LOCATION TRIMMER CAEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, active, thermic Mollic Haploxeralfs
TYPICAL PEDON: Trimmer loam - oak, shrubs, and grasses (Colors are for dry soil unless otherwise noted.)
A1--0 to 5 inches; Grayish brown (10YR 5/2) loam, brown (10YR 5/3) rubbed, very dark grayish brown (10YR 3/2) moist; moderate medium granular structure; slightly hard, friable; common fine, few medium roots; few medium tubular pores; 2 to 7 percent angular pebbles; slightly acid (pH 6.5); abrupt wavy boundary. (4 to 7 inches thick)
A3--5 to 14 inches; Grayish brown (10YR 5/2) loam, brown (10YR 5/3) rubbed, very dark grayish brown (10YR 3/2) moist; weak and moderate fine subangular blocky structure; slightly hard, friable, slightly sticky, slightly plastic; common coarse roots; common medium tubular pores; thin continuous clay films line tubular pores; slightly acid (pH 6.4); clear smooth boundary. (6 to 10 inches thick)
B21t--14 to 21 inches; Reddish brown (5YR 5/4) sandy clay loam, dark reddish brown (5YR 3/4) moist; moderate fine angular blocky structure; very hard, firm, sticky, plastic; common coarse roots; common medium tubular pores; thin continuous-clay films on faces of peds and lining pores; slightly acid (pH 6.4); clear smooth boundary. (6 to 10 inches thick)
B22t--21 to 31 inches; Yellowish red (5YR 5/6) light sandy clay loam, dark reddish brown (5YR 3/3) moist; moderate fine angular blocky structure; very hard, firm, slightly sticky, slightly plastic; few fine roots; common coarse tubular pores; thin continuous clay films on faces of peds and lining pores; slightly acid (pH 6.2); clear wavy boundary. (8 to 14 inches thick)
C--31 to 40 inches; Weathered, grayish metamorphic diorite; well fractured, cracks are coated with dark reddish brown clay films fingering down from solum above; grades to unweathered parent rock.
TYPE LOCATION: Fresno County, California; .40 mile WSW of Clingan's Junction, north side of abandoned section of State Highway 180; SW1/4NW1/4 sec. 32, T.135., R.26E., M.D.B. & M.
RANGE IN CHARACTERISTICS: Depth to a paralithic contact of weathered rock is 24 to 40 inches. The mean annual soil temperature at a depth of 20 inches is 60 degrees to 65 F. The soil temperature does not go below 41 degrees F. and is only occasionally below 47 degrees F. in January. Soil between the depths of about 5 to 15 inches becomes moist in some or all parts some time in October and remains moist all of the time until some time in May. These soils are dry all the rest of the year. Coarse fragments make up 2 to 20 percent of the solum. Coarse and very coarse sand averages 10 to 20 percent throughout the solum. The soil is neutral to medium acid, but is usually slightly acid and without a clear trend in change with depth.
The A horizon is brown or grayish brown and has hue of 10YR or 7.5 YR. It is sandy loam or loam. It has 2 to 4 percent organic matter in the upper 4 inches and less than 1 percent at a depth of 8 inches below the surface. This horizon has weak or moderate structure and in some pedons in massive in some or all parts. The A-B2t horizon boundary is gradual or there are A3 or B1 transitional horizons. The absolute clay increase from the A horizon to the B2t horizon is about 10 to 17 percent.
The B2t horizon is yellowish brown, strong brown, brown (7.5YR 5/4, 4/4), reddish brown (5YR or yellowish red. It is clay loam or sandy clay loam with 20 to 30 percent clay. The lower part of the Bt horizon is sandy loam with less than 18 percent clay in some pedons.
COMPETING SERIES: These are the Academy, Burchell, Cajalco, Coarsegold, Honn, Jacinto, Los Robles, Marguerite, Modesto, Ojai, Pachappa, Perkins, Pleasanton, Rescue, Sobrante, Whitney, and Wyo series. Academy, Burchell, Honn, Jacinto, Los Robles, Marguerite, Modesto, Ojai, Pachappa, Perkins, Pleasanton, and Wyo soils lack a paralithic contact. Cajalco soils are not clearly differentiated. (See Remarks.) Coarsegold soils have 5 to 10 percent coarse and very coarse sand. Rescue soils have a paralithic contact at depths of 40 to 70 inches. Sobrante soils have a lithic contact. Whitney soils have an absolute clay increase from the A horizon to the B2t horizon of 3 to 7 percent.
GEOGRAPHIC SETTING: Trimmer soils formed in residuum weathered from basic and metabasic igneous rocks and are sloping to very steep. Elevations are 500 to 3,500 feet. The climate is subhumid mesothermal with warm dry summers and cool moist winters. Mean annual precipitation is 18 to 30 inches with little or no snow. The mean annual temperature is about 55 degrees to 61 degrees F. The freeze-free season is about 175 to 260 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Coarsegold soils and the Ahwahnee, Auberry, Hambright, Tretten, and Trabuco soils. Ahwahnee soils have less than 18 percent clay in the argillic horizon. Auberry soils have a base saturation of less than 75 percent in the upper part of the solum. Hambright and Tretten soils have mollic epipedons. Trabuco soils have more than 35 percent clay in the argillic horizon.
DRAINAGE AND PERMEABILITY: Well to somewhat excessively drained; medium to very rapid runoff; moderately slow permeability.
USE AND VEGETATION: The principal use of these soils is for woodland range. Common trees are blue oak, interior live oak Digger pine, and common shrubs are wedgeleaf ceanothus, birchleaf mountain mahogany, and poison oak. All open space has a ground cover of annual grasses and forbs.
DISTRIBUTION AND EXTENT: The soils occur in central California where they are of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Fresno County (Eastern Fresno Area), 1971.
REMARKS: The Trimmer soils were formerly classified as Noncalcic Brown Soils. More study is needed on the differentiae of the Cajalco series and some of the other competing series.
The activity class was added to the classification in January of 2003. Competing series were not checked at that time. - ET
OSED scanned by SSQA. Last revised by state on 5/72.