LOCATION SPANA WAEstablished Series
TAXONOMIC CLASS: Medial-skeletal over sandy or sandy-skeletal, amorphic over isotic, mesic Pachic Melanoxerands
TYPICAL PEDON: Spana loam - grass (Colors are for moist soil unless otherwise noted.)
A--0 to 24 inches; very dark brown (l0YR 2/2) loam, dark grayish brown (l0YR 4/2) dry; weak fine granular structure; soft, very friable, slightly sticky, slightly plastic; many very fine roots; l5 percent pebbles; moderately acid; abrupt smooth boundary. (ll to 28 inches thick)
Bw--24 to 29 inches; very dark grayish brown (l0YR 3/2) gravelly loam, grayish brown (l0YR 5/2) dry; moderate medium subangular blocky structure; hard, firm, sticky, plastic; few very fine roots; 20 percent pebbles and 5 percent cobbles; moderately acid; clear smooth boundary. (3 to 17 inches thick)
2Cl--29 to 36 inches; dark grayish brown (l0YR 4/2) extremely gravelly coarse sandy loam, light brownish gray (l0YR 6/2) dry; massive; soft, very friable, nonsticky, nonplastic; few fine roots; 60 percent pebbles, l0 percent cobbles; moderately acid; clear smooth boundary. (7 to l5 inches thick)
2C2--36 to 60 inches; dark grayish brown (l0YR 4/2) extremely gravelly loamy sand, light brownish gray (l0YR 6/2) dry; massive; loose; 60 percent pebbles and l0 percent cobbles; moderately acid.
TYPE LOCATION: Pierce County, Washington; l,500 feet west and 2,800 feet north of the southeast corner of sec. 27, T. l8 N., R. 3 E.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 24 to 40 inches. The particle-size control section average 35 to 50 percent coarse fragments and 5 to l8 percent clay. Mean annual soil temperature ranges from 49 to 54 degrees F. These soils are usually moist but are dry in the moisture control section for 45 to 60 days following summer solstice. The melanic epipedon (also umbric) is 20 to 35 inches thick.
The A horizon has value of 2 to 4 dry, and chroma of l or 2 moist or dry. The lower part of the A horizon in some pedons is loam or sandy loam and has l0 to 30 percent coarse fragments.
The B horizon has value of 3 to 5 moist. It has 5 to l5 percent clay and has 20 to 45 percent coarse fragments. It contains faint or distinct yellowish or strong brown mottles in some pedons.
The 2C horizon is extremely gravelly coarse sandy loam, extremely gravelly loamy sand or very gravelly sandy loam.
COMPETING SERIES: These are the Fiddletown, and Wyeth series. Fiddletown soils are less than 40 inches deep to weathered schist. Wyeth soils average l8 to 27 percent clay and are loam throughout the particle-size control section.
GEOGRAPHIC SETTING: Spana soils are in slightly concave depressions or troughs or nearly level glacial outwash terraces at elevations of about l00 to 500 feet. Slopes are 0 to 3 percent. These soils formed in glacial outwash. They occur in a maritime climate with cool dry summers and mild wet winters. The mean annual precipitation ranges from 25 to 45 inches. The mean annual temperature is about 51 degrees F., and the mean annual growing season is about l65 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Nisqually and Spanaway soils. Nisqually soils are sandy. Spanaway soils are sandy-skeletal.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained; very slow runoff, moderate permeability.
USE AND VEGETATION: Most areas are in pasture or used for wildlife habitat. Native vegetation is Douglas-fir, western redcedar, red alder, bigleaf maple and a few Oregon white oak and cottonwood with an understory of grass, western brackenfern, Salal, Oregon-grape and black hawthorne.
DISTRIBUTION AND EXTENT: Western Washington. Series is of small extent.
MLRA OFFICE RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Pierce County, Washington, l974.