LOCATION CHARDOTON IDEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Xeric Paleargids
TYPICAL PEDON: Chardoton silt loam -- on a nearly level lava flow trough, at 3,100 feet elevation in rangeland. (Colors are for dry soil unless otherwise noted.)
A--0 to 1 inch; grayish brown (10YR 5/2) silt loam, very dark grayish brown (10YR 3/2) moist; moderate very fine granular structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine and fine roots; common very fine tubular and interstitial pores; neutral (pH 6.8); abrupt smooth boundary. (0 to 3 inches thick)
E--1 to 2 inches; pale brown (10YR 6/3) silt loam, brown (10YR 4/3) moist; moderate very thin platy structure parting to strong fine granular; slightly hard, very friable, slightly sticky and slightly plastic; common very fine and fine roots; many fine vesicular and very fine, and fine tubular pores; slightly alkaline (pH 7.4); abrupt wavy boundary. (1 to 4 inches thick)
2Bt1--2 to 5 inches; brown (10YR 4/3) silty clay, dark brown (10YR 3/3) moist; pale brown (10YR 6/3) silt coats on faces of peds; strong medium subangular blocky structure parting to strong very fine angular blocky; hard, firm, moderately sticky and moderately plastic; many very fine roots; many fine interstitial and common very fine tubular pores; continuous distinct clay films on faces of peds and in pores; cracks 1 to 3 mm wide; slightly alkaline (pH 7.6); abrupt wavy boundary. (1 to 4 inches thick)
2Bt2--5 to 12 inches; light yellowish brown (10YR 6/4) silty clay, brown (10YR 4/3) moist; dark yellowish brown (10YR 3/4) moist organic stains on faces of peds; strong coarse columnar structure parting to strong coarse and medium angular blocky; very hard, very firm, very sticky and very plastic; common very fine roots between peds and few very fine roots in the peds; common very fine and fine tubular pores; continuous prominent clay films on faces of peds and in pores; cracks 1 to 5 mm wide; moderately alkaline (pH 8.4); clear wavy boundary. (6 to 10 inches)
2Bt3--12 to 18 inches; pale brown (10YR 6/3) silty clay, brown (10YR 4/3) moist; common faint dark yellowish brown (10YR 3/4) moist organic stains on faces of peds; strong medium angular blocky structure; hard, firm, very sticky and very plastic; common very fine roots; few very fine tubular pores; continuous distinct clay films on faces of peds and in pores; moderately alkaline (pH 8.0); clear wavy boundary. (0 to 20 inches thick)
2Btk1--18 to 24 inches; pale brown (10YR 6/3) silty clay, brown (10YR 4/3) moist; yellowish brown (10YR 5/4) coatings on faces of peds; moderate medium angular blocky structure; hard, firm, very sticky and very plastic; common very fine roots; few very fine tubular pores; many distinct clay films on faces of peds and in pores; about 20 percent hard cicada nodules; common fine lime veins; slightly effervescent matrix; moderately alkaline (pH 8.4); clear wavy boundary. (4 to 12 inches thick)
2Btk2--24 to 28 inches; light yellowish brown (10YR 6/4) clay loam, brown (10YR 4/3) moist; dark yellowish brown (10YR 4/4) coatings on faces of peds; strong medium angular blocky structure; hard, very firm, moderately sticky and moderately plastic; common very fine roots; few very fine tubular pores; common distinct clay films on faces of peds and in pores; about 20 percent hard cicada nodules; common fine lime veins; slightly effervescent matrix; moderately alkaline (pH 8.4); abrupt wavy boundary. (0 to 12 inches thick)
3Bk1--28 to 36 inches; pale brown (10YR 6/3) loam, brown (7.5YR 4/4) moist; massive; slightly hard, friable, slightly sticky and slightly plastic; few very fine roots; few very fine tubular pores; common very fine lime veins; slightly effervescent matrix; moderately alkaline (pH 8.4); gradual smooth boundary. (6 to 24 inches thick)
3Bk2--36 to 61 inches; very pale brown (10YR 7/3) fine sandy loam, dark yellowish brown (10YR 4/4) moist; massive; slightly hard, very friable, slightly sticky and slightly plastic; common large masses of strongly effervescent segregated lime; moderately alkaline (pH 8.2); gradual wavy boundary. (0 to 30 inches thick)
3C--61 to 65 inches; light yellowish brown (10YR 6/4) fine sandy loam, brown (7.5YR 4/4); massive; slightly hard, very friable, slightly sticky and slightly plastic; slightly effervescent; moderately alkaline (pH 8.3); clear smooth boundary. (0 to 8 inches thick)
4Btkb--65 to 75 inches; pale brown (10YR 6/3) silty clay, brown (10YR 5/3) moist; strong fine angular blocky structure; very hard, firm, moderately sticky and moderately plastic; slightly effervescent; strongly alkaline (pH 8.6).
TYPE LOCATION: Ada County, Idaho; about 4 miles south of Orchard; approximately 250 feet north and 50 feet east of the southwest corner of section 8, T. 2 S., R. 4 E.; USGS Orchard Quadrangle; (Latitude - 43 degrees, 15 minutes, 33 seconds N. and Longitude - 116 degrees, 00 minutes, 54 seconds W.).
RANGE IN CHARACTERISTICS:
Average annual soil temperature - 52 to 56 degrees F.
Depth to abrupt textural change - 1 to 4 inches
Depth to calcium carbonates - 14 to 36 inches
Depth to base of argillic horizon - 25 to 48 inches
Depth to bedrock - greater than 60 inches
Particle-size control section - 35 to 55 percent clay; 0 to 5 percent rock fragments
Moisture control section - moist less than 90 consecutive days when the soil temperature is greater than 47 degrees F.
E horizon
Value - 5 or 6 dry, 3 or 4 moist
Clay content - 12 to 18 percent
Rock fragments - 0 to 5 percent total
Reaction - slightly acid through slightly alkaline
Bt horizon
Value - 4 through 6 dry, 3 through 5 moist (silt coats are 6 or 7 dry)
Chroma - 3 or 4 dry or moist
Texture - SIC, SICL or C
Clay content - 35 to 55 percent
Rock fragments - 0 to 5 percent total (mainly gravel)
Reaction - slightly acid through moderately alkaline
Btk horizon
Value - 5 through 7 dry, 3 through 5 moist
Chroma - 3 or 4 dry or moist
Texture - SIC, C, CL, SICL or SIL
Clay content - 25 to 45 percent
Rock fragments - 0 to 5 percent total (mainly gravel)
Calcium carbonate equivalent - 1 to 5 percent
Reaction - slightly alkaline or strongly alkaline
Bk horizon
Hue - 7.5YR or 10YR
Value - 6 or 7 dry, 4 or 5 moist
Chroma - 3 or 4 dry or moist
Texture - L, SIL, or VFSL
Clay content - 10 to 22 percent
Rock fragments - 1 to 5 percent (mainly gravel)
Calcium carbonate equivalent - 0 to 5 percent
Reaction - slightly alkaline or moderately alkaline
Buried Bt horizons are common, but below a depth of 60 inches.
COMPETING SERIES: These are the Acoma, Berdugo, Biscaro (T), Borda, Bowns, Brent, Gooding, Hagata (T), Jowec, Locey (T), Lodico (T), Poall, Reba and Spangenburg series. Acoma soils have 15 to 35 percent gravel in the particle-size control section. Berdugo soils are 10 to 20 inches deep to the base of the argillic horizon and have AAST of 47 to 50 degrees F. Biscaro and Hagata soils are 20 to 40 inches deep to a paralithic contact. Borda soils are 40 to 60 inches deep to bedrock and have AAST of 47 to 52 degrees F. Bowns, Locey and Lodico soils are 20 to 40 inches to bedrock. Brent soils have A horizons 8 to 12 inches thick. Gooding soils are 40 to 609 inches to a duripan. Jowec soil are 15 to 25 inches deep to base of argillic horizon. Poall soils do not have an E horizon or cicada krotovinas within the lower part of the argillic horizon. Reba soils have A horizons greater than 6 inches thick and AAST of 49 to 51 degrees F. Spangenburg soils do not have an E horizon and have AAST of 47 to 50 degrees F.
GEOGRAPHIC SETTING: Chardoton soils are lava flow troughs on shield volcanoes and lava plains. Elevations range from 2,850 to 3,500 feet. Slopes are 0 to 4 percent. The soils formed in silty alluvium from loess and weathered volcanic ash over loamy alluvium from basalt and volcanic ash. Average annual precipitation is 8 to 14 inches. Average annual temperature is 50 to 54 degrees F. Frost-free period is 130 to 150 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Catchell, Chilcott, Lankbush, Power, Tindahay soils and the competing Bowns soils. Catchell and Chilcott soils have a duripan at a depth of 20 to 40 inches. Power and Lankbush soils have less than 35 percent clay in the textural control section. Tindahay soils lack an argillic horizon and have sandy textures in the textural control section.
DRAINAGE AND PERMEABILITY: Well drained; very slow and slow runoff; very slow permeability.
USE AND VEGETATION: The Chardoton soils are used mainly for rangeland. Natural vegetation is bluebunch wheatgrass, Thurber needlegrass, basin wildrye, Wyoming big sagebrush and threetip sagebrush.
DISTRIBUTION AND EXTENT: Southwestern Idaho; MLRA 11. These soils are inextensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Ada County, Idaho, 1977.
REMARKS: Diagnostic horizons and features recognized in this pedon:
Ochric epipedon - zone from surface to 2 inches (A and E horizons)
Argillic horizon - zone from 2 to 28 inches (2Bt1, 2Bt2, 3Bt3, 2Btk1 and 2Btk2 horizons)
Abrupt textural change - at 2 inches (upper boundary of 2Bt1 horizon)
Particle-size control section - zone from 2 to 22 inches
Soil moisture regime - aridic bordering xeric
The Chardoton soils mapped in Elmore County Area, Idaho soil survey have a duripan between 40 and 60 inches deep which is not a recognized horizon of this series and should be correlated to a different series.
The classification of this pedon has been revised as of 4/00 from Xerollic Paleargids to Xeric Paleargids based on revisions to Soil Taxonomy.
The term silty alluvium used in this series concept infer a localized influence on the mixed loess and weathered ash mantle by overland flow of running water.