LOCATION MEKKADALE               CA

Established Series
Rev: PBF/CAH/ET
11/2015

MEKKADALE SERIES

The Mekkadale series consists of shallow, well drained soils that formed in alluvium from granitoid rocks. Mekkadale soils are on fan remnants. Slopes range from 4 to 30 percent. The mean annual precipitation is about 138 millimeters (5.5 inches) and the mean annual air temperature is about 18.5 degrees C (64.5 degrees F).

TAXONOMIC CLASS: Loamy, mixed, superactive, thermic, shallow Argidic Argidurids

TYPICAL PEDON: Mekkadale loam, on a north-northwest-facing, convex, 16 percent slope under desert shrubs at an elevation of 947 meters (3,106 feet). (Colors are for dry soil unless otherwise noted.) The surface is covered by approximately 25 percent fine gravel, 45 percent medium and coarse gravel and 10 percent cobbles.

A -- 0 to 3 centimeters (0 to 1 inch); yellowish brown (10YR 5/4) loam, brown (10YR 4/3) moist; weak thin platy structure; slightly hard, very friable, slightly sticky and slightly plastic; few very fine and fine roots; few very fine and fine vesicular pores; 7 percent fine gravel, and 3 percent medium and coarse gravel; slightly alkaline (pH 7.4); abrupt smooth boundary. (2 to 5 centimeters thick)

Bt -- 3 to 30 centimeters (1 to 12 inches); yellowish brown (10YR5/6) loam, strong brown (7.5YR 4/6) moist; moderate medium subangular blocky structure; moderately hard, friable, slightly sticky and moderately plastic; common very fine, few fine and very few medium roots; few very fine and fine interstitial pores; 15 percent, distinct, brown (7.5YR 4/4) clay films on ped faces; 6 percent fine gravel and 1 percent medium and coarse gravel; slightly alkaline (pH 7.4); clear wavy boundary.

Btk -- 30 to 47 centimeters (12 to 18 inches); dark yellowish brown (10YR 4/6) sandy loam, yellowish brown (10YR 5/4) moist; moderate medium subangular blocky structure; moderately hard, firm, slightly sticky and slightly plastic; very few medium roots; 20 percent, faint, yellowish brown (10YR 5/4) clay films on ped faces; 3 percent fine, prominent, irregular, soft, very pale brown (10YR 8/2) calcium carbonate masses with clear boundary within the matrix; 6 percent fine gravel and 4 percent medium and coarse gravel; very slightly effervescent; slightly alkaline (pH 7.8); clear wavy boundary. (Combined thickness of the Bt horizons is 25 to 47 centimeters)

Bkqm -- 47 to 66 centimeters (18 to 26 inches); pale brown (10YR 6/3) weakly to moderately cemented loamy sand, brown (10YR 4/3) moist; duripan with 95 percent cementation; massive; very hard, very firm, brittle; 5 percent fine, prominent, irregular, hard, very pale brown (10YR 8/2) calcium carbonate threads with clear boundary within the matrix; 2 percent fine gravel and 1 percent medium and coarse gravel; violently effervescent; moderately alkaline (pH 8.2); clear wavy boundary. (10 to 25 centimeters thick)

Ckq -- 66 to 150 centimeters (26 to 59 inches); very pale brown (10YR 7/3) gravelly loamy sand, brown (10YR 4/3) moist; massive; slightly hard, friable, nonsticky and nonplastic; 2 percent fine, very pale brown (10YR 7/3) irregular durinodes in the matrix; 20 percent fine gravel and 10 percent medium and coarse gravel; violently effervescent; moderately alkaline (pH 8.2).

TYPE LOCATION: Riverside County, California; approximately 415 meters (1,361 feet) west-northwest of the Cottonwood Visitor Center, near the junction of Pintobasin and Cottonwood Oasis Roads in Joshua Tree National Park; 592 meters (1,942 feet) east and 656 meters (2,151 feet) north of the SW corner of sec. 9, T. 5 S., R. 11 E., San Bernardino Base and Meridian; 34 degrees, 44 minutes and 59.5 seconds north latitude, and 115 degrees, 49 minutes and 41.8 seconds west longitude; USGS Cottonwood Springs 7.5 minute topographic quadrangle; UTM 11S 0608525e 3735037n (DTM: NAD83).

RANGE IN CHARACTERISTICS:

Soil moisture control section: usually dry, moist in some parts for short
periods during winter and early spring and for 10 to 20 days cumulative
between July and September following convection storms. The soils have a
typic-aridic soil moisture regime.

Soil temperature: 19 to 22 degrees C (66 to 72 F).
Surface rock fragments: 65 to 79 percent, with 10 to 30 percent fine gravel,
40 to 55 percent medium and coarse gravel and 0 to 10 percent cobbles.

Control section -
Clay content: averages 18 to 24 percent, ranges from 15 to 28 percent.
Rock fragments: 5 to 15 percent, dominantly gravel.
Organic matter: 0 to 0.5 percent.
Depth to the upper boundary of an argillic horizon: 2 to 5 centimeters (1 to
2 inches).
Depth to the upper boundary of a duripan: 36 to 50 centimeters (14 to 20
inches).

A horizon
Hue: 7.5YR or 10YR.
Value: 5 or 6 dry, and 4 or 5, moist.
Chroma: 3 to 6, moist.
Texture of the fine earth: loamy coarse sand or loam.
Clay content: 8 to 16 percent.
Rock fragments: 10 to 15 percent gravel.
Effervescence: noneffervescent to violently effervescent.
Reaction: slightly or moderately alkaline.
Other features: vesicular pores present in some pedons.

Bt or Btk horizon
Hue: 7.5YR or 10YR.
Value: 4 or 5, dry or moist.
Chroma: 4 to 6, dry or moist.
Texture of the fine earth: sandy loam or sandy clay loam.
Clay content: 15 to 28 percent.
Rock fragments: 5 to 15 percent gravel.
Effervescence: noneffervescent to violently effervescent.
Calcium carbonate equivalent: 0 to 5 percent.
Reaction: slightly to strongly alkaline.

Bkq, Bkqm or Ckq horizon
Hue: 7.5YR or 10YR.
Value: 5 to 8, dry; 3 to 7, moist.
Chroma: 2 to 4, dry; 3 to 6, moist.
Clay content: 3 to 12 percent.
Texture of the fine earth: coarse sand, loamy sand, coarse sandy loam or
sandy loam.
Rock fragments: 1 to 30 percent gravel.
Reaction: moderately to very strongly alkaline.
Calcium carbonate equivalent: 5 to 15 percent.
Cementation: extremely weak to strong cementation, 75 to 95 percent continuity.
Silica: 0 to 15 percent durinodes.

COMPETING SERIES: There are no competing series at this time.

GEOGRAPHIC SETTING: Mekkadale soils are on fan remnants. Slopes range from 4 to 30 percent. These soils formed in alluvium from granitoid rocks. Elevations range from 930 to 1,020 meters (3,050 to 3,345 feet). The climate is arid, with hot, dry summers and warm, moist winters. The mean annual precipitation is 100 to 175 millimeters (4 to 7 inches) and the mean annual air temperature is 17 to 20 degrees C (62 to 68 degrees F). The frost-free season is 270 to 320 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Coppermine, Corbilt, Edalph, Gocougs, Minhoyt, Pinkcan, Stranger and Werewolf soils. Corbilt, Edalph, Gocougs, Minhoyt, Pinkcan, and Werewolf soils are on similar landscape positions while Coppermine and Stranger soils are on adjacent hills and pediments. Coppermine and Werewolf soils have loamy-skeletal particle-size control sections, and do not have a duripan. Corbilt, Edalph, Minhoyt and Stranger soils do not have an argillic horizon and have less than 18 percent clay in the control section. Edalph soils are also very deep, sandy throughout the particle-size control section, and have a calcic horizon. In addition, Corbilt has a duripan beginning below 100 centimeters and Minhoyt has a duripan beginning at less than 18 centimeters. Stranger soils have a lithic contact between 8 and 25 centimeters. Gocougs soils have a petrocalcic horizon beginning below 50 centimeters and Pinkcan soils have a duripan beginning between 100 and 150 centimeters.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; high runoff; moderately high saturated hydraulic conductivity above the duripan, moderately low saturated hydraulic conductivity within the duripan and high saturated hydraulic conductivity below the duripan.

USE AND VEGETATION: Mekkadale soils are used for recreation and wildlife habitat. The present vegetation is mainly burrobush, creosote bush, range ratany and jojoba.

DISTRIBUTION AND EXTENT: Southern Mojave Desert of southeastern California. MLRA 30. These soils are of small extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: PHOENIX, ARIZONA

SERIES ESTABLISHED: Riverside County, California; Soil Survey of Joshua Tree National Park Soil Survey, California, 2012. The name is from a location within the soil survey area.

REMARKS: Diagnostic horizons and features in this pedon include:

Ochric epipedon - from a depth of 0 to 3 centimeters (A horizon).
Argillic horizon - from a depth of 3 to 47 centimeters (Bt and Btk horizons).
Duripan - from a depth of 47 to 66 centimeters (Bkq horizon).
Particle-size control section - from a depth of 3 to 47 centimeters (Bt and
Btk horizons).

ADDITIONAL DATA: NASIS User Pedon ID: POWA14.

Responsibility for this series was transferred from Davis to Phoenix 11/2015. The last revision to the series was 6/2012. ET

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National Cooperative Soil Survey
U.S.A.