LOCATION KREBS OREstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Calciargidic Argixerolls
TYPICAL PEDON: Krebs silt loam, rangeland. (Colors are for dry soil unless otherwise stated.)
A11--0 to 5 inches; grayish brown (10YR 5/2) silt loam, very dark grayish brown (10YR 3/2) moist; weak fine granular structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine roots; many very fine irregular pores, neutral (pH 7.0); gradual wavy boundary. (3 to 6 inches thick)
A12--5 to 10 inches; grayish brown (10YR 5/2) silty clay loam, very dark grayish brown (10YR 3/2) moist; weak medium granular to weak medium subangular blocky structure; slightly hard, friable, sticky and plastic; many very fine roots; many very fine tubular pores; neutral (pH 7.2); gradual wavy boundary. (3 to 6 inches thick)
B1--10 to 17 inches; brown (10YR 5/3) silty clay loam, dark brown (10YR 3/3) moist; moderate fine subangular blocky structure; hard, firm, sticky and plastic; common very fine roots; many very fine tubular pores; neutral (pH 7.2); gradual wavy boundary. (0 to 8 inches thick)
B2t--17 to 27 inches; pale brown (10YR 6/3) silty clay, brown (10YR 5/3) moist; weak medium prismatic structure parting to moderate medium subangular blocky; very hard, firm, sticky and plastic; few roots; many very fine tubular pores; continuous thin clay films on faces of peds and in pores; mildly alkaline (pH 7.6); gradual wavy boundary. (6 to 14 inches thick)
B3ca--27 to 36 inches; very pale brown (10YR 8/3) silty clay loam, pale brown (10YR 6/3) moist; moderate fine subangular blocky structure; hard, firm, sticky and plastic; few roots; common very fine tubular pores; moderately calcareous with thin seams of lime; moderately alkaline (pH 8.0); abrupt smooth boundary. (3 to 10 inches thick)
C1ca--36 to 48 inches; white (10YR 8/1) silty clay loam, pale brown (10YR 6/3) moist; massive; very hard, firm, sticky and plastic; few roots; few very fine irregular pores; strongly calcareous; moderately alkaline (pH 8.0); abrupt smooth boundary. (10 to 20 inches thick)
C2r--48 to 63 inches; white (10YR 8/1) partially decomposed diatomite, pale brown (10YR 6/3) moist.
TYPE LOCATION: Gilliam County, Oregon; 20 feet north of Rhea Road; SW1/4 NE1/4 SW1/4 section 20, T.3N., R.22E.
RANGE IN CHARACTERISTICS: Depth to a paralithic contact is 40 to 60 inches. Thickness of sola is 20 to 40 inches. The mollic epipedon ranges from 7 to 20 inches thick. The mean annual soil temperature ranges from 53 to 56 degrees F. Krebs soils are dry between depths of 4 and 12 inches for more than 80 consecutive days during the 4 months following the summer solstice.
The A horizon has value of 4 or 5 dry, 2 or 3 moist and chroma of 2 or 3 moist and dry.
The B2t horizon has value of 5 or 6 dry, 4 or 5 moist and chroma of 3 or 4 moist and dry. It is silty clay or clay and averages 40 to 50 percent clay.
COMPETING SERIES: These are the Encina series in the same family and the Kanarra and Simas series. Encina soils have sola less than 20 inches thick and a mean annual soil temperature of 47 to 52 degrees F. Kanarra soils have mean annual soil temperature of 50 to 52 degrees, have more than 15 percent carbonates, and are dry for less than 80 consecutive days. Simas soils have an abrupt textural change, 50 to 60 percent clay in the argillic horizon, and have annual soil temperature of 47 to 52 degrees F.
GEOGRAPHIC SETTING: Krebs soils are on uplands at elevations of 500 to 900 feet with slopes of 2 to 40 percent. These soils formed in loess in the upper part and old unconsolidated moderately fine and fine textured water lain sediments in the lower part. Summers are warm and dry with an average July temperature of 68 degrees F. Winters are cool and moist with an average January temperature of 32 degrees F. The mean annual temperature is 51 to 54 degrees F. Precipitation ranges from 9 to 10 inches annual. The frost free period is 140 to 180 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Blalock, Olex and Willis soils. Also, Blalock and Willis soils are underlain by gravelly duripans and the Olex soils are very gravelly.
DRAINAGE AND PERMEABILITY: Well drained; medium to rapid runoff; slow permeability.
USE AND VEGETATION: The principle use is range. Native vegetation is needleandthread and bluebunch wheatgrass.
DISTRIBUTION AND EXTENT: North central Oregon. The soils are inextensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Gilliam County, Oregon, 1978.