LOCATION OCHOCO OREstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Vitrixerandic Argidurids
TYPICAL PEDON: Ochoco ashy sandy loam - cultivated. (Colors are for dry soil unless otherwise noted.)
Ap--0 to 8 inches; light brownish gray (10YR 6/2) ashy sandy loam, dark grayish brown (10YR 4/2) moist; weak fine granular structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine roots; many very fine irregular pores; 15 percent sand-size pumice; neutral (pH 7.3); clear smooth boundary. (5 to 8 inches thick)
BA--8 to 16 inches; light brownish gray (10YR 6/2) ashy sandy loam, dark grayish brown (10YR 4/2) moist; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine roots; many very fine tubular pores; 10 percent sand-size pumice; neutral (pH 7.3); clear smooth boundary. (2 to 8 inches thick)
2Bt1--16 to 21 inches; pale brown (10YR 6/3) fine sandy loam, dark brown (10YR 4/3) moist; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine roots; common very fine tubular pores; few faint clay films on peds and in some pores; slightly alkaline (pH 7.4); clear wavy boundary. (0 to 5 inches thick)
2Bt2--21 to 28 inches; brown (10YR 5/3) sandy clay loam, dark brown (10YR 4/3) moist; weak medium prismatic structure parting to moderate medium subangular blocky; hard, firm, moderately sticky and slightly plastic; common very fine roots; common very fine tubular pores; 5 percent gravel; continuous faint clay films on peds; neutral (pH 7.2); clear smooth boundary. (6 to 10 inches thick)
2Btk--28 to 36 inches; brown (10YR 5/3) gravelly sandy clay loam, dark brown (10YR 4/3) moist; weak medium prismatic structure parting to moderate medium and fine subangular blocky; hard, firm, moderately sticky and slightly plastic; few very fine roots; common very fine tubular pores; few faint clay films on peds and in pores; 20 percent gravel; many seams of lime; slightly alkaline (pH 7.6); clear abrupt boundary. (4 to 10 inches thick)
3Bkqm--36 to 46 inches; pale brown (10YR 6/3) duripan, brown (10YR 5/3) moist; moderate coarse platy structure; strongly cemented with thin indurated laminar capping on surfaces of plates; rootmat on surface and a few roots in fractures; lime in segregated seams; moderately alkaline (pH 8.0); abrupt clear boundary. (5 to 10 inches thick)
3Bk--46 to 60 inches; varigated light gray (10YR 6/1) to very dark grayish brown (10YR 3/2) stratified sand, sandy loam, and sand, grayish brown (10YR 5/2) moist; massive; 40 percent rock fragments; strongly effervescent, moderately alkaline (pH 8.4).
TYPE LOCATION: Crook County, Oregon about 1,600 feet north and 2,200 feet west of the southeast corner of section 13, T14S., R.15E.
RANGE IN CHARACTERISTICS: The soils are dry for one-half to three-fourths of the time when the soil temperature is above 41 degrees F. They are dry in the moisture control section for 90 to 120 days cumulative. The mean annual soil temperature is 50 to 54 degrees F. Depth to the indurated duripan is 20 to 40 inches. Depth to bedrock is over 60 inches.
The A and BA horizons have value of 5 or 6 dry and 3 or 4 moist and chroma of 2 dry and moist. Phosphate retention is 15 to 25 percent, acid oxalate aluminum plus one-half the acid oxalate iron is 0.4 to 0.8 percent. It has 10 to 30 percent glass.
The 2Bt horizon has value of 5 or 6 dry and 3 or 4 moist and chroma of 2 or 3 moist and dry. It is fine sandy loam or sandy clay loam with 18 to 27 percent clay. It has weak or moderate medium subangular blocky and weak moderate prismatic structure. It has 0 to 10 percent sand-size pumice decreasing with depth. It has 0 to 30 percent gravel.
The 3B horizon is stratified sand to sandy loam with 35 to 70 percent gravel and cobbles. It is loose and single grained or massive.
COMPETING SERIES: There are no completing series.
GEOGRAPHIC SETTING: Ochoco soils are on terraces with slopes of 0 to 8 percent. Elevation is 2,900 to 3,100 feet. These soils formed in mixed alluvium and are mantled with a layer of ash (sandy loam) from Mt. Mazama. The climate is semiarid with a mean annual precipitation of 9 to 12 inches. Summers are warm and dry with an average temperature of 64 to 66 degrees F. Winters are cool and moist with an average temperature of 34 to 36 degrees F. The mean annual air temperature is 48 to 52 degrees F. The frost-free period is 90 to 120 days.
GEOGRAPHICALLY ASSOCIATED SOILS: This is the Prineville series. Prineville soils lack an argillic horizons and are coarse-loamy.
DRAINAGE AND PERMEABILITY: Well drained; slow to medium runoff; moderately slow permeability through the solum but very slow through the duripan.
USE AND VEGETATION: Principal uses are for potatoes, grain crops, pasture, and alfalfa. Other uses are for livestock grazing. Native vegetation consists of bluebunch wheatgrass, basin big sagebrush and sandberg bluegrass.
DISTRIBUTION AND EXTENT: Central Oregon; MLRA 10, pumice zone. The soils are moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Prineville Area, Crook County, Oregon, 1963.
REMARKS: Diagnoztic horizons and other features:
Ochric epipedon
Argillic horizon - 16 to 36 inches
Indurated duripan - 36 to 46 inches
Vitrixerandic - 0 to 16 inches.
ADDITIONAL DATA: Characterization data on one profile (S55-Oreg-7-15) reported in the Soil Survey of Prineville Area, Oregon, USDA, February, 1966.