LOCATION LEYDEN CO
Established Series
Rev. AEA-GB-KLS
05/2023
LEYDEN SERIES
The Leyden series consists of moderately deep, well drained soils that formed in gravelly and cobbly slope alluvium or colluvium overlying interbedded shale and sandstone. Leyden soils are on side slopes and ridges, and dip slopes of homoclinal ridges and hogbacks. Slopes are 5 to 70 percent. The mean annual precipitation is about 405 mm and the mean annual air temperature is about 8 degrees C.
TAXONOMIC CLASS: Fine, smectitic, mesic Aridic Argiustolls
TYPICAL PEDON: Leyden cobbly clay loam - grassland. (Colors are for dry soil unless otherwise noted.)
A--0 to 8 cm; very dark grayish brown (10YR 3/2) cobbly clay loam, very dark brown (10YR 2/2) moist; weak fine granular structure; slightly hard, friable, sticky; 20 percent cobbles; neutral (pH 6.8); clear smooth boundary. (8 to 13 cm thick)
BA--8 to 20 cm; dark grayish brown (10YR 4/2) gravelly heavy clay loam, very dark grayish brown (10YR 3/2) moist; weak medium subangular blocky structure parting to weak fine granular; slightly hard, friable, sticky; 20 percent pebbles; neutral (pH 6.6); clear smooth boundary. (0 to 13 cm thick)
Bt1--20 to 48 cm; brown (10YR 4/3) gravelly heavy clay loam, dark brown (10YR 3/3) moist; moderate medium prismatic structure parting to moderate medium subangular blocky; hard, firm, sticky; common thin clay films on the faces of peds; 20 percent pebbles; neutral (pH 6.6); gradual smooth boundary.
Bt2--48 to 74 cm; brown (10YR 5/3) gravelly clay, brown (10YR 4/3) moist; weak coarse subangular blocky structure parting to weak medium subangular blocky; hard, firm, very sticky; common thin clay films on the faces of peds; 20 percent pebbles; neutral (pH 6.8); gradual wavy boundary. (Combined thickness of the Bt horizons - 28 to 58 cm)
BC--74 to 89 cm; light yellowish brown (2.5Y 6/4) gravelly heavy clay loam, olive brown (2.5Y 4/4) moist; weak coarse prismatic structure parting to weak coarse subangular blocky; hard, firm, very sticky; 20 percent pebbles; neutral (pH 7.0); clear smooth boundary. (0 to 18 cm thick)
Cr--89 cm; light yellowish brown (2.5Y 6/4) mudstone, olive brown (2.5Y 4/4) moist; slightly alkaline (pH 7.8).
TYPE LOCATION: Jefferson County, Colorado; approximately 5 kilometers west of Denver Federal Center; 43 meters east and 64 meters south of center of sec. 7, T. 4 S., R. 69 W.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature - 8 to 11 degrees C
Depth to paralithic contact - 50 to 100 cm
Particle-size control section (weighted average):
Clay content - 35 to 50 percent
Sand content - more than 15 percent fine sand or coarser
Rock fragment content - 15 to 35 percent gravel and cobbles
A horizon
Hue: 10YR or 2.5Y
Value: 3 through 5 dry, 2 or 3 moist
Chroma: 2 or 3 dry or moist
Rock fragment content: 15 to 35 percent, dominantly cobbles or stones
Reaction: pH 6.6 to 7.8
Bt horizons
Hue: 10YR or 2.5Y
Value: 4 through 5 dry, 3 or 4 moist
Chroma: 2 or 3 dry or moist
Texture: clay or clay loam
Rock fragment content: 15 to 35 percent gravel or cobbles
Reaction: pH 6.6 to 7.8
C horizon, when present
Hue: 10YR or 2.5Y
Value: 5 through 7 dry, 4 through 6 moist
Chroma: 4 through 6, dry or moist
Texture: clay loam or sandy clay loam
Rock fragment content: 15 to 35 percent gravel or cobbles
Reaction: pH 7.4 to 8.4
Cr horizon - weathered interbedded shale and sandstone
COMPETING SERIES:
Atrail (CO) - have horizons with secondary calcium carbonate accumulations
Bethune (CO) - have calcic horizons
Blackpipe (SD) - have less than 15 percent fine sand or coarser
Boneek (SD) - are deep
Boquillas (AZ) - have horizons of lithologic discontinuities
Chapin (CO) - are moderately deep to lithic contact
Collbran (CO) - are deep
Collide (CO) - are deep
Emigrant (CO) - have less than 15 percent rock fragments
Huggins (SD) - have less than 15 percent fine sand or coarser
Kube (SD) - are deep; have less than 15 percent fine sand or coarser
Loma (CO) - are deep; have less than 15 percent rock fragments
Nuncho (WY) - are deep; have less than 15 percent rock fragments
Nunn (CO) - are deep; have less than 15 percent rock fragments
Querc (WY) - have slightly acid reaction throughout
Raku (CO) - are deep; have less than 15 percent rock fragments
Rednun (CO) - are deep; have less than 15 percent rock fragments
Richfield (KS) - are deep; have less than 15 percent rock fragments
Ryus (KS) - are deep; have less than 15 percent rock fragments
Savo (SD) - are deep; have less than 15 percent rock fragments
Showlow (AZ) - are deep; have lithologic discontinuities
Standley (CO) - are deep
Thunderbird (AZ) - are moderately deep to lithic contact
Weld (CO) - are very deep; have less than 15 percent rock fragments
Wormser (CO) - are moderately deep to lithic contact
GEOGRAPHIC SETTING:
Landform - side slopes and ridges, and dip slopes of hogbacks and homoclinal ridges
Elevation - 1,225 to 2,100 meters
Slopes - 5 to 70 percent
Parent material - gravelly and cobbly slope alluvium or colluvium over residuum of interbedded shale and sandstone
Mean annual air temperature - 7 to 11 degrees C
Mean annual precipitation - 330 to 430 mm
Frost-free period - 115 to 145 days
GEOGRAPHICALLY ASSOCIATED SOILS: None listed.
DRAINAGE AND PERMEABILITY: Well drained; medium to rapid runoff; slow permeability.
USE AND VEGETATION: Leyden soils are used primarily for grazing, recreation, wildlife, and community development. Native vegetation is blue grama, little bluestem, sideoats grama, needleandthread, western wheatgrass, forbs, and shrubs.
DISTRIBUTION AND EXTENT: Leyden soils are of small extent in the foothills along the eastern front of the Rocky Mountains in central Colorado; MLRA 49.
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Golden Area Soil Survey, Jefferson County, Colorado, 1980.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - 0 to 20 cm (A and AB horizons)
Argillic horizons - 20 to 74 cm (Bt1 and Bt2 horizons)
Depth to paralithic contact - 89 cm to bedrock (Cr horizon)
Particle-size control section - 20 to 70 cm (Bt1 and part of Bt2 horizons)
Leyden soils have a mesic soil temperature regime and an ustic soil moisture regime.
Converted to metric, formatting updated to current standards, and competing series section updated. 04/2020
National Cooperative Soil Survey
U.S.A.