LOCATION FORVIC                  ID+NV

Established Series
Rev. GHL/MD/DA/JBF
01/2019

FORVIC SERIES

The Forvic series consists of soils that are well drained and moderately deep to a duripan, that formed in alluvium and colluvium derived from welded tuff. They are on terraces, summits, and hillsides. Slopes range from 2 to 15 percent. The average annual precipitation is about 430 mm and the average annual temperature is about 6 degrees C.

TAXONOMIC CLASS: Fine, smectitic, frigid Typic Durixerolls

TYPICAL PEDON: Forvic silty clay loam - on a west facing slope of 5 percent under rangeland vegetation at 1,865 meters elevation. When described on September 27, 1979, the soil profile was slightly moist throughout. (Colors are for dry soil unless otherwise noted.)

A--0 to 18 cm; dark grayish brown (10YR 4/2) silty clay loam, black (10YR 2/1) moist; moderate medium platy structure; soft, very friable, slightly sticky and slightly plastic; many very fine and fine roots; many very fine and fine tubular pores; 10 percent gravel; slightly acid (pH 6.5); clear smooth boundary. (13 to 36 thick)

Bt1--18 to 30 cm; brown (10YR 4/3) clay, very dark grayish brown (10YR 3/2) moist; moderate fine subangular blocky structure; hard, firm, moderately sticky and moderately plastic; many very fine and fine roots; common very fine and fine tubular pores; common distinct clay films on faces of peds and in pores; 10 percent gravel; slightly acid (pH 6.5); gradual wavy boundary. (10 to 36 cm thick)

Bt2--30 to 53 cm; dark brown (10YR 3/3) gravelly clay, dark brown (10YR 3/3) moist; strong coarse prismatic structure parting to strong medium angular blocky; extremely hard, extremely firm, very sticky and very plastic; common very fine and fine roots; few very fine and fine tubular pores; many prominent clay films on faces of peds and in pores; 15 percent gravel; slightly acid (pH 6.5); abrupt smooth boundary. (0 to 36 cm thick)

Bt3--53 to 76 cm; light brown (7.5YR 6/4) very gravelly sandy clay, brown (7.5YR 4/4) moist; moderate medium angular blocky structure; hard, firm, moderately sticky and moderately plastic; common very fine and fine roots; few very fine and fine tubular pores; many distinct clay films on faces of peds and in pores; 35 percent gravel; slightly acid (pH 6.5); abrupt smooth boundary. (5 to 25 cm thick)

Bkqm--76 to 89 cm; very pale brown (10YR 8/2) duripan, very pale brown (10YR 7/3) moist; massive; extremely hard, extremely firm; few very fine and fine roots in fractures of the duripan; many continuous silica laminations running between cemented gravel; fractures are 0.6 cm wide and are 25 cm apart; violent effervescent; abrupt smooth boundary. (8 to 28 cm thick)

2Cr--89 to 99 cm; very pale brown (10YR 7/4) welded ash, dark yellowish brown (10YR 4/6) moist; moderate medium platy structure; top of plates slightly effervescent.

TYPE LOCATION: Twin Falls County, Idaho; about 19 miles southeast of Rogerson, Idaho; about 1,700 feet north and 380 feet west of the southeast corner section 21, T. 16 S., R. 18 E.; USGS Timber Butte 7.5 minute topographic quadrangle; latitude 42 degrees 01 minutes 01 seconds N and longitude 114 degrees 20 minutes 28 seconds W; WGS84 Decimal Degrees 42.0169444 latitude, -114.3411111 longitude.

RANGE IN CHARACTERISTICS:
Soil moisture: Moist in winter and spring and continuously dry in all parts for significant periods in summer and fall; xeric soil moisture regime.
Mean annual soil temperature: 6 to 7 degrees C.
Mean summer soil temperature: 16 to 17 degrees C.
Depth to duripan: 50 to 100 cm.
Mollic epipedon thickness: 50 to 76 cm.
Depth to welded ash: 60 to 127 cm.
Reaction: Slightly acid or neutral.

Particle-size control section - Clay content: Average 50 to 59 percent.
Rock fragments: Average less than 35 percent.

A horizon
Value: 3 or 4 dry.
Chroma: 1 or 2 dry or moist.
Structure: Granular, subangular blocky, or platy.

Bt Horizons
Hue: 7.5YR or 10YR.
Value: 2 through 6 dry, 2 or 4 moist.
Chroma: 2 through 4 dry or moist
Texture: Clay, gravelly clay, very gravelly sandy clay or very gravelly clay.
Rock fragments: 10 to 55 percent gravel.
Structure: Subangular blocky, angular blocky, or prismatic.
Clay films: Common or many moderately thick or thick on faces of peds and in pores.

Bkqm Horizon
Distance between fractures: 20 to 30 cm.

COMPETING SERIES: These are the Budlewis, Dranket, Hatpeak, Manard, Oshone, Peevywell and Reomis series.

Budlewis, Dranket, Manard and Reomis soils less than 50 percent clay in the particle-size control section. Hatpeak and Peevywell soils are more than 150 cm deep to bedrock. Oshone soils have a mollic epipedon that is less than 50 cm thick.

GEOGRAPHIC SETTING: Forvic soils are on terraces, summits, and hillsides. The slope ranges from 2 to 15 percent. The soils formed in alluvium and colluvium derived from welded tuff. Elevations are 1,770 to 2,015 meters. The average annual precipitation ranges from 360 to 460 mm and the average annual temperature is 5 to 6 degrees C. The frost free season is 80 to 90 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Amboat, Aninto, Brose, and Oshone soils. Amboat and Brose soils occur on summits. Amboat soils are clayey-skeletal. Brose soils are shallow to bedrock. Aninto soils occur on terrace sideslopes, are deep, and clayey-skeletal. Oshone soils occur on lower terraces, and have a thinner A horizon.

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

USE AND VEGETATION: Forvic soils are used for rangeland. Native vegetation is Idaho fescue, bluebunch wheatgrass, Nevada bluegrass, and mountain big sagebrush.

DISTRIBUTION AND EXTENT: Forvic soils are of small extent in south central Idaho and northeastern Nevada. MLRA 25.

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

SERIES ESTABLISHED: Elko County, Nevada, Northeast Part 1986.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to 53 cm (A, Bt1, and Bt2 horizons).
Argillic horizon - The zone from 18 to 76 cm (Bt1, Bt2, and Bt3 horizons)
Indurated duripan - the zone from 76 to 89 cm (Bkqm horizon).
Particle-size control section - The zone from 18 to 68 cm (Bt1, Bt2, and part of the Bt3 horizons)

ADDITIONAL DATA: Clay percent by hygrometer: 0-18 cm - 40 percent; 18-30 cm - 48 percent; 20-53 cm - 64 percent.
Base saturation: 0-18 cm - 76 percent; 18-30 cm - 75 percent; 20-53 cm - 80 percent.

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National Cooperative Soil Survey
U.S.A.