LOCATION WUKSI OREstablished Series
TAXONOMIC CLASS: Ashy-skeletal, glassy Xeric Vitricryands
TYPICAL PEDON: Wuksi very cobbly ashy loamy coarse sand, woodland. (Colors are for moist soil unless otherwise noted.)
Oi--0 to 1 inch; slightly decomposed needles, twigs, leaves. (0 to 3 inches thick)
A1--1 to 6 inches; very dark grayish brown (10YR 3/2) very cobbly ashy loamy coarse sand, light brownish gray (10YR 6/2) dry; weak fine granular structure; very soft, very friable, nonsticky, nonplastic; many very fine roots; many very fine irregular pores; 20 percent gravel 2-5 mm, 5 percent gravel 5-19 mm, 5 percent gravel 19 mm-3 inches, 15 percent cobbles and 5 percent stones; neutral (pH 6.6); clear smooth boundary. (2 to 6 inches thick)
A2--6 to 13 inches; dark brown (10YR 3/3) very cobbly ashy loamy coarse sand, pale brown (10YR 6/3) dry; single grain; loose; nonsticky, nonplastic; many very fine roots; many very fine irregular pores; 15 percent gravel 2-5 mm, 5 percent gravel 5-19 mm, 5 percent gravel 19 mm-3 inches, 15 percent cobbles and 5 percent stones; neutral (pH 6.6); gradual wavy boundary. (6 to 10 inches thick)
Bw--13 to 30 inches; strong brown (7.5YR 5/6) very cobbly ashy coarse sand, very pale brown (10YR 7/3) dry; single grain; loose, nonsticky, nonplastic; many very fine roots; many very fine irregular pores; 15 percent gravel 2-5 mm, 5 percent gravel 15-19 mm gravel, 5 percent 19 mm-3 inches gravel, 25 percent cobbles and 5 percent stones; neutral (pH 6.6); gradual wavy boundary. (6 to 20 inches thick)
C--30 to 43 inches; light reddish brown (2.5YR 6/3) extremely cobbly ashy sand, very pale brown (10YR 8/2) dry; single grain; loose; nonsticky, nonplastic; many very fine roots; many very fine irregular pores; 5 percent gravel 2-5 mm, 15 percent gravel 5 mm-3 inches, 60 percent cobbles and 5 percent stones; neutral (pH 6.6) abrupt wavy boundary. (4 to 26 inches thick)
2Bwb--43 to 61 inches; dark brown (7.5YR 3/3) extremely cobbly sandy loam, brown (7.5YR 5/4) dry; massive; slightly hard, very friable, slightly sticky, nonplastic; common very fine roots; many very fine irregular pores; 5 percent gravel 2-5 mm, 15 percent gravel 5 mm-3 inches, 60 percent cobbles and 5 percent stones; neutral (pH 6.6).
TYPE LOCATION: Deschutes County, Oregon; SW1/4 NW1/4 SW1/4 section 35, T. 19 S., R. 8 E.
RANGE IN CHARACTERISTICS: The soils are dry for 45 to 60 consecutive days during the 4-month period following the summer solstice. The mean annual soil temperature is 42 to 45 degrees F., the mean summer soil temperature is 52 to 59 degrees F. without an O horizon and 40 to 47 degrees F. with an O horizon, and the mean winter soil temperature is 32 to 35 degrees F. The solum is 14 to 35 inches thick. Depth to basalt bedrock is 60 inches or more. Depth to the buried soils is 40 to more than 60 inches. The control section consists mostly of irregular shaped hard scoriaceous lava basalt rock fragments with the voids filled with ash. The solum has 70 to 100 percent volcanic glass and glass coated aggregates, 25 to 50 percent phosphate retention, 0.4 to 1.0 percent acid oxalate extractable aluminum plus one-half iron, 15-bar moisture of 3 to 12 percent on both moist and dry samples, and moist bulk density of 0.70 to 1.00 grams per cubic centimeter. It has 0 to 5 percent clay by field estimate.
Some pedons lack an O horizon.
The A horizon has hue of 10YR or 7.5YR, value of 3 or 4 moist, 5 or 6 dry, and chroma of 2 or 3 moist and dry. It has 50 to 60 percent rock fragments with 15 to 30 percent gravel, 15 to 30 percent cobbles, and 0 to 5 percent stones.
The Bw and C horizons have hue of 10YR through 2.5YR, value of 5 or 6 moist, 7 or 8 dry, and chroma of 2 to 6 moist and 2 or 3 dry. It is very cobbly ashy coarse sand or very cobbly ashy sand. It has 50 to 85 percent rock fragments with 15 to 25 percent gravel, 25 to 60 percent cobbles, and 0 to 5 percent stones.
The 2Bwb horizon has hue of 7.5YR or 10YR, value of 3 or 4 moist, 5 or 6 dry, and chroma of 3 or 4 moist and dry. It has 60 to 90 percent rock fragments with 15 to 25 percent gravel, 40 to 60 percent cobbles, and 0 to 5 percent stones.
COMPETING SERIES: These are the Azwell, Burpeak, Chewack, Fears, Hallihan, Madrak, and Tiptop series. Fears soils have an E and Bs horizon. Hallihan soils have a cambic horizon, and are sandy loam or fine sandy loam with 7 to 18 percent clay in the fine-earth fraction. Tiptop soils have cambic horizons and acid oxalate extractable aluminum plus one-half iron of more than 1.0 percent in the control section. Burpeak soils have a cambic horizon and 5 to 12 percent field estimated clay. Chewack soil shave a cambic horizon and 1.0 to 2.0 acid oxalate aluminum plus one-half the iron. Azwell and Madrak soils are 20 to 40 inches deep to bedrock and have a cambic horizon.
GEOGRAPHIC SETTING: The Wuksi soils have nearly level to very steep slopes on lava plains at elevations of 4,500 to 6,000 feet. The soil formed in ash mixed with rock fragments of scoriaceous basalt over extremely cobbly colluvium. Slopes are 2 to 70 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 45 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 Lapine and Steiger soils. Lapine soils are ashy-pumiceous. Steiger soils are ashy.
DRAINAGE AND PERMEABILITY: Somewhat excessively drained; rapid permeability.
USE AND VEGETATION: These soils are used for timber production. Other uses are livestock grazing and wildlife. Vegetation consists of white fir, ponderosa pine, lodgepole pine, snowbrush and manzanita.
DISTRIBUTION AND EXTENT: Pumice zone of south-central Oregon; MLRA 6. The series is inextensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Crater Lake National Part, Oregon; 2001.
REMARKS: Diagnostic horizons and features recognized in this pedon:
Ochric epipedon
Andic properties - from 1 to 30 inches
Ash deposit if from Mt. Mazama.
Particle-size control section - from 1 to 41 inches