LOCATION TRUAX CAEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Aridic Argixerolls
TYPICAL PEDON: Truax fine sandy loam--on a 3 percent southeast facing slope under big sagebrush and cheatgrass at 4,280 feet elevation. (When described January 4, 1981, the soil was moist to 30 inches and dry below 30 inches. Colors are for dry soil unless otherwise stated.)
A--0 to 8 inches; brown (7.5YR 5/2) fine sandy loam, dark brown (7.5YR 3/2) moist; weak medium subangular blocky structure; loose, very friable, nonsticky and nonplastic; common very fine and fine, few medium roots; common very fine interstitial and tubular pores; 1 percent stones, 3 percent cobbles, 2 percent pebbles; slightly acid (pH 6.5); clear smooth boundary. (6 to 10 inches thick)
Bt1--8 to 17 inches; brown (7.5YR 5/4) sandy clay loam, dark brown (7.5YR 3/2) moist; moderate medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine and fine, few medium roots; common very fine interstitial and tubular pores; few thin clay films on faces of peds; 1 percent stones, 3 percent cobbles, 2 percent pebbles; neutral (pH 7.0); clear wavy boundary. (8 to 9 inches thick)
Bt2--17 to 29 inches; brown (7.5YR 5/4) sandy clay loam, dark brown (7. 5YR 3/4) moist; moderate medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few very fine, fine and medium roots; many very fine interstitial and tubular pores; common thin clay films on faces of peds; 2 percent stones, 8 percent cobbles, 2 percent pebbles; neutral (pH 7.0); clear wavy boundary. (11 to 13 inches thick)
Bw--29 to 36 inches; yellowish brown (10YR 5/4) sandy loam, brown (7.5YR 4/4) moist; moderate medium subangular blocky structure; slightly hard, friable, nonsticky and nonplastic; few very fine, fine and medium roots; many very fine interstitial and tubular pores; 2 percent stones, 8 percent cobbles, 2 percent pebbles; mildly alkaline (pH 7.5); clear wavy boundary. (6 to 12 inches thick)
Bq1--36 to 43 inches; yellowish brown (10YR 5/4) sandy loam, brown (7.5YR 4/4) moist; massive; slightly hard, firm, nonsticky and nonplastic; weakly cemented dry and non-brittle wet; few very fine roots; many very fine interstitial pores; 2 percent stones, 8 percent cobbles and 2 percent pebbles; mildly alkaline (pH 7.5); abrupt wavy boundary. (6 to 10 inches thick)
Bq2--43 to 60 inches; brown (7.5YR 5/4) sandy loam, dark brown (7.5YR 3/4) moist; massive; hard, firm, nonsticky and nonplastic, weakly cemented dry and non brittle wet; common very fine and few fine and medium roots; common very fine tubular and interstitial pores; laminar caping .5 to 2 mm thick but is discontinous, 2 percent stones, 8 percent cobbles, 2 percent pebbles; mildly alkaline (pH 7.5).
TYPE LOCATION: Siskiyou County, California; about 2 miles northeast of the town of Mount Herbron; 1 mile south of Red Rock Valley Road, 50 ft., north of dirt road; about 1,810 feet north and 1,900 feet west of the southeast corner of section 27, T. 46 N., R. 1 W.
RANGE IN CHARACTERISTICS: Depth is greater than 60 inches. The mean annual soil temperature is 48 degrees F to 52 degrees F. The soil temperature at a depth of 20 inches is above 41 degrees F from about March 15 to December 1 (255 days) and is about 47 degrees F from about April 15 to November 15 (210 days). The soil between depths of 9 to 21 inches is dry in all parts from June 15 until November 10 (145 days). The moisture control section is dry more than half the time the soil temperature is greater than 41 degrees F. Solum thickness ranges from 25 to 32 inches. Rock fragments range from 0 to 15 percent of the soil, by volume. Stones range from 0 to 2 percent. Cobbles range from 0 to 8 percent. Gravel range from 0 to 5 percent. Mollic epipedon is 14 to 19 inches thick.
The A horizon has dry color of 10YR 5/2, 5/3 or 7.5YR 5/2 and moist color of 10YR 3/2 or 7.5YR 3/2. Clay content ranges from 10 to 15 percent. Reaction is slightly acid or neutral.
The Bt1 horizon has dry color of 10YR 5/2, 5/3 or 7.5YR 5/4 and moist color of 10YR 3/3 or 7.5YR 3/2. It is sandy clay loam or loam and averages 20 to 26 percent clay with at least 4 percent more clay content than the A horizon. Reaction is slightly acid or neutral.
The Bt2 horizon has dry color 10YR 5/4, 7.5YR 5/4 or 5/2 and moist color of 7.5YR 4/4 or 3/4. It is sandy clay loam or loam and averages 20 to 25 percent clay. Reaction is slightly acid or neutral.
The Cq horizon has dry color of 10YR 5/3, 5/4, 6/4, 7/5YR 5/4, 6/2 or 6/4 and moist color of 10YR 5/4, 7.5YR 3/4, 4/4, 4/6 or 5/4. Reaction is neutral or mildly alkaline. Clay content is 10 to 15 percent.
COMPETING SERIES: These are the Bissell, Bjork, Cowiche, Dodes, Fredrickson, Indiano, Margerum, Orr, Pahrange, Ralls, Simcoe, Springmeyer and Uhaldi. Bissell soils are micaceous throughout and have less than 5 percent rock fragments. Bjork, Indiano, Pahrange and Simcoe have a lithic contact at depths less than 40 inches. Cowiche soils are mildly or moderately alkaline throughout and have an A horizon and the upper part of the B2t horizon that formed in loess 18 to 40 inches thick over uncomformable residual material. Dodes, Fredrickson and Uhaldi soils have a paralithic contact at depths less than 40 inches. Margerum soils have 20 to 40 percent pumice in the particle size control section and 15 to 35 percent pumice coarse fragments and have a solum 40 to 52 inches thick. Orr soils lack silica cementation in the C horizon, have angular blocky and prismatic structure or are massive in the Bt, are usually gravelly in the C horizon and usually have a thicker solum. Ralls soils have a mildly alkaline or moderately alkaline solum and are influenced by loess. Springmeyer soils have 15 to 35 percent rock fragments and 25 to 35 percent clay in the upper 20 inches of the argillic horizon.
GEOGRAPHIC SETTING: Truax soils are on alluvial fans. Slopes are 0 to 15 percent. The soils formed in mixed alluvium from extrusive igneous rock. Elevations are from 4,200 to 5,000 feet. The climate is semiarid with warm dry summers and cold moist winters. The mean annual precipitation is 10 to 14 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 48 degrees F. Frost-free season is 50 to 80 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Dehill (T), Orhood (T), and Searles soils. Dehill soils are coarse-loamy and lack argillic horizons. Orhood soils are 10 to 20 inches deep to a lithic contact. Searles soils are 20 to 40 inches deep to a lithic contact.
DRAINAGE AND PERMEABILITY: Well drained, slow to medium runoff moderately slow permeability.
USE AND VEGETATION: Truax soils are used for crop land, hay and pasture and rangeland. Cultivated crops commonly grown are oats and barley. Native vegetation is bluebunch wheatgrass, Idaho fescue, Nevada bluegrass and big sagebrush.
DISTRIBUTION AND EXTENT: Northeastern California. These soils are moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES PROPOSED: Siskiyou County, California; Butt Valley-Tule Lake Soil Survey, l983. The name is from a nearby local ranch.
REMARKS: Diagnostic horizons and features recognized in the pedon are:
Mollic epipedon: The zone from the surface of the soil to a depth of 17 inches (A, Bt1).
Argillic horizon: The zone from 8 to 29 inches (Bt1, Bt2).
Solum thickness: 29 inches.
Aridic moisture: Moisture control section zone from 9 to 21 inches. Dry in all parts 145 days.
Silica cementation: Zone from 36 to 60 inches is weakly cemented dry but nonbrittle wet and has discontinuous opal caps.