LOCATION FAGAN CA

Established Series
Rev. GL/TDC/RWK
12/2022

FAGAN SERIES

The Fagan series consists of deep, well drained soils that formed in material from sandstone or shale. Fagan soils are on uplands and have slopes of 5 to 50 percent. The mean annual precipitation is about 26 inches and the mean annual air temperature is about 60 degrees F.

TAXONOMIC CLASS: Fine, smectitic, thermic Typic Argixerolls

TYPICAL PEDON: Fagan clay loam, range grass. (Colors are for dry soil unless otherwise noted.)

Ap--0 to 6 inches; dark grayish brown (2.5Y 4/2) light clay loam, very dark grayish brown (10YR 3/2) moist; moderate coarse subangular blocky structure; hard, friable, nonsticky and slightly plastic; many fine roots; many fine and common coarse interstitial pores; many worm casts; moderately acid (pH 5.8); abrupt smooth boundary. (4 to 8 inches thick)

A12--6 to 10 inches; dark grayish brown (2.5Y 4/2) light clay loam, very dark grayish brown (10YR 3/2) moist; strong medium subangular blocky structure; hard, friable, sticky and slightly plastic; many fine roots; many fine interstitial pores; many worm casts; moderately acid (pH 5.8); clear smooth boundary. (4 to 8 inches thick)

B1t--10 to 16 inches; dark grayish brown (10YR 4/2) heavy clay loam, very dark grayish brown (10YR 3/2) moist; weak medium prismatic structure that parts to moderate medium subangular blocky; slightly hard, friable, slightly sticky and plastic; thin patchy clay films on faces of peds; moderately acid (pH 5.8); clear smooth boundary. (4 to 8 inches thick)

B21t--16 to 25 inches; dark grayish brown (10YR 4/2) clay, very dark grayish brown (10YR 3/2) moist; weak medium angular blocky structure; very hard, firm, sticky and very plastic; few fine interstitial pores; thin continuous clay films on faces of peds; moderately acid (pH 5.8); clear smooth boundary. (4 to 10 inches thick)

B22t--25 to 28 inches; light olive brown (2.5Y 5/6) clay, olive brown (2.5Y 4/4) moist; weak medium and coarse angular blocky structure; very hard, firm, sticky and very plastic; thin continuous clay films on faces of peds; moderately acid (pH 5.8); clear irregular boundary. (2 to 7 inches thick)

B3t--28 to 46 inches; light yellowish brown (10YR 6/4) sandy clay loam, yellowish brown (10YR 5/5) moist; common fine distinct brown (10YR 4/3) and common fine prominent black (10YR 2/1) mottles; weak fine blocky structure; hard, friable, nonsticky and slightly plastic; thin patchy clay films on faces of peds; moderately acid (pH 5.8); gradual boundary. (15 to 20 inches thick)

Cr--46 to 50 inches; light yellowish brown (10YR 6/4) soft sandstone.

TYPE LOCATION: Napa County, California; about 8 miles southwest of Napa; 3/4 mile north of State Highway 12 ; NE1/4 NW1/4 section 5, T.4N., R.3W.

RANGE IN CHARACTERISTICS: Depth to a paralithic contact is 40 to 60 inches. The mean annual soil temperature is about 60 to 64 degrees F. and the soil temperature usually is not below 47 degrees F. at any time. The soil between depths of 4 and 12 inches is usually dry from mid-May until October or early November and is moist in some or all parts the rest of the year. The organic matter is less than 1 percent between depths of 10 and 20 inches. Base saturation is 75 to 95 percent in all parts.

The A horizon is brown to very dark grayish brown (10YR 5/3, 5/2, 4/2, 3/3, 3/2; 2.5Y 5/2, 4/2, 3/2). It is clay loam, silty clay loam, or loam and is medium or slightly acid.

The B2t horizon is brown, yellowish brown, light olive brown, grayish brown, or dark grayish brown (10YR or 2.5Y 6/4, 5/6, 5/4, 5/2, 5/3, 4/2). It is sandy clay, clay or silty clay with 35 to 50 percent clay. This horizon has weak prismatic or blocky structure. It is medium or slightly acid. Most pedons have B3 or B3t horizons that are sandy clay loam or clay loam and commonly have moist value of 5 or 6 in 10YR hue.

COMPETING SERIES: These are the Gabino Los Osos, Sespe, Sween and Todos series. Gabino, Los Osos, Sespe and Sween soils are underlain by bedrock at depths of about 24 to 40 inches. Also, Gabino and Sespe soils have hue of 5YR or redder. Todos soils have Bt horizon hue of 5YR or 2.5YR.

GEOGRAPHIC SETTING: Fagan soils are at elevations of 200 to 1,500 feet and have slope gradients of 5 to 50 percent. They formed in material weathered from soft sandstone and shale. The climate is dry subhumid mesothermal with warm, dry summers and cool, moist winters. The mean annual precipitation is 24 to 35 inches. The average annual temperature is 61 to 63 degrees F.; the average January temperature is 47 degrees F.; and the average July temperature is about 70 degrees F. The frost free season is 220 to 260 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Diablo, Dibble, and Haire soils. Diablo soils are clayey throughout and have slickensides. Dibble soils lack mollic epipedons. Haire soils have base saturation of less than 50 percent in the B2t horizon.

DRAINAGE AND PERMEABILITY: Well drained; medium to rapid runoff; slow permeability.

USE AND VEGETATION: Used mostly for range. Small areas are used fr wine grape production. Natural vegetation is mostly annual grasses and forbs with some perennial grasses and a few live oaks on north slopes.

DISTRIBUTION AND EXTENT: Central part of Coast Range in California, MLRA 15. The soils are moderately extensive.

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

SERIES ESTABLISHED: Napa County, California, 1974.

National Cooperative Soil Survey
U.S.A.