LOCATION MCGRAVEY WAEstablished Series
TAXONOMIC CLASS: Medial-skeletal, ferrihydritic, frigid Alic Hapludands
TYPICAL PEDON: McGravey extremely gravelly medial loam - forestland, on a 72 percent northwest-facing slope at an elevation of 2,250 feet in a western hemlock/Pacific rhododendron-western swordfern plant association. (When described on June 25, 1990 the soil was moist throughout. Colors are for moist soil unless otherwise stated. All textures are apparent field textures.)
Oi--0 to 1 inch; slightly decomposed needles, leaves, twigs, and cones; abrupt smooth boundary. (1 to 4 inches thick)
A--1 to 6 inches; dark brown (7.5YR 4/4) extremely gravelly medial loam, yellowish brown (10YR 5/6) dry; weak very fine and fine granular and weak very fine subangular blocky structure; slightly hard, friable, nonsticky and nonplastic; weakly smeary; many very fine and common fine and medium roots; common very fine and fine tubular and irregular pores; 50 percent gravel, 15 percent cobbles; very strongly acid (pH 4.6); clear smooth boundary. (4 to 10 inches thick)
Bw1--6 to 16 inches; brown (7.5YR 4/4) extremely gravelly medial loam, yellowish brown (10YR 5/6) dry; weak very fine subangular blocky and weak very fine and fine granular structure; slightly hard, friable, nonsticky and nonplastic; weakly smeary; many very fine and common fine, medium, and coarse roots; common very fine and fine tubular and irregular pores; 50 percent gravel, 15 percent cobbles; very strongly acid (pH 4.6); clear wavy boundary.
Bw2--16 to 34 inches; brown (7.5YR 4/4) extremely gravelly medial sandy loam, strong brown (7.5YR 5/6) dry; weak very fine subangular and weak very fine and fine granular structure; slightly hard, friable, nonsticky and nonplastic; weakly smeary; many very fine and common fine, medium, and coarse roots; common very fine and fine irregular pores; 55 percent gravel, 20 percent cobbles; very strongly acid (pH 4.6); clear wavy boundary
Bw3--34 to 42 inches; dark yellowish brown (10YR 3/6) extremely gravelly medial sandy loam, brownish yellow (10YR 6/6) dry; weak very fine subangular blocky and weak very fine and fine granular structure; slightly hard, friable, nonsticky and nonplastic; weakly smeary; common very fine and fine and few medium and coarse roots; common very fine and fine irregular pores; 50 percent gravel, 15 percent cobbles, very strongly acid (pH 4.8); clear wavy boundary. (30 to 50 inches thick)
BC--42 to 62 inches; dark yellowish brown (10YR 4/6) extremely gravelly sandy loam, brownish yellow (10YR 6/6) dry; massive; soft, very friable, nonsticky and nonplastic; few very fine and fine roots; few very fine and fine irregular pores; 50 percent gravel, 15 percent cobbles; very strongly acid (pH 4.8).
TYPE LOCATION: Mason County, Washington; about 3.5 miles northeast of Brown Creek Campground, about 2,245 feet west and 1,980 feet south of the northeast corner of section 26, T. 23 N., R. 5 W. (Latitude 47 degrees, 27 minutes, 23 seconds N., Longitude 123 degrees 16 minutes, 44 seconds W.)
RANGE IN CHARACTERISTICS: Mean annual soil temperature 43 to 47 degrees F. These soils are usually moist in the soil moisture control section and are dry 0 to 30 consecutive days during summer; udic moisture regime. Depth to bedrock is 40 to over 60 inches. The particle-size control section has andic soil properties with an estimated moist bulk density of 0.50 to 0.90 g/cc., acid-oxalate extractable aluminum plus one-half of the acid-oxalate extractable iron of 2 to 4 percent, phosphate retention is 85 to 100 percent, 15-bar water retention of 15 to 30 percent for air dried samples, and 60 to 90 percent rock fragments by volume. Acid oxalate extractable iron is 1.5 to 3.0 percent. It has 2 to 5 cmol/kg of aluminum.
The A horizon has hue of 10YR or 7.5YR, value of 3 or 4 moist, and chroma of 2 through 4, or 6 moist and 4 or 6 dry. It has 5 to 15 percent organic matter.
The Bw horizon has hue of 10YR or 7.5YR, value of 3 or 4 moist and 5 or 6 dry, and chroma of 3, 4 or 6 moist and 4 or 6 dry. It is extremely gravelly medial sandy loam, extremely gravelly medial loam or extremely cobbly medial sandy loam. Reaction is strongly or very strongly acid. It has 1 to 7 percent organic matter.
The BC horizon lacks andic soil properties. It has a moist bulk density of 0.90 to 1.20 g/cc. It has less than 1 to 2 percent organic matter. It is strongly or very strongly acid.
COMPETING SERIES: This is the Sawpeak series. Sawpeak soils are 20 to 40 inches deep to bedrock.
GEOGRAPHIC SETTING: McGravey soils are on mid-slopes of mountains. Slopes are 60 to 90 percent. The soils formed in colluvium from marine basalt and associated volcanic rocks. Elevations are 1,650 to 2,700 feet. Average annual precipitation is 70 to 150 inches. Average annual temperature is 41 to 45 degrees F. Frost free season is 140 to 170 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Duckabush, Fricaba, Hammahamma, Hoodcanal, Sawpeak, Waketickeh, and Walkinshaw soils. Duckabush soils are on mountain slopes and are loamy-skeletal. Fricaba and Sawpeak soils are on mountain slopes and are moderately deep to bedrock. Hammahamma and Hoodcanal soils are on glaciated mountain slopes and glacial valleys are moderately deep to a cemented layer. Waketickeh soils are on mountain slopes and are very shallow and shallow to bedrock. Walkinshaw soils are on mountain slopes and are shallow to bedrock.
DRAINAGE AND PERMEABILITY: Well drained; moderately rapid permeability.
USE AND VEGETATION: Timber production, wildlife habitat, recreation, and watershed. Native vegetation is western hemlock, Douglas fir, western redcedar, Pacific rhododendron. western swordfern, red huckleberry, salal, and bunchberry dogwood.
DISTRIBUTION AND EXTENT: Mason and Jefferson Counties, Washington; MLRA 1. Series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Mason County, Washington, 2000; Olympic National Forest.
REMARKS: Diagnostic horizons and features recognized in this pedon are an ochric epipedon, a cambic horizon from 6 to 62 inches and andic soil properties from 1 to 42 inches. The particle-size control section is from 1 to 41 inches (A, Bw1, Bw2 and Bw3 horizons).
All depths to diagnostic horizons and other features are measured from the top of the first mineral horizon.