LOCATION WAKAMO OREstablished Series
TAXONOMIC CLASS: Clayey-skeletal, smectitic, mesic Lithic Ultic Argixerolls
TYPICAL PEDON: Wakamo very gravelly loam - on a 25 percent southwest facing slope, woodland. ( Colors are for moist soils unless otherwise noted.)
Oi-- 1 to 0 inches; organic layer of needles and twigs.
A1-- 0 to 3 inches; very dark grayish brown (10YR 3/2) very gravelly loam, light brownish gray (10YR 5/2) dry; weak fine granular structure; soft, very friable, nonsticky and nonplastic; many very fine and fine roots; many very fine and fine irregular pores; 45 percent gravel; neutral (pH 6.8); clear smooth boundary. (3 to 6 inches thick)
A2-- 3 to 11 inches; dark brown (10YR 3/3) very gravelly loam, pale brown (10YR 5/3) dry; moderate fine and medium subangular blocky structure; slightly hard, friable, nonsticky and nonplastic; common very fine and fine roots, few medium; common very fine and fine tubular pores, few medium; 50 percent gravel; neutral (pH 6.6); clear smooth boundary. (3 to 8 inches thick)
Bt1-- 11 to 15 inches; dark brown (10YR 3/3) extremely gravelly clay loam, brown (10YR 5/3) dry; moderate fine and medium subangular blocky structure; hard, firm,slightly sticky and slightly plastic; few fine and medium roots; few fine and medium tubular pores; few distinct clay films on face of peds and in pores; 60 percent gravel; neutral (pH 6.6); clear smooth boundary. (2 to 4 inches thick)
Bt2-- 15 to 18 inches; dark brown (10YR 3/3) extremely gravelly clay, brown (10YR 5/3) dry; strong fine and medium subangular blocky structure; hard, firm, sticky and plastic; few fine and medium roots; few fine and medium tubular pores; many distinct clay films on face of peds and in pores; 70 percent gravel; slightly acid (pH 6.4); abrupt smooth boundary. (2 to 4 inches thick)
R-- 18 inches; fractured sedimentary bedrock.
TYPE LOCATION: Wasco County, Oregon; 3000 feet east and 800 feet south of the NW corner of section 14, T.7 S., R.13 E. ( Warm Springs Indian Reservation).
RANGE OF CHARACTERISTICS: These soils are usually moist but are dry in the moisture control section for 60 to 90 consecutive days following the summer solstice. The mean annual soil temperature is 47 to 51 degrees F. Depth to bedrock is 10 to 20 inches. The particle-size control section is 35 to 50 percent clay and 60 to 70 percent rock fragments. The mollic epipedon is 10 to 20 inches thick and may include all or part of the argillic horizon. Base saturation is assumed to be 50 to 70 percent.
The A horizon has a value of 2 or 3 moist, 4 or 5 dry and chroma of 2 or 3 moist and dry. It contains 35 to 55 percent gravel. The upper part of the A horizon has 5 to 20 percent volcanic glass and 0.4 to 1.0 percent acid oxalate extractable aluminum plus one-half iron.
The Bt horizon has value of 3 or 4 moist, 4 or 5 dry and chroma of 3 or 4 moist and dry. It is clay loam or clay. It has 35 to 50 percent clay and 60 to 70 percent gravel.
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: Wakamo soils are on gently sloping to moderately steep south-facing side slopes of uplands. Elevations range from 2600 to 4000 feet. Slopes are 2 to 30 percent. The soil formed in residuum and colluvium derived dominantly from sedimentary rock with an influence of volcanic ash. The mean annual precipitation is 16 to 20 inches, the mean annual temperature is 45 to 49 degrees F. and the frost-free period is 90 to 120 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Fawnspring, Littlefawn, Mowako, Mutton, and Peahke soils. Fawnspring soils are fine, montmorillonitic and deep to bedrock and on north-facing side slopes. Littlefawn soils are ashy over clayey, moderately deep to bedrock, and on north-facing side slopes. Mowako soils are loamy-skeletal, moderately deep to bedrock, and on adjacent south-facing side slopes. Mutton soils are ashy-skeletal, deep to bedrock, and on north-facing side slopes. Peahke soils are loamy-skeletal, moderately deep to bedrock, and are on south-facing side slopes at higher elevations.
DRAINAGE AND PERMEABILITY: Well drained. Permeability is moderate in the surface horizons and slow in the subsoil.
USE AND VEGETATION: These soils are used for timber production, livestock grazing, watershed, and wildlife habitat. The native vegetation is Douglas fir and ponderosa pine with an understory of antelope bitterbrush, common snowberry, heartleaf arnica, and Oregon white oak.
DISTRIBUTION AND EXTENT: Mutton Mountains of North-central Oregon; MLRA 6. The soils of this series are not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Wasco County (Warm Springs Indian Reservation), Oregon, 1993.
REMARKS: Diagnostic horizons and features in this pedon include:
Mollic epipedon - the zone from the surface of the soil to a depth of approximately 18 inches (A1, A2, Bt1, Bt2 horizons).
Argillic horizon - The zone from 11 to 18 inches (Bt1,Bt2 horizons)
Particle-size control section - from 11 to 18 inches (Bt1 and Bt2 horizons)