LOCATION ALNULT WAEstablished Series
TAXONOMIC CLASS: Medial-skeletal, amorphic Spodic Haplocryands
TYPICAL PEDON: Alnult very stony medial fine sandy loam - on a south facing 72 percent slope at 4,200 feet elevation, with forb and brush vegetation. (Colors are for dry soil unless otherwise stated.)
A--0 to 6 inches; dark gray (10YR 4/1) very stony medial fine sandy loam, black (10YR 2/1) moist, weak fine crumb structure; soft, very friable, nonsticky and nonplastic; many fine and medium roots; common fine tubular and interstitial pores; 10 percent pebbles, 15 percent cobbles and 30 percent stone with 10 percent surface stones and boulders; moderately acid (pH 6.0); gradual smooth boundary. (5 to 7 inches thick)
Bhs--6 to 14 inches; dark reddish brown (5YR 3/4) very stony medial fine sandy loam, dark reddish brown (5YR 2/2) moist; weak fine subangular blocky structure; slightly hard, friable, nonsticky and nonplastic; many fine and medium roots; few fine tubular and interstitial pores; 10 percent pebbles, 15 percent cobbles and 30 percent stones; slightly acid (pH 6.2); gradual wavy boundary. (6 to 12 inches thick)
Bhs2--14 to 32 inches; dark reddish brown (5YR 3/4) very stony medial fine sandy loam, dark reddish brown (5YR 2/2) moist; weak medium subangular blocky structure; slightly hard, friable, nonsticky and nonplastic; common fine and medium roots; few fine tubular and interstitial pores; 15 percent cobbles and 30 percent stones; slightly acid (pH 6.2); gradual wavy boundary. (10 to 20 inches thick)
Bs--32 to 50 inches; brown (7.5YR 5/4) very gravelly medial fine sandy loam, dark brown (7.5YR 3/2) moist; weak medium subangular blocky structure; slightly hard, friable, nonsticky and nonplastic; few fine and medium roots; few fine tubular and interstitial pores; 20 percent pebbles, 15 percent cobbles and 10 percent stones; slightly acid (pH 6.2). (10 to 20 inches thick)
C--50 to 60 inches; reddish brown (5YR 4/4) extremely gravelly medial fine sandy loam, dark reddish brown (5YR 3/2) moist; massive; slightly hard, friable, nonsticky and nonplastic; few fine roots; few fine tubular pores; 65 percent pebbles, 10 percent cobbles and 5 percent stones; slightly acid (pH 6.2).
TYPE LOCATION: Chelan County, Washington; about 5 miles north of Stevens Pass; 1,650 feet south and 2,000 feet west of northeast corner of sec. 29, T. 26 N., R. 20 E.
RANGE IN CHARACTERISTICS: The mean soil temperature is 40 to 42 degrees F. The 0 to 40 inch particle-size control section has an estimated moist bulk density of 1.20 to 1.50 g/cc, volcanic glass content of 5 to 30 percent, acid-oxalate extractable aluminum plus one-half of the acid-oxalate extractable iron of more than 2.0 percent, 15-bar water retention of more than 12.0 percent for air dried samples and averages 40 to 80 percent coarse fragments. The solum is 30 to 55 inches thick.
The A horizon has hue of 10YR or 7.5YR, value of 4 or 5 dry, 2 or 3 moist, and chroma of 1 or 2 dry or moist. It is moderately or slightly acid. Structure is weak fine crumb or weak medium granular.
The Bhs horizon has hue of 5YR or 7.5YR, value of 3 through 5 dry, 2 or 3 moist, and chroma of 2 through 4 dry or moist. Texture is very stony medial fine sandy loam or very stony medial sandy loam. It is moderately acid or slightly acid. Structure is medium or fine weak fine subangular blocky or moderate fine subangular blocky.
The Bs horizon has hue of 5YR or 7.5YR, value of 4 through 6 dry, 3 or 4 moist, and chroma of 2 through 6 dry or moist. It is extremely gravelly medial fine sandy loam or extremely gravelly medial loam. It is moderately or slightly acid. Structure is weak or moderate subangular blocky.
The C horizon has hue of 5YR or 7.5YR, value of 4 or 5 dry, and chroma of 4 to 6 dry and 2 to 4 moist. Texture is extremely gravelly medial fine sandy loam or extremely gravelly medial loam. It is moderately or slightly acid.
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: Alnult soils are on mountainsides usually with a south exposure and formed in colluvium and residuum from granitic rocks mixed with volcanic ash. Elevations are 3,500 to 5,000 feet. Slopes are 30 to 90 percent. The soil is in a climate with warm, dry summers and cold, moist winters. The average annual precipitation is 70 to 85 inches. The mean January temperature is about 21 degrees F, mean July temperature is about 57 degrees F, and the mean annual air temperature is 39 to 41 degrees F. The growing season at 28 degrees F is 100 to 130 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Altapeak, Isella, Nimue, and Reggad soils. Altapeak soils are sandy-skeletal. Isella soils are medial. Nimue soils have more than 6 percent organic carbon in less than 30 cm. Reggad soils are fragmental.
DRAINAGE AND PERMEABILITY: Well drained, slow to rapid runoff, moderate permeability.
USE AND VEGETATION: Wildlife, watershed, and recreation. The native vegetation is western brackenfern, trillium, fireweed, pachystima, huckleberry, alder, willow, Rocky mountain maple and scattered conifer trees.
DISTRIBUTION AND EXTENT: North-central Washington. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Chelan County, Washington, 1995.
REMARKS: Diagnostic horizons and features recognized in this soil are an ochric epipedon from the mineral surface to 6 inches and a spodic horizon from 6 to 32 inches that has an assumed ratio of free iron to organic carbon of less than 0.2 in the upper 12 inches and more than 6 percent organic carbon throughout. This soil previously was called Altapeak Variant. This draft reflects a change in classification due to the Andisols order from loamy-skeletal, mixed Typic Cryohumods to medial-skeletal, Spodic Haplocryands.