LOCATION SPILYAY OREstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Ultic Palexerolls
TYPICAL PEDON: Spilyay very cobbly loam - on an 18 percent slope at an elevation of 2400 feet, woodland. (Colors are for moist soil unless otherwise noted.)
Oi--1 inch to 0; organic layer of needles and twigs.
A--0 to 8 inches; very dark grayish brown (10YR 3/2) very cobbly loam, grayish brown (10YR 5/2) dry; moderate medium granular structure parting to moderate very fine subangular blocky; soft, friable, nonsticky and nonplastic; common very fine, fine, medium and coarse roots; many very fine, fine, medium and coarse irregular pores; 25 percent cobbles and 20 percent gravel; neutral (pH 6.8); abrupt smooth boundary. (7 to 10 inches thick)
2Bt1--8 to 15 inches; dark brown (10YR 3/3) clay loam, brown (10YR 5/3) dry; strong medium subangular blocky structure; hard, firm, sticky and plastic; common very fine, fine, medium and coarse roots; common very fine, fine, medium and coarse tubular pores; common distinct clay films on faces of peds and lining pores; 10 percent gravel; neutral (pH 6.8); clear smooth boundary.
2Bt2--15 to 21 inches; brown (10YR 4/3) clay, yellowish brown (10YR 5/4) dry; strong medium prismatic structure parting to moderate coarse subangular blocky; very hard, very firm, sticky and plastic; common very fine, fine, and few medium and coarse roots; common very fine and fine tubular pores; many prominent clay films on faces of peds and lining pores; neutral (pH 6.8); clear smooth boundary.
2Bt3--21 to 32 inches; dark yellowish brown (10YR 4/4) clay, light yellowish brown (10YR 6/4) dry; strong medium subangular blocky structure; very hard, very firm, sticky and plastic; common very fine, fine and few medium and coarse roots; common very fine and fine tubular pores; many prominent clay films on faces of peds and lining pores; 5 percent gravel; neutral (pH 7.0); gradual wavy boundary.
2Bt4--32 to 41 inches; dark yellowish brown (10YR 4/4) clay, light yellowish brown (10YR 6/4) dry; moderate medium and coarse subangular blocky structure; very hard, very firm, sticky and plastic; few very fine and fine roots; few very fine and fine tubular pores; many prominent clay films on faces of peds and lining pores; 5 percent gravel; neutral (pH 7.0); gradual wavy boundary. (combined thickness of the 2Bt horizon is 26 to 53 inches)
2BCt--41 to 60 inches; brown (10YR 4/3) silt loam, light yellowish brown (10YR 6/4) dry; massive; hard, firm, slightly sticky and slightly plastic; common distinct clay films along broken planes; 5 percent gravel; neutral (pH 7.0).
TYPE LOCATION: Jefferson County, Oregon, about 1500 feet west and 2500 feet north of the SE corner of section 16, T.10 S., R.11 E. (Latitude 44 degrees, 42 minutes, 06 seconds N, Longitude 121 degrees, 25 minutes, 27 seconds W) Warm Springs Indian Reservation.
RANGE OF CHARACTERISTICS: These soils are usually moist, but are dry in all parts of the moisture control section for 60 to 90 consecutive days within the four months that follow the summer solstice. The mean annual soil temperature is 49 to 51 degrees F. Depth to bedrock is greater than 60 inches. The mollic epipedon is 10 to 15 inches thick and may include the upper part of the 2Bt horizon. The particle-size control section is 35 to 55 percent field estimated clay and has 0 to 10 percent gravel. There is a 20 to 30 percent absolute clay increase at the upper boundary of the argillic horizon.
The A horizon has value of 2 or 3 moist, 4 or 5 dry and chroma of 2 or 3 moist and dry. It has 10 to 15 percent clay and contains 20 to 30 percent cobbles and 15 to 25 percent gravel of which 5 to 10 percent is pumice. It has 30 to 40 percent volcanic glass and glass coated aggregate including 0.5 to 2 mm diameter pumice, and acid oxalate extractable aluminum plus one-half iron of 0.2 to 0.8 percent . Soil reaction is slightly acid or neutral.
The 2Bt horizon has value of 3 or 4 moist, 5 or 6 dry and chroma of 3 or 4 moist and dry. It is clay loam in the upper part of the 2Bt and clay in the lower part with clay ranging from 35 to 55 percent. It contains 0 to 10 percent gravel. Soil reaction is slightly acid or neutral.
The 2BCt horizon has value of 4 or 5 moist, 5 or 6 dry and chroma of 3 or 4 moist and dry. It is silt loam or loam and contains 0 to 10 percent gravel.
COMPETING SERIES: These are the Driscoll, Nawt (T) and Torney (T) series. Driscoll soils are dry for 45 to 60 consecutive days, have a buried argillic horizon, and are moderately well drained. Nawt soils are 40 to 60 inches deep to bedrock and have a Bk horizon. Torney soils have greater than 35 percent rock fragments in the lower part of the 2Bt horizon and secondary carbonates in the substratum.
GEOGRAPHIC SETTING: Spilyay soils are on gently sloping to moderately steep foot slopes of canyons. The soil formed in residuum and colluvium derived dominantly from semi-consolidated conglomerate and volcanic tuff with an influence of volcanic ash in the surface. Slopes are 0 to 30 percent. Elevations are 2200 to 3400 feet. The climate is characterized by cool and wet winters and hot and dry summers. The mean annual precipitation is 14 to 20 inches. The mean annual temperature is 47 to 49 degrees F. The frost-free period is 90 to 120 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Booten, Evick and Happus soils. Booten soils are on north-facing side slopes and are ashy. Evick soils are on adjacent steep south-facing side slopes of canyons, loamy, and 10 to 14 inches to volcanic tuff. Happus soils are on south-facing toe slopes of canyons, are ashy-pumiceous, and moderately deep to fragmental pumice.
DRAINAGE AND PERMEABILITY: Well drained. Permeability is slow.
USE AND VEGETATION: These soils are used for timber production, livestock grazing, watershed and wildlife habitat. The native vegetation is ponderosa pine with an understory of antelope bitterbrush, Idaho fescue, arrowleaf balsamroot and tailcup lupine.
DISTRIBUTION AND EXTENT: North-central Oregon; MLRA 6. The soils of this series are not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Jefferson County (Warm Springs Indian Reservation), Oregon, 1993.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - the zone from the surface of the soil to a depth of approximately 15 inches ( A and 2Bt1 horizons).
Argillic horizon - the zone from 8 to 39 inches (2Bt1, 2Bt2, 2Bt3 and 2Bt4 horizons).
Vitrandic feature - the zone from 0 to 8 inches (A horizon) having 30 to 40 percent volcanic glass including 0.5 to 2 mm pumice.
Pale feature - abrupt textural change at 8 inches (between A and 2Bt1 horizons)
Particle-size control section - the zone from 8 to 28 inches (2Bt1, 2Bt2, and upper 7 inches of 2Bt3 horizon)
Ultic feature - an assumed base saturation of 75 percent or less within the upper part of the argillic horizon.