LOCATION COLONA CO+NVEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Chromic Haplotorrerts
TYPICAL PEDON: Colona silty clay loam - grassland. Colors are for dry soil unless otherwise noted.)
A1--0 to 4 inches; grayish brown (2.5Y 5/2) heavy silty clay loam, dark grayish brown (2.5Y 4/2) moist; strong medium granular structure; slightly hard, very friable, sticky, plastic; noncalcareous; mildly alkaline (pH 7.8); gradual smooth boundary. (2 to 10 inches thick)
B2--4 to 16 inches; pale brown (10YR 6/3) silty clay, brown (10YR 5/3) moist; moderate medium prismatic structure that parts to fine angular blocks; slightly hard, very friable, sticky, plastic; peds are extremely hard, very firm; wide cracks between peds when dry; few thin glossy patches on the peds and few discontinuous glossy coatings in root channels and pores; calcareous; moderately alkaline (pH 8.0); gradual wavy boundary. (4 to 43 inches thick)
Cca--16 to 60 inches; light olive gray (5Y 6/2) heavy silty clay, olive gray (5Y 5/2) moist; massive; wide irregular cracks when dry; extremely hard, very firm, sticky, plastic; visible secondary calcium carbonate and calcium sulfate occurring as crystals, concretions, and in seams and streaks; content of visible carbonate and sulfate decreases with increasing depth; calcareous; moderately alkaline (pH 8.2).
TYPE LOCATION: Montrose County, Colorado; approximately .3 mile east and .2 mile south of the NW corner of Sec. 7, T. 47 N., R. 8 W.
RANGE IN CHARACTERISTICS: Depth to uniformly calcareous material normally ranges from 0 to 10 inches and is not deeper than the upper 2 inches of the B2 horizon. Depth to continuous subhorizons of visible secondary calcium carbonate accumulation ranges from 10 to 40 inches. Exchangeable sodium ranges from 0 to 15 percent in a major part of the control section. Gypsum content of the control section ranges from 0 to 15 percent by weight. The control section is normally silty clay or clay and averages 35 to 60 percent clay, 20 to 60 percent silt, and 5 to 40 percent sand, with less than 15 percent being fine or coarser sand. Rock fragments range from 0 to about 5 percent in most COLONA subhorizons of the control section and are mainly 1/2 to 3 inches in diameter. A majority of subhorizons above 40 inches has hue of 7.5YR or yellower.
The A horizon has hue of 5Y through 7.5YR, value of 5 through 7 dry, 3 through 6 moist, and chroma of 1 through 3. It is mildly or moderately alkaline.
The B2 horizon has hue of 5Y through 7.5YR, value of 5 through 7 dry, 4 through 6 moist, and chroma of 1 through 6. It ranges from mildly alkaline through strongly alkaline.
The Cca horizon has hue of 5Y through 7.5YR. It is moderately or strongly alkaline and has 3 to 14 percent calcium carbonate equivalent which decreases with increasing depth.
COMPETING SERIES: These are the Deaver, Heldt, and Stutzman series. Deaver soils have bedrock at depths of less than 40 inches. Heldt soils are moist in some part of the moisture control section more than one- fourth the time soil temperature is 41 degrees F, or higher. Stutzman soils have a total extensibility of less than 2.4 inches and do not develop wide cracks when dry.
GEOGRAPHIC SETTING: The Colona soils are on nearly level to gently sloping terraces and alluvial fans. Slopes range from about 0 to 6 percent. The soils formed in thick calcareous fine textured transported materials derived from silty sedimentary rocks, volcanic flow rocks, and tuffs. At the type location the mean annual precipitation is about 8 to 10 inches with peak periods of precipitation in the spring and early summer in Colorado and in winter and spring in Nevada. Mean annual temperature is 45 to 49 degrees F, and mean summer temperature is 69 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Duckett soils and the competing Stutzman soils. Duckett soils are poorly drained and have a calcic horizon.
DRAINAGE AND PERMEABILITY: Well drained; slow to very slow runoff; slow to very slow permeability.
USE AND VEGETATION: These soils are used as grazing land, native hay meadow, and for growing irrigated crops. Native vegetation is mainly winterfat, halogeton, sagebrush, little rabbitbrush, blue grama, cactus, and western wheat.
DISTRIBUTION AND EXTENT: Western Colorado, east-central Nevada. This series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Delta-Montrose Area, Colorado, 1957.
REMARKS: Last updated by the state 1/74.