LOCATION PINSPRING CAEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, thermic Typic Haploxeralfs
TYPICAL PEDON: Pinspring loam, fallow, on a slope of 2 percent at 2040 feet elevation. (When described on September 12, 1984 the soil was slightly moist below a depth of 6 inches. Colors are for dry soil unless otherwise noted.)
Ap--0 to 6 inches; grayish brown (2.5Y 5/2) loam, very dark grayish brown (2.5Y 3/2) moist; massive; hard, friable, sticky and slightly plastic; few very fine roots; few very fine tubular pores; neutral (pH 7.1); clear smooth boundary. (4 to 8 inches thick)
A--6 to 14 inches; grayish brown (2.5Y 5/2) loam, very dark grayish brown (2.5Y 3/2) moist; massive; hard, friable, sticky and slightly plastic; few very fine roots; common very fine and few fine tubular pores; neutral (pH 7.2); clear wavy boundary. (8 to 10 inches thick)
ABt--14 to 25 inches; pale brown (10YR 6/3) loam, mixed dark brown and brown (10YR 3/3 and 4/3) moist; massive; hard, friable, sticky and plastic; few very fine roots; common very fine and fine tubular pores; very few thin clay films in pores; slightly alkaline (pH 7.6); clear wavy boundary. (0 to 12 inches thick)
Bt--25 to 30 inches; mixed light yellowish brown and pale brown (10YR 6/4 and 6/3) clay loam, mixed yellowish brown and brown (10YR 5/4 and 4/3) moist; weak medium angular blocky structure; hard, friable, sticky and plastic; common very fine and few fine tubular pores; few thin clay films on ped faces and in pores; few pressure faces on peds; few very fine manganese stains on ped faces; slightly alkaline (pH 7.6); abrupt smooth boundary. (5 to 10 inches thick)
2Btq--30 to 39 inches; very pale brown (10YR 7/4) continuous weakly silica cemented sandy loam, yellowish brown (10YR 5/4) moist; weak very fine prismatic structure parting to moderate fine angular blocky; extremely hard, very firm and brittle, slightly sticky and nonplastic; few fine tubular pores; common thin clay films on ped faces; few fine and medium manganese stains on ped faces; moderately alkaline (pH 8.0); gradual wavy boundary. (6 to 15 inches thick)
3Btk-- 39 to 53 inches; yellow (2.5Y 7/6) loam, light olive brown (2.5Y 5/6) moist; weak very fine and fine prismatic structure parting to strong fine angular blocky; hard, friable, slightly sticky and slightly plastic; few fine tubular pores; many thin clay films on ped faces; few fine and medium manganese stains on ped faces; violently effervescent, lime segregated into common fine and medium soft masses; moderately alkaline (pH 8.4); gradual wavy boundary. (12 to 16 inches thick)
4Bt-- 53 to 62 inches; pale yellow (2.5Y 7/4) loam, light olive brown (2.5Y 5/4) moist; weak fine angular blocky structure; hard, friable, slightly sticky and slightly plastic; few fine tubular pores; common thin clay films on ped faces; 8 percent gravel; few fine and medium manganese stains on ped faces; moderately alkaline (pH 8.0).
TYPE LOCATION: San Luis Obispo County; California; 1 mile north of highway 58 on the dirt road to the Las Yeguas Ranch, then west 0.4 miles on farm road, then 173 feet south of the farm road on magnetic bearing SSE 164 degrees. It is 2,100 feet west and 173 feet south of the northeast corner of section 35, T.29 S., R.18 E., California Valley Quadrangle.
RANGE IN CHARACTERISTICS: The thickness of the solum ranges from 25 to 40 inches. The mean annual soil temperature ranges from 60 to 67 degrees F. The soil between the depths of 6 and 17 inches is moist in some part from December 15 until May 1 and is moist in all parts for at least 60 consecutive days from January 15 to March 15. The soil is dry in all parts for about 210 days and has a xeric bordering on aridic moisture regime. Depth to weakly silica cemented material (2Btq) is 25 to 40 inches.
The A horizon has color of 10YR 5/2, 5/3, 6/2 or 6/3; 2.5Y 5/2 or 6/2 and moist color of 10YR 3/2, 3/3 or 4/3; 2.5Y 3/2. Clay content is 18 to 27 percent. Organic carbon is 0.6 to 2 percent. Reaction is neutral or mildly alkaline.
The Bt horizon has color of 10YR 6/3 or 6/4; 2.5Y 6/2 or 6/4 and moist color of 10YR 3/3, 4/3, 4/4 or 5/4; 2.5Y 4/2 or 4/4. Textures are clay loam or silty clay loam. Clay content is 27 to 35 percent. Reaction is mildly alkaline or moderately alkaline.
The 2Btq horizon has a color of 10YR 6/4 or 7/4; 2.5Y 6/4 or 7/4 and moist color of 10YR 4/4 or 5/4; 2.5Y 4/4 or 5/4. Clay content is 12 to 16 percent. It is very hard or extremely hard when dry and firm to extremely firm and brittle when moist. Reaction is mildly alkaline or moderately alkaline.
The 3Bt and 4Bt horizons have colors of 10YR 6/3, 6/4 or 7/4; 2.5Y 6/4, 7/4 or 7/6 and moist color of 10YR 4/4 or 5/4; 2.5Y 4/4, 5/4 or 5/6. Clay content is 18 to 27 percent. Gravel content is 0 to 10 percent. The matrix is noneffervescent to violently effervescent, lime is disseminated or segregated as common fine and medium filaments, seams or soft masses. Reaction is mildly alkaline or moderately alkaline.
COMPETING SERIES: These are the Academy (T), Bellysprings (T), Burchell, Cajalco (T), Coarsegold, Hicksville, Honn (T), Jacinto, Modesto, Olashes, Perkins, Pleasanton, Rescue, Sobrante, Sodabay, Trimmer and Whitney. Academy, Bellysprings, Cajalco, Coarsegold, Sobrante, Trimmer and Whitney soils have a paralithic contact at depths of 20 to 40 inches. Burchell soils are somewhat poorly drained and have strong gleyed colors at 45 inches. Hicksville soils are moist in all parts from Dec. 1 to May 1. Honn soils have 15 to 35 percent coarse fragments throughout and have a mean annual precipitation of 25 to 40 inches. Jacinto soils have fine sandy loam textures, average less than 25 percent clay throughout and have a mean annual precipitation of 15 to 25 inches. Modesto soils have a perched water table at less than 5 feet and electrical conductivity of greater than 16 throughout. Olashes soils are moist in some or all parts from from November through May and lacks carbonates in the 13 horizon. Sodabay soils are composed of amorphous materials weathered from volcanic ash. Perkins soils have a Bt horizon with hues of 5YR and 2.5YR. Pleasanton soils have a solum thickness of 40 to 80 inches. Rescue soils have a paralithic contact at 40 to 80 inches.
GEOGRAPHIC SETTING: Pinspring soils are on alluvial plains. Slopes are 0 to 5 percent. They formed in alluvial material weathered from mixed sources. Elevations are 1950 to 2400 feet. The climate is semiarid with hot dry summers and cool moist winters. Mean annual precipitation is 8 to 10 inches. Mean January temperature is about 46 degrees F., the mean July temperature is about 77 degrees F. and the mean annual temperature ranges from 58 to 62 degrees F. Frost- free season is 175 to 200 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Beam, Jenks(T), Panoza(T), Polonio, Thomhill(T) and Yeguas (T) soils. Beam soils are less than 20 inches to a paralithic contact. Jenks(T) and Panoza(T) soils are 20 to 40 inches to a paralithic contact. Polonio soils lack and argillic horizon. Thomhill(T) soils have a mollic epipedon and lack an argillic horizon. Yeguas (T) soils have a fine textural control section and are well drained.
DRAINAGE AND PERMEABILITY: Moderately well drained; slow runoff; permeability is slow.
USE AND VEGETATION: The soil is used for dry farmed small grain crops and some livestock grazing. The main crops grown on this soil are barley and wheat.
DISTRIBUTION AND EXTENT: Eastern San Luis Obispo County in the Carrizo Plain. These soils are not extensive. MLRA is 17.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: San Luis Obispo County, California; Carrizo Plain Area 1985. Soil name was coined from Pinole Spring.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the zone from the soil surface to about 14 inches.
Argillic horizon - the zone from about 25 to 30 inches (Bt horizon).
Silica cemented material - the zone from about 30 to 39 inches (2Btq horizon).
ADDITIONAL DATA: Pedon number is S84 CA-079-032-1 through 7.