LOCATION JEHEMY CA

Established Series
RJ/DCE/MAV/GML
04/2019

JEHEMY SERIES

The Jehemy series consists of very deep well drained soils that formed in alluvium material derived mostly from sedimentary rock sources. Jehemy soils are on marine terraces and hills and have slopes of 2 to 20 percent. The mean annual precipitation is about 230 millimeters (11 inches) and the mean annual temperature is about 16 degrees C (61 degrees F).

TAXONOMIC CLASS: Fine, smectitic, isothermic Sodic Haplusterts

TYPICAL PEDON: Jehemy clay-on a north facing slope of 4 percent under a cover of slender oats, Mediterranean barley, soft chess and Australian saltbush at 220 meters (730 feet) elevation. (Colors are for dry soil unless otherwise stated. When described on October 21, l984, the soil was slightly moist to 51 centimeters (20 inches) and moist below.)

An1--0 to 20 centimeters (0 to 8 inches); light brownish gray (10YR 6/2) clay, dark grayish brown (10YR 4/2) moist; strong medium angular blocky structure; extremely hard, firm, very sticky and very plastic; many very fine roots; many very fine interstitial and tubular pores; moderately alkaline (pH 8.0); clear smooth boundary. (15 to 25 centimeters; 6 to 10 inches thick)

An2--20 to 46 centimeters (8 to 18 inches); light brownish gray (10YR 6/2) clay, brown (10YR 4/3) moist; strong medium and coarse prismatic parting to strong medium and coarse angular blocky structure; extremely hard, firm, very sticky and very plastic; common very fine roots; many very fine tubular pores; common wedge shape aggregates; moderately alkaline (pH 8.0); gradual smooth boundary. (25 to 36 centimeters; 10 to 14 inches thick)

An3--46 to 71 centimeters (18 to 28 inches); pale brown (10YR 6/3) clay, brown (10YR 4/3) moist; strong coarse and very coarse prismatic structure; extremely hard, firm, very sticky and very plastic; common very fine roots; common very fine tubular pores; common wedge shape aggregates and few intersecting slickensides; slightly alkaline (pH 7.5); gradual smooth boundary. (25 to 51 centimeters; 10 to 20 inches thick)

Cn1--71 to 112 centimeters (28 to 44 inches); light brownish gray (2.5Y 6/2) clay, dark grayish brown (2.5Y 4/2) moist; strong coarse and very coarse prismatic parting to strong medium and coarse angular blocky structure; extremely hard, firm, very sticky and very plastic; few very fine roots; many very fine tubular pores; few wedge shape aggregates and few intersecting slickensides; slightly alkaline (pH 7.8); gradual wavy boundary. (33 to 41 centimeters; 13 to 16 inches thick)

Cn2--112 to 152 centimeters (44 to 60 inches); light brownish gray (2.5Y 6/2) clay with few faint brownish yellow (10YR 6/6) mottles, dark grayish brown (10YR 4/2) moist; yellowish brown (10YR 5/6) mottles moist; strong coarse angular blocky structure, extremely hard, firm, very sticky and very plastic; few very fine roots; common very fine tubular pores; slightly alkaline (pH 7.5).

TYPE LOCATION: San Nicolas Island, California, going southwest from the Fire station #4 about 1.0 kilometer (0.6 miles) and then about 90 meters (300 feet) going southeast from the paved road past two gullies to site, about 90 meters (300 feet) southeast from the tall metal frame antenna tower; 33.2399056 degrees latitude, -119.4902556 degrees longitude; UTM Zone 11, 3680648.46n, 267972.92e; U.S.G.S. Quad Name: San Nicolas Island.

RANGE IN CHARACTERISTICS: The depth to bedrock is greater than 150 centimeters. The mean annual soil temperature is about 17 degrees C (62.6 degrees F.), and the difference between the mean summer and the mean winter is about 5 degrees C (9 degrees F). The soil between the depths of 15 and 26 centimeters (6 and 14 inches) is dry in all parts from about May or June to November and is moist in all parts of the soil moisture control section from January to mid-March 60 to 75 days. The soil temperature is always above 8 degrees C (47 degrees F). The moisture regime is ustic bordering on aridic. When dry, the soil develops cracks that are at least 1 cm wide and 15 to 36 centimeters (6 to 12 inches) apart at a depth of 71 centimeters (28 inches). The cracks remain open from sometime in June or July until sometime in October. The soil is neutral or moderately alkaline. Some pedons have finely disseminated calcium carbonate or calcium carbonate is segregated as few fine seams, filaments or threads. ESP ranges from 15 to 35 to a depth of 112 centimeters (44 inches) and the electrical conductivity is 4 to 8 desisiemens per meter.

The An horizon has dry colors of 10YR 5/2, 5/3, 6/2, 6/3; 2.5Y 5/2 or 6/2, and moist colors of 10YR 3/2, 3/3, 4/2, 4/3; 2.5Y 3/2, or 4/2. It has 40 to 60 percent clay. It has few wedge shape aggregates and few intersecting slickensides in the lower part of the A horizon.

The Cn horizon has dry colors of 10YR 6/2, 6/3; 2.5Y 6/2 or 6/4, and moist colors of 10YR 4/2, 4/3; 2.5Y 4/2 or 4/3. Some pedons have few faint mottles and iron stains, 10YR 7/4, 6/6, or 7/6; moist color is 10YR 5/4, 4/6, or 5/6. Texture is clay and clay loam. ESP is 5 to 20.

Channeled and overwashed phases are also recognized, overwashed phases are loams or sandy loams about 20 to 36 centimeters (8 to 14 inches) thick. The overwash soil material is the result of accelerated past erosion from the steeper slopes.

COMPETING SERIES: This is the Notspier series. Notspier soils are 51 to 102 centimeters (20 to 40 inches) to soft bedrock, have moist values in the upper 30 centimeters (12 inches) of less than 3.5 and are located on hills and terraces on San Clemente Island.

GEOGRAPHIC SETTING: The Jehemy soils are on marine terraces and hills and have slopes of 2 to 20 percent. The soils formed in alluvium material derived mostly from sedimentary rock sources. Elevation ranges from 150 to 270 meters (490 to 885 feet). The climate is subhumid with warm dry summers and cool moist winters. Mean annual precipitation is about 250 to 310 millimeters (10 to 12 inches). Mean January temperature is about 12.2 degrees C (54 degrees F), mean July temperature is about 17.8 degrees C (64 degrees F), and mean annual temperature is about 16 degrees C (61 degrees F). Frost-free season is about 365 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Nicolas, Olf and the Vizcapoint soils. Nicolas soils are sands or loamy sands throughout the profile and are on dunes. Olf and Vizcapoint soils have argillic horizons and are on marine terraces.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; slow to rapid runoff; low saturated hydraulic conductivity.

USE AND VEGETATION: Used mainly for military maneuvers and wildlife habitat. Vegetation is mostly slender oats, red brome, soft chess, Australian saltbush, and Mediterranean barley.

DISTRIBUTION AND EXTENT: San Nicolas Island, Ventura County, California. The soils are not extensive.

SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Davis, California

SERIES ESTABLISHED: Channel Islands Soil Survey Area, San Nicolas Island part, Ventura County, California, 1985. The name is from Jehemy Beach.

REMARKS:

Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon: the zone from a depth of 0 to 71 centimeters (0 to 28 inches). (A1, A2, A3,)

Ustic bordering aridic moisture regime: Moist in all parts for 60 to 75 days after December 21st.

Isothermic temperature regime: Mean annual soil temperature is about 61 degrees F, mean summer and mean winter differ by only 8 or 9 degrees F. This pedon has samples S84CA 111-003-5, 6, and 7, from Lincoln, Nebraska.

OSD revised during correlation of the San Nicolas Island Interim Report in 2018.

ADDDITIONAL DATA:

NASIS PEDON ID: 1982CA111001
Classified using the Twelfth Edition Keys to Soil Taxonomy (2014)

National Cooperative Soil Survey
U.S.A.