LOCATION CAHONA CO+UTEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, mesic Calcidic Haplustalfs
TYPICAL PEDON: Cahona loam, on a south facing, 4 percent slope in rangeland at an elevation of 6,800 feet. (Colors are for dry soil unless otherwise noted.)
A1--0 to 1 inch; reddish brown (5YR 4/4) loam, dark reddish brown (5YR 3/4) moist; single grain; loose, loose, nonsticky and nonplastic; slightly effervescent; slightly alkaline (pH 7.5); clear smooth boundary. (1 to 8 inches thick)
A2--1 to 5 inches; reddish brown (5YR 4/4) loam, dark reddish brown (5YR 3/4) moist; moderate fine granular structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine roots throughout; common very fine discontinuous tubular pores; noneffervescent; slightly alkaline (pH 7.4); clear smooth boundary. (0 to 6 inches thick)
Bt--5 to 15 inches; yellowish red (5YR 4/6) clay loam, reddish brown (5YR 4/4) moist; moderate medium prismatic structure parting to moderate medium angular blocky; hard, friable, slightly sticky and moderately plastic; common fine roots throughout; common fine discontinuous tubular pores; slightly effervescent; slightly alkaline (pH 7.8); gradual smooth boundary. (4 to 16 inches thick).
Btk--15 to 25 inches; yellowish red (5YR 5/6) clay loam, reddish brown (5YR 4/4) moist; weak medium prismatic structure parting to moderate medium angular blocky; hard, friable, moderately sticky and moderately plastic; common fine and medium roots throughout; common fine discontinuous tubular pores; common fine irregular soft masses of carbonate; violently effervescent; moderately alkaline (pH 8.0); clear wavy boundary. (3 to 15 inches thick).
Bk1--25 to 38 inches; pinkish white (5YR 8/2) loam, light reddish brown (5YR 6/3) moist; weak coarse prismatic structure parting to moderate medium subangular blocky; hard, firm, slightly sticky and moderately plastic; common medium roots throughout; 43 percent calcium carbonate equivalent; violently effervescent; strongly alkaline (pH 8.6); clear wavy boundary. (6 to 20 inches thick).
Bk2--38 to 60 inches; pinkish gray (5YR 7/2) loam, light reddish brown (5YR 6/3) moist; massive; hard, firm, slightly sticky and slightly plastic; common medium roots throughout; violently effervescent; moderately alkaline (pH 8.4)
TYPE LOCATION: Dolores County, Colorado; about 5 miles northwest of Dove Creek; located about 500 feet south and 1500 feet east of the northwest corner of sec. 9, T. 41 N., R. 19 W.; Dove Creek USGS quad; lat. 37 degrees 47 minutes 12 seconds N. and long. 108 degrees 56 minutes 24 seconds W., NAD
RANGE IN CHARACTERISTICS:
Soil moisture regime: ustic bordering on aridic
Soil temperature regime: mesic
Mean annual soil temperature: 48 to 52 degrees F
Mean annual summer soil temperature: 63 to 67 degrees F
Depth to secondary calcium carbonate: 5 to 30 inches
Depth to calcic horizon: 20 to 40 inches
Depth to the base of the argillic horizon: 20 to 30 inches
Particle-size control section (weighted average):
Clay content: 18 to 35 percent
A horizon:
Hue: 5YR or 7.5YR
Value: 4 to 7 (3 to 6 moist)
Chroma: 2 to 6
Texture: fine sandy loam, loam or silt loam
Rock fragment content: 0 to 5 percent
Calcium carbonate equivalent: 0 to 1 percent
Reaction: neutral or slightly alkaline
Bt and Btk horizons:
Hue: 5YR or 7.5YR
Value: 4 to 7 dry (3 to 5 moist)
Chroma: 2 to 6
Texture: loam, clay loam or silty clay loam
Calcium carbonate equivalent: 0 to 10 percent
Rock fragment content: 0 to 5 percent
Reaction: slightly to strongly alkaline
Bk horizon:
Hue: 5YR to 7.5YR
Calcium carbonate equivalent: 15 to 50 percent
Reaction: slightly to strongly alkaline
COMPETING SERIES: These are the Canina, Kucu, Plughat and Villegreen series. Canina soils have a discontinuity between 20 and 40 inches. Kucu soils have a lithologic discontinuity. Plughat soils are deep. Villegreen soils are moderately deep.
GEOGRAPHIC SETTING:
Parent material: eolian material derived from sandstone
Landform: hills and mesas
Slopes: 1 to 12 percent
Elevation: 6,200 to 7,400 feet
Mean annual temperature: 46 to 50 degrees F
Mean annual precipitation: 13 to 16 inches
Precipitation is fairly evenly distributed throughout the year with July and August being slightly wetter and June being slightly dryer.
Frost-free period: 100 to 120 days
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Wetherill, Pulpit, and Sharps series. All these soils are on the same landscape positions as Cahona. Wetherill soils have a calcic horizon below 40 inches. Pulpit and Sharps soils have bedrock above 40 inches.
DRAINAGE AND PERMEABILITY: well drained, medium to very high runoff, moderately slow or slow permeability
USE AND VEGETATION: These soils are used for dryland and irrigated cropland, and for grazing. The native vegetation is scattered twoneedle pinyon and Utah juniper, big sagebrush, Indian ricegrass, muttongrass, and western wheatgrass.
DISTRIBUTION AND EXTENT: Southwest Colorado and southeast Utah. LRR D, MLRA 36. This series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Canyonlands Area, Utah - parts of Grand and San Juan counties Utah. August 1983.
REMARKS: This OSED reclassified the Cahona series into the 13 to 16 inch precipitation zone in southwest Colorado and Utah. Change results from the Four Corners Climate Conference of 10/92. Type location was moved to better reflect the central concept of the Cahona series.
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon: The zone from 0 to 5 inches. (A1, A2 horizons)
Argillic horizon: The zone from 5 to 25 inches. (Bt, Btk horizons)
Calcic horizon: The zone from 25 to 60 inches. (Bk1, Bk2)
Particle size control section: The zone from 5 to 25 inches. (Bt, Btk)
Classified according to Keys to Soil Taxonomy Ninth Edition, 2003.