Established Series
Rev. RCH


The Yokohl Series is a member of a fine, montmorillonitic, thermic family of Typic Durixeralfs. The soils have reddish brown, clay loam A horizons, reddish brown, clay Bt horizons abruptly overlying reddish brown duripans. The soils are developed on alluvium from basic igneous rocks.

TAXONOMIC CLASS: Fine, smectitic, thermic Typic Durixeralfs

TYPICAL PEDON: Yokohl clay loam - annual grass pasture (Colors for dry conditions unless otherwise noted).

A1--0 to 12 inches; Reddish brown (5YR 4/3) clay loam containing slight amounts of gravel, dark reddish brown (5YR 3/3 moist; massive; hard, friable, plastic and sticky; many fine roots; many fine pores; neutral (pH 6.9 to 7.1); abrupt smooth boundary. (6 to 15 inches thick).

B2t--12 to 20 inches; Reddish brown (5YR 4/4) clay containing slight amount of gravel, reddish brown (5YR 4/3) moist; strong medium blocky structure; very hard, very firm, very plastic and very sticky; thick continuous clay films; neutral (pH 7.2); abrupt boundary. (4 to 12 inches thick).

C1m--20 to 23 inches; Between reddish brown (5YR 4/4) and yellowish red (5YR 5/5) strongly cemented iron-silica duripan, reddish brown (5YR 4/5) when moist; intermittently slightly calcareous, the lime mainly segregated in thin light colored seams; purplish black manganese stains in seams; few fine gravel; moderately alkaline (pH 8.2); clear smooth boundary. (2 to 4 inches thick).

C2m--23 to 48 inches; Light brown (7.5YR 6/4) weakly to moderately cemented iron-silica duripan, brown (7.5 YR 5/4) moist; massive; very hard, very firm; moderately calcareous with lime concentrated in seams; moderately alkaline (pH 8.2); gradual smooth boundary. (14 to 18 inches thick).

C3--48 inches+; Pale brown (10YR 6/3) gravelly loam, stratified; brown (10YR 5/3) moist; massive; hard, firm; moderately alkaline (pH 8.0); calcareous. (Several feet thick).

TYPE LOCATION: Tulare County, California, SE1/4 Sec. 32, T. 18 S., R. 27 E.

RANGE IN CHARACTERISTICS: The soils have ochric epipedons (massive and hard dry and/or chromas of 4 or more) argillic horizon and duripan. The soils are usually moist but dry for 60 consecutive days in the summer. The mean annual soil temperature is 59 degrees to 72 degrees F. Mineralogy is montmorillonitic. The solum thickness is 10 to 27 inches to the duripan. Differences in thickness and texture of the profile correspond to differences in micro-relief. The soils on the mounds are thicker and slightly coarser in texture than soils in the intermound areas. Depth to the hardpan is variable in color from brown, dark brown, reddish brown to dark reddish brown (7.5YR 5/4, 4/3; 5YR 3/4, 4/4, 4/3); in texture from fine sandy loam to heavy loam; in reaction from medium acid to mild alkaline (pH 6.0-7.4). Structure is massive to blocky and consistence is hard to very hard. The B2t horizon ranges in color from reddish brown and dark reddish brown in 5YR and 2.5YR hues with values of 3 and 4 and chromas of 4 to 6; in texture from heavy clay loam and clay to gravel and/or cobbly clay; in reaction from medium to mildly alkaline (pH 6.0-7.4). Structure is strong blocky medium to strong prismatic and consistence is very hard to extremely hard. The Cm horizons range in color from light brown to light red and dark red (7.5YR to 2.5YR). The Cm is indurated and contains seams of lime and is usually gravelly. It ranges in color from light brown, reddish yellow, to dark red in 7.5YR to 2.5YR hues. Reaction is neutral to moderately alkaline. The parent material usually consists of moderately coarse or medium textured
stratified alluvium.

COMPETING SERIES: These include in the same family Jesbel, Keyes, Madera and Tuscan. The Jesbel soils have dark grayish brown A horizons, dark brown sandy clay Bt horizons and white duripans which are lime-silica cemented. The Keyes soils have grayish brown A and B horizons. The Madera soils have light yellowish brown to yellowish brown A and B horizons. The Tuscan soils lack abrupt AB boundary and are slightly to medium acid throughout. Similar soils in another subgroup are Redding, San Joaquin, Gloria and Palo Cedro. These soils have abrupt AB boundaries With 15 percent clay increase within 1 inch, and Bt horizons have more than 35 percent clay in all parts.

GEOGRAPHIC SETTING: The Yokohl soils occur on gently sloping old fans and terraces on alluvium from dominately basic igneous rock. They occur at elevations of less than 500 feet, in a semiarid, mesothermal climate with mean annual rainfall of 10 to 15 inches, with hot, dry summers and cool, moist winters. Mean annual temperature is about 63 degrees F., average January temperature about 45 degrees F., and average July temperature about 79 degrees F. Frost-free
season averages about 260 days.

GEOGRAPHICALLY ASSOCIATED SOILS: Academy, Cajalco, Honcut, Ryer, Wyman and Porterville. The Cajalco soils are on the uplands underlain by basic igneous rock. The Honcut, Wyman, and Porterville soils are on recent alluvium. The Academy and Ryer soils are on old terraces and fans.

DRAINAGE AND PERMEABILITY: Soils are well drained. Runoff is very slow to rapid and permeability ia slow to very slow.

USE AND VEGETATION: Mostly for annual range but also for irrigated pasture. Vegetation ia annual grasses, forbs, and weeds.

DISTRIBUTION AND EXTENT: Eastern edge of San Joaquin Valley and intermountain Valleys of southern California. The soils are of moderate extent.


SERIES ESTABLISHED: Visalia Area, California, 1935. Source of name is Yokohl Creek, Tulare County.

REMARKS: The soils were formerly classified in the (maximal) Noncalcic Brown group.

OSED scanned by SSQA. Last revised by state on 7/67.

National Cooperative Soil Survey