LOCATION NEMAH WAEstablished Series
TAXONOMIC CLASS: Fine, isotic, acid, isomesic Vertic Endoaquepts
TYPICAL PEDON: Nemah silty clay loam - forested. (Colors are for moist soil unless otherwise noted. All textures are apparent field textures. Soil was wet when described.)
0l--4 to 2 inches; sphagnum moss, leaves, twigs, and stems.
02--2 inches to 0; black (5YR 2/l) decomposed organic materials; many roots. (l to 4 inches thick)
All--0 to 5 inches; black (5YR 2/l) silty clay loam, very dark gray (N 3/) dry; weak fine subangular blocky structure; hard, friable, sticky and plastic; many medium and fine roots; very porous; about 20 percent organic matter; very strongly acid (pH 4.6); clear smooth boundary. (4 to 5 inches thick)
Al2--5 to 8 inches; very dark brown (l0YR 2/2) silty clay, dark gray (l0YR 4/l); common medium faint grayish brown (2.5Y 5/2) and yellowish red (5YR 5/8) mottles; very hard, firm, very sticky and very plastic; common medium and fine roots; many fine tubular and interstitial pores; about l0 percent organic matter; very strongly acid (pH 4.6); clear wavy boundary. (0 to 4 inches thick)
B2lg--8 to l3 inches; dark grayish brown (l0YR 4/2) clay, light gray (2.5Y 7/2) dry; common coarse distinct grayish brown (2.5Y 5/2) and strong brown (7.5YR 5/8) mottles; moderate medium prismatic structure; extremely hard, firm, very sticky and very plastic; few fine roots; many fine tubular and interstitial pores; very dark grayish brown (l0YR 3/2) coatings on some faces of peds; very strongly acid (pH 4.8); gradual wavy boundary. (5 to l0 inches thick)
B22g--l3 to 26 inches; gray (N 6/) clay, light gray (2.5Y 7/2) dry; common coarse distinct strong brown (7.5YR 5/8) mottles; moderate medium prismatic structure; extremely hard, firm, very sticky, and plastic; few fine roots along prism faces; many fine tubular and interstitial pores; very dark grayish brown (l0YR 3/2) coating on some faces of peds; very strongly acid (pH 4.8); gradual wavy boundary. (l0 to l5 inches thick)
B23g--26 to 36 inches; gray (N 6/) clay, light gray (2.5Y 7/2) common coarse distinct strong brown (7.5YR 5/8) mottles; weak medium prismatic structure; extremely hard, firm, very sticky and very plastic; few fine roots along prism faces; many fine tubular and interstitial pores; extremely acid (pH 4.3); gradual wavy boundary. (l0 to l6 inches thick)
IICg--36 to 60 inches; gray (N 6/) very gravelly clay, light gray (2.5YR 7/2) common coarse distinct strong brown (7.5YR 5/8) mottles; massive; extremely hard, firm, very sticky and very plastic; 40 percent water worn pebbles; very strongly acid.
TYPE LOCATION: Grays Harbor County, Washington; ll miles north of Montesano on the Wynoochee Valley road; l00 feet east of road, mile south of Upper School House logging road; northeast corner of NW1/4,NW1/4 sec. 23, T. l9 N., R. 8 W.
RANGE IN CHARACTERISTICS: The soils are saturated most of the year unless artificially drained. Depth to IICg horizon ranges from 30 to 40 inches. Rooting depth is normally limited to less than 20 inches by the high water table. The soils are very strongly acid or extremely acid throughout. The particle-size control section is dominantly clay, and averages 5 to 25 percent coarse fragments.
The A horizon has hue of 5YR through neutral, value of 2 or 3 moist, 3 or 4 dry, and chroma of 0 through 2 moist and dry. It has no to many distinct mottles.
The B2g horizon has hue of l0YR to neutral, value of 4 through 7 moist and dry, and chroma of 0 through 2 moist and dry. It is clay or silty clay and ranges from 45 to 60 percent clay. This horizon has weak or moderate prismatic structure.
The IICg horizon has hue of l0YR to neutral, value of 4 through 7 moist and dry and chroma of 0 through 2 moist and dry. It is clay, silty clay, or silty clay loam. It has 30 to 60 percent clay and l5 to 50 percent coarse fragments.
COMPETING SERIES: This is the Sekiu series. Sekiu soils lack coarse fragments in the particle-size control section.
GEOGRAPHIC SETTING: The Nemah soils are on depressed positions on glaciofluvial, marine and river terraces at elevations of 20 to 4000 feet. These soils formed in alluvium derived from mixed sediments. Nemah soils occur in a coastal marine climate with relatively cool summers and mild wet winters. The average annual precipitation is 70 to l00 inches. Average January temperature is 39 degrees F., average July temperature is 62 degrees F., mean annual temperature is 50 degrees F., and the growing season (28 degrees F.) is 200 to 240 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Copalis, Hoquiam, and Willapa soils. These soils lack an aquic moisture regime and are well to moderately well drained.
DRAINAGE AND PERMEABILITY: Poorly drained; slow runoff or ponded, very slow permeability.
USE AND VEGETATION: Most areas have red alder, Sitka spruce, western hemlock, western redcedar with an understory of sedges, grass, rushes, skunk cabbage, and willow. Small areas have been drained and used for improved pasture and hay.
DISTRIBUTION AND EXTENT: Coastal areas of Western Washington. Series is moderate extent.
MLRA OFFICE RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Grays Harbor County (Grays Harbor County Area), Washington, l970.
REMARKS: Classification only changed 4/94 because of recent amendments to Soil Taxonomy.