LOCATION JUANALO COEstablished Series
TAXONOMIC CLASS: Loamy, mixed, superactive, calcareous, mesic Lithic Torriorthents
TYPICAL PEDON: Juanalo gravelly fine sandy loam, on a northeast facing, 3 percent slope in rangeland at an elevation of 5,240 feet. (Colors are for dry soil unless otherwise noted.) When described on 4/10/2000 the soil was moist from 1 to 11 inches. The surface is covered by 50 percent limestone channers, 2 percent limestone flagstones.
A1--0 to 1 inch; light yellowish brown (10YR 6/4) gravelly fine sandy loam, yellowish brown (10YR 5/4) moist; moderate very fine granular structure; soft, very friable, nonsticky and nonplastic; 25 percent gravel, 1 percent channers; violently effervescent; moderately alkaline (pH 8.2); abrupt smooth boundary.
A2--1 to 3 inches; light yellowish brown (10YR 6/4) loam, yellowish brown (10YR 5/4) moist; moderate very fine granular structure; soft, very friable, slightly sticky and slightly plastic; common very fine roots throughout; common fine vesicular pores; 2 percent channers; 33 percent calcium carbonate equivalent; violently effervescent; moderately alkaline (pH 8.4); clear smooth boundary.
Bw--3 to 9 inches; yellowish brown (10YR 5/4) loam, dark yellowish brown (10YR 4/4) moist; weak medium subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; common very fine roots throughout; common fine vesicular pores; many distinct clay bridges on the faces of peds; 5 percent gravel, 1 percent channers; 29 percent calcium carbonate equivalent; violently effervescent; moderately alkaline (pH 8.4); abrupt irregular boundary.
Bk--9 to 11 inches; very pale brown (10YR 7/4) very channery loam, yellowish brown (10YR 5/4) moist; massive; soft, very friable, slightly sticky and slightly plastic; common very fine roots around rocks; 10 percent gravel, 40 percent channers; 1-2 mm calcium carbonate coats on the bottom of coarse fragments; 65 percent calcium carbonate equivalent; violently effervescent; moderately alkaline (pH 8.4); abrupt irregular boundary.
R--11 inches; Juana Lopez Limestone, member of the Mancos Shale formation.
TYPE LOCATION: Montezuma County, Colorado; about 15 miles southwest of Towaoc, Ute Mountain Reservation; located in an unsectionized area; Sentinel Peak SW, Colorado USGS quad; lat. 37 degrees 4 minutes 13.69 seconds N. and long. 108 degrees 54 minutes 59.54 seconds W., NAD 27.
RANGE IN CHARACTERISTICS:
Soil moisture: Typic aridic moisture regime.
Mean annual soil temperature: 54 to 58 degrees F
Depth to lithic contact: 10 to 20 inches to Juana Lopez limestone
Depth to cambic horizon: 1 to 4 inches
Particle-size control section (weighted average):
Clay content: 18 to 35 percent
Rock fragments: 0 to 35 percent
A horizon: (Thickness 1-4 inches)
Hue: 10YR
Value: 5 or 6 (4 or 5 moist)
Chroma: 4 or 5
Texture: fine sandy loam, loam
Clay content: 10 to 27 percent
Rock fragments: 5 to 35, mainly limestone gravel
Calcium carbonate equivalent: 15 to 35 percent
EC (mmhos/cm): 0 to 2
Gypsum: 0 to 1 percent
SAR: 0 to 2
Reaction: moderately alkaline
Bw horizon: (Thickness 6 - 8 inches)
Hue: 10YR
Value: 4 or 6 dry or moist
Chroma: 4 or 5
Texture: loam, silt loam, clay loam
Clay content: 18 to 35 percent
Rock fragments: 0 to 15 percent
Calcium carbonate equivalent: 15 to 35 percent
EC (mmhos/cm): 0 to 2
Gypsum: 0 to 1 percent
SAR: 0 to 2
Reaction: moderately alkaline
Bk horizon: (Thickness 0-5 inches)
Hue: 10YR
Value: 6 or 7 dry, 5 or 6 moist
Chroma: 4 or 5
Texture: loam, silt loam, clay loam
Clay content: 18 to 35 percent
Rock fragments: 15 to 60
Calcium carbonate equivalent: 20 to 70 percent
EC (mmhos/cm): 0 to 2
Gypsum: 0 to 1 percent
SAR: 0 to 2
Reaction: moderately alkaline
COMPETING SERIES: These are the Braf (UT), Casmos (UT), Farb (NM), and Moenkopie (AZ) series. These soils lack cambic horizons and generally contain less than 15 calcium carbonate.
GEOGRAPHIC SETTING:
Parent material: residuum derived from Juana Lopez limestone, member of the Mancos Shale formation
Landform: Mesas and structural benches
Slopes: 1 to 6 percent
Elevation: 4,800 to 5,700 feet
Mean annual temperature: 52 to 56 degrees F
Mean annual precipitation: 7 to 10 inches
Precipitation pattern: uniform with slight dip in May and June and slight increase in July and August
Frost-free period: 135 to 160 days
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Gypsey and Persayo series, and Badlands. The Gypsey soils are moderately deep and are on mesas. The Persayo soils are shallow over shale, lack cambic horizons and are on hills.
DRAINAGE AND PERMEABILITY: Well drained, medium runoff, moderate permeability.
USE AND VEGETATION: Rangeland. Native vegetation is galleta, alkali sacaton saltbush, fringed sage and cactus.
DISTRIBUTION AND EXTENT: Southwest Colorado; MLRA 35; minor extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona.
SERIES ESTABLISHED: Montezuma County, Colorado, Ute Mountain Area, Colorado and New Mexico, 2005.
REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Series control section: The zone from 0 to 11 inches.
Particle-size control section: The zone from 0 to 11 inches. (A1, A2, Bw, Bk horizons)
Ochric epipedon: The zone from 0 to 3 inches. (A1, A2 horizons)
Cambic horizon: The zone from 3 to 9 inches. (Bw horizon)
Lithic contact: The contact with Juana Lopez Limestone at 11 inches. (R horizon)
Other features: The Bk horizon has the properties of a calcic horizon, but lacks the thickness to qualify.
This soil does not classify as an Aridisol because the lower boundary of the cambic horizon does not extend below 10 inches.
The assignment of the cation-exchange activity class is inferred from lab data from similar soils in the surrounding area.
ADDITIONAL DATA: Calcium carbonate amounts were determined with a field calcimeter.
Classified according to Keys to Soil Taxonomy Ninth Edition, 2003