LOCATION SPANAWAY                WA

Established Series
Rev ASZ/RJE
05/2012

SPANAWAY SERIES

The Spanaway series consists of very deep, somewhat excessively drained soils that formed in glacial outwash. They are on terraces and plains. Slopes are 0 to 15 percent. The mean annual precipitation is about 1,270 millimeters. The mean annual temperature is about 10 degrees C.

TAXONOMIC CLASS: Sandy-skeletal, isotic, mesic Typic Humixerepts

TYPICAL PEDON: Spanaway gravelly sandy loam - fern-grass prairie. (Colors are for moist soil unless otherwise stated.)

Oa--0 to 3 centimeters; black (10YR 2/1) highly decomposed plant material, very dark brown (10YR 2/2) dry; mostly from grass roots and moss. (0 to 4 centimeters thick)

A--3 to 38 centimeters; black (10YR 2/1) gravelly sandy loam, very dark grayish brown (10YR 3/2) dry; weak fine granular structure; soft, very friable, nonsticky and nonplastic; many fine roots; very high in organic matter content, has mellow, sooty feel; 34 percent gravel; strongly acid (pH 5.4); clear smooth boundary. (25 to 50 centimeters thick)

Bw--38 to 48 centimeters; dark grayish brown (10YR 4/2) very gravelly sandy loam, grayish brown (10YR 5/2) dry; weak fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; common fine roots; 45 percent gravel, 10 percent cobbles; moderately acid (pH 5.8); clear smooth boundary. (8 to 20 centimeters thick)

2C--48 to 150 centimeters; light brownish gray (10YR 6/2) dry; extremely gravelly sand; single grained; loose; few fine roots; 60 percent gravel, 10 percent cobbles; slightly acid (pH 6.1).

TYPE LOCATION: Pierce County, Washington; 1.6 kilometers south of Spanaway, east of Pacific Avenue in the SE1/4 SW1/4 section. 33, T. 19 N., R. 3 E.

RANGE IN CHARACTERISTICS: Solum thickness is 35 to 70 centimeters. The mean annual soil temperature is 9 to 12 degrees C. These soils are usually moist but are dry in the moisture control section for 75 to 90 consecutive days following summer solstice. The umbric epipedon is 25 to 50 centimeters thick. Rock fragments are 35 to 85 percent, with 35 to 60 percent gravel, 0 to 60 percent cobbles and 0 to 5 percent stones

The A horizon has hue of 10YR through 5YR, value of 2 to 4 dry, and chroma of 1 or 2 moist and dry. It has weak granular or blocky structure and is moderately acid or strongly acid.

The Bw horizon has value of 4 or 5 dry and 3 or 4 moist. It is very gravelly sandy loam, very gravelly loam or extremely gravelly sandy loam. It has weak fine or medium blocky structure and is strongly acid to slightly acid.

The 2C horizon has hue of 7.5YR to 2.5Y, value of 5 or 6 dry and 4 or 5 moist and chroma of 2 through 4 dry or moist. It is extremely gravelly sand or extremely gravelly loamy sand with or without thin layers of sandy loam. It is massive or single grained and is slightly acid or neutral.

COMPETING SERIES: There are no competing series.

GEOGRAPHIC SETTING: Spanaway soils are on glacial outwash terraces and plains at elevations of about 30 to 150 meters. Slopes are 0 to 15 percent. These soils formed in glacial outwash. These soils are in a maritime climate with cool, dry summers and mild, wet winters. The mean annual precipitation is 890 to 1650 millimeters. The mean annual temperature is about 10.5 degrees C. The frost-free season is 150 to 200 days

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Nisqually and Spana soils. Nisqually soils are sandy. Spana soils are loamy-skeletal and have an umbric epipedon more than 50 centimeters thick.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Somewhat excessively drained; slow runoff; high saturated hydraulic conductivity.

USE AND VEGETATION: Used for woodland, pasture, cropland, homesites and wildlife habitat. Native vegetation is Douglas-fir, Oregon white oak, shore pine, and red alder with an understory of salal, western brackenfern, western swordfern, scotchbroom, common snowberry, red huckleberry, Oregon-grape, rose, creambush oceanspray, Indian plum, Solomons-seal and Idaho fescue.

DISTRIBUTION AND EXTENT: Southwestern Washington; MLRA 2. Series is of moderate extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon

SERIES ESTABLISHED: Pierce County, Eastern Puget Sound Basin Reconnaissance, Washington, 1909.

REMARKS: Diagnostic horizons and other features;
Umbric epipedon from 3 to 38 centimeters
Some pedons have a cambic horizon
In 2012 the series was reclassified from medial-skeletal over sandy or sandy-skeletal, amorphic over isotic, mesic Typic Melanoxerands; due to the lack of andic soil properites.

ADDITIONAL DATA: Partial laboratory data pedon 72WA041013.

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National Cooperative Soil Survey
U.S.A.