LOCATION TAGUS CAEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, thermic Calcic Haploxerolls
TYPICAL PEDON: Tagus loam, on a slope of less than 1 percent in a leveled, fallow field at 260 feet elevation. (Colors are for dry soil unless otherwise stated. When described 12/9/86 the soil was dry from 0 to 17 inches and slightly moist below.)
Ap1--0 to 8 inches; grayish brown (2.5Y 5/2) loam, very dark grayish brown (2.5Y 3/2) moist; weak medium and fine subangular blocky structure; slightly hard, friable, nonsticky and nonplastic; common medium, fine, and very fine roots; many medium, fine, and very fine tubular and many medium and fine interstitial pores; slightly alkaline (pH 7.4); clear wavy boundary.
Ap2--8 to 17 inches; grayish brown (10YR 5/2) loam, very dark grayish brown (10YR 3/2) moist; weak medium and fine subangular blocky structures; slightly hard, friable, slightly sticky and slightly plastic; common medium, fine, and very fine roots; many fine and very fine tubular pores; slightly alkaline (pH 7.7); clear wavy boundary. (Combined thickness of the Ap horizons is 10 to 20 inches).
Bk1--17 to 27 inches; brown (10YR 5/3) loam, dark grayish brown (2.5Y 4/2) moist; weak medium and fine subangular blocky structure; slightly hard, friable, slightly sticky and plastic; common medium, fine, and very fine roots; many fine and very fine tubular pores; slightly effervescent, disseminated carbonates and strongly effervescent, carbonates segregated in common medium and fine irregular soft masses; moderately alkaline (pH 8.2); clear wavy boundary. (5 to 15 inches thick).
Bk2--27 to 40 inches; light yellowish brown (2.5Y 6/4) fine sandy loam, brown (10YR 4/3) moist; massive; slightly hard, friable, nonsticky and slightly plastic; common medium, fine, and very fine roots; many fine and very fine tubular pores; strongly effervescent, disseminated carbonates and violently effervescent, carbonates segregated in common medium and fine irregular filaments and soft masses; moderately alkaline (pH 8.3); clear wavy boundary. (7 to 18 inches thick)
Bk3--40 to 63 inches; light yellowish brown (2.5Y 6/4) loam, brown (10YR 4/3) moist; massive; slightly hard, friable, slightly sticky and slightly plastic; common fine and very fine roots; many fine and very fine tubular pores; slightly effervescent, disseminated carbonates and strongly effervescent, carbonates segregated in few fine irregular filaments; strongly alkaline (pH 8.6).
TYPE LOCATION: Tulare County, California; about 7 miles west of Tagus; about 0.3 miles north of Ave. 264 on dirt farm road (Rd. 46), and 250 feet east of second row of almond trees; 1,400 feet east and 1,850 feet north of the southwest corner of Sec. 15, T. 19 S., R. 23 E., MDB&M; Latitude 26 degrees, 16 minutes, 27 seconds north and Longitude 119 degrees, 28 minutes, 9 seconds west; Goshen Quadrangle.
RANGE IN CHARACTERISTICS:
Soil temperature: 64 to 67 degrees F.
Mollic epipedon thickness: 10 to 20 inches.
Depth to soft, powdery secondary carbonates: 10 to 20 inches.
A Horizon--10YR 4/1, 4/2, 4/3, 5/1, 5/2, 5/3 and 2.5Y 4/2, 5/2; 10YR 2/1, 2/2, 3/1, 3/2, 3/3 and 2.5Y 2/2, 3/2 moist.
Bk Horizon--10YR 4/2, 4/3, 4/4, 5/2, 5/3, 5/4, 6/2, 6/3, 6/4 and 2.5Y 4/2, 4/4, 5/2, 5/4, 6/2, 6/4; 10YR 2/2, 3/3, 3/4, 4/2, 4/3, 4/4, 5/2, 5/3, 5/4 and 2.5Y 3/2, 4/2, 4/4, 5/2, 5/4 moist.
Texture: Loam, fine sandy loam, or sandy loam.
Clay content: 10 to 18 percent.
Structure: Subangular blocky or it is massive.
Reaction: Moderately alkaline or strongly alkaline.
Calcium carbonate equivalent: 6 to 10 percent in the upper part and 1 to 3 in the lower part.
Carbonates: Slightly effervescent to violently effervescent; few to many, fine to medium filaments, threads and soft masses of carbonates.
COMPETING SERIES: This is the Oquin series (CA). Oquin soils are 20 to 40 inches to soft rock.
GEOGRAPHIC SETTING: Tagus soils are on fan terraces and have slopes of 0 to 2 percent. The soils formed in alluvium derived from granitic rock sources. Elevations are 230 to 400 feet. The climate is semiarid and has hot, dry summers and cool, moist winters. The average annual precipitation is 9 to 12 inches. The mean annual temperature is 62 degrees to 65 degrees F. The frost-free period is 250 to 300 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Akers (T), Colpien (T), Grangeville, Nord, Tujunga, and Yettem soils. Akers soils lack a mollic epipedon. Grangeville and Yettem soils lack a calcic horizon and lack large amounts of secondary carbonates. Colpien and Nord soils have mollic epipedons that are greater than 20 inches thick. Tujunga soils have sandy particle size families and lack mollic epipedons.
DRAINAGE AND PERMEABILITY: Well drained; negligible to low runoff; moderate permeability.
USE AND VEGETATION: This soil is used for irrigated cropland to grow cotton, corn, wheat, barley, walnuts, almonds and alfalfa. It is also used for dairy and cattle production and building site development.
DISTRIBUTION AND EXTENT: The southern part of the San Joaquin Valley, California. It is not extensive in MLRA-17.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Tulare County, West Part, California, 1999.
REMARKS: The soil name is from a local town.
Diagnostic horizons and features recognized in this pedon:
1. Mollic epipedon -- The zone from the soil surface to a depth of about 17 inches (Ap1 and Ap2 horizons).
2. Calcic horizon -- The zone from a depth of 17 to 40 inches (Bk1 and Bk2 horizons).
3. Lab analysis for this typical pedon-sample numbers 88P5294S, 95S and 96S.
4. Regular decrease of organic carbon with increasing depth (see lab data).
Changed classification from typic to calcic and removed carbonates from surface due to additional information.