LOCATION BLALOCK OREstablished Series
TAXONOMIC CLASS: Loamy, mixed, superactive, mesic, shallow Haploduridic Durixerolls
TYPICAL PEDONS: Blalock loam, rangeland. (Colors are for dry soil unless otherwise stated.)
A11--0 to 2 inches; grayish brown (10YR 5/2) loam, very dark grayish brown (10YR 3/2) moist; moderate thin platy structure; slightly hard, friable, nonsticky and nonplastic; many very fine roots; many very fine tubular pores; neutral (pH 7.0); abrupt smooth boundary. (2 to 4 inches thick)
A12--2 to 7 inches; brown (10YR 5/3) loam, dark brown (10YR 3/3) moist; weak coarse prismatic structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine roots; many very fine tubular pores; neutral (pH 7.2); clear smooth boundary. (2 to 6 inches thick)
B21--7 to 12 inches; yellowish brown (10YR 5/4) loam, brown (10YR 4/3) moist; weak medium subangular blocky structure; hard, friable, sticky and plastic; common very fine roots; many very fine tubular pores; 5 percent pebbles; mildly alkaline (pH 7.4); clear smooth boundary. (2 to 6 inches thick)
B22--12 to 18 inches; pale brown (10YR 6/3) gravelly loam, brown (10YR 4/3) moist; weak medium subangular blocky structure; hard, friable, slightly sticky and slightly plastic; common very fine roots; many very fine tubular pores; common light gray soft fragments (1 - 3 mm); 25 percent pebbles; mildly alkaline (pH 7.6); abrupt smooth boundary. (4 to 6 inches thick)
IIClsicam--18 to 26 inches; white (10YR 8/1) very gravelly duripan, light brownish gray (10YR 6/2) moist; massive; indurated silica laminar capping; strongly cemented and indurated, extremely hard; 50 percent pebbles and 5 percent cobbles; very strongly calcareous. (4 to 12 inches thick)
IIC2ca--26 to 41 inches; pale brown (10YR 6/3) gravelly loam, brown (10YR 5/3) moist; massive; slightly sticky and slightly plastic; 15 percent pebbles; strongly calcareous; strongly alkaline (pH 8.6); abrupt wavy boundary. (15 to 20 inches thick.) IIIC3r--41 inches; weathered shale.
TYPE LOCATION: Gilliam County, Oregon; 300 feet south of gravelled county road, in SE1/4 NE1/4 NE1/4 section 28, T.3N., R.22E.
RANGE IN CHARACTERISTICS: Depth to the duripan ranges from 10 to 20 inches. These soils are usually dry in all parts of the soil above the duripan. Mean annual soil temperature is 54 to 56 degree F. Some pedons have secondary lime above the duripan. Depth to weathered shale commonly is 40 to 60 inches.
The A horizon has chroma of 2 or 3.
The B horizon has value of 5 or 6 dry, 3 or 4 moist and chroma of 3 or 4 dry, 2 or 3 moist. It is loam or gravelly loam and averages 18 to 25 percent clay and more than 15 percent coarser than very fine sand. This horizon has weak medium subangular blocky or weak medium prismatic structure.
COMPETING SERIES: These are the Gorst and Moxee soils in the same family and the Baker and Willis series. Baker and Willis soils have a duripan at depths of 20 to 40 inches. Also, Willis soils have less than 15 percent coarser than very fine sand. Gorst soils have a noncalcareous duripan thicker than 12 inches. Moxee soils have less than 18 percent clay in the particle size control section.
GEOGRAPHIC SETTING; Blalock soils are on old river terraces at elevations of 500 to 900 feet and have slopes of 0 to 15 percent. They formed in medium textured mixed alluvium reworked by wind. The climate is semiarid with moist winters and dry summers. Mean winter temperature is 34 to 36 degrees F., mean summer temperature is 71 to 73 degrees F., and mean annual temperature is 52 to 54 degrees F. Mean annual precipitation is 9 to 11 inches. The frost-free season is 160 to 190 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Olex and Roloff soils and the competing Willis soils. Olex soils lack a duripan and are very gravelly. Roloff soils lack a duripan and are moderately deep to basalt.
DRAINAGE AND PERMEABILITY: Well drained; slow runoff; moderate permeability.
USE AND VEGETATION: These soils are used primarily for range. Other uses are wildlife habitat and water supply purposes. Vegetation is mainly bunchgrasses, forbs, and shrubs.
DISTRIBUTION AND EXTENT: North-central Oregon. This series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Gilliam County, Oregon, l978.
NSTH 17, RECLASSIFICATION ONLY, 3/95