LOCATION PERSIS WAEstablished Series
TAXONOMIC CLASS: Medial over sandy or sandy-skeletal, amorphic over isotic, mesic Andic Haplohumods
TYPICAL PEDON: Persis sandy loam--on a 5 percent south facing slope under coniferous forest at 1,520 feet elevation. (Colors are for moist soil unless otherwise stated. All textures are apparent field textures. When described the soil was moist throughout).
Oi--3 1/2 to 1/2 inches; mosses, needles, partially decomposed wood fragments. (1 to 5 inches thick)
Oa--1/2 inch to 0; decomposed forest litter (1/2 to 7 inches thick)
E--0 to 1 1/2 inches; brown (7.5YR 4/2) sandy loam, pinkish gray (7.5YR 6/2) dry; moderate fine and very fine subangular blocky structure; soft, very friable, slightly sticky, slightly plastic; weakly smeary; common very fine, fine, and medium roots; many very fine tubular pores; 2 percent rounded pebbles; NaF pH 9.2; extremely acid (pH 4.2); abrupt smooth boundary. (0 to 5 inches thick)
Bhs--1 1/2 to 4 inches; dark reddish brown (5YR 3/2) sandy loam, reddish brown (5YR 4/3) dry; moderate fine subangular blocky structure; slightly hard friable, slightly sticky, slightly plastic; weakly smeary; common very fine and fine roots, few medium roots; many very fine tubular pores; 2 percent rounded pebbles; NaF pH 11.5; extremely acid (pH 4.4); clear irregular boundary. (2 to 7 inches thick)
Bs1--4 to 13 inches; dark reddish brown (5YR 3/4) loam, brown (7.5YR 5/4) dry; weak fine and medium subangular blocky structure; slightly hard, friable, slightly sticky, slightly plastic, weakly smeary; few very fine and fine roots; common very fine tubular pores; 2 percent rounded pebbles; NaF pH 12.0+; strongly acid (pH 5.4); clear wavy boundary (0 to 9 inches thick)
Bs2--13 to 15 inches; dark brown (7.5YR 4/4) loam, light brown (7.5YR 6/4) dry; weak fine and medium subangular blocky structure; soft, friable, slightly sticky, slightly plastic; weakly smeary; few very fine and fine roots; common very fine tubular pores; 5 percent rounded pebbles; NaF pH 12.0+; strongly acid (pH 5.4); clear wavy boundary.
Bs3--15 to 29 inches; strong brown (7.5YR 4/6) loam, reddish yellow (7.4YR 6/6) dry; weak fine and medium subangular blocky structure; soft, friable, slightly sticky, slightly plastic; weakly smeary; few very fine roots; common very fine tubular pores; 5 percent rounded pebbles; NaF pH 12.0+; moderately acid (pH 5.6); clear wavy boundary. (Combined thickness of the Bs horizon is 15 to 30 inches.)
2C--29 to 60 inches; grayish brown (2.5Y 5/2) sand, light brownish gray (2.5Y 7/2) dry; massive; slightly hard, firm, nonsticky, nonplastic; weakly compact in place; common very fine interstitial pores; 5 percent rounded pebbles; NaF pH 11.5; moderately acid (pH 5.8)
TYPE LOCATION: Snoqualmie Pass Area, King County, Washington; along a spur road of the Weyerhaeuser Company 30 Road; 600 feet east, 1,400 feet south of the northwest corner, sec. 16, T. 25 N., R. 9 E.
RANGE IN CHARACTERISTICS: Depth to the 2C horizon ranges from 20 to 37 inches. Mean annual soil temperature is estimated to range from 47 to 49 degrees F. Rock fragments average from 0 to 15 percent by volume in the upper part of the control section and from 0 to 25 percent in the lower part.
The E horizon has hue of 7.5YR or 10YR moist or dry, value of 4 or 5 moist, 6 or 7 dry, and chroma of 1 or 2 moist or dry.
The Bhs and Bsl horizons have hue of 2.5YR or 5YR moist, 5YR or 7.5YR dry, value of 3 or 4 moist, 4 or 5 dry, and chroma of 2 through 4 moist or dry. Texture is fine sandy loam or loam. Reaction is extremely acid or very strongly acid in the Bhs horizon, and very strongly acid or strongly acid in the Bsl horizon.
The Bs2 and Bs3 horizons have hue of 5YR or 7.5YR moist, 7.5YR or 10YR dry, value of 4 or 5 moist, 6 or 7 dry, and chroma of 4 through 6 moist or dry. Texture is fine sandy loam or loam. Reaction is strongly acid or moderately acid.
Some pedons have a loamy sand 2Bs horizon with hues of 7.5YR moist, 10YR dry, value of 5 moist, 6 dry, and chroma of 6 moist or dry.
The 2C horizon has hue of 10YR or 2.5Y, value of 4 or 5 moist, 6 or 7 dry, and chroma of 2 or 3 moist or dry. Texture is loamy sand, sand, gravelly loamy sand or gravelly sand. Rock fragments range from 0 to 25 percent by volume.
COMPETING SERIES: These are the Klaus, Lynnwood, and Solduc soils in other families. Klaus and lynnwood soils have less than 6 percent organic carbon in the upper 10 cm of the spodic horizon. In addition, Klaus soils are sandy-skeletal and Lynnwood soils are sandy throughout. Solduc soils are skeletal.
GEOGRAPHIC SETTING: Persis soils are on stream terraces above the normal flood plain. These soils are confined to the major stream valleys on the west slope of the northcentral Cascade Mountains. Persis soils formed in volcanic ash and alluvium overlying sandy deltaic deposits associated with proglacial lakes. Slopes are 0 to 8 percent. Elevations range from 1,000 to 1,600 feet. The climate is marine influenced, with relatively cool, dry summers and cool, wet winters. Average annual precipitation ranges from 80 to 120 inches, which occurs mainly as rainfall between October and March. The mean January temperature is about 31 degrees F, mean July temperature is about 62 degrees F, and the mean annual temperature is about 47 degrees F. The growing season (28 degrees F) is 169 to 180 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Marblemount, Philippa, Rober, Snoqualmie, Teneriffe, and the competing Klaus soils. All these soils except Klaus and Snoqualmie soils are frigid. Marblemount are 20 to 40 inches to a paralithic contact consisting of dense glacial till. Rober soils are coarse-silty and are frigid. Snoqualmie soils lack a spodic horizon and are sandy-skeletal.
DRAINAGE AND PERMEABILITY: Well drained; slow ro very slow runoff; moderate permeability in the solum, rapid permeability in the substratum.
USE AND VEGETATION: Timber production, watershed and wildlife habitat are the principal uses. native overstory vegetation is Douglas-fir, western hemlock, western redcedar and red alder. Understory vegetation includes salal, western swordfern, red huckleberry, bunchberry dogwood, and vine maple.
DISTRIBUTION AND EXTENT: Major stream valleys on the wet slopes of the Cascade Mountains in northwestern Washington. Series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Snoqualmie Pass Area, King County, Washington, 1986.
REMARKS: Partial data is available on one pedon. Laboratory numbers 80T7404-7405. Diagnostic horizons and features recognized in this pedon are an albic horizon from the mineral surface to 2 inches, a spodic horizon from 2 to 29 inches, and a lithologic change form coarse-loamy to sandy material at 29 inches. The spodic horizon is assumed to have more than 6 percent organic carbon in the upper 4 inches (Bhs horizon).