LOCATION SWANSONLAKE CO

Established Series
Rev. CRP/JCK
04/2019

SWANSONLAKE SERIES

The Swansonlake series consists of very deep, poorly drained soils that formed in alluvium or slide deposits. These soils are in drainageways, flood plains, sags or sag ponds. Slopes are 0 to 6 percent. Mean annual precipitation is about 559 mm, and mean annual air temperature is about 3.3 degrees C.

TAXONOMIC CLASS: Fine, mixed, active Argic Cryaquolls

TYPICAL PEDON: Swansonlake loam in native rangeland at an elevation of 2,551 meters. (Colors are for moist soil unless otherwise noted.)

Oe--0 to 3 cm: mucky peat; very strongly acid (pH 5.0); abrupt smooth boundary.

A--3 to 13 cm; black (10YR 2/1) loam, dark gray (2.5Y 4/1) dry; weak medium and coarse granular structure; slightly hard, friable, slightly sticky and slightly plastic; many fine and very fine roots and common medium and coarse roots; 2 percent gravel; neutral (pH 6.8); clear wavy boundary. (10 to 40 cm thick)

Bt1--13 to 34 cm; black (10YR 2/1) clay, very dark gray (10YR 3/1) dry; weak coarse subangular blocky structure parting to weak medium subangular blocky; very hard, firm, very sticky and very plastic; many fine and very fine roots and common medium and coarse roots; few fine dendritic tubular pores; many prominent clay films on faces of peds; few fine and medium yellowish brown (10YR 5/4) oxidized iron concentrations; 2 percent gravel; neutral (pH 7.0); clear wavy boundary. (15 to 25 cm thick)

Bt2--34 to 75 cm; dark grayish brown (10YR 4/2) clay, grayish brown (10YR 5/2) dry; weak coarse subangular blocky structure parting to weak medium subangular blocky; very hard, firm, very sticky and very plastic; common fine and very fine, and few medium roots; few fine dendritic tubular pores; many distinct clay films on faces of peds; common fine, medium and coarse yellowish brown (10YR 5/6) oxidized iron concentrations and common fine, medium, and coarse yellowish brown (10YR 5/8) oxidized iron concentrations; many fine and medium gray (10YR 5/1) iron depletions; 2 percent gravel; neutral (pH 7.2); gradual wavy boundary.

Bt3--75 to 120 cm; grayish brown (10YR 5/2) clay, light brownish gray (10YR 6/2) dry; weak fine and medium subangular blocky structure; very hard, firm, very sticky and very plastic; common fine and very fine, and few medium roots; few fine dendritic tubular pores; many distinct clay films on faces of peds; many medium and coarse yellowish brown (10YR 5/6) oxidized iron concentrations; many medium and coarse gray (10YR 6/1) iron depletions; 5 percent gravel; slightly alkaline (pH 7.4); gradual wavy boundary. (combined thickness of Bt2 and Bt3 horizons is 56 to 90 cm)

Btg--120 to 154 cm; greenish gray (10Y 5/1) clay, greenish gray (10Y 5/1) dry; weak medium and coarse subangular blocky structure; very hard, firm, very sticky and very plastic; very few fine roots; very few fine dendritic tubular pores; many distinct clay films on faces of peds; common very fine yellowish brown (10YR 5/8) oxidized iron concentrations; many coarse and very coarse very dark greenish gray (5GY 3/1) iron depletions; 10 percent gravel; neutral (pH 7.2).

TYPE LOCATION: Montrose County, Colorado; about 762 meters north and 152 meters west of the southeast corner of section 18 T 48N, R 7W; USGS Cimarron Topographic Quadrangle, NAD27; 38 degrees, 25 minutes, 8.7 seconds north latitude and 107 degrees, 33 minutes, 39.0 seconds west longitude.

RANGE IN CHARACTERISTICS:
Mean annual soil temperature - 2.7 to 5.4 degrees C
Mollic epipedon thickness - 25 to 65 cm
Depth to seasonal high water table - 15 to 46 cm
Particle-size control section (weighted average):
Clay content - 35 to 60 percent
Rock fragments - 0 to 15 percent

A horizon
Hue: 10YR or 2.5Y
Value: 3, 4 or 5 dry; 2 or 3 moist
Chroma: 1, 2 or 3
Texture: loam or clay loam
Clay content: 20 to 32 percent
Rock fragments: 0 to 15 percent--0 to 15 percent gravel, 0 to 10 percent cobbles, 0 to 5 percent stones
Reaction: pH 6.6 to 7.4

Bt1 horizon
Hue: 10YR or 2.5Y
Value: 3, 4 or 5 dry; 2 or 3 moist
Chroma: 1, 2 or 3
Texture: clay or clay loam
Clay content: 35 to 60 percent
Rock fragments: 0 to 15 percent--0 to 15 percent gravel, 0 to 10 percent cobbles, 0 to 5 percent stones
Reaction: pH 6.6 to 7.4

Bt2 and Bt3 horizons
Hue: 10YR, 2.5Y or 5Y
Value: 3, 4, 5 or 6 dry; 3, 4 or 5 moist
Chroma: 1, 2 or 3
Texture: clay or clay loam
Clay content: 35 to 60 percent
Rock fragments: 0 to 15 percent--0 to 15 percent gravel, 0 to 10 percent cobbles, 0 to 5 percent stones
Reaction: pH 6.8 to 7.8

Btg horizon
Hue: 2.5Y, 5Y or 10Y
Value: 3, 4, 5 or 6 dry; 3, 4 or 5 moist
Chroma: 1, 2 or 3
Texture: clay or clay loam
Clay content: 28 to 60 percent
Rock fragments: 0 to 25 percent--0 to 25 percent gravel, 0 to 10 percent cobbles, 0 to 5 percent stones
Reaction: pH 6.8 to 7.8

COMPETING SERIES: There are no competing series.

GEOGRAPHIC SETTING:
Landform - drainageways, flood plains, sags or sag ponds
Elevation - 2,530 to 3,048 meters
Slope - 0 to 6 percent
Parent material - alluvium or slide deposits
Mean annual precipitation - 508 to 610 mm
Mean annual air temperature - 1.7 to 4.4 degrees C
Frost-free period - 30 to 75 days

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Beachcanyon and Groomer series.

DRAINAGE AND PERMEABILITY: Poorly drained; slow to very slow permeability.

USE AND VEGETATION: Swansonlake soils are used for livestock grazing and wildlife habitat. Native vegetation is mainly Nebraska sedge, smallwing sedge, tufted hairgrass, Baltic rush, willow and cinquefoil.

DISTRIBUTION AND EXTENT: Swansonlake soils are of small extent in southwestern Colorado. MLRA 48A.

SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Bozeman, Montana

SERIES ESTABLISHED: Montrose County, Colorado - Ridgway Area, Colorado, Parts of Delta, Gunnison, Montrose, and Ouray Counties, 2019.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - from 3 to 34 cm (A and Bt1 horizons)
Argillic horizon - from 13 to 154 cm (Bt1, Bt2, Bt3 and Btg horizons)
Redoximorphic concentrations - from 13 to 154 cm (Bt1, Bt2, Bt3 and Btg horizons)
Redoximorphic depletions - from 34 to 154 cm (Bt2, Bt3 and Btg horizons)
Particle-size control section - from 13 to 63 cm (Bt1 and part of Bt2 horizon)

Swansonlake soils have a cryic temperature regime and an aquic moisture regime.

National Cooperative Soil Survey
U.S.A.