LOCATION BERDUGO OREstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Xeric Paleargids
TYPICAL PEDON: Berdugo silt loam, 0 to 3 percent slopes, rangeland. (Colors are for dry soil unless otherwise noted.)
A--0 to 1 inch; light brownish gray (10YR 6/2) silt loam, dark grayish brown (10YR 4/2) moist; moderate medium platy structure; slightly hard, friable, sticky and slightly plastic; many fine and very fine and few coarse roots; common fine vesicular pores; 10 percent gravel; neutral (pH 7.2); abrupt wavy boundary. (1 to 5 inches thick)
2Bt1--1 to 4 inches; pale brown (10YR 6/3) silty clay loam, brown (10YR 4/3) moist; moderate very fine blocky structure; slightly hard, friable, sticky and plastic; common very fine and few fine and coarse roots; common very fine tubular pores; common faint clay films; mildly alkaline (pH 7.8); clear wavy boundary.
2Bt2--4 to 12 inches; pale brown (10YR 6/3) silty clay loam, brown (10YR 5/3) moist; weak medium subangular blocky structure; slightly hard, friable, sticky and plastic; common fine and few very fine roots; common very fine tubular pores; common faint clay films; moderately alkaline (pH 8.0); gradual irregular boundary. (The combined thickness of the Bt horizon is 6 to 15 inches.)
3Bkq--12 to 17 inches; pale brown (10YR 6/3) silt loam, brown (10YR 4/3) moist; weak medium subangular blocky structure; hard, firm and brittle, slightly sticky and slightly plastic; few fine and very fine roots; few fine tubular pores; strongly effervescent; moderately alkaline (pH 8.2); gradual wavy boundary. (0 to 5 inches thick)
3BC--17 to 26 inches; pale brown (10YR 6/3) loam, brown (10YR 4/3) moist; weak medium subangular blocky structure; slightly hard, friable, nonsticky and nonplastic; few fine roots; few fine tubular pores; moderately alkaline (pH 8.2); clear wavy boundary. (7 to 40 inches thick)
4C--26 to 39 inches; pale brown (10YR 6/3) loamy sand, dark brown (10YR 3/3) moist; massive; slightly hard, very friable, nonsticky and nonplastic; common fine roots; few fine tubular pores; 10 percent gravel; moderately alkaline (pH 8.2); clear smooth boundary. (0 to 14 inches thick)
5C--39 to 45 inches; pale brown (10YR 6/3) extremely gravelly sand, dark brown (10YR 3/3) moist; massive; loose, nonsticky and nonplastic; common fine roots; 10 percent cobbles, 75 percent gravel; moderately alkaline (pH 8.2); clear wavy boundary. (0 to 10 inches thick)
6C--45 to 65 inches; pale brown (10YR 6/3) gravelly sandy loam, brown (10YR 4/3) moist; massive; slightly hard, friable, nonsticky and nonplastic; few fine roots; few fine tubular pores; 20 percent gravel; moderately alkaline (pH 8.2).
TYPE LOCATION: Harney County, Oregon; 5.5 miles southwest of Blitzen townsite in the SW1/4 NW1/4 section 35, T. 34 S., R. 30 E.
RANGE IN CHARACTERISTICS: The soils are usually dry in all parts of the moisture control section for one-half to three-fourths of the time when the soil temperature is greater than 41 degrees F. The soil temperature is above 41 degrees F. from mid-April to mid-November. The mean annual soil temperature is 47 to 50 degrees F. Depth to bedrock is more than 60 inches. The argillic horizon is 6 to 15 inches thick and contains 35 to 45 percent clay. The combined A and Bt horizon thickness is 10 to 20 inches. Some strata below the argillic horizon are weakly cemented. Depth to the stratified C horizon is 20 to 50 inches. Relic mottles may be present below 40 inches.
The A horizon has value of 4 to 7 dry, 3 to 5 moist and chroma of 2 or 3 moist and dry. It is neutral to moderately alkaline.
The Bt horizon is silty clay loam, silty clay or clay with 35 to 45 percent clay. It has value of 5 or 6 dry, 4 or 5 moist, and chroma of 3 moist and dry. It is mildly or moderately alkaline. Structure is weak or moderate blocky.
The Bk or BC horizon is loam, clay loam or very fine sandy loam. Hue is 10YR or 2.5Y, value is 6 to 8 dry, 3 or 4 moist and chroma is 2 to 4 moist and dry.
The C horizon is stratified loam, loamy sand, gravelly sandy loam, and extremely gravelly sand. Hue is 10YR or 2.5Y, value is 6 to 8 dry, 3 or 4 moist and chroma is 2 to 4 moist and dry.
COMPETING SERIES: These are the Acoma, Borda, Bowns, Brent, Chardoton, Gooding, Mahala, Phing, Poall, Reba, Sorf, Spangenburg, and Verdico series. Acoma soils have over 45 percent sand and 15 to 35 percent rock fragments in the particle-size control section. Borda soils have 45 to 60 percent clay in the particle-size control section, have prismatic structure in the Bt horizon and are slightly acid to neutral in the solum. Bowns, Mahala and Verdico soils have bedrock at 20 to 40 inches. Brent soils have a mean annual soil temperature of 50 to 54 degrees F., have an E horizon and a loam surface layer over 9 inches thick. Chardoton soils have an E horizon and a mean annual soil temperature of 51 to 56 degrees F. Gooding soils have a duripan at 40 to 60 inches, have an E horizon and a calcic horizon below the Bt layer. Phing soils have medium or coarse prismatic structure in the upper part of the subsoil, have a weakly cemented layer at 20 to 40 inches, and lack secondary carbonates above 40 inches. Poall soils are on hills, have strong prismatic structure in the upper part of the subsoil and have a solum over 60 inches thick. Reba soils have columnar structure in the upper part of the subsoil and have 1 to 3 percent organic matter to a depth of 15 to 18 inches. Sorf soils have a mean annual soil temperature of 51 to 54 degrees F., have 45 to 60 percent clay in the Bt horizon and have 20 to 60 percent surface rock fragments. Spangenburg soils have 45 to 60 percent clay in the upper part of the argillic horizon and have moderate prismatic structure.
GEOGRAPHIC SETTING: Berdugo soils are on lake terraces and have slopes of 0 to 5 percent. The soils formed in lacustrine sediments with components of loess, volcanic ash and diatomaceous earth. Elevations are 4,500 to 5,500 feet. The mean annual precipitation is 8 to 10 inches. The mean annual temperature is 46 to 50 degrees F. The frost-free period is 70 to 100 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Spangenburg soils and the Enko, Catlow and Norad soils. Enko and Catlow soils lack argillic horizons. Norad soils have fine-silty argillic horizons.
DRAINAGE AND PERMEABILITY: Well drained; slow permeability.
USE AND VEGETATION: The soils are used for range. Potential native vegetation is Wyoming big sagebrush, bluebunch wheatgrass and Thurber needlegrass.
DISTRIBUTION AND EXTENT: Pleistocene lake basins of southeastern Oregon, MLRA 24. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Lake County, Oregon, Southern Part, 1991.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon
Argillic horizon - 1 to 12 inches (2Bt1, 2Bt2 horizons)
Pale feature - 15 percent clay increase between the A and 2Bt horizons.
Although the boundary is abrupt and the clay increase qualifies for Paleargids, the percent clay throughout the Bt is on the low range for fine family and the structure is weak and/or moderate blocky. The "more" typical Paleargids have strong or moderate prismatic or columnar structure and clay content is higher in the upper part of the subsoil and may decrease with depth.