LOCATION JACKFLAT                CA

Established Series
Rev. EWB-JVC-JBF
03/2017

JACKFLAT SERIES

The Jackflat series consists of deep, well drained soils that formed in colluvium and slope alluvium derived from granodiorite. Jackflat soils are on mountains. Slopes are 4 to 30 percent. The mean annual precipitation is about 500 mm and the mean annual temperature is about 4 degrees C.

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive Xeric Argicryolls

TYPICAL PEDON: Jackflat very gravelly coarse sandy loam--rangeland. (Colors are for dry soil unless otherwise noted.) The soil surface is covered with 25 percent gravel, 5 percent cobbles, and 2 percent stones.

A1--0 to 3 cm; grayish brown (10YR 5/2) very gravelly coarse sandy loam, very dark grayish brown (10YR 3/2) moist; weak fine granular structure; soft, very friable, nonsticky and nonplastic; common very fine roots; many very fine interstitial pores; 30 percent gravel and 5 percent cobbles; slightly acid (pH 6.4); clear smooth boundary. (3 to 8 cm thick)

A2--3 to 15 cm; grayish brown (10YR 5/2) very gravelly sandy loam, very dark grayish brown (10YR 3/2) moist; moderate fine and medium subangular blocky structure; soft, very friable, slightly sticky and nonplastic; many very fine and fine roots; common very fine tubular and interstitial pores; 40 percent gravel, 5 percent cobbles, and 5 percent stones; slightly acid (pH 6.4); clear wavy boundary. (10 to 20 cm thick)

Bt1--15 to 36 cm; brown (10YR 5/3) very gravelly sandy loam, very dark grayish brown (10YR 3/2) moist; moderate fine and medium subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine, fine and medium roots; common very fine tubular and interstitial pores; common distinct clay films on faces of peds and lining pores; 40 percent gravel, 5 percent cobbles, and 5 percent stones; slightly acid (pH 6.4); clear wavy boundary. (18 to 30 cm thick)

Bt2--36 to 58 cm; brown (7.5YR 5/3) extremely cobbly sandy clay loam, brown (7.5YR 4/4) moist; strong medium subangular blocky structure; very hard, firm, moderately sticky and moderately plastic; common very fine and few fine and medium roots; common very fine tubular and interstitial pores; many distinct clay films on faces of peds and lining pores; 40 percent gravel, 15 percent cobbles, and 10 percent stones; slightly acid (pH 6.4); clear wavy boundary. (20 to 36 cm thick)

Bt3--58 to 114 cm; light yellowish brown (10YR 6/4) very stony sandy clay loam, yellowish brown (10YR 5/6) moist; moderate medium subangular blocky structure; hard, friable, moderately sticky and slightly plastic; few very fine roots; common very fine tubular and interstitial pores; common distinct clay films on faces of peds and few prominent clay films lining pores; 25 percent gravel, 5 percent cobbles, and 20 percent stones; 25 percent paragravel; slightly acid (pH 6.4); clear wavy boundary. (38 to 58 cm thick)

2Cr--114 cm; weathered granodiorite.

TYPE LOCATION: Mono County, California; on the Toiyabe National Forest about 1 mile northeast of Wild Horse Mountain on Jackass Flat; in a nonsectionized township near the projected southeast corner of section 18, T. 8 N., R. 24 E.; USGS Risue Canyon latitude 7.5 minute topographic quadrangle; 38 degrees 32 minutes 5.9 seconds N and longitude 119 degrees 22 minutes 32.5 seconds W; WGS84 Decimal Degrees 38.5349722 latitude, -119.3756944 longitude.

RANGE IN CHARACTERISTICS:
Soil moisture: Usually moist in the moisture control section during late fall, winter, and spring; dry from July through early October for 75 to 90 consecutive days in the four months following the summer solstice; xeric soil moisture regime that borders on aridic.
Mean annual soil temperature: 6 to 8 degrees C.
Mean summer soil temperature: 12 to 15 degrees C.
Mollic epipedon thickness: 25 to 40 cm; includes the Bt1 horizon.
Depth to base of argillic horizon: 100 to 150 Cm.
Depth to bedrock: 100 to 150 cm to a paralithic contact. The paralithic materials below the contact are weathered granitic rock.

Particle-size control section - Clay content: Averages 18 to 27 percent.
Rock fragments: Averages 35 to 60 percent. Lithology of rock fragments is granodiorite.

A horizons
Value: 4 or 5 dry, 2 or 3 moist.
Chroma: 2 or 3, dry or moist.
Organic matter content: 2 to 4 percent.
Reaction: Slightly acid or neutral.

Bt1 horizon
Chroma: 2 or 3, dry or moist.
Texture: Very gravelly sandy loam or very gravelly sandy clay loam.
Clay content: 15 to 25 percent.
Rock fragments: 35 to 60 percent.
Organic matter content: 1 to 3 percent.
Reaction: Slightly acid or neutral.

Bt2 and Bt3 horizons
Hue: 10YR or 7.5YR.
Value: 5 or 6 dry, 4 or 5 moist.
Chroma: 3 or 4 dry, 4 or 6 moist.
Clay content: 20 to 27 percent.
Rock fragments: 35 to 60 percent.
Reaction: Slightly acid or neutral.

COMPETING SERIES: These are the Boneyard, Chamberlain, Cowlow, Crandall, Forsey, Fourme, Itwo, Packer, Scuffe, Stopatoe, Successloop, Tagum, Toquima, Winada, and Zeebar series.

Bonyard, Cowlow, Itwo, and Toquima soils are moderately deep to lithic contacts. Chamberlain, Forsey, Fourme, Successloop and Zeebar soils are very deep. Crandall soils are deep to lithic contacts and have horizons with secondary carbonates. Packer soils are deep and very deep to lithic contacts and have depth to the base of the argillic horizon within 53 cm of the soil surface. Scuffe, Stopatoe, Tagum, and Winada soils are moderately deep to paralithic contacts.

GEOGRAPHIC SETTING: Jackflat soils are on mountains. They typically occur on summit and shoulder positions. They formed in colluvium and slope alluvium derived from granodiorite. Slopes are 4 to 30 percent. Elevations range from 2,440 to 2,740 meters. The climate is subhumid-continental with cold, moist winters and cool, dry summers. The mean annual precipitation is 400 to 600 mm, the mean annual temperature is 3 to 6 degrees C, and the frost-free period is 30 to 60 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bakscratch, Elaero, and Grandridge soils. Bakscratch soils are shallow to paralithic contacts. Elaero soils are moderately deep to paralithic contacts and have a frigid temperature regime. Grandridge soils are shallow to paralithic contacts and have a frigid temperature regime.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; medium surface runoff; moderately high saturated hydraulic conductivity.

USE AND VEGETATION: Jackflat soils are used for rangeland, recreation, watershed, and wildlife habitat. The native vegetation is mainly mountain big sagebrush, snowberry, and western needlegrass.

DISTRIBUTION AND EXTENT: Eastern California, on the east side of the Sierra Nevada Range. These soils are not extensive with about 700 acres of the series mapped to date. MLRAs 22A and 26.

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

SERIES ESTABLISHED: Mono County (Toiyabe National Forest Area), California, 2006.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to 36 cm (A1, A2, and Bt1 horizons).
Argillic horizon - The zone from 15 to 114 cm (Bt1, Bt2, and Bt3 horizons).
Paralithic contact - The boundary at 114 cm to underlying soft bedrock (2Cr layer).
Particle-size control section - The zone from 15 to 65 cm (Bt1 and Bt2 horizons and part of the Bt3 horizon).

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National Cooperative Soil Survey
U.S.A.