LOCATION CULTUS ORTentative Series
TAXONOMIC CLASS: Ashy, glassy Humic Xeric Vitricryands
TYPICAL PEDON: Cultus ashy sandy loam, woodland. (Colors are for moist soil unless otherwise noted.)
A--0 to 6 inches; very dark brown (10YR 2/2) ashy sandy loam, dark grayish brown (10YR 4/2) dry; weak very fine granular structure; very soft, very friable, nonsticky and nonplastic; many very fine roots; many very fine irregular pores; 10 percent paragravel pumice (2 to 19 millimeters); slightly acid (pH 6.2); clear wavy boundary. (5 to 8 inches thick)
Bw1--6 to 13 inches; dark brown (7.5YR 3/2) ashy loamy sand, brown (10YR 4/3) dry; massive; very soft, very friable, nonsticky and nonplastic; many very fine roots; many very fine irregular pores; 10 percent paragravel pumice (2 to 19 millimeters); slightly acid (pH 6.3); gradual wavy boundary.
Bw2--13 to 18 inches; dark brown (7.5YR 3/3) ashy loamy sand, brown (10YR 5/3) dry; massive; very soft, very friable, nonsticky and nonplastic; many very fine roots; many very fine irregular pores; 10 percent paragravel pumice (2 to 19 millimeters); slightly acid (pH 6.3); gradual wavy boundary. (Combined thickness of the Bw1 and Bw2 horizon is 11 to 18 inches)
Bw3--18 to 30 inches; dark brown (7.5YR 3/3) ashy loamy sand, yellowish brown (10YR 5/4) dry; massive; very soft, very friable, nonsticky and nonplastic; many very fine and few fine roots; many very fine irregular pores; 10 percent paragravel pumice (2 to 19 millimeters); slightly acid (pH 6.2); abrupt wavy boundary. (8 to 16 inches thick)
2Ab--30 to 41 inches; dark brown (7.5YR 3/3) paragravelly ashy sandy loam, brown (10YR 5/3) dry; massive; soft, very friable, slightly sticky, nonplastic; many very fine and few fine roots; many very fine irregular pores; 20 percent paragravel pumice (2 to 19 millimeters), 5 percent cobbles and 5 percent stones; slightly acid (pH 6.2); abrupt irregular boundary. (8 to 24 inches thick)
2Bwb--41 to 60 inches; black (5YR 2/1) very gravelly glacial till mixed with pumice; massive hard, firm; common fine and very fine roots.
TYPE LOCATION: Deschutes County, Oregon; SW NW section 32, T. 15 S., R. 9 E.
RANGE IN CHARACTERISTICS: The soils are usually moist and are dry for 45 to 60 consecutive days in the control section during the 4 month period following the summer solstice. The mean annual soil temperature is 42 to 45 degrees F. and mean summer soil temperature without an O horizon is 52 to 59 degrees F. and with an O horizon is 40 to 47 degrees F. and mean winter soil temperature is 32 to 35 degrees F. Depth to very gravelly glacial till (2Bwb horizon) is 40 to 60 inches. Depth to bedrock is 60 inches or more. The upper 30 to 40 inches 70 to 100 percent glass and glass-coated aggregates, phosphate retention of 25 to 50 percent, acid oxalate extractable aluminum plus one-half iron of 0.4 to 0.9 percent, 15-bar moisture of less than 10 percent (air-dried), and moist bulk density of 0.70 to 1.00 grams per cubic centimeter.
Some pedons have an O horizon up to 3 inches thick.
The A horizon has hue of 7.5YR or 10YR, value of 2 or 3 moist, 4 or 5 dry, and chroma of 2 or 3 moist and dry. It has 5 to 20 percent paragravel pumice 2 to 19 mm in diameter.
The Bw horizon has hue of 10YR or 7.5YR, value of 3 or 4 moist, 4 to 6 dry, and chroma of 3 or 4 moist and dry. It is ashy loamy sand or ashy loamy fine sand with 5 to 20 percent paragravel pumice 2 to 19 millimeters in diameter.
The 2Ab horizon has hue of 7.5YR or 10YR, value of 2 or 3 moist, 4 or 5 dry, and chroma of 2 or 3 moist and dry. It has 10 to 20 percent paragravel pumice 2 to 19 mm in diameter, 5 to 10 percent gravel 19 mm to 3 inches in diameter, 5 to 10 percent cobbles and up to 5 percent stones.
The 2Bwb horizon is very gravelly glacial till with 35 to 50 percent gravel, 5 to 15 percent cobbles, and 0 to 5 percent stones.
COMPETING SERIES: These are the Goffpeak (T), Kittleson, Shroyton, Steiger, and Sycan series. Goffpeak soils have 35 to 75 percent pumice in the lower part of the particle-size control section and has acid oxalate extractable aluminum plus one-half iron of more than 2.0 percent. Kittleson soils have cambic B horizons, glass content of 50 to 70 percent in the control section, and are 40 to 60 inches to bedrock. Shroyton soils have cambic B horizons and are 40 to 60 inches to a lithic contact. Steiger soils have an ochric epipedon and lack glacial till within 40 to 60 inches. Sycan soils have redox features below 40 inches, and lack glacial till within 40 to 60 inches.
GEOGRAPHIC SETTING: The Cultus soils are on nearly level to very steep glacial moraines at elevations of 3,500 to 5,000 feet. The soils formed in ash and pumice over glacial materials. Slopes are 0 to 65 percent. The climate is characterized by cold wet winters and cool dry summers. The mean annual precipitation is 25 to 40 inches. The mean annual temperature is 40 to 43 degrees F. The mean January temperature is about 22 degrees F., and the mean July temperature is about 59 degrees F. The frost-free period is 0 to 50 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Shukash and Wuksi soils. Shukash soils are ashy over loamy-skeletal. Wuksi soils are ashy-skeletal.
DRAINAGE AND PERMEABILITY: Somewhat excessively drained; rapid permeability to the 2Ab horizon and moderately rapid below.
USE AND VEGETATION: These soils are used for timber production. Other uses include grazing and wildlife. Vegetation consists of grand fir, Douglas fir, lodgepole pine, ponderosa pine, snowbrush and elk sedge.
DISTRIBUTION AND EXTENT: Uplands of central Oregon; MLRA 6. The series is moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES PROPOSED: Deschutes County, Oregon, 1972.
REMARKS: Diagnostic horizons and features recognized in this pedon:
Mollic epipedon - from 0 to 18 inches (A, Bw1, Bw2 horizons)
Andic properties - from 0 to 41 inches (A, Bw1, Bw2, Bw3, 2Ab horizons) based on lab data from associated Steiger series.
Particle-size control section - from 0 to 40 inches
Ash deposit is from Mt. Mazama