LOCATION KELSO WAEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, mesic Ultic Palexeralfs
TYPICAL PEDON: Kelso silt loam--grass pasture on a 1 percent west-facing slope at an elevation of 200 feet. The soil was moist throughout when described. (Colors are for moist soil unless otherwise stated)
Ap--0 to 11 inches; very dark grayish brown (10YR 3/2) silt loam, grayish brown (10YR 5/2) dry; weak coarse subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common fine roots; common fine continuous tubular pores; strongly acid (pH 5.3); clear smooth boundary. (10 to 13 inches thick)
BA--11 to 18 inches; dark yellowish brown (10YR 4/4) silt loam, light yellowish brown (10YR 6/4) dry; weak coarse subangular blocky structure parting to weak fine subangular blocky; slightly hard, friable, slightly sticky and slightly plastic; common fine roots; common fine continuous tubular pores; moderately acid (pH 5.7); gradual smooth boundary. (7 to 10 inches thick)
Bt1--18 to 25 inches; dark yellowish brown (10YR 4/4) silty clay loam, light yellowish brown (10YR 6/4) dry; weak coarse prismatic structure parting to moderate fine angular blocky; hard, friable, sticky and plastic; few discontinuous distinct brown (7.5YR 4/4) coats on faces of peds; common fine roots; many fine continuous tubular pores; few fine faint pale brown (10YR 6/3) mottles along pores; strongly acid (pH 5.5); clear smooth boundary. (7 to 10 inches thick)
Bt2--25 to 34 inches; yellowish brown (10YR 5/4) silty clay loam, light yellowish brown (10YR 6/4) dry; many coarse prominent pale brown (10YR 6/3) mottles, very pale brown (10YR 7/3) dry; weak coarse prismatic structure parting to moderate fine angular blocky; slightly hard, friable, slightly sticky and slightly plastic; few patchy distinct manganese or iron manganese coats on faces of peds; few very fine roots between peds; many fine continuous tubular and few medium continuous tubular pores; strongly acid (pH 5.2); abrupt smooth boundary. (7 to 11 inches thick)
Bt/E--34 to 45 inches (B part 65 percent of horizon) yellowish brown (10YR 5/4) silty clay loam, very pale brown (10YR 7/4) dry; (E part 35 percent of horizon) grayish brown (2.5Y 5/2) silt loam, white (2.5Y 8/2) dry; many coarse prominent weak red (2.5YR 5/2) mottles; moderate fine angular blocky structure; hard, friable, sticky and plastic; few distinct dark brown (7.5YR 3/4) clay films on faces of peds; common fine continuous tubular pores; strongly acid (pH 5.2) clear smooth boundary. (10 to 15 inches thick)
Bt3--45 to 60 inches; dark yellowish brown (10YR 4/4) silt loam, light yellowish brown (10YR 6/4) dry; many coarse prominent pinkish gray (5YR 6/2) mottles; moderate medium angular blocky structure; hard, friable, sticky and plastic; very few patchy distinct very dark gray (5Y 3/1) manganese or iron-manganese coats on faces of peds; few fine and medium continuous tubular pores; clay films in pores; strongly acid (pH 5.2).
TYPE LOCATION: Cowlitz County, Washington. About 2 miles southwest of Castle Rock, 835 feet west and 300 feet south of the northeast corner of section 14, T. 9 N., R. 2 W.
RANGE IN CHARACTERISTICS: These soils are usually moist, but are dry in the moisture control section for 60 to 75 consecutive days following summer solstice. The average annual soil temperature at a depth of 20 inches ranges from 48 to 52 degrees F. Depth to the Bt/E horizon is more than 30 inches. Reaction is moderately acid or strongly acid throughout.
The A horizon has value of 2 or 3 moist, 4 or 5 dry, and chroma of 2 or 3 moist and dry.
The BA horizon has hue of 10YR, value of 3 or 4 moist, 4 through 6 dry, and chroma of 4 through 6 moist, 2 through 4 dry.
The Bt horizons have hue of 10YR, value of 4 or 5 moist and 6 dry, and chroma of 2 to 4 moist or dry and is distinctly or prominently mottled. It is silt loam or silty clay loam.
The Bt part of the Bt/E horizon has hues of 5YR through 10YR, value of 4 or 5 moist and 5 through 7 dry, and chroma of 4 through 6 moist or dry. Texture is silt loam or silty clay loam. The E part of the Bt/E horizon has hue of 2.5Y, value of 4 or 5 moist and 7 or 8 dry, and chroma of 2 moist or dry.
The lower part of the Bt3 horizon is stratified in some pedons ranging in texture from fine sandy loam to silty clay.
COMPETING SERIES: This is the Willakenzie series in other family. Willakenzie soils are 20 to 40 inches deep to a paralithic contact.
GEOGRAPHIC SETTING: Kelso soils developed in old alluvium from mixed sources on high stream terraces and terrace escarpments at elevations of 50 to 200 feet. The climate is characterized by warm, dry summers and cool, wet winters. The average January temperature is about 38 degrees F and in July it is 64 degrees F. The average annual air temperature is about 51 degrees F. The average annual precipitation is 40 to 60 inches. The growing season (28 degrees F) is 220 to 240 days. The frost free season (32 degrees F.) is 165 to 180 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Hazeldell, Kalama, and Olympic soils. Kalama soils are fine-loamy. Hazeldell and Olympic soils are well drained and are in a clayey family.
DRAINAGE AND PERMEABILITY: Moderately well drained; slow runoff; slow permeability. Depth to a perched seasonal high water table is 2 to 3 feet from December through March.
USE AND VEGETATION: Used for timber and cropland. Hay and pasture are the common crops. Some areas are used for homesites. Native vegetation is Douglas-fir, red alder, western redcedar, and bigleaf maple, with an understory of western brackenfern, western swordfern, salal, western hazel, red huckleberry, trailing blackberry, and red elderberry.
DISTRIBUTION AND EXTENT: Southwest Washington. Kelso series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Reconnaissance Survey of Southwestern Washington, 1911.
REMARKS: Diagnostic horizons and features recognized in this pedon are an umbric epipedon from the surface to 11 inches and an argillic horizon from 18 to 60 inches. Characterization data are available on this series, NSSL Pedon number S84WA-015-012.