LOCATION SECURITY           CO
Established Series
Rev. RM/GB
01/2009

SECURITY SERIES


The Security series consists of moderately deep, well drained soils that formed in material weathered from granite or mixed granite, gneiss and schist. Security soils are on mountain side slopes and ridges and have slopes of 5 to 65 percent. The mean annual precipitation is about 18 inches and the mean annual temperature is about 45 degrees F.

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Typic Haplustalfs

TYPICAL PEDON: Security very gravelly coarse sandy loam-Forested. (Colors are for dry soil unless otherwise indicated.)

Oi--0 to 1 inch; decomposing needle, leaves, and twigs.

A--1 to 6 inches; dark gray (10YR 4/1) very gravelly coarse sandy loam, very dark gray (10YR 3/1) moist; weak fine granular structure; soft, very friable; nonsticky and nonplastic; 40 percent pebbles; many fine and common roots; many fine interstitial pores, slightly acid (pH 6.5); clear wavy boundary. (5 to 8 inches thick)

E--6 to 14 inches; light brown (7.5YR 6/4) very gravelly sandy loam; brown to dark brown (7.5YR 4/4) moist; weak fine granular structure; slightly hard, very friable, nonsticky, and nonplastic; 40 percent pebbles; many fine and common roots; many fine interstitial pores slightly acid (pH 6.4); clear wavy boundary. (0 to 10 inches thick)

Bt--14 to 22 inches; light brown (7.5YR 6/4) very gravelly sandy clay loam, dark brown (7.5YR 3/4) moist; weak medium subangular blocky structure; very hard, friable, sticky, and slightly plastic; 45 percent pebbles; few fine roots; slightly acid (pH 6.5); clear wavy boundary. (8 to 10 inches thick)

C--22 to 26 inches; light brown (7.5YR 6/4) very gravelly sandy loam, strong brown (7.5YR 4/6) moist; massive; slightly hard, very friable, nonsticky, and nonplastic; 45 percent pebbles; few fine roots; slightly acid (pH 6.4); abrupt wavy boundary. (4 to 10 inches thick)

Cr--26 inches; (grus) weathered granite.

TYPE LOCATION: Douglas County, Colorado, .2 mile northwest of Highway 67 at Moonridge in the NE1/4 of Sec. 5, T. 8 S., R. 69 W.

RANGE IN CHARACTERISTICS: The mean annual soil temperature ranges from 43 to 46 degrees F. Depth to a paralithic contact ranges from 20 to 40 inches. Reaction ranges from moderately acid to neutral (5.6 to 7.3).

The A horizon has hue of 7.5YR or 10YR, value of 3 through 5, 2 or 3 moist, and chroma of 1 through 3.

The E horizon, when present, has hue of 7.5YR or 10YR, value of 5 through 7, 4 through 6 moist, and chroma of 2 through 4. It has textures of gravelly or very gravelly loam or sandy loam, or loam. Rock fragments are pebble size and range from 30 to 50 percent.

The Bt horizon has hue of 7.5YR or 10YR, values of 4 through 7, 3 through 5 moist, and chroma of 2 through 6. It is very gravelly sandy clay loam or clay loam. Rock fragments are pebble size and range from 35 to 55 percent.

The C horizon has hue of 5YR through 10YR, values of 5 or 6, 3 through 5 moist, and chroma of 2 through 6. Textures are very gravelly or extremely gravelly sandy loam. Rock fragments are pebble size and range from 40 to 65 percent.

The Cr horizon is weathered granite (grus). When excavated, it becomes strong brown, extremely gravelly sand, or strong brown, extremely gravelly loamy sand. The pebble size fractions range from 1/8 inch to 1 1/2 inch in diameter and comprise 80 to 90 percent of this horizon.

COMPETING SERIES: These are the Colomex (NM), Crackercreek (WA), Laventana (NM), Sheek (CO), Sonsela (NM), and Xankey (NM) soils. The Crackercreek and Laventana soils are deep. All the other competing soils are very deep.

GEOGRAPHIC SETTING: The Security soils are on mountain side slopes, hills, and ridges, and have slopes ranging from 5 to 65 percent. These soils formed in deeply weathered granite rock of the Pikes Peak Formation of mixed granite, gneiss and schist. At the type location, the mean annual precipitation ranges from 15 to 20 inches. The mean annual temperature is 45 degrees F., and the frost free season is less than 100 days. Elevation ranges from 6,000 to 8,500 feet.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Colomex (NM Sphinx, Legault, and Peeler soils. The Sphinx and Legault soils are sandy-skeletal and the Peeler soils are fine-loamy.

DRAINAGE AND PERMEABILITY: Well drained; medium runoff; moderately rapid permeability.

USE AND VEGETATION: These soils are used for watershed, wildlife, recreation, and limited timber production. Vegetation consists of ponderosa pine, mountain mahogany, Douglas-fir, Gambel oak, yucca, Oregon-grape, grasses, and forbs. Areas above timberline have alpine grasses and forbes.

DISTRIBUTION AND EXTENT: Mountainous areas along the Front Range of Colorado. The series is of small extent.

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

SERIES ESTABLISHED: Pike National Forest, Eastern part, Douglas County Colorado, 1984.

REMARKS: Diagnostic features include an argillic horizon from 14 to 22 inches. A paralithic contact is at 26 inches. Last updated by the state 12/92.


National Cooperative Soil Survey
U.S.A.