LOCATION BONJON WAEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, isotic, frigid Oxyaquic Glossudalfs
TYPICAL PEDON: Bonjon extremely gravelly sandy loam - forestland, on a 48 percent slope with a northeasterly aspect at an elevation of 2,980 feet in a western hemlock/Pacific rhododendron plant association. (When described on October 29, 1993, the soil was moist throughout. Colors are for moist soil unless otherwise stated.)
Oi--0 to 1 inch; slightly decomposed needles, leaves and twigs; abrupt smooth boundary. (1 to 2.5 inches thick)
E--1 to 9 inches; dark brown (10YR 4/3) extremely gravelly sandy loam, very pale brown (10YR 7/3) dry; weak very fine and fine granular and weak very fine subangular blocky structure; slightly hard, friable, nonsticky and nonplastic; many very fine and common fine, medium, and coarse roots; many very fine and fine irregular pores; 60 percent gravel, 10 percent cobbles; moderately acid (pH 6.0); clear smooth boundary. (5 to 10 inches thick)
B/E--9 to 15 inches; 80 percent dark yellowish brown (10YR 4/4) (B) and 20 percent dark brown (10YR 4/3) very pale brown (10YR 7/3) dry (E) extremely gravelly sandy loam; weak very fine subangular blocky and weak very fine granular structure; slightly hard, friable, nonsticky and nonplastic; many very fine and common fine, medium, and coarse roots; many very fine and fine irregular pores; 60 percent gravel, 5 percent cobbles; moderately acid (pH 5.8); clear smooth boundary. (5 to 10 inches thick)
Bt1--15 to 23 inches; dark yellowish brown (10YR 4/4) extremely gravelly sandy loam; weak very fine and fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine, fine, medium, and coarse roots; common very fine and fine irregular pores; few distinct clay films on faces of peds and lining pores; 55 percent gravel, 5 percent cobbles; moderately acid (pH 5.8); clear smooth boundary.
Bt2--23 to 33 inches; yellowish brown (10YR 5/4) extremely gravelly sandy loam, light yellowish brown (10YR 6/4) dry; weak very fine and fine subangular blocky structure; slightly hard, friable, slightly sticky and nonplastic; common very fine, fine, and medium and few coarse roots; common very fine and fine irregular pores; common faint clay films on faces of peds and lining pores; 60 percent gravel, 10 percent cobbles; moderately acid (pH 5.8); clear wavy boundary. (Combined thickness of the Bt horizon is 17 to 38 inches.)
BCt--33 to 46 inches; olive brown (2.5Y 4/3) extremely gravelly loamy sand, pale yellow (2.5Y 7/3) dry; massive; slightly hard, friable, nonsticky and nonplastic; common very fine, fine, medium and coarse roots; common very fine irregular pores; few faint clay films on faces of peds; few fine faint olive brown (2.5Y 4/3) moist and light gray (2.5Y 7/2) dry irregularly shaped iron depletions with clear boundaries in the matrix; 60 percent gravel, 15 percent cobbles; moderately acid (pH 5.8); abrupt wavy boundary. (12 to 15 inches thick)
Cdt--46 to 61 inches; olive brown (2.5Y 4/3) extremely gravelly loamy sand, light yellowish brown (2.5Y 6/3) dry; massive, hard, brittle, nonsticky and nonplastic; few very fine irregular pores; few distinct clay films on faces of peds; few fine distinct olive brown (2.5Y 4/3) moist and light gray (2.5Y 7/2) dry irregularly shaped iron depletions with clear boundaries in the matrix; few fine distinct strong brown (7.5YR 4/6) moist and reddish yellow (7.5YR 6/6) dry irregularly shaped masses of iron accumulation with clear boundaries in the matrix; 50 percent gravel, 20 percent cobbles; moderately acid (pH 5.8).
TYPE LOCATION: Clallam County, Washington, about 1 mile south of Three O'Clock Ridge, about 2,375 feet north and 135 feet west of the southeast corner of Section 24, T. 28 N., R. 4 W. (Latitude 47 degrees, 54 minutes, 12 seconds N., Longitude 123 degrees, 07 minutes, 09 seconds W.)
RANGE IN CHARACTERISTICS: Mean annual soil temperature is 44 to 47 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 densic material (dense till) is 40 to 60 inches. Depth to redox features is 30 to 45 inches. Depth to the argillic horizon is 10 to 20 inches. Base saturation by sum of bases is 50 to 90 percent throughout the profile. The particle-size control section has 13 to 20 percent clay. The particle-size control section has 40 to 80 percent rock fragments by volume.
The E horizon has hue of 10YR or 2.5Y moist and dry and value of 3 or 4 moist and 6 or 7 dry and chroma of 2 or 3 moist and dry.
The B/E horizon for the B portion has value of 3 or 4 moist 5 or 6 dry and chroma of 4 or 5 dry. The E portion has hue of 10YR or 2.5Y moist and dry, value of 3 or 4 moist, 6 or 7 dry and chroma of 2 or 3 moist and dry. It is extremely gravelly sandy loam, very gravelly loam, or very gravelly sandy loam. Texture of B and E material are the same.
The Bt horizon has hue of 10YR or 2.5Y moist and dry, value of 3 through 5 moist and 5 through 7 dry, and chroma of 3 through 6 moist and 3 through 5 dry. It is extremely gravelly sandy loam, very gravelly sandy loam, or very gravelly sandy clay loam.
The BCt horizon has value of 6 or 7 dry and chroma of 3 or 4 dry. It is extremely gravelly loamy sand, extremely gravelly sandy loam, or very gravelly sandy loam.
The Cdt horizon has value of 5 through 7 dry and chroma of 3 or 4 dry. It is extremely gravelly loamy sand, extremely gravelly sandy loam, or very gravelly sandy loam. Reaction is moderately or slightly acid. It has a moist bulk density of 1.50 to 2.00 g/cc.
COMPETING SERIES: This is the Graywolf series. Graywolf soils lack a densic contact.
GEOGRAPHIC SETTING: Bonjon soils are on glacial valleys. Slopes are 30 to 60 percent. The soils formed in colluvium and residuum from a mixture of alpine and continental till. Elevations are 2,100 to 3,100 feet. Average annual precipitation is 45 to 65 inches. Average annual temperature is 42 to 44 degrees F. The frost-free season is 150 to 170 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Graywolf, Juandefuca, Pennycreek, Slidecamp, Tunnelcreek, and Wellesley soils. Graywolf and Slidecamp soils are on low relief, dissected uplands and are very deep. Juandefuca, Pennycreek, and Tunnelcreek soils are on mountain slopes and are well drained. Wellesley soils are on glacial valleys and have a xeric moisture regime.
DRAINAGE AND PERMEABILITY: Moderately well drained; moderately rapid permeability through the solum. Bonjon soils have a perched zone of saturation above the densic layer at 2.5 and 4.0 feet from November through April.
USE AND VEGETATION: Timber production, wildlife habitat, recreation, and watershed. Native vegetation is western hemlock, Douglas-fir, western redcedar, Pacific rhododendron, Oregon-grape, and princes pine.
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
Albic horizon - 1 to 9 inches (E horizon)
Glossic horizon - 9 to 15 inches (B/E horizon)
Argillic horizon - 15 to 33 inches (Bt1 and Bt2 horizons)
Densic layer - 46 to 61 inches (Cd layer)
PSCS - 15 to 33 inches (Bt1 and Bt2 horizons)
All depths to diagnostic horizons and other features are measured from the top of the first mineral horizon.