LOCATION TOLBY                   NM+CO

Established Series
Rev. GWA/CDL/LWH/SJJ
11/2013

TOLBY SERIES

The Tolby series consists of very deep, excessively drained, rapidly permeable soils that formed in coarse textured stony colluvium from acid igneous rocks. These soils are on convex mountain slopes with slopes ranging from 25 to 60 percent. Mean annual precipitation is about 25 inches and mean annual air temperature is about 34 degrees F.

TAXONOMIC CLASS: Sandy-skeletal, mixed Typic Dystrocryepts

TYPICAL PEDON: Tolby very stony loam - forested. (Colors are for dry soil unless otherwise noted. )

Oi--0 to 3 inches; forest litter.

Oe--3 to 4 inches; decayed forest litter.

A--4 to 15 inches; grayish brown (10YR 5/2) very stony loam, brown (10YR 4/3) moist; moderate medium and fine granular structure; slightly hard, friable, slightly sticky, slightly plastic; many fine and coarse roots; 40 percent angular gravel, cobble, and stones; extremely acid (pH 4.4); clear smooth boundary. (9 to 14 inches thick)

Bw--15 to 26 inches; pale brown (10YR 6/3) extremely gravelly loam, dark yellowish brown (10YR 3/4) moist; common distinct redox concentrations of reddish brown (5YR 4/3), dark reddish brown (5YR 3/3) moist on fragments; massive; soft, very friable, slightly sticky and slightly plastic; many fine medium and coarse roots; 80 to 95 percent coarse fragments; extremely acid (pH 4.4); clear wavy boundary. (8 to 18 inches thick)

2C1--26 to 34 inches; brown (10YR 5/3) very gravelly loamy sand, dark yellowish brown (10YR 3/4) moist; common distinct redox concentrations of reddish brown (5YR 4/3) dark reddish brown (5YR 3/3) moist; weak medium subangular blocky structure parting to moderate fine granular; soft, very friable nonsticky and nonplastic; few fine roots; 35 percent angular gravel and cobble; very strongly acid (pH 5.0); clear wavy boundary. (7 to 12 inches thick)

2C2--34 to 48 inches; yellowish brown (10YR 5/4) very cobbly loamy sand, dark brown (10YR 3/3) moist; common distinct redox concentrations of reddish brown (5YR 4/3), dark reddish brown (5YR 3/3) moist; weak medium platy structure parting to moderate medium granular; soft, very friable, nonsticky and nonplastic; few fine roots; 45 percent angular gravel and cobble; strongly acid (pH 5.4); clear wavy boundary. (11 to 20 inches thick)

2C3--48 to 61 inches; pale brown (10YR 6/3) very cobbly sandy loam, dark yellowish brown (10YR 4/4) moist; common distinct redox concentrations of brown (7.5YR 5/4), brown (7.5YR 4/4) moist; weak medium platy structure parting to weak fine subangular blocky; soft, very friable; nonsticky and nonplastic; few fine roots; 50 percent angular gravel and cobble; strongly acid (pH 5.4); clear wavy boundary. (10 to 15 inches thick)

2C4--61 to 84 inches; pale brown (10YR 6/3) extremely cobbly loamy sand, dark yellowish brown (10YR 4/4) moist; many distinct redox depletions of very dark gray (7.5YR 3/1), black (7.5YR 2/1) moist; weak medium platy structure parting to weak fine subangular blocky; soft, very friable, nonsticky and nonplastic; 70 percent angular gravel and cobble; moderately acid (pH 5.6).

TYPE LOCATION: Colfax County, New Mexico; 6 1/2 miles north-northeast of Eagle Nest, New Mexico on the northeast wooded slope of Baldy Mountain near the source of South Ponil Creek. Unsectionized area.

RANGE IN CHARACTERISTICS:
Soil moisture - The SMCS is moist in at least some part all year. Udic moisture regime.

The depth to the base of the Bw is 18 to 32 inches.

Particle size control section - averages sandy skeletal.

Coarse fragments - angular and range from 35 to 90 percent in the Bw horizon; and from 30 to 75 percent of the C horizon.

Reaction - ranges from extremely acid in the surface to moderately acid at depth of about 60 inches.

Mean annual soil temperature - estimated at 36 degrees F, and the mean summer soil temperature is estimated at 43 degrees F.

O horizon - 1 to 5 inches.

Bw horizon:
Hue: 7.5YR or 10YR
Value: 5 or 6 dry, 3 or 4 moist
Chroma: 3 or 4 dry or moist

2C horizon:
Hue: 7.5YR or 10YR
Value: 5 or 6 dry, 3 or 4 moist
Chroma: 3 or 4 dry or moist
Texture: dominantly loamy sand, but some pedons have layers of sandy loam.

COMPETING SERIES: These are the Elting (AK) , Mirror Lake (UT) and Priestlake (ID) series. Elting soils have a mean annual soil temperature of less than 36 degrees F.. Mirror lake soils formed in glacial till derived from quartzite and sandstone. Priestlake soils have illuvial clay accumulations.

GEOGRAPHIC SETTING: The Tolby soils are on very steep, stony, convex mountain slopes with elevations ranging from 9,000 to 12,000 feet. Slopes range from 25 to 60 percent. The soils formed in coarse textured, stony colluvium from acid igneous rocks. The climate is continental with annual precipitation ranging from 25 to 30 inches. The mean annual air temperature is 34 to 39 degrees F, and the mean summer air temperature is estimated at 41 degrees F.. Frost-free period is less than 90 days. In Colorado the elevation is a low as 7800 feet.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Angostura and Bundo soils. Angostura soils have thick E horizons. Bundo soils have an argillic horizon.

DRAINAGE AND PERMEABILITY: Excessively drained; medium runoff; rapid permeability.

USE AND VEGETATION: Wildlife, recreation, timber production. Engelmann spruce, Subalpine fir, Bristlecone pine, Limber pine and high mountain grasses are the principal plants.

DISTRIBUTION AND EXTENT: Northern New Mexico and southern Colorado. This series is moderately extensive. LRR-E, MLRA 48A.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana

SERIES ESTABLISHED: Colfax County, New Mexico, 1974.

REMARKS: Diagnostic horizons and features recognized in this pedon are:

Ochric epipedon - the zone from 0 to 15 inches (O and A horizons)

Cambic horizon - the zone from 15 to 26 inches (Bw horizon)

ADDITIONAL DATA: S87CO-107-004, S91CO-097-002, S91CO-117-006, S91CO-117-010.

---

National Cooperative Soil Survey
U.S.A.