LOCATION BONIDU WAEstablished Series
TAXONOMIC CLASS: Medial-skeletal, ferrihydritic, isomesic Aquic Udivitrands
TYPICAL PEDON: Bonidu very gravelly medial silt loam-forestland, on a 35 percent northerly aspect at an elevation of 1,040 feet in a western hemlock/swordfern-foamflower plant association. (When described on March 29, 1994, the soil was moist throughout. Colors are for moist soil unless otherwise stated. All textures are apparent field textures.)
Oi--0 to 2 inches; slightly decomposed needles, leaves, and twigs; abrupt smooth boundary. (1 to 4 inches thick)
A1--2 to 6 inches; dark brown (10YR 3/3) very gravelly medial silt loam, light yellowish brown (10YR 6/4) dry; weak very fine, fine, and medium subangular blocky and weak very fine and fine granular structure; slightly hard, friable, nonsticky and nonplastic; weakly smeary; many very fine and fine and common fine, medium, and coarse roots; many very fine and fine tubular and irregular pores; 30 percent gravel, 5 percent cobbles; moderately acid (pH 5.6); clear smooth boundary.
A2--6 to 14 inches; dark brown (10YR 3/3) very gravelly medial silt loam, light yellowish brown (10YR 6/4) dry; weak very fine, fine, and medium subangular blocky and weak very fine and fine granular structure; slightly hard, friable, slightly sticky and slightly plastic; weakly smeary; common very fine, fine, medium, and coarse roots; common very fine and fine tubular and irregular pores; 30 percent gravel, 5 percent cobbles; moderately acid (pH 5.8); clear smooth boundary. (Combined thickness of the A horizon is 5 to 12 inches thick.)
Bw1--14 to 24 inches; dark yellowish brown (10YR 3/4) very gravelly medial silt loam, very pale brown (10YR 7/4) dry; weak very fine, fine, and medium subangular blocky and weak very fine and fine granular structure; slightly hard, friable, slightly sticky and slightly plastic; weakly smeary; common very fine, fine, medium, and coarse roots; common very fine and fine tubular and irregular pores; 25 percent gravel, 15 percent cobbles; moderately acid (pH 5.8); clear wavy boundary.
Bw2--24 to 33 inches; dark yellowish brown (10YR 3/4) very gravelly medial silt loam, very pale brown (10YR 7/4) dry; weak very fine, fine, and medium subangular blocky and weak very fine and fine granular structure; slightly hard, friable, slightly sticky and slightly plastic; weakly smeary; common very fine, fine, and medium and few coarse roots; common very fine and fine tubular and irregular pores; 30 percent gravel, 15 percent cobbles; moderately acid (pH 5.6); clear wavy boundary. (Combined thickness of the Bw horizon is 20 to 30 inches)
BC--33 to 43 inches; olive brown (2.5Y 4/4) very cobbly silt loam, pale yellow (2.5Y 7/4) dry; weak very fine, fine, and medium subangular blocky and weak very fine and fine granular structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine and fine and few medium and coarse roots; common very fine and fine tubular and irregular pores; few fine distinct light olive brown (2.5Y 5/3) iron depletions on ped faces; 20 percent gravel, 25 percent cobbles; moderately acid (pH 5.6); abrupt wavy boundary. (7 to 18 inches thick)
Cd--43 to 62 inches; olive brown (2.5Y 4/4) very gravelly sandy loam, pale yellow (2.5Y 7/4) dry; massive; hard, brittle, nonsticky and nonplastic; few very fine irregular pores; few fine distinct light olive brown (2.5Y 5/3) iron depletions on ped faces and few fine distinct strong brown (7.5YR 5/6) masses of iron accumulation on ped faces; 30 percent gravel, 10 percent cobbles; moderately acid (pH 5.6).
TYPE LOCATION: Clallam County, Washington, about 6 miles south of Pillar Point, about 350 feet west and 1,145 feet south of the northeast corner of Section 3, T. 30 N., R. 11 W. (Latitude 48 degrees, 07 minutes, 47 seconds N., Longitude 124 degrees, 05 minutes, 35 seconds W.)
RANGE IN CHARACTERISTICS: Mean annual soil temperature is 47 to 50 degrees F. The difference between the mean summer and mean winter soil temperature is 5 to 9 degrees F. These soils are usually moist, and are dry 30 to 45 consecutive days in the soil moisture control section; udic moisture regime. Depth to dense till is 40 to 60 inches. Depth to redox features is 25 to 35 inches. The particle-size control section has andic soil properties with a cumulative thickness of 25 to 35 inches and 35 to 60 percent rock fragments by volume. The andic soil material has an estimated moist bulk density of 0.70 to 0.90 g/cc, acid-oxalate extractable aluminum plus one half of the acid-oxalate extractable iron of 2 to 3 percent, phosphate retention of 85 to 100 percent, 15-bar water retention of 12 to 15 percent for air dried samples and 20 to 30 percent for moist samples. Acid oxalate extractable iron is 1.5 to 3.0 percent.
The A horizon has hue of 10YR or 7.5YR moist and dry and chroma of 3 or 4 moist. Reaction is strongly or moderately acid. It has 5 to 10 percent organic matter.
The Bw horizon has hue of 10YR or 2.5Y moist and dry and value of 3 or 4 moist and 6 or 7 dry. It is very gravelly medial silt loam, very cobbly medial silt loam, or very gravelly medial loam. It has 1 to 7 percent organic matter.
The BC horizon has hue of 2.5Y or 10YR moist and dry and value of 6 or 7 dry. It is very cobbly silt loam, very gravelly loam, or very gravelly sandy loam. Reaction is moderately or slightly acid.
The Cd horizon has hue of 2.5Y or 5Y moist and dry and chroma of 3 or 4 moist. It is very gravelly sandy loam or very gravelly loam. Reaction is moderately or slightly acid. The moist bulk density is 1.50 to 2.00 g/cc.
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: Bonidu soils are on ground moraines and glaciated mountain slopes. Slopes are 15 to 50 percent. The soils formed in continental glacial till. Elevations are 400 to 1,200 feet. Average annual precipitation is 75 to 130 inches. Average annual temperature is 46 to 48 degrees F. The frost-free season is 140 to 160 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Kickinghorse, Klahowya, and Ovington soils. Kickinghorse and Ovington soils are on glaciated mountain slopes are well drained and underlain by bedrock. Klahowya soils are on ground moraines and are medial.
DRAINAGE AND PERMEABILITY: Moderately well drained; moderate over slow permeability. Bonidu soils have a perched zone of saturation above the dense till from November through April.
USE AND VEGETATION: Timber production, wildlife habitat, recreation, and watershed. Native vegetation is western hemlock, western redcedar, Sitka spruce, western swordfern, threeleaf foamflower, deer fern, red huckleberry, Alaska huckleberry, devilsclub, and salmonberry.
DISTRIBUTION AND EXTENT: Clallam County, Washington; MLRA 1. Series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Clallam County, Washington, 2000; Olympic National Forest.
REMARKS: Diagnostic horizons and features recognized in this pedon are the following:
Ochric epipedon
Cambic horizon - 14 to 43 inches
Andic soil properties - 2 to 33 inches (A1, A2, Bw1, and Bw2 subhorizons)
Densic layer - 43 to 62 inches
PSCS - zone from 2 to 42 inches (from 2 to 33 inches is medial-skeletal and ferrihydritic and from 33 to 42 inches is loamy-skeletal and isotic). The thicknest part is medial-skeletal.
All depths to diagnostic horizons and other features are measured from the top of the first mineral horizon.