LOCATION HIGHHORN OREstablished Series
TAXONOMIC CLASS: Loamy-skeletal, isotic, frigid Vitrandic Haploxerepts
TYPICAL PEDON: Highhorn very gravelly ashy silt loam - on a 43 percent convex south-facing slope; woodland. (Colors are for moist soils unless otherwise noted.)
0i--0 to 3 inches; partially decomposed pine needles, grass and twigs.
A1--3 to 7 inches; black (10YR 2/1) very gravelly ashy silt loam, dark grayish brown (10YR 4/2) dry; weak fine granular structure; soft, very friable, nonsticky, nonplastic, and moderately smeary; many very fine and fine roots; many very fine and fine irregular pores; 40 percent gravel; moderately acid (pH 6.0); clear smooth boundary.
A2--7 to 12 inches; very dark brown (10YR 2/2) very gravelly ashy silt loam, brown (10YR 4/3) dry; moderate fine and medium subangular blocky structure; soft, very friable, nonsticky, nonplastic and slightly smeary; common very fine and fine roots; common very fine and fine irregular pores; 35 percent gravel; moderately acid (pH 6.0); clear smooth boundary. (Combined thickness of the A horizon is 7 to 14 inches)
2BAb--12 to 19 inches; dark brown (10YR 3/3) very gravelly silty clay loam, yellowish brown (10YR 5/4) dry; moderate fine and medium subangular blocky structure; slightly hard, firm slightly sticky and slightly plastic; few fine and medium roots; few fine and medium continuous vertical tubular pores; 45 percent gravel; slightly acid (pH 6.2); clear smooth boundary. (6 to 9 inches thick)
2Bwb1--19 to 26 inches; brown (10YR 4/3) very gravelly silty clay loam, light yellowish brown (10YR 6/4) dry; strong fine and medium subangular blocky structure; slightly hard, firm, slightly sticky and slightly plastic; few fine and medium roots; few fine and medium continuous vertical tubular pores; 45 percent gravel; slightly acid (pH 6.2); clear smooth boundary.
2Bwb2--26 to 35 inches; dark yellowish brown (10YR 4/4) very gravelly silty clay loam, light yellowish brown (10YR 6/4) dry; strong medium and coarse subangular blocky structure parting to fine subangular blocky; hard, very firm, moderately sticky and moderately plastic; few and medium roots; few fine and medium continuous vertical tubular pores; few thin coatings on face of peds; 50 percent gravel; slightly acid (pH 6.4); clear wavy boundary.
2Bwb3--35 to 46 inches; yellowish brown (10YR 5/4) extremely gravelly silty clay loam, light yellowish brown (10YR 6/4) dry; strong medium and coarse subangular blocky structure; hard, firm slightly sticky and slightly plastic; 70 percent gravel; neutral (pH 6.6); abrupt smooth boundary. (Combined thickness of the 2Bwb horizon is 25 to 40 inches)
3R--46 inches; argillite.
TYPE LOCATION: Baker County, Oregon; 300 feet north of the center of sec. 35, T. 8 S., R. 38 E.
RANGE IN CHARACTERISTICS: These soils are usually moist but are dry in the moisture control section for 45 to 75 consecutive days following the summer solstice. The mean annual soil temperature is 43 to 47 degrees F. Depth to bedrock is 40 to 60 inches. Hues are 10YR or 7.5YR. Thickness of the ash mantle is 7 to 14 inches. The particle-size control section averages 27 to 35 percent clay and 35 to 75 percent rock fragments.
The A horizon has value of 2 or 3 moist, 4 or 5 dry and chroma of 1 through 3 moist and dry. It has 35 to 50 percent gravel and 0 to 10 percent cobbles. It contains 40 to 60 percent glass and glass-coated aggregate. Acid oxalate aluminum plus one-half the iron is 0.4 to 1.0 percent. It is slightly or moderately smeary. The moist bulk density is 0.85 to 0.95 grams per cubic centimeter.
The 2Bwb horizon has value of 4 or 5 moist, 5 or 6 dry and chroma of 3 or 4 moist and dry. It is very gravelly silty clay loam, very gravelly clay loam, extremely gravelly silty clay loam, or extremely gravelly clay loam. Field estimated clay is 27 to 35 percent. It has 35 to 70 percent gravel and 0 to 10 percent cobbles.
COMPETING SERIES: These are the Blinn, Brevco (T), Coxit (T), Huntrock, Jimbluff (T), Lekrem (T), Longort(T), Noil, Ontrail (T), Radercreek (T), Redpeak (T), Santop (T), Seeburg (T), and Thout series. Blinn, Brevco, Huntrock, Redpeak, Santop, and Thout soils are moderately deep to a lithic contact. Coxit, Jimbluff, Lekrem, Longort, Ontrail and Seeburg soils are very deep. Noil soils are moderately deep to a paralithic contact. Radercreek soils have less than 27 percent clay in the particle-size control section.
GEOGRAPHIC SETTING: Highhorn soils are on moderately steep to steep south-facing side slopes of mountains. Elevation is 3,800 to 7,200 feet. Slopes are 12 to 75 percent. The soil is formed in colluvium derived dominantly from argillite with an influence of volcanic ash in the surface. The climate is characterized by cold wet winters and hot dry summers. The mean annual precipitation is 20 to 30 inches. The mean annual temperature is 40 to 45 degrees F. The frost-free period is 45 to 90 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Crackler, Rouen, Stices and competing Huntrock series. Crackler, Rouen and Stices have a volcanic ash mantle over 14 inches thick and are on north slopes. Rouen soils are 20 to 40 inches to bedrock.
DRAINAGE AND PERMEABILITY: Well drained. Permeability is moderate in the surface horizons and moderately slow in the subsoil.
USE AND VEGETATION: These soils are used for timber production, watershed and wildlife habitat. The native vegetation is ponderosa pine, Douglas fir and grand fir with an understory of pinegrass and elk sedge.
DISTRIBUTION AND EXTENT: The Blue Mountains of Northeastern Oregon; MLRA 43. The soils are of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Baker County Area, Oregon, 1988.
REMARKS: Diagnostic horizons and features in this pedon are:
Ochric epipedon - the zone from 3 to 12 inches (A1, A2 horizons).
Vitrandic feature - from 3 to 12 (A1, A2 horizons).
Cambic horizon - the zone from 19 to 46 inches (2Bwb1, 2Bwb2, 2Bwb3).
Diagnostic horizons and features measured from the top of the first mineral layer.
Classification revisions 3/01 from Vitrandic Xerochrepts to Vitrandic Haploxerepts based on 8th edition of Keys to Soil Taxonomy.
Classification revisions 5/03 from mixed, superactive mineralogy and CEC activity class to isotic mineralogy.