LOCATION LONGDAY                 CA+NV

Established Series
Rev. EWB-JVC-JBF
12/2022

LONGDAY SERIES

The Longday series consists of very deep, well drained soils that formed in colluvium and residuum derived from tuff, andesite, tuff-breccia, or metavolcanic rock. Longday soils are on mountains. Slopes are 15 to 50 percent. The mean annual precipitation is about 600 mm and the mean annual temperature is about 3 degrees C.

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Typic Argixerolls

TYPICAL PEDON: Longday extremely gravelly fine sandy loam--rangeland. (Colors are for dry soil unless otherwise noted.) The soil surface is covered with 75 percent gravel and 15 percent cobbles.

A1--0 to 5 cm; grayish brown (10YR 5/2) extremely gravelly fine sandy loam, very dark grayish brown (10YR 3/2) moist; moderate very thick platy structure; soft, very friable, slightly sticky and slightly plastic; many very fine and common fine roots; many very fine vesicular pores; 60 percent gravel; neutral (pH 7.2); clear smooth boundary. (5 to 10 cm thick)

A2--5 to 13 cm; brown (10YR 5/3) extremely gravelly fine sandy loam, dark brown (10YR 3/3) moist; moderate fine granular structure; soft, very friable, slightly sticky and slightly plastic; many very fine, common fine, and few medium roots; common very fine interstitial; 60 percent gravel and 5 percent cobbles; neutral (pH 7.0); clear smooth boundary. (5 to 15 cm thick)

Bt1--13 to 33 cm; brown (10YR 5/3) extremely gravelly sandy clay loam, dark brown (10YR 3/3) moist; moderate medium subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine and fine, and few medium and coarse roots; common very fine interstitial and few fine tubular pores; few faint clay films on faces of peds, lining pores, and coating rock fragments; 55 percent gravel and 10 percent cobbles; neutral (pH 7.0); clear smooth boundary. (15 to 25 cm thick)

Bt2--33 to 56 cm; brown (10YR 5/3) extremely gravelly sandy clay loam, brown (10YR 4/3) moist; moderate medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine and few fine roots; common very fine interstitial and few fine and very fine tubular pores; common distinct clay films on faces of peds, lining pores, and coating rock fragments; 50 percent gravel and 10 percent cobbles; neutral (pH 6.8); clear wavy boundary. (23 to 50 cm thick)

Bt3--56 to 152 cm; pale brown (10YR 6/3) extremely gravelly sandy clay loam, brown (10YR 4/3) moist; weak medium and coarse subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; few very fine and fine roots; few very fine tubular and interstitial pores; few faint clay films on faces of peds, lining pores, and coating rock fragments; 50 percent gravel and 10 percent cobbles; neutral (pH 6.8).

TYPE LOCATION: Mono County, California; on the Toiyabe National Forest in the Sweetwater Mountains about 1.7 miles east of South Sister; approximately 1,300 feet south and 900 feet west of the southeast corner of section 6, T. 7 N., R. 25 E.; USGS Mount Patterson 7.5 minute topographic quadrangle; latitude 38 degrees 29 minutes 17.2 seconds N and longitude 119 degrees 16 minutes 10.6 seconds W; WGS84 Decimal Degrees 38.4881111 latitude, -119.2696111 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 60 to 80 consecutive days in the four months following the summer solstice; typic xeric soil moisture regime.
Mean annual soil temperature: 6 to 7 degrees C.
Mean summer soil temperature: 15 to 17 degrees C.
Mollic epipedon thickness: 25 to 40 cm; includes the Bt1 horizon.
Depth to base of argillic horizon: 114 to more than 150 cm.
Depth to bedrock: 150 to 200 cm.

Particle-size control section - Clay content: Averages 18 to 25 percent.
Rock fragments: Averages 60 to 85 percent, mainly gravel. Lithology of rock fragments is andesite, tuff, tuff-breccia, or metavolcanic rock.

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: Extremely gravelly sandy clay loam, extremely gravelly loam, or extremely gravelly sandy loam.
Clay content: 18 to 25 percent.
Rock fragments: 60 to 85 percent.
Organic matter content: 1 to 3 percent.
Reaction: Slightly acid or neutral.

Bt2 and Bt3 horizons
Value: 5 or 6 dry.
Chroma: 3 or 4 dry or moist.
Texture: Extremely gravelly sandy clay loam, extremely gravelly loam, or extremely gravelly sandy loam.
Clay content: 18 to 25 percent.
Rock fragments: 60 to 85 percent.
Reaction: Slightly acid or neutral.

COMPETING SERIES: These are the Clanalpine, Devaul, Elaero, Glideski, Heechee, Heenlake, Holmes, Horrocks, Hoskin, Howcan, Pequop, Moreypeak, Suak, Valmar, Vitale, and Wambolt series.

Clanalpine, Elaero, Heenlake, and Moreypeak soils are moderately deep to paralithic contacts. Devaul soils are deep to paralithic contacts. Glideski soils a C horizon with 6 to 18 percent clay. Heechee, Holmes, and Howcan soils have depth to base of the argillic horizon of less than 100 cm. Horrocks soils are deep to lithic contacts and have depth to base of the argillic horizon of 36 to 100 cm. Hoskin, Suak, Valmar, and Vitale soils are moderately deep to lithic contacts. Pequop soils have subhorizons of the argillic horizons with less than 60 percent rock fragments and have horizons with identifiable secondary carbonates. Wambolt soils average 27 to 35 percent clay in the particle-size control section and have rock fragments which are mainly quartzite.

GEOGRAPHIC SETTING: Longday soils are on mountains. They typically occur on backslope positions. They formed in colluvium and residuum derived from andesite, tuff, tuff-breccia, and metavolcanic rocks. Slopes are 15 to 50 percent. Elevations range from 2,440 to 3,150 meters. The climate is subhumid-continental with cold, moist winters and cool, dry summers. The mean annual precipitation is 500 to 760 mm, the mean annual temperature is 3 to 4 degrees C, and the frost-free period is 30 to 60 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Dab and Thiefridge soils. Dab soils have thick mollic epipedons. Thiefridge soils are shallow to lithic contacts.

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

USE AND VEGETATION: Longday soils are used for rangeland, recreation, watershed, and wildlife habitat. The native vegetation is mainly low sagebrush, pine needlegrass, bluegrass, and prairie junegrass.

DISTRIBUTION AND EXTENT: Eastern California and western Nevada, on the east side of the Sierra Nevada Range. These soils are not extensive with about 5,000 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 33 cm (A1, A2, and Bt1 horizons).
Argillic horizon - The zone from 13 to 152 cm (Bt1, Bt2, and Bt3 horizons).
Particle-size control section - The zone from 13 to 63 cm (Bt1 and Bt2 horizons and part of the Bt3 horizon).

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National Cooperative Soil Survey
U.S.A.