LOCATION SPEELYAI WAEstablished Series
TAXONOMIC CLASS: Mixed, mesic, shallow Typic Xeropsamments
TYPICAL PEDON: Speelyai gravelly loamy sand--woodland. (Colors are for moist soil unless otherwise stated.)
A1--0 to 2 inches; very dark gray (10YR 3/1) gravelly loamy sand, dark gray (10YR 4/1) dry; single grain; loose, nonsticky and nonplastic; many fine and medium roots; many fine and very fine pores; 15 percent pebbles; neutral (pH 6.6); abrupt smooth boundary.
A2--2 to 5 inches; dark gray (10YR 4/1) gravelly loamy sand, light brownish gray (10YR 6/2) dry; single grain; loose, nonsticky and nonplastic; many fine and medium roots; many fine pores; 25 percent pebbles; very strongly acid (pH 5.0); clear smooth boundary. (Combined thickness of the A horizon is 4 to 6 inches)
C--5 to 11 inches; gray (10YR 5/1) gravelly sand, light gray (10YR 6/1) dry; single grain; loose, nonsticky and nonplastic; common fine roots; many fine pores; 30 percent pebbles; moderately acid (pH 5.6); clear smooth boundary. (6 to 8 inches thick)
Cqm--11 to 60 inches; gray (N5/) weakly cemented very gravelly sand, light gray (N7/) dry; massive; extremely hard, extremely firm, nonsticky and nonplastic; common fine roots in the upper 3 inches, few fine roots to 30 inches, none below; few fine pores; moderately acid (pH 5.6).
TYPE LOCATION: Cowlitz County, Washington; 150 feet northeast of South Toutle Road in a cutbank on the right side of the entrance to large gravel pit. About 0.2 miles southeast of Toutle; 2,100 feet west and 2,000 feet north of the southeast corner, sec. 30, T.10 N.,R. 1 E.
RANGE IN CHARACTERISTICS: These soils are usually moist but are dry in the moisture control section for 45 to 60 consecutive days following summer solstice. The average annual soil temperature ranges from 49 to 53 degrees F. Depth to weakly cemented lahar ranges from 10 to 20 inches. The soil is 10 to 25 percent volcanic ash and 15 to 35 percent rock fragments in the particle-size control section. Soil reaction ranges from neutral to very strongly acid throughout.
The A horizon has value of 3 or 4 moist, 4 to 6 dry, and chroma from 1 to 3 moist and dry.
The C and Cqm horizons have value of 4 or 5 moist, 5 to 8 dry, and chroma of 0 to 2 moist and dry. They are 15 to 35 percent pebbles and 5 to 25 percent volcanic ash.
COMPETING SERIES: This is the Pacifico series. Pacifico soils are 5 to 15 percent granitic rock fragments and lack volcanic ash in the particle-size control section.
GEOGRAPHIC SETTING: Speelyai soils occupy dissected lahar terraces at elevations of 400 to 600 feet. They formed in aerially deposited volcanic ash and lahar of sand, gravel, and volcanic ash overlying weakly cemented very gravelly lahar. Slopes are 0 to 60 percent. The climate is marine and is characterized by warm, dry summers and cool, moist winters. The average annual precipitation is 55 to 70 inches, which falls mostly as rainfall during the winter. The average annual air temperature is about 50 degrees F. The growing season (28 degrees F) is 200 to 240 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Greenwater, Natal, Sara, Seaquest, and Solo series. Natal soils are fine and poorly drained. Sara, Seaquest, and Viola have an argillic horizon. In addition, Sara and Seaquest soils are fine. Solo soils are more than 20 inches deep to cemented lahar. Greenwater soils are deep sand.
DRAINAGE AND PERMEABILITY: Moderately well drained. Runoff is very slow to very rapid. Permeability is very rapid above the cemented substratum and slow in the substratum. A perched water table is as high as 6 to 18 inches at times from November to April.
USE AND VEGETATION: Used mainly for timber production. Some areas have been cleared and used for hay, pasture, and rural homesites. Native vegetation consists of Douglas-fir, western hemlock, bigleaf maple, and red alder with an understory of western brackenfern, cascade Oregon-grape, salal, western hazel, and trailing blackberry.
DISTRIBUTION AND EXTENT: Cowlitz County, Washington. The series is small in extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Cowlitz County, Washington, 1967.
REMARKS: Diagnostic horizons and features recognized in this pedon are: a ochric epipedon from the mineral surface to 5 inches, a particle-size control section from the mineral surface to 11 inches that averages 23 percent rock fragments, and contact with weakly cemented lahar at 11 inches.