LOCATION SREDNIC OREstablished Series
TAXONOMIC CLASS: Ashy, glassy, frigid Vitrixerandic Haplodurids
TYPICAL PEDON: Srednic very gravelly coarse sandy loam - rangeland, on a 3 percent slope at an elevation of 4,260 feet. (Colors are for dry soil unless otherwise stated.)
A--0 to 2 inches; brown (10YR 4/3) very gravelly coarse sandy loam; very dark brown (10YR 2/2) moist; single grained; loose, nonsticky and nonplastic; few very fine roots; 35 percent gravel; neutral (pH 6.6); abrupt smooth boundary. (1 to 2 inches thick)
Bw1--2 to 6 inches; brown (10YR 5/3) gravelly loam, very dark grayish brown (10YR 3/2) moist; weak fine and medium subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; common very fine and few fine roots; few very fine tubular pores; 30 percent gravel; slightly alkaline (pH 7.6); clear smooth boundary.
Bw2--6 to 17 inches; brown (10YR 5/3) gravelly sandy loam, very dark grayish brown (10YR 3/2) moist; weak fine and medium subangular blocky structure; soft, very friable, nonsticky and slightly plastic; common very fine, and few fine, medium and coarse roots; few very fine tubular pores; 30 percent gravel; slightly alkaline (pH 7.6); clear smooth boundary. (Combined thickness of the Bw1 and Bw2 horizons is 11 to 19 inches)
Bw3--17 to 25 inches; pale brown (10YR 6/3) gravelly loam, dark brown (10YR 3/3) moist; moderate medium and coarse subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine, and few fine and medium roots; common very fine tubular pores; slightly effervescent with disseminated lime; 25 percent gravel and 5 percent cobbles; moderately alkaline (pH 8.0); abrupt wavy boundary. (8 to 12 inches thick)
Bkqm1--25 to 27 inches; light gray, white and very pale brown (10YR 7/2, 8/1, 7/4) strongly cemented duripan, light yellowish brown and very pale brown (10YR 6/4, 7/4) moist; few very fine roots; strongly effervescent with disseminated lime; abrupt smooth boundary. (1 to 3 inches thick)
Bkqm2--27 to 30 inches; light gray, white and very pale brown (10YR 7/2, 8/1, 7/4) indurated duripan with pockets of weathered bedrock, light yellowish brown and very pale brown (10YR 6/4, 7/4) moist; violently effervescent with disseminated lime; abrupt smooth boundary. (2 to 20 inches thick)
2R--30 inches; welded tuff.
TYPE LOCATION: Harney County, Oregon, in the Diamond Craters Outstanding Natural Area, about 2,200 feet north and 1,500 feet west of the southeast corner of section 10, T. 29 S., R. 32 E., on the Diamond, OR 7.5' quadrangle. (Latitude 43 degrees, 3 minutes, 56 seconds N, Longitude 118 degrees, 44 minutes, 42 seconds W)
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 45 to 47 degrees F. The soil moisture control section is dry for one-half to three-fourths of the time when the soil temperature is above 41 degrees F. The mollic colors in the Bw horizon are from the parent material. The depth to hard bedrock is 25 to 50 inches. The thickness of the solum and depth to an indurated duripan is 20 to 40 inches. Depth to carbonates is 12 to 20 inches. The particle size control section averages 15 to 35 percent rock fragments mainly as gravel sized cinders and 5 to 18 percent clay. It contains 40 to 85 percent volcanic glass in the 0.02 to 0.25 mm size fraction. Phosphate retention is 15 to 25 percent. The acid oxalate aluminum plus one-half the iron is 0.5 to 1.0 percent.
The A horizon has values of 4 or 5 dry, 2 or 3 moist; and chroma of 2 or 3. It has 1 to 3 percent organic matter. It has 35 to 50 percent gravel size cinders.
The upper part of the Bw has values of 4 or 5 dry. It is gravelly sandy loam, gravelly loam, and very gravelly sandy loam. Rock fragment content is 15 to 40 percent. Clay content is 5 to 18 percent. It has 0.5 to 1 percent organic matter.
The lower part of the Bw horizon has values of 5 or 6 dry, 2 or 3 moist, and chromas of 2 through 4. It is gravelly sandy loam or gravelly loam. Rock fragment content is 15 to 35 percent by volume. Clay content is 5 to 18 percent. Reaction is mildly to moderately alkaline.
The Bkqm horizon has values dry of 7 or 8 dry, 6 or 7 moist, and chromas of 1 through 4.
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: Srednic soils are on hills and have slopes of 2 to 20 percent. The soils formed in residuum from cinders and eolian sand over welded tuff and basalt. Elevations are 4,100 to 4,700 feet. The climate is charcterized by cold, moist winters, and hot dry summers. The mean annual precipitation is 10 to 12 inches. The mean annual temperature is 43 to 45 degrees F. The frost free period is 50 to 80 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Aval, Flank, and Pomerening soils. Aval and Flank soils are shallow to bedrock. Pomerening soils are very deep.
DRAINAGE AND PERMEABILITY: Well drained, slow runoff; permeability is moderate.
USE AND VEGETATION: The soils are used for willdife habitat. Potential native vegetation is basin big sagebrush, needleandthread, and Thurber needlegrass.
DISTRIBUTION AND EXTENT: Holocene age volcanic areas of southeast Oregon; MLRA 23. Series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Harney County, Oregon, 1997.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon
Cambic horizon - from 6 to 17 inches, (Bw1, Bw2 horizons)
Indurated duripan - from 27 to 30 inches, (Bkqm2 horizon)
Particle-size control section - from 10 to 25 inches, (Bw2, Bw3 horizons) contains over 40 percent volcanic glass in the 0.02 to 0.25 mm size fraction.
ADDITIONAL DATA: Partial laboratory data is available for this soil. Reference sample S93OR-025-002 from Harney County, Oregon, NSSL Lincoln, NE.