LOCATION LEROUX CO+WY
Tentative Series
Rev. BWC-GB-KLS
05/2023
LEROUX SERIES
The Leroux soils consist of very deep, moderately well drained soils on mountain and valley side slopes. These soils formed in residuum and colluvium derived from interbedded sandstone and shale and basalt. Slopes range from 5 to 40 percent. Mean annual precipitation is 740 mm and mean annual air temperature is 3 degrees C.
TAXONOMIC CLASS: Fine, smectitic Aquic Argicryolls
TYPICAL PEDON: Leroux loam - woodland. (colors are for dry soil unless otherwise noted.)
Oi--0 to 8 cm; mat of slightly decomposed needles, twigs, and leaves.
A1--8 to 18 cm; brown (7.5YR 4/2) loam, dark brown (7.5YR 3/2) moist; weak fine and medium subangular blocky structure parting to moderate fine and medium granular; slightly hard, very friable, nonsticky and slightly plastic; 5 percent gravel, 5 percent cobbles, 1 percent stones; neutral (pH 6.8); clear smooth boundary.
A2--18 to 36 cm; brown (7.5YR 5/2) loam, dark brown (7.5YR 3/2) moist; moderate fine and medium subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; 5 percent gravel, 5 percent cobbles, one percent stones; slightly acid; (pH 6.4) clear smooth boundary. (Combined thickness of A horizons - 25 to 50 cm)
Bt1--36 to 64 cm; reddish brown (5YR 5/3) clay loam, reddish brown (5YR 4/4) moist; moderate fine and medium subangular blocky structure; hard, friable, sticky and plastic; many faint clay films on faces of peds; 5 percent gravel, 5 percent cobbles, one percent stones; moderately acid (pH 5.8); clear smooth boundary. (25 to 30 cm thick)
Bt2--64 to 87 cm; light reddish brown (5YR 6/3) clay, reddish brown (5YR 4/4) moist; strong fine and medium subangular blocky structure; hard, firm, sticky and plastic; many faint clay films on faces of peds; 5 percent gravel, 5 percent cobbles, one percent stones; strongly acid (pH 5.4); clear wavy boundary. (Combined thickness of Bt horizons - 50 to 80 cm)
BCt--87 to 105 cm; light reddish brown (5YR 6/4) sandy clay, reddish brown (5YR 5/3) moist; massive; hard, firm, sticky and plastic; common faint clay films on faces of peds; common, medium and coarse, distinct and prominent, yellowish brown (10YR 5/6) redox concentrations; 5 percent gravel, 5 percent cobbles, one percent stones; strongly acid (pH 5.4); clear wavy boundary. (15 to 25 cm thick)
C--105 to 130 cm; light brown (7.5YR 6/4) clay, brown (7.5YR 5/3) moist; massive; hard, friable, sticky and plastic; common, medium and coarse, distinct and prominent, yellowish brown (10YR 5/6) redox concentrations; 5 percent gravel, 5 percent cobbles, one percent stones; strongly acid (pH 5.4); clear wavy boundary. (20 to 30 cm thick)
2C--130 to 160 cm; very pale brown (10YR 8/2) stratified clay loam and fine sandy loam, light brownish gray (10YR 6/2) moist; massive; hard to soft, friable to soft, slightly sticky to nonsticky and nonplastic to plastic; common, medium and coarse, distinct and prominent, yellowish brown (10YR 5/6) redox concentrations; 5 percent gravel, 5 percent cobbles; strongly acid (pH 5.4).
TYPE LOCATION: Delta County, Colorado; on Leroux Creek Road in the SE1/4 of the SE1/4 of Sec. 19, T. 12 S., R. 92 W.; Lat. 38 degrees, 59 minutes, 23 seconds N.; Long. 107 degrees, 42 minutes, 23 seconds W.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature--3 to 6 degrees C
Mean summer soil temperature--7 to 8 degrees C
Mollic epipedon thickness--25 to 50 cm
Rock fragment content--0 to 15 percent, and are typically gravel and cobbles
The soil is saturated for 3 months or more during the spring and summer.
Mottles--medium to coarse, distinct and prominent (10YR 5/6) at depths of 76 cm or more.
A horizon
Hue--10YR or 7.5YR
Value--4 or 5 dry, 2 or 3 moist
Chroma--2 or 3
Reaction--pH 6.1 to 7.3
Bt horizons
Hue--10YR through 5YR
Value--5 or 6 dry, 4 or 5 moist
Chroma--3 to 4
Texture--clay loam, clay or sandy clay
Clay content--35 to 55 percent
Reaction--pH 5.1 to 6.0
C horizons
Hue--10YR or 7.5YR
Value--6 through 8 dry, 5 or 6 moist
Chroma--2 through 4
Reaction--pH 5.1 to 6.0
COMPETING SERIES: There currently are no other competing series in this family.
GEOGRAPHIC SETTING:
Landform--Leroux soils are on mountain and valley side slopes
Elevation--2625 to 3100 meters
Slope--5 to 40 percent
Parent material-- residuum and colluvium derived from interbedded sandstone and shale and basalt
Mean annual precipitation--660 to 810 mm
Mean annual air temperature--1 to 4 degrees C
Frost-free period--45 to 85
GEOGRAPHICALLY ASSOCIATED SOILS: None listed.
DRAINAGE AND PERMEABILITY: Moderately well drained; medium to rapid runoff; slow permeability. A water table is at 60 to 90 cm during the months of April to July.
USE AND VEGETATION: This soil is used for timber production, livestock grazing, wildlife habitat, and recreation. In Colorado it is in the Engelmann spruce-Subalpine fir woodland site.
DISTRIBUTION AND EXTENT: Leroux soils are of small extent in west-central Colorado and western Wyoming; MLRA 48A.
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Bozeman, Montana
SERIES PROPOSED: Delta County (Grand Mesa-West Elk Soil Survey Area) Colorado, 1988.
REMARKS: This soil is named after Leroux Creek in the Grand Mesa National Forest.
Diagnostic features include:
Mollic epipedon--8 to 36 cm (A1 to A2 horizons)
Argillic horizon--36 to 87 cm (Bt1 and Bt2 horizons)
Aquic feature--saturated continuously for 3 months or more within 100 cm of mineral surface
Particle-size control section--36 to 86 cm (Bt1 and Bt2 horizons)
Converted to metric and O horizons were updated to start at zero. Competing series section was not updated. 05/2023
National Cooperative Soil Survey
U.S.A.