LOCATION SUDDEN ID
Established Series
IRD CBR/EED
05/2018
SUDDEN SERIES
Landscape--alluvial plains, hills
Landform--flood plains
Slope--0 to 4 percent
Parent material--alluvium derived from igneous rock
Mean annual precipitation--about 550 mm
Mean annual air temperature--about 3.3 degrees C
Depth class--very deep
Drainage class--poorly drained
Soil moisture regime--aquic
Soil temperature regime--cryic
TAXONOMIC CLASS: Fine, smectitic Vertic Cryaquolls
TYPICAL PEDON: Sudden loam in a meadow (Colors are for moist soil unless otherwise noted.)
A--0 to 10 cm; very dark grayish brown (10YR 3/2) loam, dark grayish brown (10YR 4/2) dry; weak fine subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; common fine and few medium and coarse roots throughout; few very fine tubular pores; slightly alkaline (pH 7.6); clear smooth boundary
Ag--10 to 23 cm; very dark grayish brown (10YR 3/2) silty clay loam, dark grayish brown (10YR 4/2) dry; moderate medium angular blocky structure parting to weak thin platy; slightly hard, firm, moderately sticky and moderately plastic; common very fine and fine roots; common very fine tubular pores; 5 percent gravel; 1 percent fine prominent spherical yellow (10YR 7/8 and 10YR 8/8) masses of oxidized iron; slightly alkaline (pH 7.4); clear smooth boundary
Btg1--23 to 38 cm; very dark grayish brown (10YR 3/2) clay loam, dark gray (10YR 4/1) dry; moderate medium prismatic structure parting to moderate medium angular blocky; very hard, firm, moderately sticky and moderately plastic; few very fine and fine roots; few very fine and fine tubular pores; 15 percent faint clay films on surfaces along pores; 1 percent fine prominent spherical yellow (10YR 7/8) masses of oxidized iron; slightly alkaline (pH 7.4); clear smooth boundary
Btg2--38 to 64 cm; very dark gray (10YR 3/1) clay, gray (10YR 5/1) dry; weak medium prismatic structure parting to strong medium angular blocky; very hard, very firm, moderately sticky and moderately plastic; few very fine and fine roots; few very fine and fine tubular pores; 5 percent gravel; 25 percent faint clay films on all faces of peds; 1 percent fine prominent spherical yellow (10YR 8/8) masses of oxidized iron; slightly alkaline (pH 7.4); abrupt smooth boundary
2ABtssb--64 to 94 cm; black (10YR 2/1) clay, very dark gray (10YR 3/1) dry; strong coarse columnar structure parting to strong coarse angular blocky; extremely hard, extremely firm, very sticky and very plastic; few fine roots; few very fine tubular pores; 5 percent gravel; 50 percent distinct clay films on all faces of peds; 100 percent prominent slickensides (pedogenic) on all faces of peds; neutral (pH 7.2); clear wavy boundary
2Btss--94 to 124 cm; dark grayish brown (2.5Y 4/2) clay, grayish brown (2.5Y 5/2) dry; strong coarse angular blocky structure; extremely hard, extremely firm, very sticky and very plastic; 10 percent gravel; 50 percent distinct clay films on all faces of peds; 100 percent prominent slickensides (pedogenic) on all faces of peds; neutral (pH 7.2); clear wavy boundary
2Cg--124 to 157 cm; dark grayish brown (2.5Y 4/2) clay, light brownish gray (2.5Y 6/2) dry; massive; extremely hard, extremely firm, very sticky and very plastic; 10 percent gravel; prominent organic stains on vertical faces of peds, very dark gray (10YR 3/1) moist; 10 percent medium prominent spherical yellow (10YR 7/8 and 10Y 8/8) masses of oxidized iron; slightly alkaline (pH 7.8)
TYPE LOCATION: Clark County, Idaho; latitude 44.43743 degrees north, longitude 111.77290 west, datum WGS 84
RANGE IN CHARACTERISTICS:
Mean annual soil temperature--3.3 to 6.1 degrees C
Thickness of mollic epipedon--90 to 120 cm
Depth to argillic horizon--15 to 42 cm
Depth to endosaturation--20 to 40 cm in April through June
Linear extensibility--greater than 6 cm in zone from the surface to a depth of 100 cm
Particle-size control section (weighted averages)
Clay content--42 to 60 percent
Total rock fragment content--0 to 5 percent
A and Ag horizons
Value--2 or 3 moist
Chroma--2 or 3 dry
Texture (less than 2-mm fraction)--loam, silty clay loam, silt loam
Clay content--14 to 35 percent
Reaction--pH 6.8 to 7.8
Thickness--15 to 34 cm
Btg horizon
Value--3 or 4 dry
Chroma--1 or 2 moist
Texture (less than 2-mm fraction)--clay, clay loam, silty clay
Clay content--35 to 60 percent
Gravel content--0 to 10 percent
Reaction--pH 7.2 to 7.8
Thickness--40 to 100 cm
2ABtssb horizon (where present)
Texture (less than 2-mm fraction)--clay, clay loam, silty clay
Clay content--35 to 60 percent
Gravel content-- 0 to 10 percent
Reaction--pH 7.2 to 7.8
Thickness--0 to 45 cm
2Btss horizon (where present)
Texture (less than 2-mm fraction)--clay, clay loam, silty clay
Clay content--35 to 60 percent
Gravel content--0 to 15 percent
Reaction--pH 7.2 to 7.8
Thickness--0 to 35 cm
2Cg horizon (where present)
Texture (less than 2-mm fraction)--clay, clay loam, silty clay
Clay content--35 to 60 percent
Gravel content--5 to 15 percent
Reaction--pH 7.2 to 7.8
COMPETING SERIES:
Egeria,
Railway,
Silvies--no argillic horizon
Narrows--calcic horizon
Wetbag--mean annual soil temperature higher than 6.1 degrees C
GEOGRAPHIC SETTING:
Elevation--1670 to 2190 m
Mean annual precipitation--330 to 610 mm
Mean annual air temperature--2.2 to 4.0 degrees C
Frost-free period--30 to 65 days
GEOGRAPHICALLY ASSOCIATED SOILS: None listed
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class--poorly drained
Saturated hydraulic conductivity (Ksat)--0.1 to 25.0 um/sec
USE AND VEGETATION:
Major uses--grassland pasture
Potential natural vegetation--Nevada bluegrass, alpine timothy, meadow barley, Baltic rush
DISTRIBUTION AND EXTENT: Small extent in southeastern Idaho; MLRAs 12 and 13
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Clark County, Idaho; 2018
REMARKS:
Diagnostic horizons and other features in this pedon
Mollic epipedon--zone from the surface to a depth of 94 cm
Aquic conditions--zone from 10 to 157 cm during the growing season in normal years
Argillic horizon--zone from 38 to 124 cm
Slickensides--zone from 64 to 124 cm
Particle-size control section--zone from 38 to 88 cm
Taxonomic version--Twelfth Edition, 2014
National Cooperative Soil Survey
U.S.A.