LOCATION SKAMO WAEstablished Series
TAXONOMIC CLASS: Medial, mixed, mesic Aquic Hapludands
TYPICAL PEDON: Skamo silt loam, forested. (Colors are for moist soil unless otherwise noted.)
01--1 1/2 to 1/4 inch; needles, twigs, moss and mycelium.
02--1/4 inch to 0; black (10YR 2/1) decomposed remains of needles, leaves, twigs and moss.
A11--0 to 3 inches; very dark brown (10YR 2/2) silt loam, grayish brown (10YR 5/2) dry; moderate fine granular structure; hard, friable, slightly sticky, slightly plastic and weakly smeary; many fine and medium roots; common medium vesicular and interstitial pores; slightly acid (pH 6.4); clear smooth boundary. (1 to 3 inches thick)
A12--3 to 10 inches; very dark grayish brown (10YR 3/2) silt loam, grayish brown (10YR 5/2) dry; moderate fine subangular blocky structure; hard, friable, slightly sticky, slightly plastic and weakly smeary; many fine and medium roots; many fine and medium interstitial pores; slightly acid (pH 6.2); clear smooth boundary. (0 to 8 inches thick)
A3--10 to 19 inches; very dark yellowish brown (10YR 3/3) silty clay loam, brown (10YR 5/3) dry; moderate fine subangular blocky structure; very hard, firm, slightly sticky, slightly plastic and weakly smeary; common fine and medium roots; common fine and medium interstitial pores; medium acid (pH 5.8); clear smooth boundary. (7 to 10 inches thick)
B21--19 to 29 inches; dark yellowish brown (10YR 3/4) silty clay loam, brown (10YR 5/3) dry; common fine very dark grayish brown (10YR 3/2) stains on surfaces of peds; moderate fine subangular and angular blocky structure; very hard, friable, sticky and plastic; few fine roots; medium and fine tubular and interstitial pores; thin discontinuous clay films on faces of peds; very strongly acid (pH 5.0); clear wavy boundary. (6 to 16 inches thick)
B22--29 to 48 inches; dark brown (10YR 4/3) silty clay loam, brown (10YR 5/3) dry, many medium distinct grayish brown (2.5Y 5/2) mottles, few fine pale brown (10YR 6/3) mottles dry; moderate very fine subangular and angular blocky structure; very hard, friable, sticky and plastic; few fine roots; common fine and medium tubular pores; thin discontinuous clay films on faces of peds; very strongly acid (pH 4.8); clear wavy boundary. (12 to 24 inches thick)
C1--48 to 60 inches; dark brown (10YR 4/3) silty clay loam, brown (10YR 5/3) dry; common medium distinct dark reddish brown (2.5YR 3/4) and light olive brown (2.5YR 5/4) mottles, strong brown (7.5YR 5/8) dry; massive; very hard, friable, slightly sticky, slightly plastic and weakly smeary; few very fine roots; common fine and medium vertical tubular pores; strongly acid (pH 5.2). (8 to 18 inches thick)
IIC2--60 to 80 inches; stratified, discontinuous lenses of medium sand, loamy sand, silty clay loam and silty clay.
TYPE LOCATION: Grays Harbor County, Washington; 1 mile northwest of Cedarville on Langabeer Road; 100 feet south and adjacent to west side of private road entrance of Firdale farm; NW1/4 NW1/4 SW1/4 section 15, T.16N., R.5W.
RANGE IN CHARACTERISTICS: The solum is more than 40 inches thick. The umbric epipedon is 10 to 20 inches thick. The mean annual soil temperature ranges from 48 to 51 degrees F. The particle size control section is 35 to 45 percent apparent clay. Organic carbon is less than 4 percent in the upper 2/3 of the control section. Depth to mottles with chroma of 2 or less ranges from 24 to 40 inches.
The A horizon has hue of 10YR or 7.5YR, value of 2 or 3 moist, 4 or 5 dry, and chroma of 2 or 3. The A3 horizon is silt loam or silty clay loam. It has moderate granular or subangular blocky structure. It is medium acid or strongly acid.
The B2 horizon has hue of 7.5YR through 2.5Y, value of 3 or 4 moist, 5 through 7 dry, and chroma of 3 or 4. It is silty clay loam or silty clay. This horizon has moderate subangular blocky or angular blocky structure. It is strongly acid or very strongly acid.
The C horizon has hue of 10YR or 2.5Y, value of 3 through 5 moist, 5 through 7 dry, and chroma of 3 or 4. It is silt loam, silty clay loam or silty clay. It strongly acid or very strongly acid.
The IIC horizon is stratified layers and lenses of gravelly sand, loamy sand, silt loam, silty clay loam or silty clay. It is lacking in some pedons.
COMPETING SERIES: These are the Arta, Astoria, Boistfort, Bunker, Copalis, Elochoman, Hoquiam, Ilwaco, Kinney, Knappton, Lebam, Lytell, Makah, Mopang, Narel, Newskah, Oyhut, Palix, Papac, Silcox, Vesta, Wallville, Willapa, Zenker and Zyzyl series. Arta soils have 27 to 35 percent clay. Astoria and Boistfort soils lack mottles. Bunker soils have 20 to 35 percent clay, 15 to 35 percent basalt fragments and lack mottles. Copalis and Papac soils have a paralithic contact within a depth of 40 inches. Elochoman and Hoquiam soils have less than 35 percent clay and lack mottles. Ilwaco, Mopang and Newskah soils have less than 35 percent clay, have 4 to 7 percent organic carbon in the upper 2/3 of the control section and lack mottles. Kinney soils have 22 to 30 percent clay, 25 to 35 percent hard rock fragments and lack mottles. Knappton soils have 20 to 35 percent clay, 4 to 7 percent organic carbon in the upper 2/3 of the control section, 15 to 35 percent hard rock fragments and lack mottles. Lebam and Vista soils have 4 to 7 percent organic carbon in the upper 2/3 of the control section and lack mottles. Lytell, Zenker and Zyzyl soils have less than 35 percent clay, 35 to 80 percent soft rock fragments and lack mottles. Makah soils have less than 35 percent clay, have 4 to 7 percent organic carbon in the upper 2/3 of the control section, 15 to 30 percent hard rock fragments, 15 to 40 percent soft rock fragments and lack mottles. Narel and Palix soils have less than 35 percent clay, 4 to 7 percent organic carbon in the upper 2/3 of the control section, 20 or more percent soft rock fragments and lack mottles. Oyhut soils have less than 35 percent clay, 10 to 35 percent hard rock fragments and a petroferric contact at a depth of 24 to 40 inches. Silcox soils are sandy loam or fine sandy loam with 10 to 18 percent clay, have 10 to 35 percent hard rock fragments and lack mottles. Wallville soils have less than 35 percent clay, 35 to 60 percent soft breccia fragments and lack mottles. Willapa soils have less than 35 percent clay and have 4 to 7 percent organic carbon in the upper 2/3 of the control section.
GEOGRAPHIC SETTING: Skamo soils are on terraces and fans at elevations ranging from 50 to 300 feet. These soils formed in alluvium from adjacent uplands. Slopes are 0 to 15 percent. The annual precipitation is 50 to 90 inches with relatively cool summers and mild, wet winters. The mean annual temperature is 50 degrees F. and the frost free season is 160 to 190 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Centralia, Melbourne, Montesa, Wishkah and the competing Astoria and Lytell soils. Centralia and Melbourne soils lack an umbric epipedon. Also, Montesa soils are coarse, loamy and Wishkah soils are fine.
DRAINAGE AND PERMEABILITY: Moderately well drained; slow runoff; moderately slow permeability.
USE AND VEGETATION: Most of these soils are cleared and used for cropland or pasture. Grass hay is the principal crop. Native cover is mainly western hemlock, western red cedar, Douglas fir, red alder, bigleaf maple and and understory of vine maple, western brachenfern, western swordfern, salmonberry, salal and huckleberry.
DISTRIBUTION AND EXTENT: Southwestern Washington. The series is of small extent.
MLRA OFFICE RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Grays Harbor County, Washington, 1973.
REMARKS: Classification only changed 4/94 because of recent amendments to Soil Taxonomy.