LOCATION PINHEAD OREstablished Series
TAXONOMIC CLASS: Medial-skeletal, amorphic Vitric Haplocryands
TYPICAL PEDON: Pinhead very gravelly sandy loam - on a nearly level slope, woodland. (Colors are for moist soil unless otherwise noted.)
0i--0 to 2 inches; organic layer of needles and twigs.
A--2 to 10 inches; dark brown (7.5YR 3/3) very gravelly ashy sandy loam, brown (10YR 4/3) dry; weak fine granular structure; soft, very friable, nonsticky and nonplastic; many very fine, fine and few medium and coarse roots; many very fine, fine and few medium and coarse irregular pores; 40 percent gravel and 5 percent cobbles; moderately acid (pH 5.6); clear smooth boundary.
AB-10 to 20 inches; dark brown (7.5YR 3/4) very gravelly ashy sandy loam, dark yellowish brown (10YR 4/4) dry; weak fine and medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; many very fine, fine and few medium roots; many very fine, fine and few medium tubular pores; 40 percent gravel and 10 percent cobbles; strongly acid (pH 5.5); clear smooth boundary. (Combined thickness of the a horizon is 10 to 20 inches)
Bw-20 to 32 inches; dark yellowish brown (10YR 4/4) extremely gravelly medial sandy loam, yellowish brown (10YR 5/4) dry; moderate fine and medium subangular blocky structure; slightly hard, friable, nonsticky and nonplastic; common very fine and fine roots; common very fine and fine tubular pores; 50 percent gravel and 20 percent cobbles; strongly acid (pH 5.5); clear wavy boundary.(10 to 16 inches thick)
BC1--32 to 40 inches; dark yellowish brown (10YR 3/4) extremely cobbly medial sandy loam, yellowish brown (10YR 5/4) dry; massive; hard, firm, nonsticky and nonplastic; few very fine and fine roots; few very fine and fine tubular pores; 40 percent gravel and 30 percent cobbles; moderately acid (pH 5.8); clear wavy boundary.(7 to 15 inches thick)
BC2--40 to 62 inches; dark yellowish brown (10YR 3/4) extremely cobbly medial sandy loam, light yellowish brown (10YR 6/4) dry; massive; hard, firm, nonsticky and nonplastic; 15 percent stones, 30 percent cobbles and 30 percent gravel; moderately acid (pH 5.6).
TYPE LOCATION: Wasco County, Oregon: 1500 feet south and 2500 feet east of the NW corner of section 14, T. 6 S., R. 9 E. (Warm Springs Indian Reservation) (Latitude 45 degrees, 03 minutes, 08 seconds N., Longitude 121 degrees, 37 minutes, 59 seconds E.).
RANGE IN CHARACTERISTICS: These soils are usually moist and are not dry in all parts of the soil moisture control section for as long as 45 consecutive days in the four months that follow the summer solstice. The mean annual soil temperature is 36 to 40 degrees F. Depth to andesite bedrock is greater than 60 inches. Hue is 10YR or 7.5YR. The particle-size control section has 45 to 80 percent rock fragments and 10 to 15 percent clay. Phosphate retention is more than 85 percent and acid oxalate aluminum plus 1/2 iron is between 2 and 5 percent in the less than 2.0 mm fraction. There is 25 to 40 percent volcanic glass and glass aggregate in the 0.02 to 2.0 mm fraction. The 15-bar water is 15 to 20 percent on air dried samples and less than 30 percent on undried samples. The moist bulk density is 0.80 to 0.90g/cc. It is moderately to strongly acid. Acid oxalate extractable silica is 0.7 to 2.0 percent throughout the zone having andic soil properties.
The A and AB horizon has value of 2 or 3 moist, 4 or 5 dry and chroma of 3 or 4 moist and dry. It is very gravelly ashy sandy loam, very stony ashy sandy loam, or very bouldery ashy sandy loam and has 5 to 55 percent gravel, 5 to 20 percent cobbles, 0 to 30 percent stones, and 0 to 30 percent boulders.
The Bw horizon has value of 3 or 4 moist, 5 or 6 dry and chroma of 3 or 4 moist and dry. Rock fragments range from 45 to 80 percent of which 30 to 50 percent are gravel and 15 to 30 percent are cobbles.
The BC horizon has value of 3 or 4 moist, 5 or 6 dry and chroma of 3 or 4 moist and dry. It is medial loamy sand or medial sandy loam. Rock fragments range from 60 to 85 percent of which 30 to 40 percent are gravel, 20 to 30 percent are cobbles and 10 to 15 percent are stones.
COMPETING SERIES: This is the Llaorock series. Llaorock soils have acid oxalate extractable silica of 1 to 3 percent in the surface and 3 to 5 percent throughout the subsoil.
GEOGRAPHIC SETTING: Pinhead soils are on nearly level to very steep side slopes of mountains. Elevations range from 3400 to 6400 feet. Slopes are 0 to 65 percent. The soil formed in colluvium and residuum derived dominantly from andesite with an influence of volcanic ash. The climate is characterized by cold and wet winters and cool and moist summers. The mean annual precipitation is 70 to 110 inches. The mean annual temperature is 34 to 38 degrees F. The frost-free period is 10 to 45 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Jojo and Piumpsha soils. Jojo soils are 20 to 40 inches to bedrock, have less than 15 percent 15-bar water (dry), and are on adjacent slopes. Piumpsha soils are medial, have an argillic horizon, and are in concave positions.
DRAINAGE AND PERMEABILITY: Somewhat excessively drained. Permeability is moderately rapid to rapid.
USE AND VEGETATION: These soils are used for timber production, watershed and wildlife habitat. The native vegetation is subalpine fir, western hemlock, silver fir, Douglas fir, noble fir, mountain hemlock, western white pine and lodgepole pine with an understory of common beargrass, big huckleberry, Pacific rhododendron, and grouse blueberry.
DISTRIBUTION AND EXTENT: North-central Oregon; MLRA 3. The soils of this series are of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Wasco County (Warm Springs Indian Reservation), Oregon, 1993.
REMARKS: Diagnostic horizons an features in this pedon include:
Ochric epipedon
Cambic horizon - from 20 to 32 inches (Bw horizon).
Andic soil properties - from mineral soil surface to 62 inches.
Particle-size control section - from mineral soil surface to 42 inches (A, AB, Bw, BC1, BC2 horizons).
Medial-skeletal family - from 16.1 to 18.7 percent 15-bar water on air-dry sample and 63 percent (calculated) rock fragments.
ADDITIONAL DATA: Pinhead reference sample # S90OR-065-003, pedon # 90P356, NSSL, NE, 6/90; partial laboratory sample.