LOCATION LUCE ORTentative Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, mesic Durinodic Xeric Aquicambids
TYPICAL PEDON: Luce silt loam, hayland. (Colors are for moist conditions unless otherwise noted.)
Ap--0 to 7 inches; grayish brown (10YR 3/2) silt loam, light brownish gray (10YR 6/2) dry; weak medium and fine granular structure; slightly hard, friable, sticky, plastic; abundant roots; common fine and very fine tubular pores; moderately alkaline (pH 8.0); clear smooth boundary. (4 to 8 inches thick)
A12--7 to 13 inches; dark brown (10YR 3/3) silt loam, pale brown (10YR 6/3) dry; moderate medium subangular blocky structure; slightly hard, very friable, slightly sticky, slightly plastic; plentiful roots; few very fine and fine tubular pores; calcareous; moderately alkaline (pH 8.2); gradual smooth boundary. (5 to 8 inches thick)
AC--13 to 18 inches; dark brown (10YR 3/3) silt loam, brown (10YR 5/3) dry; moderate medium subangular blocky structure; slightly hard, very friable, slightly sticky, slightly plastic; plentiful roots; common fine and few very fine tubular pores; calcareous; moderately alkaline (pH 8.2); clear smooth boundary. (4 to 20 inches thick)
C1--18 to 23 inches; dark brown (10YR 3/3) silt loam, brown (10YR 5/3) dry; massive; very hard, firm, nonsticky, nonplastic; few roots; many very fine and fine pores; strongly calcareous; weakly cemented; nonopal coatings or durinodes; moderately alkaline (pH 8.2); clear smooth boundary. (2 to 6 inches thick)
IIC2--24 to 38 inches; dark grayish brown (10YR 4/2) silty clay loam, light brownish gray (10YR 6/2) dry; massive; hard, friable, sticky, plastic; few roots; common very fine and fine pores; strongly calcareous; moderately alkaline (pH 8.2); gradual smooth boundary. (10 to 30 inches thick)
IIC3--38 to 45 inches; dark brown (10YR 3/3) silty clay loam, light gray (10YR 7/2) dry; massive; hard, friable, sticky, plastic; few roots; few very fine pores; strongly calcareous; moderately alkaline (pH 8.2); gradual smooth boundary. (0 to 24 inches thick)
IIC4--45 to 50 inches; brown to dark brown (10YR 4/3) silty clay loam, massive; hard, friable, sticky, plastic; very few roots; calcareous; moderately alkaline (pH 8.2).
TYPE LOCATION: Grant County, Oregon; about 4 1/2 miles west of Mt. Vernon; 225 feet south of Highway 26, 150 feet east of section line NW1/4 SW1/4 section 26, T. 13 S., R. 29 E.
RANGE IN CHARACTERISTICS: These soils are usually dry but moist in some part of the surface 12 inches for a continuous period equal to more than 1/4 of the time that the soil temperature at 20 inches exceeds 41 degrees F. The mean annual soil temperature ranges from 47 to about 53 degrees F. The soil is calcareous and ranges from moderately to strongly alkaline. No strongly contrasting textures are within 40 inches of the surface and no bedrock is within 60 inches. The 10 to 40 section ranges in texture from silt loam to silty clay loam with a weighted average of 20 to 32 percent clay and with less than 15 percent coarser than very fine sand. The brittle horizon is less than 6 inches thick, weakly to moderately cemented and occurs at depths ranging from 16 to 36 inches. Loose gravel, sand or volcanic ash may occur at depths below 40 inches.
The A horizon has hues of 10YR, chromas of 2 or 3, and values of 6 or 7 dry and 3 or 4 moist.
The AC and C horizons have color values of 3 to 4 moist and 5 to 7 dry with chromas of 2 to 3 moist and dry. The upper horizons are moderately affected by excess salt and sodium.
COMPETING SERIES: Stanfield soils have a duripan and have less than 18 percent clay in their control sections. Umapine soils have less than 18 percent clay in their control sections and have sodium saturation that is 15 percent or more in the upper 20 inches and decreases below. Sagemoor, Shano, and Warden soils lack the brittle horizon and are neutral or mildly alkaline in the surface soils.
GEOGRAPHIC SETTING: Luce soils occur on gently sloping low alluvial fans. The regolith consists of stratified medium and moderately fine textured alluvium from mixed materials. Elevations range from 1,700 to 3,800 feet. The climate is semiarid with a mean annual precipitation of 10 to 14 inches. The average July temperature is about 68 degrees F. The average January temperature is about 32 degrees F., and the mean annual temperature is about 50 degrees F. The average frost-free period is 100 to 150 days. The yearly fluctuation is large with 30 days being common.
GEOGRAPHICALLY ASSOCIATED SOILS: These include the Hack, Courtrock and Powder soils. All have mollic epipedon and lack weakly cemented or brittle horizons.
DRAINAGE AND PERMEABILITY: Somewhat poorly to moderately well drained. Runoff is medium and internal drainage is moderate to slow. Permeability is slow to moderate.
USE AND VEGETATION: Mostly cultivated for hay and pasture production. Principal crops include alfalfa, alfalfa-grass, and grass-clover.
DISTRIBUTION AND EXTENT: East-central Oregon. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES PROPOSED: Grant County, Oregon, 1959. (Source of name is a school in Grant County, Oregon).
REMARKS: The series was formerly classified in the Brown soils.
NSTH 17, RECLASSIFICATION ONLY, 3/95