LOCATION MENOKEN COEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, mesic Ustic Haplocambids
TYPICAL PEDON: Menoken silty clay loam - cropland. (Colors are for dry soil unless otherwise noted.)
Ap--0 to 5 inches; light brownish gray (10YR 6/2) light silty clay loam; grayish brown (10YR 5/2) moist; moderate very fine granular structure; soft, very friable, slightly sticky, slightly plastic; the upper 1/2 inch of this horizon is a soft vesicular crust when dry, calcareous; moderately alkaline (pH 8.0); clear smooth boundary. (4 to 6 inches thick)
B2--5 to 18 inches; light yellowish brown (2.5Y 6/3) light silty clay loam; light olive brown (2.5Y 5/3) moist; weak medium prismatic structure that parts to medium subangular blocks; slightly hard, friable, slightly sticky, slightly plastic; peds are hard; few glossy patches on faces of peds; calcareous; moderately alkaline (pH 8.0); gradual smooth boundary. (5 to 24 inches thick)
C1ca--18 to 30 inches; light brownish gray (2.5Y 6/2) silty clay loam; grayish brown (2.5Y 5/2) moist; massive; hard, friable, slightly sticky, slightly plastic; visible secondary calcium carbonate occurring as concretions, and in thin seams and streaks; few crystals of calcium sulfate; calcareous; moderately alkaline (pH 8.2); gradual smooth boundary. (6 to 16 inches thick)
IIC2--30 to 60 inches; soft platy claystones, loamstones, and siltstones; calcareous; contains common gypsum crystals.
TYPE LOCATION: Montrose County, Colorado; approximately 1,200 feet east and 1/4 mile north of center of Sec. 11, T. 50 N., R. 10 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 30 inches. Exchangeable sodium ranges from 0 to 15 percent in a major part of the control section and no subhorizon more than 3 inches thick a depth of above 20 inches exceeds these limits. Weighted average gypsum content of the control section ranges from 0 to 1.5 percent by weight. Depth to the paralithic contact ranges from 20 to 40 inches. The control section is typically silt loam or silty clay loam, but averages 18 to 35 percent clay, 25 to 60 percent silt, and 10 to 45 percent sand. Rock fragments range from 0 to about 5 percent in most subhorizons above the bedrock. They are mainly 1/8 to 1/2 inch in diameter and are mostly shale chips. A majority of subhorizons above the bedrock have hue of 7.5YR or yellower, although a few thin subhorizons redder than 7.5YR are in some pedons.
The A horizon has hue of 5Y through 7.5YR, value of 5 through 8 dry, 3 through 7 moist, and chroma of 1 through 4. It is mildly or moderately alkaline (1:5 dilution unbuffered organic dye). 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. Subhorizons redder than 7.5YR are in some pedons. This horizon is mildly or moderately alkaline (1.5 dilution unbuffered organic dye).
The C horizon has hue of 5Y through 7.5YR. Subhorizons redder than 7.5YR are in some pedons. This horizon is moderately or strongly alkaline (1:5 dilution unbuffered organic dye). Calcium carbonate accumulation ranges from 3 to 14 percent.
COMPETING SERIES: These are the Alicia, Calabasas, Las Lucas, and Modell series. Alicia soils have hue of 5YR or redder in a majority of subhorizons of the control section. Calabasas, Las Lucas, and Modell soils lack a paralithic contact at depths of less than 40 inches.
GEOGRAPHIC SETTING: The Menoken soils are on gently to steeply sloping hills, ridges, mesa tops, and valley sideslopes. Slopes typically range from about 2 to 40 percent or more. The soils formed in moderately thin calcareous silty medium to moderately fine materials weathered from sedimentary bedrocks. At the type location the mean annual precipitation is about 10 inches with peak periods of precipitation in the spring and early summer months. Mean annual temperature is 46 degrees F., and summer temperature is 72 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Chipeta and Persayo soils. Chipeta soils are fine textured, lack a cambic horizon, and overlie bedrock at depths of less than 20 inches. Persayo soils lack a cambic horizon and have bedrock at depths of less than 20 inches.
DRAINAGE AND PERMEABILITY: Well drained; medium to rapid runoff; moderate to slow permeability.
USE AND VEGETATION: Used as grazing land or for irrigated cropland. Native vegetation is sage, cactus, snakeweed, blue grama, and western wheat.
DISTRIBUTION AND EXTENT: Western Colorado. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Delta-Montrose Area, Colorado, 1965.
REMARKS: Last updated by the state 4/73.