LOCATION STEARNS OREstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, calcareous, mesic Cumulic Endoaquolls
TYPICAL PEDON: Stearns silt loam, on a 1 percent slope, pasture. (Colors are for moist soils unless otherwise noted.)
A-- 0 to 4 inches; very dark brown (10YR 2/2) silt loam, grayish brown (10YR 5/2) dry; moderate fine subangular blocky structure parting to moderate fine granular; slightly hard, very friable, moderately sticky and moderately plastic; common very fine roots, few fine; common very fine tubular pores; slightly effervescent; very strongly alkaline (pH 9.2); clear wavy boundary. (3 to 10 inches thick)
Bkn1-- 4 to 9 inches; dark brown (10YR 3/3) silty clay loam, grayish brown (10YR 5/3) dry; moderate very fine subangular blocky structure; slightly hard, very friable, moderately sticky and moderately plastic; few very fine and fine roots; few very fine tubular pores; strongly effervescent; very strongly alkaline (pH 9.6); clear wavy boundary.
Bkn2-- 9 to 18 inches; very dark gray (10YR 3/1) silty clay loam, dark grayish brown (10YR 4/2) dry; few very fine faint light brownish gray (10YR 6/2) redox depletions; moderate fine subangular blocky structure; slightly hard, very friable, moderately sticky and moderately plastic; few very fine and fine roots; common very fine tubular pores; slightly effervescent; very strongly alkaline (pH 9.6); clear wavy boundary.
Bkn3--18 to 32 inches; very dark brown (10YR 2/2) loam, grayish brown (10YR 5/2) dry; few very fine faint light brownish gray (10YR 6/2) redox depletions; weak fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few very fine roots; many very fine tubular pores; slightly effervescent; strongly alkaline (pH 8.6); clear wavy boundary. (Combined thickness of Bkn horizon ranges from 20 to 35 inches.)
2Bk-- 32 to 52 inches; very dark grayish brown (10YR 3/2) silt loam, grayish brown (10YR 5/2) dry; common very fine distinct light brownish gray (10YR 6/2) redox depletions; massive; slightly hard, friable, moderately sticky and slightly plastic; slightly effervescent; moderately alkaline (pH 8.4); clear wavy boundary. (15 to 25 inches thick)
2C-- 52 to 60 inches; very dark grayish brown (10YR 3/2) fine sandy loam, grayish brown (10YR 5/2) dry; massive; slightly hard, very friable, slightly sticky and slightly plastic; moderately alkaline (pH 8.0).
TYPE LOCATION: Crook County, Oregon; located 2,200 feet south and 2,200 feet east of the NW corner of section 8, T. 15 S, R. 16 E; about 0.5 miles south of the Crook County fairgrounds in Prineville, Oregon.
RANGE OF CHARACTERISTICS: These soils are usually moist but are dry for 60 to 90 consecutive days during the four month period following the summer solstice. The mean annual soil temperature ranges from 50 to 54 degrees F. Depth to bedrock is greater than 60 inches. Depth to the 2C horizon is 40 to 60 inches. The mollic epipedon is 24 to 40 inches thick. The solum is slightly to strongly effervescent throughout. The particle-size congtrol section has a weighted average clay content of 18 to 27 percent. Depth to the water table is 1.0 to 1.5 feet from March to April.
The A horizon has value of 2 or 3 moist, 4 or 5 dry, and chroma of 2 or 3 moist and dry. It is slightly to very strongly alkaline. SAR is 13 to 30.
The Bkn horizon has value of 2 or 3 moist, 4 or 5 dry, and chroma of 1 through 3 moist and dry. It is silty clay loam, loam, or sandy loam. It is moderately to very strongly alkaline. SAR is 25 to 70. It has 15 to 30 percent clay.
The 2Bk horizon has value of 2 or 3 moist, 4 or 5 dry, and chroma of 2 or 3 moist and dry. It is moderately to very strongly alkaline. SAR is 13 to 30.
The 2C horizon has value of 3 or 4 moist, 5 or 6 dry, and chroma of 2 or 3 moist and dry. It is silt loam, fine sandy loam or very fine sandy loam. It is slightly to strongly alkaline. SAR is 10 to 20.
COMPETING SERIES: This is the Winner series. Winner soils are somewhat poorly drained and lack the SAR values of 13 or more.
GEOGRAPHIC SETTING: Stearns soils are on nearly level low terraces at elevations of 2,700 to 3,200 feet. Slopes range from 0 to 2 percent. The soils formed in mixed alluvium weathered from basalt, andesite, and pumice. 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 ASSCOCIATED SOILS: These are the Boyce, Crooked, Era, Metolius, and Powder soils. Boyce soils are poorly drained, fine-silty over sandy or sandy-skeletal and are on adjacent floodplains. Crooked soils are coarse-loamy and somewhat poorly drained. Powder soils are well drained, coarse-silty soils and are on adjacent floodplains. Metolius soils are well drained and are noncalcareous. Era soils are somewhat excessively drained soils and are on adjacent high terraces.
DRAINAGE AND PERMEABILITY: Poorly drained with a water table at 1.0 to 1.5 feet from March through April; permeability is moderately slow. Flooding is rare due to protection from dams.
USE AND VEGETATION: Stearns soils are used mainly for pasture. Native vegetation is inland saltgrass 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 features in this pedon include:
Mollic epipedon - the zone from the surface to a depth of 32 inches (A and Bkn horizons)
Aquic moisture regime - (Aquolls) SAR of over 13 from 32 inches decreasing below a depth of 32 inches.
Cumulic - mollic epipedon from 0 to 32 inches
ADDITIONAL DATA: Characterization data for one pedon (S55-Oreg-7-1) reported in Soil Survey Prineville Area, Oregon, 1966.