LOCATION CHAPIN COEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Aridic Argiustolls
TYPICAL PEDON: Chapin loam - grassland. (Colors are for dry soil unless otherwise noted.)
A1--0 to 6 inches; brown (7.5YR 5/3) loam, dark brown (7.5YR 3/3) moist; strong fine granular structure; soft, very friable, slightly sticky, slightly plastic; noncalcareous; neutral (pH 7.0); clear smooth boundary. (4 to 10 inches thick)
B1--6 to 10 inches; reddish brown (5YR 5/3) light clay loam, dark reddish brown (5YR 3/3) moist; moderate fine subangular blocky structure that parts to coarse granules; slightly hard, very friable, slightly sticky, slightly plastic; primary peds are very hard; few thin glossy patches on faces of some peds; noncalcareous; neutral (pH 7.0); clear smooth boundary. (3 to 10 inches thick)
B2t--10 to 20 inches; reddish brown (5YR 5/4) heavy clay loam, reddish brown (5YR 4/4) moist; moderate fine prismatic structure that parts to fine angular blocks; slightly hard, very friable, sticky, plastic; peds are extremely hard; continuous wax-like coatings on faces of peds and wax-like coatings and fillings in root channels and pores; wax-like rims around the entrance to some soil pores; noncalcareous; mildly alkaline (pH 7.4); clear wavy boundary. (7 to 24 inches thick)
B3ca--20 to 25 inches; reddish brown (5YR 5/4) clay loam, reddish brown (5YR 4/4) moist; weak medium prismatic structure that parts to medium subangular blocks; slightly hard, very friable, slightly sticky, slightly plastic; peds are very hard; few thin glossy patches on the faces of peds and a few discontinuous glossy coatings on the inside of root channels and pores; visible secondary calcium carbonate occurring as concretions and in thin seams and streaks; calcareous; moderately alkaline (pH 8.2); clear wavy boundary. (3 to 8 inches thick)
Cca--25 to 36 inches; pinkish gray (5YR 7/2) light clay loam, reddish brown (5YR 5/3) moist; massive; very hard, friable, slightly sticky, slightly plastic; strong accumulation of secondary carbonate in finely divided marl-like forms; calcareous; moderately alkaline (pH 8.4); abrupt wavy boundary. (3 to 23 inches thick)
R--36 to 40 inches; hard reddish brown calcareous sandstone.
TYPE LOCATION: Montezuma County, Colorado; on the edge of a burned area approximately 330 feet north of Archeological Site 1464 in Sec. 7, T. 34 N., R. 15 W.
RANGE IN CHARACTERISTICS: Depth to uniformly calcareous material normally ranges from 6 to 30 inches and is not shallower than the upper 3 inches of the B2t horizon. Depth to the lithic contact ranges from 20 to 40 inches. Depth to the base of the argillic horizon ranges from 17 to 36 inches. Depth to the calcic horizon ranges from 15 to 30 inches. ESP ranges from 0 to 15 percent in the solum, but exceeds 15 percent in the Cca horizon of some pedons. A majority of subhorizons above the bedrock have hue of 5YR or redder, although subhorizons yellower than 5YR occur in some pedons. Rock fragments range from 0 to 15 percent by volume in a major part of the solum and C horizon above the bedrock. They are mainly 1/2 to 10 inches in diameter.
The A horizon has hue of 10YR through 5YR, value of 4 or 5 dry, 2 or 3 moist, and chroma of 1 through 3. It is neutral or mildly alkaline (1:5 dilution unbuffered organic dye).
The B2t horizon has hue of 7.5YR through 10R, value of 5 through 7 dry, 3 through 6 moist, and chroma of 1 through 6. It is typically heavy sand from 15 to 55 percent with more than 15 percent fine or coarser sand. This horizon is neutral to moderately alkaline.
The C horizon has hue of 7.5YR through 10R. It is typically loam or clay loam but clay ranges from 18 to 35 percent, silt from 5 to 50 percent, and sand from 20 to 70 percent. This horizon is moderately or strongly alkaline (1:5 dilution unbuffered organic dye). Calcium carbonate of the fine earth ranges from 15 to 50 percent.
COMPETING SERIES: These are the Boneek, Collbran, Dagflat, Emigrant, Gobar, Loma, Nunn, Rednun, Richfield, Ryus, Sofia, Torreon, and Wormser series. Boneek, Torreon, and Wormser soils have hue yellower than 5YR in the B2t horizon. Also, Wormser soils lack a calcic horizon. Collbran, Gober, Loma, Nunn, Rednun, Richfield, Ryus, and Sofia soils lack a lithic contact at depths of less than 40 inches. Dagflat soils are fine-loamy and are noncalcareous throughout. Emigrant soils have a paralithic contact at depths of less than 40 inches and are shallower than 17 inches to the base of the argillic horizon.
GEOGRAPHIC SETTING: The Chapin soils are on gently to moderately sloping mesa tops, hills, ridges, and valley side slopes. Slopes typically range from about 0 to 20 percent or more. The soil formed in moderately thin, calcareous, reddish brown or brown materials originating partly as eolian materials, alluvium from reddish brown sedimentary rocks or residuum from such formations. At the type location the mean annual precipitation is about 16 inches with nearly equal precipitation in all months. Mean annual temperature is 50 degrees F and mean summer temperature is 70 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cliffhouse and Roubideau soils. Cliffhouse soils have a paralithic contact at depths of less than 40 inches. Roubideau soils have an ochric epipedon and have less than 35 percent clay in the argillic horizon.
DRAINAGE AND PERMEABILITY: Well drained; slow to medium runoff; moderate to slow permeability.
USE AND VEGETATION: Used as grazing land, recreation or as dry or irrigated cropland. Native vegetation is oakbrush, pinyon, juniper, western wheatgrass, blue grama, and junegrass.
DISTRIBUTION AND EXTENT: Western Colorado. This series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Western Colorado Reconnaissance Survey, 1939.
REMARKS: Last updated by the state 4/73.