LOCATION ORHOOD             CA

ORHOOD SERIES

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, mesic Lithic Argixerolls

TYPICAL PEDON: Orhood very cobbly loam - on a 6 percent south facing slope under big sagebrush, squirreltail, cheatgrass and western juniper at 4,600 feet elevation. (Colors are for dry soil unless otherwise stated. When described on July 28, 1982, the soil was dry throughout.)

A--0 to 4 inches; grayish brown (10YR 5/2) very cobbly loam, very dark grayish brown (10YR 3/2) moist; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine and fine roots; common very fine and fine interstitial pores; 10 percent stones, 34 percent cobbles and 6 percent gravel, neutral (pH 7.0); clear smooth boundary. (3 to 5 inches thick)

BAt--4 to 8 inches; grayish brown (10YR 5/2) very cobbly loam, very dark grayish brown (10YR 3/2) moist; moderate medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine and fine roots; few very fine and fine interstitial and tubular pores; few thin clay films bridging sand grains; 10 percent stones; 30 percent cobbles and 10 percent gravel; neutral (pH 7.0); clear wavy boundary. (3 to 5 inches thick)

Bt1--8 to 11 inches; grayish brown (10YR 5/2) very cobbly clay loam, very dark grayish brown (10YR 3/2) moist; moderate medium subangular blocky structure; hard, firm, sticky and plastic; common very fine, fine and few medium roots; few very fine and fine tubular pores; common moderately thick clay films on faces of peds; 10 percent stones, 30 percent cobbles and 10 percent gravel; neutral (pH 7.0); gradual wavy boundary. (2 to 5 inches thick)

Bt2--11 to 14 inches; yellowish brown (10YR 5/4) very cobbly clay loam, dark yellowish brown (10YR 3/4) moist; moderate medium angular blocky structure; hard, firm, sticky and plastic; common very fine, fine and few medium roots; few very fine and fine tubular pores; many moderately thick clay films on faces of peds and in pores; 10 percent stones, 30 percent cobbles and 10 percent gravel; neutral (pH 7.0); clear wavy boundary. (2 to 5 inches thick)

Bt3--14 to 16 inches; light yellowish brown (10YR 6/4) very cobbly loam, dark yellowish brown (10YR 4/4) moist; moderate medium angular blocky structure; slightly hard, friable, slightly sticky and plastic; common fine roots; common very fine and fine tubular pores; common moderately thick clay films on faces of peds; 10 percent stones, 30 percent cobbles, 10 percent gravel; neutral (pH 7.0); abrupt wavy boundary. (1 to 3 inches thick)

R--16 inches; hard extrusive igneous rock.

TYPE LOCATION: Siskiyou County, California; about 11 miles east of Macdoel, 350 feet west of dirt road; 1,584 feet north and 1,884 feet east of the southwest corner of sec. 30, T.46 N., R.2 E.

RANGE IN CHARACTERISTICS: Depth to extrusive igneous rock ranges from 14 to 20 inches. The mean annual soil temperature is 48 degrees to 51 degrees F. The soil temperature at a depth of 20 inches is above 41 degrees F from mid March to early December (225 days) and is above 47 degrees F from mid April to mid November (210 days). The soil between depths of 12 to 20 inches is dry in all parts from mid June until mid November (140 to 150 days). The soil moisture control section is dry more than half the time the soil temperature is above 41 degrees F. Surface is covered by 35 to 50 percent rock fragments.

The A horizon color is 10YR 5/2, 5/3 or 7.5YR 5/3. Moist color is 10YR 3/2, 3/3 or 7.5YR 3/2. It is very cobbly loam, very stony loam or very stony sandy loam and averages 10 to 15 percent clay. Rock fragments range from 35 to 60 percent. Stones and cobbles range from 30 to 45 percent. Gravel range from 5 to 15 percent. Organic matter ranges from 1 to 3 percent in the surface.

The Bt horizon color is 10YR 4/3, 5/2, 5/3, 5/4, 6/4; 7.5YR 5/2 or 5/4. Moist color is 10YR 3/2, 3/3, 3/4, 4/4; 7.5YR 3/2, 3/4 or 4/2. It is very cobbly loam or very cobbly clay loam. Clay content ranges from 18 to 32 percent and averages 20 to 27 percent. Rock fragments range from 35 to 55 percent. Stones range from 5 to 10 percent. Cobbles range from 20 to 30 percent. Gravel range from 10 to 15 percent.

COMPETING SERIES: These are the Argabak (T WA), Bellehenlen (NV), Brier (ID), Chinabutte (T ID), Clovercreek (OR), Duco (NV), Gwin (WA), Horseflat (T WA), Reywat (ID), Upatad (NV) and Windry (T WA). Argabak (T) soils are less than 14 inches deep to bedrock. Bellehelen, Brier, Chinabutte (T), Clovercreek and Gwin have a xeric moisture regime. Duco soils have a soil temperature of 50 degrees to 53 degrees F. and average 27 to 35 percent clay in the textural control section. Horseflat (T) and Windry (T) soils have AB horizons. Reywat soils are dry 60 to 80 days have Bt horizons that are typically mildly or moderately alkaline and are calcareous in the lower part. Upatad soils have 27 to 35 percent clay in the particle-size control section.

GEOGRAPHIC SETTINGS: Orhood soils are on mountains and hills. Slopes are 2 to 50 percent. The soils formed in material weathered from extrusive igneous rock. Elevation is 4,100 to 6,500 feet. The climate is semiarid with warm dry summers and cold moist winters. Mean annual precipitation is 10 to 16 inches. Snowfall is 10 to 20 inches. Mean January temperature is about 30 degrees F; mean July temperature is about 65 degrees F; mean annual temperature is about 44 to 50 degrees F. Frost-free season is 50 to 100 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Dehill, Hedox, Porterfield, Ricketts, and Searles soils. Dehill soils are greater than 60 inches deep. Hedox soils are 20 to 40 inches deep to a paralithic contact. Porterfield soil are loamy and over a paralithic contact. Ricketts and Searles soils are 20 to 40 inches deep.

DRAINAGE AND PERMEABILITY: Well drained; slow to rapid runoff; moderately slow permeability.

USE AND VEGETATION: Orhood series are used for grazing and juniper wood products such as firewood and fence posts. Vegetation is western juniper an understory of mountain big sagebrush, bluebunch wheatgrass, Idaho fescue, thumber needlegrass, and rubber rabbitbrush.

DISTRIBUTION AND EXTENT: North Central California. These soils are moderately extensive. MLRA is 21.

MLRA OFFICE RESPONSIBLE: Reno, Nevada

SERIES ESTABLISHED: Siskiyou County, California; Butte Valley-Tule Lake Soil Survey 1988.

REMARKS: Diagnostic horizons and features recognized in this pedon are:

Mollic epipedon--Zone from the surface to a depth of 11 inches (A, BAt, Bt1 horizons).

Argillic horizon--Zone from 4 to 16 inches (BAt, Bt1, Bt2, Bt3 horizons). Clay content ranges from 18 to 32 but averages 20 to 27 percent clay.

Lithic contact--16 inches (R horizon).

Loamy-skeletal Family--The particle-size control section (4 to 16 inches) weighted average clay content is 25 percent.

Moisture regime--Aridic-zone from about 12 inches to the lithic contact. Moisture control section is dry (less than 15 bar) throughout 145 days.