LOCATION OVERGAARD AZEstablished Series
TAXONOMIC CLASS: Fine, mixed, active, frigid Typic Paleustalfs
TYPICAL PEDON: Overgaard gravelly loam-forest. (Colors are for dry soil unless otherwise noted.)
Oe--0 to 1 inches; decomposed and partially decomposed litter.
A--1 to 3 inches; grayish brown (10YR 5/2) gravelly loam, very dark grayish brown (10YR 3/2) moist; weak fine granular structure; soft, friable, nonsticky and nonplastic; many fine roots; common very fine interstitial pores; 20 percent pebbles; moderately acid (pH 6.0); clear smooth boundary. (2 to 4 inches thick)
E--3 to 11 inches; light brownish gray (10YR 6/2) gravelly loam, dark grayish brown (10YR 4/2) moist; massive; slightly hard, friable, nonsticky and nonplastic; many fine and few coarse roots; common fine interstitial and common very fine vesicular pores; 20 percent pebbles; moderately acid (pH 6.0); abrupt smooth boundary. (2 to l0 inches thick)
Btl--11 to 21 inches; brown (7.5YR 5/4) gravelly light clay, brown (7.5YR 4/4) moist; moderate medium subangular blocky structure; hard, firm, sticky and plastic; many fine and few coarse roots; few fine tubular pores; many moderately thick clay films on faces of peds and in pores; common dark organic stains on ped faces; 20 percent pebbles; slightly acid (pH 6.5); gradual wavy boundary. (8 to l3 inches thick)
Bt2--21 to 32 inches; reddish brown (5YR 5/4) gravelly clay, reddish brown (5YR 4/4) moist; moderate medium subangular and angular blocky structure; very hard, firm, sticky and very plastic; few fine and coarse roots; few fine tubular pores; continuous thick clay films on faces of peds; 25 percent pebbles; neutral (pH 6.6); gradual wavy boundary. (l0 to l5 inches thick)
Bt3--32 to 43 inches; reddish brown (5YR 5/4) gravelly clay, yellowish red (5YR 4/6) moist; few medium distinct brown (7.5YR 5/4) mottles; dark reddish brown (5YR 3/4) moist; weak medium subangular blocky structure; hard, firm, sticky and plastic; few very fine roots; few fine tubular pores; common moderately thick clay films on faces of peds; 30 percent pebbles; neutral (pH 6.6); gradual wavy boundary. (l0 to l8 inches thick)
C--43 to 53 inches; mottled brown (7.5YR 5/4) and reddish brown (5YR 5/4) very gravelly clay loam dry and moist; massive slightly hard, firm, slightly sticky and slightly plastic; very few very fine roots; few fine tubular pores; 45 percent pebbles; neutral (pH 7.0).
TYPE LOCATION: Navajo County, Arizona. SWl/4 of section 9,T.7N., R.22E.; l/2 mile south of Dry Lake (Note: County is unsurveyed. Location is approximate based on extended grid from surveyed areas.).
RANGE IN CHARACTERISTICS:
Soil moisture: Typic ustic moisture regime.
The thickness of the solum typically is 40 to 50 inches, but ranges from 32 to 60 inches.
The soil temperature is 43 1/4 to 47 1/4 F.
Rock fragments range l0 to 35 percent.
A horizon
Hue: l0YR to 7.5YR
Value: 4 or 5 dry and 2 to 4 moist
Chroma: 2 moist or dry.
E horizon
Hue: l0YR or 7.5YR
Value: 6 or 7 dry and 4 or 5 moist
Chroma: 2 moist or dry
Bt horizon
Hue: 5YR and 7.5YR
Value: 4 or 5 dry and 3 to 5 moist
Chroma: 4 to 6 moist and dry
Texture: commonly gravelly clay, but the range includes sandy clay loam or clay loam
Clay content: greater than 35 percent
Rock fragments: l0 to 35 percent gravel.
Calcium carbonate: Some pedons have up to 2 percent calcium carbonate below 40 inches.
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: The Overgaard soils are on undulating high stream terraces, plateaus, and hillslopes and have gradients of 0 to 35 percent. These soils formed in mixed alluvium. The climate is humid with cool moist summers and cold moist winters. Elevations are 6,400 to 7,300 feet. Average annual precipitation ranges from l8 to 24 inches. Mean annual temperature is about 45 1/4 F; average January temperature is 26 1/4 F.; average July temperature is 64 1/4 F. Frost-free season varies from 75 to l00 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Brolliar, McVickers, and Soldier soils. Brolliar soils have a lithic contact within 40 inches. McVickers soils lack an abrupt boundary between the A2 and argillic horizons. Soldier soils are medium to very strongly acid in the lower solum.
DRAINAGE AND PERMEABILITY: Well drained; slow to medium runoff; slow permeability.
USE AND VEGETATION: Used mainly for the production of timber, grazing wildlife, and water supply. Vegetation consists of ponderosa pine, scattered Gambel oak, Arizona fescue, mountain muhly, Junegrass, and pine dropseed.
DISTRIBUTION AND EXTENT: Central and northern Arizona. The series is extensive. MLRA 39.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Holbrook-ShowLow Area, Navajo County, Arizona; l962.
REMARKS: In October 2000, taxonomic classification was converted to the closest match found in Soil Taxonomy, Second Edition 1999. Some update was made to horizon nomenclature, competing series section, etc. Other placements may be more appropriate after a complete update.
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from 1 to 3 inches (A horizon)
Albic horizon - The zone from 3 to 11 inches (E horizon)
Argillic horizon - The zone from 11 to 43 inches (Bt horizons)
Abrupt textural change and Pale- feature - The increase of more than 20 percent clay with an abrubt boundary at 11 inches. (E to Bt1 horizons)
Classified according to Keys to Soil Taxonomy Tenth edition, 2006