LOCATION SKAMO WA
Established Series
Rev. CJM/DRU/EED
05/2017
SKAMO SERIES
Landscape--valleys, drift plains
Landform--terraces, alluvial fans
Slope--0 to 15 percent
Parent material--old alluvium
Mean annual precipitation--2400 mm
Mean annual air temperature--10 degrees C
Depth class--very deep
Drainage class--moderately well drained
Soil moisture regime--udic
Soil temperature regime--isomesic
Soil moisture subclass--aquic
TAXONOMIC CLASS: Medial, ferrihydritic, isomesic Aquic Fulvudands
TYPICAL PEDON: Skamo medial silt loam on a flat, forested terrace at an elevation of 50 m (When described on March 15, 2016, the soil was moist to a depth of 71 cm and saturated from a depth of 71 to 150 cm.)
Oi--0 to 3 cm; slightly decomposed plant material; abrupt smooth boundary
A1--3 to 15 cm; medial silt loam, black (10YR 2/1) moist, very dark grayish brown (10YR 3/2) dry; strong fine granular structure; soft, very friable, moderately sticky and slightly plastic; moderately smeary; common very fine, fine, and medium roots and few coarse roots; many very fine and few medium irregular pores and few very fine tubular pores; strongly acid (pH 5.4); clear wavy boundary
A2--15 to 37 cm; medial silty clay loam, very dark brown (10YR 2/2) moist, dark brown (10YR 3/3) dry; strong fine granular structure; soft, very friable, moderately sticky and slightly plastic; moderately smeary; common very fine to medium roots and few coarse roots; many very fine and few medium irregular pores and few very fine tubular pores; strongly acid (pH 5.4); clear wavy boundary
Bw--37 to 52 cm; medial silty clay loam, brown (7.5YR 4/4) moist, light brown (7.5YR 6/4) dry; strong very fine subangular blocky structure; slightly hard, very friable, moderately sticky and moderately plastic; weakly smeary; few very fine and fine and medium roots; common very fine and fine and few medium tubular pores; very strongly acid (pH 5.0); abrupt wavy boundary
Bg1--52 to 70 cm; medial silty clay loam, brown (10YR 5/3) moist, very pale brown (10YR 7/4) dry; strong very fine subangular blocky structure; moderately hard, friable, very sticky and moderately plastic; weakly smeary; few very fine to medium roots; common very fine and fine and few medium tubular pores; 10 percent fine distinct iron depletions, gray (10YR 6/1) moist, lining pores and 10 percent very fine prominent masses of oxidized iron, strong brown (7.5YR 5/6) moist, lining pores; very strongly acid (pH 4.9); gradual wavy boundary
Bg2--70 to 97 cm; medial silty clay loam, brown (7.5YR 4/4) moist, light yellowish brown (10YR 6/4) dry; strong very fine subangular blocky structure; hard, firm, very sticky and moderately plastic; weakly smeary; few very fine roots; common very fine and few fine tubular pores; 15 percent fine prominent iron depletions, light brownish gray (10YR 6/2) moist, lining pores and 20 percent fine prominent masses of oxidized iron, strong brown (7.5YR 5/8) moist, throughout; very strongly acid (pH 4.8); clear wavy boundary
Bg3--97 to 150 cm; medial silty clay loam, strong brown (7.5YR 5/6) moist, brownish yellow (10YR 6/6) dry; moderate fine subangular blocky structure; hard, firm, very sticky and moderately plastic; weakly smeary; few very fine roots; common very fine and few fine tubular pores; 5 percent medium prominent manganese masses, black (10YR 2/1) moist, in matrix; 20 percent fine prominent light iron depletions, light brownish gray (10YR 6/2) moist, lining pores; and 20 percent fine distinct masses of oxidized iron, strong brown (7.5YR 5/8) moist, throughout; strongly acid (pH 5.2)
TYPE LOCATION: Grays Harbor County, Washington; 1 km east of U.S. Highway 101 between Hoquiam and Humptulips on Polson Camp Road; 495 m east and 270 m north of the southwest corner of section 36, T. 20 N., R. 10 W., Willamette Meridian; latitude 47.1719920 degrees north, longitude 123.8724800 degrees west, datum WGS 84 (coordinates determined with a GPS)
RANGE IN CHARACTERISTICS:
Mean annual soil temperature--9 to 12 degrees C
Umbric epipedon thickness--25 to 50 cm
Depth to aquic conditions--50 to 100 cm
Particle size-control section
Phosphate retention--85 percent or more
Ammonium oxalate extractable Al plus 1/2 Fe--2 percent or more
1/3-bar bulk density--0.70 to 0.90 g/cm3
Water content at 1500 kPa--less than 100 percent (medial)
A horizons
Hue--7.5YR, 10YR
Value--2 or 3 moist, 3 to 5 dry
Chroma--2 or 3
Fine-earth texture--silt loam, silty clay loam
Clay content--20 to 35 percent
Reaction (pH)--4.5 to 5.5
Combined thickness--25 to 50 cm
Bw horizon
Hue--7.5YR, 10YR
Value--3 or 4 moist, 6 or 7 dry
Chroma--3 or 4
Fine-earth texture--silt loam, silty clay loam
Clay content--20 to 40 percent
Reaction (pH)--4.5 to 5.5
Thickness--10 to 25 cm
Bg1 and Bg2 horizons
Hue--7.5YR, 10YR
Value--3 to 6 moist, 6 or 7 dry
Chroma--1 to 4
Fine-earth texture--silt loam, silty clay loam
Clay content--20 to 40 percent
Reaction (pH)--4.5 to 5.5
Thickness--30 to 90 cm
Bg3 horizon
Hue--7.5YR, 10YR, 2.5Y
Value--3 to 6 moist, 6 or 7 dry
Chroma--1 to 6
Fine-earth texture--silt loam, silty clay loam, silty clay
Clay content--20 to 50 percent
Reaction (pH)--4.5 to 5.5
Thickness--30 to 60 cm
2C horizon (where present)
Variegated colors
Fine-earth texture--stratified sand, loamy sand, silt loam, silty clay loam, silty clay
Clay content--0 to 40 percent
Rock fragment content--0 to 30 percent
COMPETING SERIES: None
GEOGRAPHIC SETTING:
Elevation--15 to 150 m
Mean annual precipitation--1800 to 3100 mm
Mean annual air temperature--9 to 11 degrees C
Frost-free period--200 to 240 days
GEOGRAPHICALLY ASSOCIATED SOILS:
Wishkah--aquic conditions within 25 to 50 cm of the soil surface; in drainageways and depressions of similar landforms
Lytell--paralithic contact within 100 cm of the soil surface; no aquic conditions; on adjacent hills
Hoquiam--cemented layers within 100 to 150 cm of the soil surface, no aquic conditions within 100 cm of the soil surface; on adjacent uplands
Grehalem--27 to 35 percent clay in the particle-size control section; no andic soil properties; on adjacent flood plains
Nemah--aquic conditions to the soil surface; in depressions on similar landforms
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class--moderately well drained
Depth to apparent seasonal water table--50 to 100 cm at times from November to March
Saturated hydraulic conductivity (Ksat)--moderately high or high in the A horizon, moderately low or moderately high in the B horizon
USE AND VEGETATION:
Use--forest production, wildlife habitat
Native vegetation--western hemlock, western red cedar, Sitka spruce, Douglas-fir, red alder, bigleaf maple, vine maple, red elderberry, salmonberry, salal, red huckleberry, western sword fern, Oregon oxalis
DISTRIBUTION AND EXTENT: Southwestern Washington; MLRA 4A; small extent
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Grays Harbor County, Washington; 1973
REMARKS:
Diagnostic horizons and other features in this pedon
*Particle-size control section--zone from 3 to 103 cm
*Umbric epipedon--zone from 3 to 37 cm
*Cambic horizon--zone from 3 to 150 cm
*Andic soil properties--zone from 3 to 150 cm
*Aquic conditions--zone from 55 to 150 cm
*Redoximorphic depletions with chroma 2 or less--zone from 55 to 150 cm
01/2017--This official series description was updated according to SSR01 Technical Note-Content and Format of Official Series Descriptions (revised 12/2015). Type location moved, and classification changed to isomesic Fulvudands based on an update project, and review of series distribution and extent. Further data collection is required to confirm soil temperature regime. The competing Arta soils should be included with future update work as their distribution and series concept overlap.
04/1994--Previously classified as medial, mesic, Andic Haplumbrepts. Classification change based on amendments to Soil Taxonomy establishing the Andisol soil order.
National Cooperative Soil Survey
U.S.A.