LOCATION LEDOW WAEstablished Series
TAXONOMIC CLASS: Sandy, mixed, mesic Mollic Xerofluvents
TYPICAL PEDON: Ledow sand, brush and trees. (Colors are for moist soil unless otherwise stated.)
O--2 inches to 0; leaves and twigs.
A1--0 to 8 inches; very dark gray (10YR 3/1) sand, dark grayish brown (10YR 4/2) dry; single grained; loose; common roots; 10 percent sand-size volcanic ash; neutral (pH 6.8); gradual smooth boundary. (6 to 10 inches thick)
C1--8 to 20 inches; very dark grayish brown (10YR 3/2) fine sand, grayish brown (10YR 5/2) dry; single grained; loose; common roots; 10 percent sand size volcanic ash; neutral (pH 6.6); abrupt wavy boundary. (11 to 13 inches thick)
IIC2--20 to 24 inches; dark brown (10YR 3/3) silt loam, yellowish brown (10YR 5/4) dry; weak medium subangular blocky structure that parts to moderate very fine and fine subangular blocky; slightly hard, very friable, nonsticky and nonplastic; many roots; common very fine tubular pores; slightly acid (pH 6.4); abrupt wavy boundary. (1 to 5 inches thick)
IIIC3--24 to 60 inches; very dark gray (10YR 3/1) fine sand, dark grayish brown (10YR 4/2) dry; single grained; loose; neutral (pH 6.6).
TYPE LOCATION: Lewis County, Washington; 875 feet south of the north 1/4 corner sec. 17, T.11N., R.1W.
RANGE IN CHARACTERISTICS: The mean annual soil temperature at a depth of 20 inches ranges from 47 degrees to 53 degrees F. Rock fragments are less than 10 percent. These soils are usually moist but they are dry in all parts between depths of 12 and 35 inches for 60 to 75 consecutive days in moist years. The soil ranges from neutral to slightly acid. Sand-size volcanic ash ranges from 0 to 15 percent. These soils are dark colored because of the dark colored sand grains.
The A horizon has value of 2 or 3 moist, 4 or 5 dry, and chroma of 1 or 2 moist or dry. This horizon is single grained or has weak subangular blocky structure.
The C horizon has value of 2 or 3 moist, 4 or 5 dry, and chroma of 1 through 3 moist and 2 through 4 dry. It is commonly sand or fine sand with layers of silt loam or fine sandy loam that range in thickness from 1 to 5 inches.
COMPETING SERIES: These are the Avawatz series in the same family and the Greenwater and Pilchuck series. Avawatz soils have a mean annual soil temperature of about 57 degrees F., are dry for more than 90 consecutive days following summer solstice and have colors with a value of 4 moist and 6 dry in the C horizon. Greenwater and Pilchuck soils are not stratified and have a regular decrease in organic matter.
GEOGRAPHIC SETTING: Ledow soils are on flood plains. Elevations range from 75 to 1,200 feet. Slopes are 0 to 3 percent. The soils formed in mixed alluvium dominantly from andesite and basalt with lesser amounts of volcanic ash and pumice. The soils are in a cool and humid climate with annual precipitation ranging from 50 to 80 inches. Mean January temperature is about 35 degrees F.; the mean July temperature is about 64 degrees F.; the mean annual temperature is about 50 degrees F.; and the frost-free season is 125 to 200 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cloquato, Newberg, Puyallup, Schooley, and Siler soils and the competing Greenwater soils. Cloquato, Newberg, Puyallup, and Siler soils have a mollic epipedon. Schooley soils are coarse-loamy and have an aquic moisture regime.
DRAINAGE AND PERMEABILITY: Somewhat excessively drained; slow runoff; moderate permeability. These soils are subject to frequent, brief flooding during the winter and early spring.
USE AND VEGETATION: Most areas are used for cropland. Hay, grass pasture, and small grains are the principal crops. Native vegetation is alder, cottonwood, and Douglas-fir with an understory of vine maple, salmonberry, western swordfern, trailing blackberry, and Oregon-grape.
DISTRIBUTION AND EXTENT: Southwestern Washington. Series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Lewis County, Washington, 1976.