LOCATION SIESTA AZEstablished Series
TAXONOMIC CLASS: Fine, smectitic, frigid Typic Haplustalfs
TYPICAL PEDON: Siesta cobbly silt loam-forest. (Colors are for dry soil unless otherwise noted.)
Oi & Oe--0 to 1 inch; decomposed and partially decomposed pine needles.
A1--1 to 3 inches; dark reddish gray (5YR 4/2) cobbly silt loam, dark reddish brown (5YR 3/2) moist; weak thin platy structure; soft, friable, slightly sticky and slightly plastic; many fine roots; common very fine pores; few fine dark concretions; 25 percent cobbles and pebbles; neutral (pH 6.6); abrupt smooth boundary. (2 to 6 inches thick)
A2--3 to 6 inches; reddish brown (5YR 4/3) light clay loam, dark reddish brown (5YR 3/3) moist; weak coarse platy parting to moderate medium granular structure; slightly hard, friable, slightly sticky and slightly plastic; many fine roots; common medium pores; few fine dark concretions; 5 percent pebbles; neutral (pH 6.6); clear smooth boundary. (l to 3 inches thick)
B--6 to 9 inches; reddish brown (5YR 4/4) clay, dark reddish brown (5YR 3/4) moist; strong fine subangular blocky structure; hard, friable, sticky and plastic; few medium and large roots; few fine pores; few fine dark concretions; l0 percent pebbles; neutral (pH 6.8); clear smooth boundary. (2 to 7 inches thick)
Bt1--9 to 22 inches; reddish brown (2.5YR 4/4) clay, dark reddish brown (2.5YR 3/4) moist; moderate medium angular blocky structure; hard, friable, very sticky and very plastic; few fine, medium and coarse roots; many fine pores; few thin clay films on faces of peds; few fine dark concretions; l0 percent pebbles; neutral (pH 6.6); gradual smooth boundary. (l0 to 20 inches thick)
Bt2--22 to 32 inches; red (2.5YR 4/6) gravelly clay, dark red (2.5YR 3/6) moist; weak medium angular blocky structure; very hard, firm, sticky and plastic; few fine, medium and coarse roots; few fine pores; few thin clay films as bridges and on faces of peds; few fine dark concretions; 20 percent pebbles; neutral (pH 7.3); gradual smooth boundary. (l0 to 20 inches thick)
Bt3--32 to 47 inches; red (2.5YR 5/6) gravelly clay loam, dark red (2.5YR 3/6) moist; massive; slightly hard, friable, slightly sticky and slightly plastic; few coarse roots; few thin clay films as bridges and on cinders; 30 percent cinders; moderately alkaline (pH 8.0); abrupt irregular boundary. (6 to l5 inches thick)
R--47 to 49 inches; Basalt with few thin coatings of calcium carbonate in joints.
TYPE LOCATION: Coconino County, Arizona. NEl/4, section 32, T.l5N., R.9E.; l/2 mile south of Banfield.
RANGE IN CHARACTERISTICS:
Soil moisture regime: Typic ustic moisture regime.
The soil temperature is 43 to 47 .
Rock fragments range from 5 to 35 percent.
The thickness of the solum typically is 36 to 50 inches but ranges from 30 to 70 inches.
Fine dark concretions (iron and manganese oxides) throughout in most pedons.
A horizon
Hue: 7.5YR or 5YR
Value: 4 or 5 dry, 2 or 3 moist
Chroma: 2 to 4 moist or dry.
B2t horizon
Hue: 2.5YR
Value: 3 or 4 dry, 2 or 3 moist
Chroma: 4 to 6 moist or dry
Texture: clay loam with greater than 35 percent clay
Percent base saturation: greater than 60 in the Bt3 horizon.
COMPETING SERIES: These are the
Burnac (NM),
Burnson (CO),
Campspass (MT),
Goldbug (CO),
Goldvale (CO),
Ishkoten (NM),
Larkson (CO),
Loghill (CO),
McVickers (),
Silesca (CO) and
Spud (NM) series.
Burnac soils: have an E horizon with an abrupt boundary over the B2t and formed mostly in parent materials derived from basalt and have greater than 35 percent rock fragments below the particle-size control section.
Burnson soils: do not have E horizons.
Campspass: has horizons of calcium carbonate accumulation.
Goldbug, Goldvale, Larkson and Spud soils are very deep.
Ishkoten and Silesca soils are moderately deep to sandstone and shale. Ishkoten soils formed in parent materials from the
Animas
Formation and have hues as yellow as 2.5Y. Silesca soils have hues as red as 5YR.
Goldvale soils: have a particle-size control section dominated by medium and coarse, angular, granitic sand.
Larkson soils: have hue of 7.5YR and yellower.
Loghill soils: have accumulations of secondary calcium carbonate and have 15 to 50 percent rock fragments in the Btk and Bk horizons.
Spud soils: formed in parent material weathered from basalt with modification from underlying sandstone and shale.
Silesca soils: have a lithic or paralithic contact at 20 to 40 inches below the mineral surface.
GEOGRAPHIC SETTING: Siesta soils are on gently sloping to moderately steep ridges and hillslopes and have gradients of l to 20 percent. The soil formed in deep colluvium and alluvium from pyroclastic rocks and basalt. The climate is subhumid with warm moist summers and cold moist winters. Elevations range from 6,800 to 8,000 feet. Mean annual precipitation is 20 to 25 inches. Mean annual air temperature is 45 F.; average January temperature is 26 F.; average July temperature is 64 F. Frost-free season is 75 to l00 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Brolliar and Sponseller soils. Brolliar soils have a lithic contact within 40 inches. Sponseller soils have a particle size control section of l8 to 27 percent clay.
DRAINAGE AND PERMEABILITY: Well drained; slow to medium runoff; moderately slow to slow permeability.
USE AND VEGETATION: Used mainly for growing timber, grazing, wildlife habitat, and water supply. Vegetation consists of ponderosa pine and scattered Gambel oak, Junegrass, mountain muhly, and squirreltail.
DISTRIBUTION AND EXTENT: North central Arizona and north central and northern New Mexico. The series is of moderate extent. MLRA 39.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Beaver Creek Area, Arizona; l965.