LOCATION RISBECK WAEstablished Series
TAXONOMIC CLASS: Coarse-silty, mixed, superactive, calcareous, mesic Duric Torriorthents
TYPICAL PEDON: Risbeck silt loam, cultivated. (Colors are for dry soil unless otherwise stated.)
Ap--0 to 8 inches; pale brown (10YR 6/3) silt loam, dark grayish brown (10YR 4/2) moist; weak fine and medium granular structure; soft, very friable, slightly sticky, slightly plastic; many roots; 5 to 10 percent lime silica cemented fragments; slightly effervescent; moderately alkaline (pH 8.4); abrupt smooth boundary. (4 to 10 inches thick)
C1ca--8 to 19 inches; pale brown (10YR 6/3) silt loam, brown (10YR 4/3) moist; massive; hard, firm, slightly sticky, slightly plastic; many roots; few very fine and fine pores; lime occurs in pores, root channels, and fractures; 5 to 10 percent lime silica weakly cemented fragments; strongly effervescent; moderately alkaline (pH 8.4); clear wavy boundary. (8 to 12 inches thick)
C2casi--19 to 32 inches; pale brown (10YR 6/3) silt loam, brown (10YR 5/3) moist; massive; very hard, very firm, slightly sticky, slightly plastic; few roots; few very fine and fine pores; lime occurs in pores, root channels, and fractures; 10 to 40 percent lime silica, weakly cemented fragments and durinodes; violently effervescent; moderately alkaline (pH 8.4); clear wavy boundary. (8 to 15 inches thick)
C3casi--32 to 43 inches; light gray (10YR 7/2) silt loam, grayish brown (10YR 5/2) moist; massive; very hard, very firm, slightly sticky, slightly plastic; few roots; few very fine and fine pores; 15 to 40 percent lime silica cemented fragments and durinodes; lime occurs in pores; root channels and fractures; violently effervescent; strongly alkaline (pH 8.6); clear wavy boundary. (8 to 12 inches thick)
C4ca--43 to 60 inches; pale brown (10YR 6/3) silt loam, brown (10YR 5/3) moist; massive; very hard, firm, slightly sticky, slightly plastic; few roots; few very fine and fine pores; intermittent weakly to strongly lime silica cemented lenses 1/16 to 1 inch thick; 5 to 10 percent lime silica weakly cemented fragments; slightly effervescent; moderately alkaline (pH 8.2).
TYPE LOCATION: Whitman County, Washington; 1,800 feet west and 2,400 feet north of the SE corner of section 18, R.40E.
RANGE IN CHARACTERISTICS: Depth to secondary carbonates ranges from 0 to 10 inches. These soils are usually dry between depths of 4 and 12 inches. The mean annual soil temperature at depth of 20 inches ranges from 48 to 52 degrees F. Lime silica weakly cemented fragments and durinodes range from 5 to 45 percent in all horizons. Lime silica weakly cemented lenses occur through out the profile and thickness ranges from 1/16 to 3 inches.
The Ap horizon has value of 5 or 6 dry, 3 or 4 moist, and chroma of 2 or 3 dry or moist.
The C1ca horizon has value of 6 or 7 dry, 4 or 5 moist, and chroma of 2 or 3 dry or moist. It has weak subangular blocky structure or is massive. This horizon is moderately or strongly alkaline.
COMPETING SERIES: These are the Beryl and Linco seies. Beryl soils have a fine sandy loam control section. Linco soils are gravelly fine sandy loam.
GEOGRAPHIC SETTING: These soils are at elevations of 1,200 to 2,200 feet above sea level on undulating to hilly uplands. They formed in calcareous loess of Bull Lake and pre Bull Lake age and the surface layer of recent loess. The climate is continental temperate with warm, dry summers and cool, moist winters. The mean annual precipitation is 12 to 15 inches. The mean January temperature is 29 degrees F.; the mean July temperature is 69 degrees F.; and the mean annual temperature is 49 degrees F. The frost free season is 130 to 155 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Benge, Chard, Endicott, Hermiston, Onyx, and Walla Walla soils. All of these soils have a mollic epipedon and depth to secondary lime is more than 20 inches. Endicott soils have a cemented duripan at depths of 20 to 40 inches and are calcareous at a depth of 17 inches.
DRAINAGE AND PERMEABILITY: Well drained; medium to rapid runoff; moderate to moderately slow permeability.
USE AND VEGETATION: Used for small grain production and for grazing. Native vegetation is beardless wheatgrass, bluebunch, Sandberg bluegrass, big sagebrush, rabbittbrush, and yarrow.
DISTRIBUTION AND EXTENT: Eastern Washington. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Whitman County, Washington, 1975.
REMARKS: This series is a Xeric intergrade to the aridic moisture regime. The series was previously classified as Haploduridic Xeric.