LOCATION AGUA DULCE              CA

Established Series
Rev. GAW-LCL
01/2023

AGUA DULCE SERIES

The Agua Dulce series have grayish brown, slightly acid, stony loam and loam A horizons, brown, slightly acid, very cobbly and gravelly clay loam B2t horizons, and light yellowish brown, slightly acid, very gravelly loamy coarse sand C horizons over conglomerate at a depth of 40 inches.

TAXONOMIC CLASS: Loamy-skeletal, mixed, active, thermic Mollic Haploxeralfs

TYPICAL PEDON: Agua Dulce stony loam native cover used for grazing (Colors are for dry soil unless otherwise noted.)

A1--0 to 3 inches; grayish brown (10YR 5/2) stony loam, very dark grayish brown (10YR 3/2) moist; weak very fine and fine granular structure; slightly hard, friable, nonsticky, nonplastic; common very fine roots; common very fine, few fine tubular pores; about 10 to 15 percent by volume stone, cobblestones and gravel; slightly acid (pH 6.5); abrupt smooth boundary. (3 to 6 inches thick)

A3--3 to 6 inches; grayish brown (10YR 5/2) heavy loam, dark brown (10YR 3/3) moist; massive; hard, friable, slightly sticky, slightly plastic; common very fine roots; common very fine, few fine tubular pores; few thin clay films as bridges between mineral grains; about 10 to 12 percent fine gravel; slightly acid (pH 6.5); clear smooth boundary. (3 to 6 inches thick)

B2t--6 to 20 inches; brown (7.5YR 5/4) very cobbly clay loam, brown (7.5YR 4/4) moist; strong medium and coarse angular blocky structure; hard, firm, sticky, plastic; few very fine roots mostly on faces of peds; common very fine tubular pores; many moderately thick clay films on faces of peds; about 25 percent cobblestones and 30 to 35 percent gravel; slightly acid (pH 6.5); abrupt wavy boundary. (12 to 18 inches thick)

C1--20 to 40 inches; light yellowish brown (10YR 6/4) very gravelly loamy coarse sand, yellowish brown (10YR 5/4) moist; massive; weakly consolidated; hard, firm, nonsticky, nonplastic; few very fine roots; few very fine interstitial pores; about 10 percent cobblestones and 65 to 75 percent gravel; slightly acid (pH 6.5).

C2--40 to 48 inches; weakly consolidated conglomerate.

TYPE LOCATION: Los Angeles County, California; west of Agua Dulce, 0.7 miles south of Davenport Road on power line road; SE 1/4 NW 1/4 sec. 34, T. 5 N., R. 14 W.

RANGE IN CHARACTERISTICS: The solum is about 20 to 30 inches thick. The mean annual soil temperature is about 65 F. and the soil temperature usually is not below 47 F. at any time. The soil between depths of about 8 to 25 inches is usually dry all of the time from mid-April until mid-December and is moist in some or all parts all the rest of the year. Rock fragments are mostly cobblestones and gravel with some larger stones; fragments make up 20 to 50 percent of the A horizon and 35 to 80 percent of the B and C horizons. The soil profile is slightly or medium acid, mostly slightly acid.

The A horizon is grayish brown or brown (10YR 5/2, 5/3; 7.5YR 5/2, 5/4) and has 1 1/2 to 3 percent organic matter in the upper 4 to 5 inches and less than 1 percent at the bottom of the horizon. It is massive in some or all parts or has weak structure.

The B2t horizon is brown to yellowish brown (7.5YR 5/4, 5/6; 10YR 5/4, 5/6). It is loam or clay loam with about 25 to 35 percent clay. This horizon has about 5 to 10 percent more clay absolute than the A horizon. Upper horizon boundaries are gradual or there are transitional horizons or both. The B2t horizon has weak to strong angular or subangular blocky structure.

The C2 horizon readily slakes in water, has considerable pores and is not regraded as a paralithic contact although it has few if any roots.

COMPETING SERIES: These are the Keefers, Modjeska, Pleasanton, and Wasioja series. Keefers soils have more than 35 percent clay in the argillic horizon. Modjeska soils lack enough clay increase in the B horizon to have an argillic horizon. Pleasanton and Wasioja soils have less than 35 percent rock fragments in the argillic horizon and Wasioja soils have an aridic moisture regime.

GEOGRAPHIC SETTING: The Agua Dulce soils are steep and are on hills at elevation of 2,200 to 2,700 feet. They formed in weakly consolidated non-marine gravelly sediments from mixed and granitic sources. The climate is dry subhumid mesothermal with warm dry summers and cool moist winters. Mean annual precipitation is 12 to 14 inches. Average January temperature is 53 F, average July temperature is 73 F, and mean annual temperature is 63 F. The freeze-free season is 265 to 285 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Castaic and Las Posas soils. Castaic soils lack argillic horizons. Las Posas soils have less than 35 percent rock fragments and the argillic horizon is reddish with hue of 2.5YR.

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

USE AND VEGETATION: Used for range. Vegetation is juniper, yucca, annual grasses, forbs, and some perennial grasses.

DISTRIBUTION AND EXTENT: Intermountain foothills in southern California. The soils are inextensive.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California

SERIES PROPOSED: Los Angeles County, California, 1973.

REMARKS: The Agua Dulce soils were formerly classified as Noncalcic Brown soils. These soils are transitional in vegetation, setting, and soil properties to mesic temperature and aridic moisture regimes.

Last revised by the state on 10/73.

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National Cooperative Soil Survey
U.S.A.