches. Occasional basalt boulders are in any part in some pedons The particle-size control section averages 35 to 50 percent clay. The B horizon has a base saturation ( by NH4OAc) of 60 to 70 percent. The umbric epipedon is 10 to 25 inches thick.
The A horizons have hue of 7.5YR, value of 3 moist and 4 or 5 dry, and chroma of 2 or 3 moist and 3 or 4 dry. Texture is silty clay loam or silt loam with 20 to 35 percent clay. It has 1 to 10 percent gravel and 0 to 5 percent cobbles. It has 1 to 5 percent Fe/Mn concretions. Reaction ranges from very strongly acid to slightly acid.
The AB or BA horizons have hue of 7.5YR, value of 3 or 4 moist, 4 or 5 dry, chroma of 3 or 4 moist, and 4 to 6 dry. Texture is silt loam or silty clay loam with 24 to 40 percent clay. It has 1 to 15 percent gravel and 0 to 5 percent cobbles. It has 1 to 5 percent Fe/Mn concretions. Reaction ranges from strongly acid to slightly acid.
The Bw horizon has hue of 7.5YR or 5YR, value of 3 or 4 moist, 4 or 5 dry, chroma of 3 to 6 moist and 4 to 6 dry. Texture is silty clay loam or silty clay with 28 to 45 percent clay. It has 1 to 20 percent gravel, and 0 to 10 percent cobbles. It has 1 to 5 percent Fe/Mn concretions. Reaction ranges from strongly acid to slightly acid.
The 2Bt horizon has hue of 7.5YR or 5YR, value of 3 or 4 moist, 4 or 5 dry, chroma of 3 to 6 moist and 4 to 6 dry. Texture is silty clay loam or silty clay with 35 to 50 percent clay. It has 1 to 15 percent gravel, and 0 to 5 percent cobbles. It has 1 to 5 percent Fe/Mn concretions. Reaction ranges from strongly acid to moderately acid.
The 2BCt horizon, when present has hue of 7.5YR or 5YR, value of 3 or 4 moist, 4 or 5 dry, chroma of 3 to 6 moist and 4 to 6 dry. Texture is silty clay loam, clay, or silty clay with 35 to 50 percent clay. It has 3 to 35 percent paragravel, 0 to 15 percent paracobbles, 1 to 30 percent gravel, 0 to 30 percent cobbles, and 0 to 15 stones. Reaction ranges from strongly acid to moderately acid.
COMPETING SERIES: These are the Bateman and Mooner (T) series.
Bateman soils - ochric epipedon; 20 to 35 percent gravel and cobbles of siltstone and sandstone origin in the lower part of the argillic horizon.
Moomer soils - ochric epipedon; dry for more than 60 consecutive days following the summer solstice; 5 to 55 percent parafragments of basalt origin in the pscs.
A series with a similar Xeric Haplohumults classification is the Georgotte soil.
Georgotte soils - ochric epipedon; 25 to 35 percent clay, 2 to 30 percent gravel and 0 to 25 percent cobbles of gabbro origin, and 0 to 35 percent paragravel and 0 to 5 percent paracobbles of mudstone origin in the pscs
GEOGRAPHIC SETTING: The Saum soils are on summits and side slopes in areas that have been affected by mass movement. Slopes are 2 to 90 percent. The soils occur at elevations of 250 to 1600 feet. The soils formed in colluvium and residuum from various members of the Columbia River Basalt Group (CRBG). The climate is characterized by warm, wet winters and hot, dry summers. The average annual precipitation is 40 to 50 inches. The average annual temperature is 50 to 54 degrees F., average January temperature is 39 to 40 degrees F., and average July temperature is 65 to 67 degrees F. The frost-free period is 165 to 210 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cornelius, Helvetia, Gelderman, Jory, Kinton, Laurelwood, Nekia, and the competing Parrett (T) soils. Gelderman and Nekia soils are 20 to 40 inches to bedrock. Laurelwood soils a particle-size control section with 27 to 35 percent clay. Helvetia soils are moderately well drained. Jory soils have a base saturation of less than 35 percent ( by Sum of Cations) in the lower Bt horizons.. Kinton and Cornelius soils have fragipans. Helvetia soils are on toeslopes and footslopes at lower elevations. Gelderman, Nekia, and Jory soils are on more stable landforms. Laurelwood, Cornelius, and Kinton soils are in areas highly influenced by loess.
DRAINAGE AND PERMEABILITY: Well drained; slow to rapid surface runoff; moderate slow permeability.
USE AND VEGETATION: These soils are used mainly for production of berries, orchards, small grains, seed crops, timber, hay and pasture. Other uses include wildlife habitat, recreation, Christmas trees, vineyards, and homesites. Vegetation includes an overstory of Douglas-fir, grand fir, Oregon white oak with an understory of western sword fern, Pacific poison oak, California hazelnut, common snowberry, and yerba buena.
DISTRIBUTION AND EXTENT: Foothills of the Willamette Valley, Oregon. MLRA 2. The series is inextensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Washington County, Oregon, 1975.
REMARKS: The diagnostic horizons and features recognized in this pedon include:
Umbric epipedon - from a depth of 0 to 13 inches (Ap and A horizons).
Cambic horizon - from a depth of 22 to 35 inches (Bw horizon).
Argillic horizon - from a depth of 35 to 68 inches (2Bt and 2BCt horizons). Particle-size control section - 35 to 55 inches.
Classification revised 12/2006 from fine-loamy, mixed, superactive, mesic Xeric Haplohumults to fine, mixed, active Ultic Palexeralfs based on full lab characterization data and field documentation of the Saum concept as having bedrock at depths greater than 60 inches. Areas of out-of-date mapping currently mapped as Saum will be updated to reflect the revised concept or as a deep Haploxeralfs.
ADDITIONAL DATA: Characterization data from 4 representative pedon with User Pedon ID # s 01OR-071-008, 02OR-071-002, 02OR-071-003, 03OR-071-001, and 03OR-071-005.