LOCATION LITHGOW OR+IDEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, mesic Xeric Haplargids
TYPICAL PEDON: Lithgow gravelly loam, range. (Colors are for dry soil unless otherwise noted.)
A1--0 to 3 inches; light brownish gray (10YR 6/2) gravelly loam, very dark grayish brown (10YR 3/2) moist; moderate fine granular and weak thin platy structure; slightly hard, friable, slightly sticky, slightly plastic; common very fine roots; many very fine irregular pores; 30 percent pebbles; neutral (pH 6.8); clear wavy boundary. (1 to 5 inches thick)
B1--3 to 8 inches; light brownish gray (10YR 6/2) gravelly clay loam, dark grayish brown (10YR 4/2) moist; moderate fine granular structure; hard, friable, slightly sticky, slightly plastic; common very fine roots; many very fine tubular pores; 25 percent pebbles; neutral (pH 6.8); abrupt wavy boundary. (0 to 8 inches thick)
B21t--8 to 17 inches; light brownish gray (10YR 6/2) very gravelly clay loam, dark grayish brown (10YR 4/2) moist; weak medium subangular blocky structure; hard, firm, sticky, plastic; few very fine roots; many very fine tubular pores; few thin clay films on peds; 40 percent pebbles 2 to 10 mm in diameter; neutral (pH 7.0); clear wavy boundary. (6 to 15 inches thick)
B22t--17 to 22 inches; light brownish gray (10YR 6/2) very gravelly clay loam, dark grayish brown (10YR 4/2) moist; weak fine and medium subangular blocky structure; hard, firm, sticky, plastic; few very fine roots; many very fine tubular pores; common thin clay films in pores and few thin films on surfaces of peds; 50 percent pebbles 2 mm to 1 1/2 inches in diameter; neutral (pH 7.0); abrupt wavy boundary. (4 to 15 inches thick)
IIR--22 inches; rhyolitic tuff.
TYPE LOCATION: Wasco County, Oregon; 300 feet north of road in the SW1/4 SE1/4 SE1/4 section 33, T. 8 S., R. 18 E.
RANGE IN CHARACTERISTICS: The mean annual soil temperature ranges from 49 to 53 degrees F. (estimated). Lithgow soils are usually dry but are moist in some part between depths of 4 and 12 inches for a continuous period equal to more than one quarter of the time that the soil temperature exceeds 41 degrees F., and moist between depths of 4 and 12 inches for at least 60 days out of the 120 days following the 3-month period following the summer solstice. The amount of pebbles ranges from 20 to 30 inches thick and depth to bedrock ranges from 20 to 40 inches. The sola are noncalcareous throughout and are neutral to mildly alkaline.
The A horizon has value of 3 or 4 moist, and chroma of 2 or 3 moist and dry. It is gravelly or stony loam or clay loam, and has weak or moderate platy and granular structure.
The B2 horizon has value of 6 or 7 dry and 4 or 5 moist, and chroma of 1 or 2. It is gravelly or very gravelly clay loam with a weighted average of 27 to 35 percent clay, and has weak or moderate subangular blocky structure. Clay films are few to common and thin.
COMPETING SERIES: These are the Basket, Old Camp, Plush, Searles and Washoe series. Basket soils have mean annual soil temperature of less than 47 degrees F., and also have coarse textured calcic horizons. Old Camp soils have a lithic contact at depths of less than 20 inches. Searles soils have mollic epipedon. Washoe and Plush soils are deeper than 40 inches to bedrock.
GEOGRAPHIC SETTING: Lithgow soils are on hilly and mountainous areas at elevations of 2,000 to 3,300 feet. The soils are mostly on south-facing slopes of 20 to about 70 percent. These soils formed in mixed loess and colluvium and old unconsolidated moderately fine textured sediments over tuffs, rhyolite or semiconsolidated sediments. The climate is semiarid continental with a mean annual precipitation of 9 to 10 inches. Average July temperature is about 68 degrees F. Mean winter temperature is about 32 degrees F. Mean annual temperature ranges from 47 to 51 degrees F. The average frost-free period (32 degrees F.) is 80 to 110 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Simas, Sorf, and Willowdale soils. All of these soils have less than 35 percent coarse fragments. Simas soils have mollic epipedons and fine textured argillic horizons. Sorf soils have fine textured argillic horizons. Willowdale soils are deep alluvial soils with mollic epipedons.
DRAINAGE AND PERMEABILITY: Well-drained; medium to rapid runoff; moderately slow permeability.
USE AND VEGETATION: The principal use is range. Other uses are wildlife and water supply purposes. Native plants are bluebunch wheatgrass, Sandberg bluegrass and big sagebrush.
DISTRIBUTION AND EXTENT: Central Oregon. The series is inextensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Wasco County (Trout Creek-Shaniko Area), Oregon, 1970.
REMARKS: These soils were formerly classified as Brown soils.
NSTH 17, RECLASSIFICATION ONLY, 3/95