LOCATION LITTLEGRAY ID
Tentative Series
BAG/NHK/DJP
02/2020
LITTLEGRAY SERIES
The Littlegray series consists of moderately deep, well drained soils that formed in loess influenced slope alluvium over basalt. These soils are on hillslopes. Slopes range from 2 to 8 percent. Mean annual precipitation is about 525 mm and the mean annual air temperature is about 2.0 degrees C.
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive Xeric Argicryolls
TYPICAL PEDON: Littlegray loam in rangeland; (Colors are for dry soil unless otherwise noted.)
A--0 to 3 cm; dark grayish brown (10YR 4/2) loam, very dark brown (10YR 2/2) moist; weak very fine granular structure; soft, very friable, nonsticky, nonplastic; 2 percent gravel; slightly acid (pH 6.2); clear wavy boundary.
BA--3 to 19 cm; grayish brown (10YR 5/2) sandy loam, very dark gray (10YR 3/1) moist; weak medium subangular blocky structure; soft, very friable, nonsticky, nonplastic; 2 percent gravel; moderately acid (pH 6.0); clear wavy boundary.
Bt1--19 to 38 cm; brown (10YR 5/3) sandy loam, dark brown (10YR 3/3) moist; weak medium subangular blocky structure; slightly hard, very friable, nonsticky, nonplastic; 10 percent faint clay films on all faces of peds and clay bridges between sand grains; 2 percent gravel; moderately acid (pH 6.0); clear wavy boundary.
Bt2--38 to 56 cm; yellowish brown (10YR 5/4) sandy loam, dark yellowish brown (10YR 3/4) moist; weak medium subangular blocky structure; slightly hard, very friable, nonsticky, nonplastic; 10 percent faint clay films on all faces of peds and clay bridges between sand grains; 10 percent gravel; moderately acid (pH 5.6); abrupt irregular boundary.
R--56 cm; basalt
TYPE LOCATION: Caribou County, Idaho; USGS Wayan West topographic quadrangle; latitude 42.9428680 degrees north, longitude 111.4858066 degrees west, datum WGS84.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature--1.7 to 5.0 degrees C
Thickness of mollic epipedon--24 to 39 cm
Depth to argillic--4 to 19 cm
Depth to bedrock--50 to 100 cm
Particle-size control section (weighted averages)
Clay content--14 to 18 percent
Total rock fragments--2 to 15 percent
A horizon
Hue--7.5YR to 10YR
Value--4 or 5 dry, 2 or 3 moist
Chroma--2 or 3 dry, 1 or 2 moist
Clay content--8 to 12 percent
Total rock fragments--2 to 5 percent
Reaction--pH 5.6 to 6.5
Thickness--3 to 5 cm
AB or BA horizon
Hue--7.5YR or 10YR
Value--4 or 5 dry, 2 or 3 moist
Chroma--2 or 3 dry, 1 to 3 moist
Texture (less than 2 mm fraction)--sandy loam or loam
Clay content--9 to 16 percent
Total rock fragments--2 to 5 percent
Reaction--pH 5.6 to 6.5
Thickness--14 to 22 cm
Bt horizons
Hue--7.5YR or 10YR
Value--4 or 5 dry, 3 or 4 moist
Chroma--3 or 4 dry, 2 to 4 moist
Texture (less than 2 mm fraction)--sandy loam, silt loam, or loam
Clay content--13 to 20 percent
Total rock fragments--2 to 15 percent
Reaction--pH 5.6 to 6.5
Thickness--33 to 73 cm
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING:
Landform--hillslopes
Elevation--1,890 to 2025 meters
Slope--2 to 8 percent
Parent material--loess influenced slope alluvium over basalt
Climate--long, cold winters; cool, moist springs; short, cool summers
Mean annual precipitation--475 to 600 mm
Mean annual air temperature--0.6 to 3.3 degrees C
Frost-free period--30 to 65 days
GEOGRAPHICALLY ASSOCIATED SOILS: None listed
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; 5 to 50 um/sec
USE AND VEGETATION: Littlegray soils are primarily used for wildlife habitat and grazing. The potential native vegetation is mountain big sagebrush and Idaho fescue.
DISTRIBUTION AND EXTENT: Littlegray soils are of small extent in southeastern Idaho; MLRA 43B.
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Bozeman, Montana
SERIES PROPOSED: Caribou County, Idaho, 2019. Littlegray series is derived from a nearby landmark.
REMARKS: Diagnostic horizons and features recognized in this pedon:
Mollic epipedon--0 to 38 cm (A, BA, and Bt1 horizons)
Argillic horizon--19 to 56 cm (Bt1 and Bt2 horizons)
Lithic contact--56 cm (R horizon)
Particle-size control section--19 to 56 cm
Littelgray soils have a cryic temperature regime and a xeric moisture regime.
Taxonomic version: Twelfth Edition, 2014
National Cooperative Soil Survey
U.S.A.