LOCATION LAWEN OREstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, frigid Calciargidic Argixerolls
TYPICAL PEDON: Lawen sandy loam, rangeland. (Colors are for dry soil unless otherwise noted.)
A--0 to 10 inches; brown (10YR 5/3) fine sandy loam, dark brown (10YR 3/3) moist; single grained; loose; very friable, nonsticky and nonplastic; many fine roots; slightly alkaline (pH 7.8); clear smooth boundary. (10 to 14 inches thick)
Bt--10 to 15 inches; brown (10YR 5/3) loam, dark brown (10YR 3/3) moist; moderate fine and medium subangular blocky structure; hard, friable, slightly sticky and slightly plastic; common fine roots; common very fine tubular pores; few faint clay films in pores and bridging sand grains; moderately alkaline (pH 8.2); abrupt smooth boundary. (5 to 12 inches thick)
Btk--15 to 25 inches; pale brown (10YR 6/3) fine sandy loam, brown (10YR 4/3) moist; weak medium prismatic structure parting to weak medium subangular blocky; hard, friable, nonsticky and nonplastic; common fine roots; common very fine tubular pores; few faint clay films in pores and bridging sand grains; common filiments of lime; slightly effervescent; moderately alkaline (pH 8.2); clear smooth boundary. (5 to 15 inches thick)
Bk--25 to 40 inches; pale brown (10YR 6/3) fine sandy loam, brown (10YR 4/3) moist; weak coarse subangular blocky structure; hard, friable, nonsticky and nonplastic; common very fine tubular pores; common filiments of lime, slightly effervescent; moderately alkaline (pH 8.2); clear wavy boundary. (10 to 20 inches thick)
C--40 to 60 inches; pale brown (10YR 6/3) fine sandy loam, brown (10YR 4/3) moist; massive; soft, very friable, nonsticky and nonplastic; moderately alkaline (pH 8.4).
TYPE LOCATION: Harney County, Oregon; 400 feet west of Newton Road and 4 miles south of U.S. Highway 20 in the SE1/4 SE1/4 SE1/4 section 24, T. 23 S., R. 32 1/2 E.
RANGE IN CHARACTERISTICS: The soil is dry for one-half to three-fourths of the time when the temperature is greater than 41 degrees F. The mean annual soil temperature is 45 to 47 degrees F. Depth to bedrock is more than 60 inches. The particle-size control section averages 8 to 18 percent clay and more than 15 percent sand coarser than very fine sand. Depth to secondary carbonates is 15 to 26 inches. The mollic epipedons is 10 to 14 inches thick.
The A horizon has chroma of 2 or 3 moist and dry. It has 5 to 10 percent clay. Most pedons have a thin 1 inch layer on the surface that has a dry value of 6.
The Bt and Btk horizons are loam or fine sandy loam. It is slightly or moderately alkaline. The upper part is noncalcareous with the lower part slightly to strongly calcareous. It has 10 to 18 percent clay.
The Bk and C horizons have 5 to 10 percent clay. It is slightly or moderately alkaline.
COMPETING SERIES: There are no other series in this family.
GEOGRAPHIC SETTING: The soils are on lake terraces on basin floors at elevations of 4,000 to 4,500 feet. Slopes are 2 to 5 percent. The soils formed in alluvium reworked by wind in the upper part. The climate is semiarid and summers are dry. The mean annual precipitation is 10 to 12 inches and the mean annual temperature is 43 to 45 degrees F. The frost-free period is 50 to 80 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Ausmus, Crowcamp, Poujade, and Voltage series. Ausmus and Poujade soils have a natric horizon. Crowcamp soils are fine textured. Voltage soils have a calcic horizon.
DRAINAGE AND PERMEABILITY: Well drained; slow runoff; moderate permeability.
USE AND VEGETATION: The soils are used mainly for rangeland. Vegetation commonly is basin big sagebrush, western needlegrass, Indian ricegrass, and basin wildrye. Some areas are irrigated and used for alfalfa hay and grain.
DISTRIBUTION AND EXTENT: Lake basins in south-central Oregon; MLRA 23. The series is moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Harney County, Oregon, 1997.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon from 0 to 10 inches.
Argillic horizon from 10 to 25 inches.
Secondary carbonate accumulation from 15 to 40 inches
Particle-size control section from 10 to 25 inches, averages 10 percent clay.