LOCATION LOS GATOS CAEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, active, mesic Typic Argixerolls
TYPICAL PEDON: Los Gatos clay loam - annual grass and brush. (Colors are for dry soil unless otherwise noted).
A1--0 to 6 inches; brown (7.5YR 5/4) light clay loam, dark brown (7.5YR 3/3) moist; strong medium granular structure; hard, friable, slightly sticky, slightly plastic; common very fine roots; many fine and very fine interstitial, few medium tubular pores; many worm casts and rodent burrows; slightly acid (pH 6.5); clear smooth boundary. (4 to 6 inches thick)
A2--6 to 15 inches; brown (7.5YR 5/4) light clay loam, dark brown (7.5YR 3/3) moist; moderate medium subangular blocky structure; hard, friable, slightly sticky, slightly plastic; few very fine roots; many fine and very fine interstitial and tubular and few medium tubular pores; common worm casts and rodent burrows; slightly acid (pH 6.3); clear smooth boundary. (5 to 11 inches thick)
BAt--15 to 25 inches; brown (7.5YR 5/4) clay loam, dark brown (7.5YR 3/3) moist; moderate medium subangular blocky structure; hard, friable, slightly sticky, slightly plastic; few very fine roots; many fine and very fine interstitial and tubular and few medium tubular pores; many thin clay films in pores and on peds; slightly acid (pH 6.2); abrupt wavy boundary. (7 to 12 inches thick)
Bt--25 to 36 inches; yellowish red (5YR 5/6) gravelly clay loam, reddish brown (5YR 4/5) moist; weak medium subangular blocky structure; very hard, firm, sticky, plastic; few medium and fine roots; many very fine interstitial and tubular and few fine and medium tubular pores; thin continuous clay films in pores and on peds; about 15 percent medium and fine shale fragments; moderately acid (pH 5.9); abrupt wavy boundary. (8 to 12 inches thick)
R--36 to 46 inches; very pale brown (10YR 7/4) sandstone; reddish brown (5YR 4/4) clay films on rock faces in fractures; rock shattered in upper few inches, becoming nearly massive within depth of 10 inches.
TYPE LOCATION: Santa Clara County, California; road cut on Monte Bello Road, 1 1/2 miles southeast of Black Mountain on the crest of Monte Bello Ridge; southern part of the SW 1/4 SE 1/4 of sec. 19, T. 7 S., R. 2 W.
RANGE IN CHARACTERISTICS: Depth to sandstone is 24 to 40 inches. The soil between depths of about 5 and 12 inches usually is dry from sometime in May until sometime in October. It usually is moist the rest of the year. The mean annual soil temperature is 54 to 58 degrees F and the soil temperature is very briefly, if ever, below 47 degrees F. Typically, there are few rock fragments in the upper horizons and less than 35 percent in the lower horizons. The solum ranges from neutral to moderately acid. Typically, the A horizon is slightly acid and the B horizon is moderately acid.
The A horizon is mostly brown, dark brown, grayish brown, dark grayish brown, or yellowish brown in 10YR or 7.5YR hue and some pedons are reddish brown in 5YR hue. Moist value and moist chroma are 2 or 3. This horizon is fine sandy loam, loam or clay loam. It has granular or subangular blocky structure or has crumb structure in the upper part. The lower boundary of the A horizon is gradual or an A3 horizon or a BA horizon is present. The organic matter ranges from 2 to 6 percent.
The Bt horizon is pinkish gray, light reddish brown, reddish yellow, brown, strong brown, or light brown in 7.5YR hue or reddish brown or yellowish red in 5YR hue. It is heavy loam, sandy clay loam, or clay loam with less than 35 percent clay. Absolute clay increases from A horizon to B2t horizon ranges from about 5 to about 9 percent. The Bt horizon has weak or moderate subangular blocky structure. In some pedons, it rests on bedrock. In other pedons, there is a brownish yellow or yellowish brown B3 horizon or a C horizon above the bedrock.
COMPETING SERIES: These are the Colma, Dragoon, Gilroy, Glenrose, Ladd, Lobitos, Los Osos, Mehlhorn, Sobrante, and Sweeney series. Colma, Lobitos, and Sweeney soils lack brown and reddish color of 7.5YR and 5YR hue in the Bt horizon. Colma, Dragoon, Glenrose, Ladd, and Sweeney soils lack a lithic contact at depths of less than 40 inches. Gilroy soils have a mean soil temperature of 59 to 64 degrees F. Los Osos soils have more than 35 percent clay in the argillic horizon. Mehlhorn soils have a mean soil temperature of less than 54 degrees F. Sobrante soils lack a mollic epipedon.
GEOGRAPHIC SETTING: Los Gatos soils are on steep to very steep mountainous areas at elevations of 200 to 4,000 feet. They formed in residuum from sandstone, shale and metasedimentary rock. The climate is subhumid mesothermal with warm dry summers and cool moist winters. Mean annual precipitation is 20 to 70 inches. The mean annual temperature is about 52 to 56 degrees F with an average January temperature of about 47 degrees F and an average July temperature of about 68 degrees F. Freeze-free season is about 200 to 330 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Gamboa, Godde, Henneke, Maymen, Millsholm, Plaskett, and Sur soils. All of these except the Henneke soils lack an argillic horizon. Gamboa, Henneke, Plaskett, and Sur soils have more than 35 percent rock fragments in the texture control section. Godde soils ahve bedrock at depths of less than 20 inches. Maymen and Millsholm soils have ochric epipedons.
DRAINAGE AND PERMEABILITY: Well-drained; rapid to very rapid runoff; moderate permeability.
USE AND VEGETATION: Most areas are used for watershed or wildlife protection. Some areas are used for range and a few of the lesser sloping areas have been planted to orchards and vineyards. Brush is the principal vegetation with some areas of hardwoods and grass.
DISTRIBUTION AND EXTENT: Coast ranges of northern and central California. The soils are extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Santa Clara County (Santa Clara Area), California, 1946.
REMARKS: The soils formerly were classified as (minimal) Brunizems. Some soils classified as Los Gatos in the past are thermic and are now excluded from the series.
The activity class was added to the classification in February of 2003. Competing series were not checked at that time. - ET