LOCATION HENMEL CAEstablished Series
TAXONOMIC CLASS: Fine, smectitic, thermic Typic Argiaquolls
TYPICAL PEDON: Henmel clay loam - on a smooth slope of 1 percent in a cultivated field at 95 feet elevation. (Colors are for dry soil unless otherwise stated. When described on March 11, 1981, the soil was moist throughout and saturated below 60 inches).
Ap--0 to 6 inches; dark grayish brown (10YR 4/2) clay loam, very dark grayish brown (2.5Y 3/2) moist; moderate medium and coarse subangular blocky structure; hard, firm, slightly sticky and plastic; few very fine roots; few very fine tubular pores; 28 percent clay content; EC is 1.4 mmhos/cm; ESP is 7; moderately alkaline (pH 8.0); clear smooth boundary. (5 to 10 inches thick)
A--6 to 15 inches; dark grayish brown (2.5Y 4/2) clay loam, very dark grayish brown (2.5Y 3/2) moist; common fine prominent dark yellowish brown and gray (10YR 4/6; 5Y 5/1) mottles; common fine prominent dark brown and dark olive gray (10YR 4/3; 5Y 3/2) mottles moist; moderate medium and coarse subangular blocky structure; hard, firm, slightly sticky and plastic; few very fine and fine roots; few very fine tubular pores; 28 percent clay content; very few thin clay films bridging sand grains; moderately alkaline (pH 8.0); clear wavy boundary. (6 to 10 inches thick)
Bt1--15 to 22 inches; grayish brown (2.5Y 5/2) silty clay loam, dark grayish brown (2.5Y 4/2) moist; common fine prominent dark yellowish brown and gray (10YR 4/4; 5Y 5/1) mottles; many fine prominent dark brown and dark olive gray (10YR 4/3; 5Y 3/2) mottles moist; moderate coarse angular blocky structure; hard, firm, sticky and plastic; common very fine and few fine roots; few very fine and fine tubular pores; 35 percent clay content; EC is 1.2 mmhos/cm; ESP is 7; few thin clay films on peds; moderately alkaline (pH 8.0); clear smooth boundary. (6 to 9 inches thick)
B2t--22 to 37 inches; grayish brown (2.5Y 5/2) silty clay, very dark grayish brown (2.5Y 3/2) moist; common fine prominent dark yellowish brown and gray (10YR 4/4; 5Y 5/1) mottles; common fine distinct grayish brown and very dark gray (2.5Y 4/2; 5Y 3/1) mottles moist; strong coarse prismatic structure; hard, very firm, sticky and very plastic; few very fine roots; common very fine and fine tubular pores; common thin clay on peds; 41 percent clay content; EC is 1.5 mmhos/cm; ESP is 9; moderately alkaline (pH 8.0); gradual smooth boundary. (8 to 17 inches thick)
2BC--37 to 44 inches; dark grayish brown (10YR 4/2) sandy clay, very dark grayish brown (2.5Y 3/2) moist; common fine prominent gray (5Y 5/1) mottles, common fine distinct very dark gray (5Y 3/1) mottles moist; weak coarse subangular blocky structure; hard, firm, sticky and plastic; few very fine roots; few very fine tubular pores; 36 percent clay content; common thin clay films on peds; EC is 1.6 mmhos/cm; ESP is 10; slightly effervescent with disseminated lime and segregated as few fine filaments; moderately alkaline (pH 8.0); clear smooth boundary. (0 to 8 inches thick)
2CK--44 to 66 inches; dark brown (10YR 3/3) sandy loam; brown (10YR 4/3) moist; few fine distinct dark yellowish brown (10YR 4/6) mottles; common fine prominent olive gray (5Y 5/2), few fine prominent very dark gray (5Y 3/1), and common medium prominent gray (5Y 5/1) mottles moist; massive; slightly hard, friable, slightly sticky and plastic; no roots; common very fine tubular pores; 19 percent clay content; few thin clay films bridging sand grains; slightly effervescent with disseminated lime and segregated as few fine filaments; moderately alkaline (pH 8.0).
TYPE LOCATION: Merced County, California; about 3 miles north of the city of Los Banos; 2,500 feet north of intersection of Johnson Road and Henry Miller Avenue, 40 feet west of drainage ditch which bisects the NE 1/4 of SW 1/4 of section 34, or 2,400 feet east and 2,300 feet north of the SW corner of section 34, T.9 S., R.10 E.
RANGE IN CHARACTERISTICS: The soil is more than 60 inches deep. The moisture control section of 5 to 14 inches is moist throughout from about January 1 to June 1 and dry throughout from about July 1 to November 1. The mean annual soil temperature is 62 degrees F. The soil temperature is below 47 degrees F in parts of January and February but is never below 41 degrees F at anytime.
The A horizon is 10YR 4/2, 4/3, 4/4, 5/2, 5/3; 2.5Y 4/2 or 5/2. Moist colors are 10YR 3/2; or 2.5Y 3/2. It ranges from 19 to 35 percent clay content. Organic matter ranges from 1 to 3 percent. Some pedons are slightly effervescent.
The Bt horizon is 10YR 4/2, 4/3, 5/3; or 2.5Y 5/2. Moist colors are 10YR 3/2, 3/3, 4/3, 4/4, 5/4; 2.5Y 3/2, 4/2 or 4/4. It is silty clay loam, silty clay, or clay and ranges from 35 to 45 percent clay content but is always 6 to 10 percent (absolute) more than the A horizon. Some pedons are slightly to strongly effervescent. Some pedons do not have a 2BC horizon.
The 2C horizon is 10YR 3/3, 4/4 or 5/3. Moist colors are 10YR 3/2, 3/3, 4/3, 4/4, 5/4; 2.5Y 4/4 or 5/4. It is sandy loam or sandy clay loam and has 15 to 25 percent clay content. The reaction is moderately alkaline or strongly alkaline.
COMPETING SERIES: This is the Armenia series in the same family and the Bolfar, Britto, Dosamigos, Dospalos, Orestimba, Pescadero, Pedcat, and Stanislaus series in other families. Armenia soils have BC horizons in the lower part of the B horizon with Fe-Mn concretions, are slightly acid to mildly alkaline and noneffervescent, and are moist in the moisture control section most of the summertime. Bolfar soils are fine-loamy and do not have an argillic horizon. Britto, Orestimba, Pescadero, and Pedcat soils have natric horizons. Dosamigos soils have more than 15 ESP in the C horizon and lack an argillic horizon. Stanislaus soils are well drained and lack an argillic horizon.
GEOGRAPHIC SETTING: Henmel soils are on low alluvial fans adjacent to the valley basin rim. They have formed in mixed alluvium dominantly from sedimentary rock sources. They are on nearly level topography. Elevations are 95 to 110 feet. The climate is semiarid with hot dry summers and cool moist winters. Mean annual precipitation is 9 to 12 inches and occurs only in the winter months. The mean January temperature is 46 degrees F; mean July temperature is 79 degrees F; and mean annual temperature is 63 degrees F. Frost-free season is 210 to 280 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Pedcat and Stanislaus soils, and the Turlock and Woo soils. Turlock soils have a natric horizon and are fine-loamy. Woo soils are well drained and fine-loamy.
DRAINAGE AND PERMEABILITY: Poorly drained; slow runoff; slow permeability. Drainage has been improved by use of open drains; however, the water table is between 36 and 60 inches in depth from December through March.
USE AND VEGETATION: These soils are leveled and used as irrigated cropland. The main types of crops grown are field crops and alfalfa, with small acreages of irrigated pasture.
DISTRIBUTION AND EXTENT: These soils occur on low alluvial fans adjacent to the basin rim of the Central San Joaquin Valley. They are not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Merced County, California, 1984.
REMARKS: These soils were formerly included with and mapped as the Orestimba series in the Los Banos Area, series 1939 report. These soils are being differentiated by having a mollic epipedon and less than 15 percent exchangeable sodium. pH determined by colorimetric method using Thymol Blue and Hellige-Truog Triplex indicators. EC and ESP determined by saturation extract and versenate titration. Presence of lime determined by 10 percent HC1 solution. Texture determined by modified Bouyoucos method. Organic matter determined by Walkley-Black digestion method.
Last revised by the state on 5/85.