LOCATION CROOKED OREstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, mesic Sodic Aquicambids
TYPICAL PEDON: Crooked ashy sandy loam, in an area of Crooked-Stearns complex, 0 to 2 percent slopes, pasture. (Colors are for moist soil unless otherwise noted.)
A-- 0 to 6 inches; dark brown (10YR 3/3) ashy sandy loam, pale brown (10YR 6/3) dry; moderate very fine granular structure; slightly hard, very friable, nonsticky and slightly plastic; common very fine and fine roots; common very fine interstitial pores; 20 percent sand-size (0.25 to 1.0 mm) pumice, light brownish gray (10YR 6/2) dry; slightly effervescent; strongly alkaline (pH 8.6); clear wavy boundary. (5 to 12 inches thick)
Bn1-- 6 to 25 inches; dark brown (10YR 3/3) ashy sandy loam, pale brown (10YR 6/3) dry; moderate fine subangular blocky structure; slightly hard, very friable, nonsticky and nonplastic; common very fine and fine roots; common very fine tubular pores; 20 percent sand-size (0.25 to 1.0 mm) pumice, light brownish gray (10YR 6/2) dry; slightly effervescent; very strongly alkaline (pH 9.6); clear wavy boundary.
Bn2-- 25 to 38 inches; brown (10YR 4/3) ashy sandy loam, light gray (10YR 7/2) dry; moderate fine subangular blocky structure; slightly hard, friable, nonsticky and slightly plastic; few very fine and common fine roots; few very fine tubular pores; 30 percent sand-size (0.25 to 1.0 mm) pumice, light brownish gray (10YR 6/2) dry; slightly effervescent; very strongly alkaline (pH 9.6); abrupt wavy boundary. (Combined thickness of the Bn horizon ranges from 20 to 35 inches.)
2C1-- 38 to 44 inches; light brownish gray (10YR 6/2) silt, white (10YR 8/2) dry; massive; extremely hard, extremely firm, nonsticky and nonplastic; slightly effervescent; very strongly alkaline (pH 9.4); abrupt wavy boundary.
3C2-- 44 to 55 inches; light gray (10YR 7/2) and light brownish gray (10YR 5/2) coarse sand, white (10YR 8/1) dry; single grain; loose, nonsticky and nonplastic; slightly effervescent; very strongly alkaline (pH 9.4); clear wavy boundary. (Combined thickness of the 2C and 3C horizons range from 0 to 18 inches.)
4C3-- 55 to 60 inches; brown (10YR 4/3) loam, pale brown (10YR 6/3) dry; massive; slightly hard, friable, slightly sticky and slightly plastic; slightly effervescent; strongly alkaline (pH 8.8).
TYPE LOCATION: Crook County, Oregon; about 1 mile south of the Crook County Fairgrounds in Prineville, Oregon; 2,400 feet south and 2,200 feet east of the NW corner of section 8, T.15 S, R.16 E.
RANGE IN CHARACTERISTICS: These soils are usually dry and the moisture control section is dry for 90 to 120 days cumulative when the soil temperature exceeds 41 degrees F. The mean annual soil temperature is 50 to 54 degrees F. Depth to bedrock is greater than 60 inches. Depth to the 2C horizon is 25 to 38nches. Depth to a water table is 1.5 to 3.0 feet and is present from March through April. Sand-size (0.25 to 1.0mm) pumice content in the solum is 15 to 30 percent. The solum has a phosphate retention of 15 to 25 percent and acid oxalate aluminum plus one-half the iron is 0.4 to 0.8 percent. The weighted average clay content of the particle-size control section is 10 to 18 percent.
The A horizon has value of 3 or 4 moist, 5 or 6 dry, and chroma of 2 or 3 moist and dry. SAR is 5 to 13.
The Bn horizon has value of 3 or 4 moist, 5 through 7 dry, and chroma of 2 or 3 moist and dry. It is sandy loam or fine sandy loam. SAR is 13 to 30.
The 2C and 3C horizons, when present, has value of 5 through 7 moist, 7 or 8 dry, and chroma of 1 or 2 moist and dry. It is silt, loamy sand, or sand and is slightly to strongly effervescent. It has 0 to 5 percent clay. SAR is 13 to 30.
The 4C3 horizon has value of 4 or 5 moist, 6 or 7 dry, and chroma of 2 or 3 moist and dry. It is loam, silt loam, or clay loam with 15 to 30 percent clay and is slightly to strongly effervescent. SAR is 10 to 20.
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: Crooked soils are on nearly level low terraces at elevations of 2,700 to 3,200 feet. These soils formed in mixed alluvium with an influence of volcanic ash in the surface. The climate is characterized by cool, moist winters and hot, dry summers. The mean annual precipitation is 9 to 12 inches, the mean annual temperature is 48 to 52 degrees F, and the frost-free period is 90 to 120 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These include Boyce, Era, Metolius, Powder, and Stearns. Boyce soils are poorly drained, fine-silty over sandy or sandy-skeletal and are on floodplains. Stearns soils are poorly drained, fine-loamy, and calcareous soils in depressions on low terraces. Powder soils are well drained, coarse-silty soils and are on floodplains adjacent to streams. Metolius soils do not have a high pH and are located on low terraces. Era soils are somewhat excessively drained soils and are on adjacent high terraces.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained; permeability is moderately rapid over moderately slow. Historically, flooding was frequent or occasional but due to protection from dams is now rare.
USE AND VEGETATION: This soil is used mainly for pasture. Native vegetation is inland saltgrass, basin wildrye, and greasewood.
DISTRIBUTION AND EXTENT: Central Oregon; MLRA 10, pumice zone. This series is not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Prineville Area, Crook County, Oregon, 1963.
REMARKS: Diagnostic horizons and other features:
Ochric epipedon
Cambic horizon - from a depth of 6 inches to 38 inches (Bn1 and Bn2 horizons)
Aquic greatgroup - water table is 20 to 36 inches below the soil surface during March and April
Sodic subgroup - SAR greater than 13 from 6 to 55 inches (Bn1, Bn2, 2C1 and 3C2 horizons)
Vitrixerandic properties - the zone from 0 to 38 inches.