LOCATION ALLENS PARK COEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, frigid Typic Haplustalfs
TYPICAL PEDON: Allens Park coarse sandy loam, woodland. (Colors are for dry soil unless otherwise noted.)
Oi--0 to 2 inches; slightly decomposed organic material, chiefly bark, twigs, needles, and the remains of understory plants.
Oe--2 to 4 inches; partially decomposed organic material like that of the above horizon.
A--4 to 6 inches; dark gray (10YR 4/1) coarse sandy loam, very dark gray (10YR 3/1) moist; moderate fine granular structure; soft, very friable; 5 percent gravel; much medium to coarse angular granite sand; neutral (pH 6.8); gradual smooth boundary. (0 to 4 inches thick)
E--6 to 14 inches; light brownish gray (10YR 6/2) coarse sandy loam, grayish brown (10YR 5/2) moist; weak medium platy structure parting to moderate fine granules; soft, very friable; vesicular; 10 percent fine granite gravel; much medium and coarse angular granite sand; neutral (pH 6.6); gradual wavy boundary. (5 to 12 inches thick)
B/E--14 to 21 inches; mixed colors of light brownish gray (10YR 6/2) and brown (10YR 5/3) coarse sandy loam matrix containing nodules and seams of sandy clay loam, grayish brown (10YR 5/2) moist and brown (10YR 4/3) moist; weak medium subangular blocky structure parting to moderate fine granules; very hard, very friable; common thin glossy patches on surfaces of clayey peds; 10 percent fine granite gravel; much medium and coarse angular granite sand; slightly acid (pH 6.4); gradual wavy boundary. (5 to 10 inches thick)
Bt--21 to 30 inches; brown (10YR 5/3) coarse sandy clay loam, brown (10YR 4/3) moist; moderate medium subangular blocky structure; extremely hard, friable; thin continuous wax-like coatings on faces of peds; wax-like coatings and fillings in pores and root channels; 10 percent fine angular granite gravel; slightly acid (pH 6.4); gradual wavy boundary. (8 to 30 inches thick)
R--30 inches; granite bedrock.
TYPE LOCATION: Boulder County, Colorado; about 1/2 mile northeast of Gross Reservoir; in an unsectionized area, 450 feet south and 1900 feet east of the southwest corner sec. 16, T. 1 S. R. 71 W.; approximate latitude 39 degrees 57 minutes 22 seconds N., longitude 105 degrees 21 minutes 12 seconds W., NAD 83.
RANGE IN CHARACTERISTICS: (from the mineral soil surface)
Soil moisture: dry throughout the moisture control section for 60 to 150 days in most years and are dry throughout the entire soil for periods of 10 to 30 days each year during the period soil temperature at 20 inches is above 41 degrees F. Ustic moisture regime.
Mean annual soil temperature ranges from 40 degrees to 46 degrees F.
Mean summer soil temperature ranges from 48 degrees F. to 58 degrees F. with an O horizon.
Thickness of the solum: 18 to 40 inches.
Depth to lithic contact: 20 to 40 inches.
Weak skeletons occur on surfaces of peds in parts of the Bt horizon in some pedons.
Content of organic carbon in the A horizon: 1 to 3 percent and decreases uniformly with depth.
Base saturation: 60 to 100 percent .
Coarse fragment content: 0 to 35 percent, mainly angular granite gravel and cobbles.
The sand fraction contains large amounts of medium and coarse angular granite sand.
Packing patterns of sand grains within the matrix tend to be cubical with a significant proportion of flat bearing surfaces between sand grains.
Horizons of low organic matter content have a greater than normal differential in consistence between moist and dry conditions and the soils are said to be "hard setting" when dry.
The E horizon:
Hue: 2.5Y through 7.5YR
Value: 6 or 7 dry, 4 through 6 moist,
Chroma: 2 through 4
Reaction: slightly acid to slightly alkaline
This horizon is usually platy but is granular or subangular blocky in some pedons.
It is soft to slightly hard.
The Bt horizon:
Hue: 2.5Y through 7.5YR
Value: 5 or 6 dry, 4 or 5 moist
Chroma: 2 through 6
Texture:, sandy clay loam
Clay content: 18 to 35 percent
Silt content: 5 to 30 percent
Sand content: 45 to 70 percent with more than 35 percent fine sand or coarser and with a relatively high percentage of medium and coarse angular granitic sand.
When air dry, this horizon is extremely hard and semi-cemented.
It has oriented clay films in some portions.
Reaction: slightly acid to slightly alkaline.
Some pedons have sandy clay loam C horizons below depths of 19 inches.
COMPETING SERIES: These are the
Alderon (WY),
Bayerton (WY),
Belltower (MT),
Elbeth (CO),
Elbuck (NM),
Elmark (MT),
Haugan (MT),
Heflin (CO),
Hoyt (MT),
Jemco (CO),
Jemez (NM),
Kunz (UT),
Kwiavu (CO),
Littlepine (CO),
Losindios (NM),
Lumpgulch (MT),
Northrim (CO),
Plome (CO),
Rule (CO),
Shoemaker (NM),
Sweetweed (MT), and
Tunitcha (NM) series.
Alderon, Belltower, Elmark, and Rule soils: 20 to 40 inches to paralithic contact.
Bayerton soils: have secondary carbonates at depths of 15 to 36 inches
Elbeth, Elbuck, Haugan, Heflin, Hoyt, Kunz, Kwiavu, Littlepine, Losindios, Northrim, Plome, Sweetweed and Tunitcha, soils: lack a lithic contact at depths of less than 40 inches.
Jemco soils: are dry in
May and June.
Jemez soils: formed in slope alluvium derived from tuff and latite.
Lumpgulch soils: lack B/E horizons.
Shoemaker soils: lack E and B/E horizons.
Tunitcha soils: have paralithic contact at depths of 40 to 60 inches.
GEOGRAPHIC SETTING:
Landform: mountain slopes, hills, and ridges.
Slopes: 5 to 50 percent.
Parent material: sediments weathered residually from underlying granite or sandstone bedrock.
Average annual precipitation: 18 to 24 inches, with peak periods of precipitation in the spring and summer.
Mean annual temperature: 42 to 45 degrees F., the mean summer temperature is 60 to 62 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Fern Cliff and Goldvale series. Fern Cliff soils lack continuous argillic horizons. Goldvale soils are fine textures.
DRAINAGE AND PERMEABILITY: Well drained; medium to high runoff; medium permeability above the bedrock.
USE AND VEGETATION: These soils are used principally as pastureland, for forestry, or for recreational purposes. Principal native vegetation is ponderosa pine, and sparse understory of grasses and sedges.
DISTRIBUTION AND EXTENT: Central foothill areas of Colorado. LRR E; The series has a moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Boulder Area, Colorado; 1971.
REMARKS:
Diagnostic horizons an features recognized in this pedon are:
Albic horizon: the zone from 6 to 14 inches. (E horizon)
Argillic horizon: the zone from 21 to 30 inches. (Bt horizon)
Lithic contact: granite bedrock at 30 inches.
The vegetation statement was revised on October 2007 to reflect the vegetation at the type location. Prior to 2007 the statement was lodgepole pine, spruce, and a sparse understory of grasses and sedges. On southerly aspects, ponderosa pine
The typical pedon location was updated in 07/2007 to be consistent with the location as given in the Boulder County Area soil survey. This location conflicts with the original OSD location (NW1/4 NW1/4 Sec. 35, T. 2 N., R. 71 W.) It is believed that the Boulder soil survey location is correct.