LOCATION MATTERHORN OREstablished Series
TAXONOMIC CLASS: Sandy-skeletal, mixed, frigid Typic Calcixerolls
TYPICAL PEDON: Matterhorn gravelly fine sandy loam, forested. (Colors are for moist soil unless otherwise noted.)
Ak1--0 to 3 inches; very dark gray (10YR 3/1) gravelly fine sandy loam, dark gray (10YR 4/1) dry; weak fine granular structure; slightly hard, very friable, nonsticky and nonplastic; common fine, medium and few coarse roots; many very fine irregular pores; 15 percent gravel and 5 percent cobbles; slightly effervescent; moderately alkaline (pH 8.0); clear wavy boundary. (2 to 6 inches thick)
Ak2--3 to 10 inches; very dark grayish brown (10YR 3/2) cobbly sandy loam, dark gray (10YR 4/1) dry; weak fine and medium subangular blocky structure; slightly hard, very friable, nonsticky and nonplastic; common fine, medium, and few coarse roots; many very fine irregular pores; 10 percent gravel and 10 percent cobbles; strongly effervescent; moderately alkaline (pH 8.0); abrupt wavy boundary. (3 to 10 inches thick)
Bk1--10 to 27 inches; dark grayish brown (10YR 4/2) and grayish brown (10YR 5/2) extremely cobbly loamy sand, grayish brown (10YR 5/2) and light brownish gray (10YR 6/2) dry; single grain; loose, nonsticky and nonplastic; common fine, medium, and few coarse roots; many very fine and fine irregular pores; calcium carbonate pendants on undersides of rock fragments; 40 percent cobbles and 30 percent gravel; strongly effervescent; moderately alkaline (pH 8.2); gradual wavy boundary. (5 to 20 inches thick)
Bk2--27 to 46 inches; multicolored extremely cobbly sand; single grain; loose, nonsticky and nonplastic; few coarse roots to about 40 inches; calcium carbonate pendants on undersides of rock fragments; 40 percent cobbles, 25 percent gravel, and 10 percent stones; strongly effervescent; moderately alkaline (pH 8.2); gradual wavy boundary. (15 to 25 inches thick)
Bk3--46 to 63 inches; multicolored extremely gravelly sand; single grain; loose, nonsticky and nonplastic; 50 percent gravel and 20 percent cobbles; slightly effervescent; moderately alkaline (pH 8.0).
TYPE LOCATION: Wallowa County, Oregon; about 1 mile west of Joseph, Oregon; 1,200 feet north and 500 feet west of the SE corner of section 25, T. 2 S., R. 44 E.
RANGE IN CHARACTERISTICS: These soils are usually moist, but are dry in all parts of the moisture control section for 60 to 90 consecutive days during the summer. The mean annual soil temperature is 44 to 47 degrees F. The depth to bedrock is greater than 60 inches. The thickness of the mollic epipedon is 10 to 15 inches and may include part of the Bk1 horizon. The depth to the calcic horizon is 10 to 15 inches. The particle-size control section averages less than 5 percent clay and more than 65 percent rock fragments.
The Ak horizons have value of 2 or 3 moist, 4 or 5 dry and chroma of 1 or 2 moist and dry and has 5 to 10 percent clay. The Ak1 horizon has 10 to 20 percent gravel and 0 to 5 percent cobbles. The Ak2 horizon is cobbly sandy loam or gravelly sandy loam with 10 to 20 percent gravel and 5 to 15 percent cobbles. The calcium carbonate equivalent is 5 to 10 percent in the Ak horizons. It is slightly or moderately alkaline.
The Bk1 horizon has value of 3 to 5 moist, 4 to 6 dry and chroma of 2 or 3 moist and dry. The Bk2 and Bk3 horizons are multicolored. The texture is loamy sand or sand with 20 to 50 percent cobbles, 15 to 50 percent gravel, and 0 to 10 percent stones. The calcium carbonate equivalent is 15 to 20 percent in the Bk1 and Bk2 horizons and 5 to 10 percent in the Bk3 horizon.
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: The Matterhorn soils are on stream terraces. They formed in alluvium and glacial outwash. Slope is 0 to 3 percent. Elevation is 3800 to 4500 feet. The mean annual precipitation is 13 to 17 inches. The climate is characterized by cold wet winters and hot dry summers. The mean annual temperature is 42 to 45 degrees F., and the mean frost-free period is 70 to 100 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cheval, Eggleson, and Redmount soils. The Cheval soils are somewhat poorly drained and are on adjacent flood plains. The Eggleson soils are moderately well drained and are on adjacent flood plains. The Redmount soils are deep, coarse-loamy soils on adjacent outwash plains.
DRAINAGE AND PERMEABILITY: Somewhat excessively drained; slow runoff; moderately rapid permeability.
USE AND VEGETATION: These soils are used for timber production, and homesites. Native vegetation is mainly ponderosa pine, Douglas fir, and Rocky mountain juniper with an understory of pinegrass, bluebunch wheatgrass, Idaho fescue, and common snowberry.
DISTRIBUTION AND EXTENT: Northeastern Oregon; MLRA 9. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Wallowa County Area, Oregon, 1998.
REMARKS: Diagnostic horizons and features in this pedon are:
Mollic epipedon - from the surface to 10 inches (Ak1 and Ak2 horizons).
Calcic feature - 10 to 46 inches (Bk1 and Bk2 horizons) with secondary calcium carbonate accumulation and more than 15 percent calcium carbonate equivalent.
Particle-size control section - 10 to 40 inches average 70 percent rock fragments and 5 percent clay.