LOCATION QUAMON COEstablished Series
TAXONOMIC CLASS: Sandy-skeletal, mixed, frigid Typic Ustorthents
TYPICAL PEDON: Quamon cobbly sandy loam - grassland. (Colors are for dry soil unless otherwise noted.)
A1--0 to 5 inches; brown (10YR 5/3) cobbly sandy loam, dark brown (10YR 4/3) moist; moderate fine granular structure; soft, very friable; 30 percent cobbles and gravel, mostly basalt; many dark magnetic mineral grains in the sand and silt fractions; calcareous; moderately alkaline (pH 8.2); gradual smooth boundary. (4 to 6 inches thick)
C1--5 to 16 inches; brown (10YR 5/3) gravelly sandy loam, dark brown (10YR 4/3) moist; weak coarse subangular blocky structure that parts to fine granules; soft, very friable; 25 percent gravel and cobbles, mostly basalt; many dark magnetic mineral grains in the sand and silt fractions; calcareous; moderately alkaline (pH 8.2); gradual smooth boundary. (4 to 16 inches thick)
IIC2--16 to 60 inches; light yellowish brown (10YR 6/4) very cobbly loamy sand, yellowish brown (10YR 5/4) moist; single grained; loose; 65 percent cobbles and gravel, mostly basalt; many dark mineral grains in the sand fraction; calcareous; moderately alkaline (pH 8.2).
TYPE LOCATION: Rio Grande County, Colorado; 100 feet west and 1,300 feet south of the NE corner of Sec. 18, T. 40 N., R. 8 E.
RANGE IN CHARACTERISTICS: Mean annual soil temperature is 43 degrees F. and mean summer soil temperature is 61 degrees F. Depth to calcareous materlal ranges from 0 to 10 inches. The soils range from neutral to strongly alkaline. Depth to sandy-skeletal material ranges from 12 to 25 inches. The control section averages 0 to 5 percent gypsum and a majority of subhorizons above 24 inches do not exceed 3 percent. Exchangeable sodium ranges from 0 to 15 percent and conductivity ranges from 0 to 14 millimhos above a depth of 24 inches except that thin subhorizons totaling less than 4 inches in thickness and containing more than 15 percent exchangeable sodium or with conductivity exceeding 14 millimhos occur inconsistently in some pedons. The upper part of the control section above the sandy-skeletal material has 5 to 18 percent clay, 35 to 85 percent fine or coarser sand and 0 to 35 percent rock fragments, dominantly 1 to 10 inches in diameter. Hue ranges from 5Y through 7.5YR except that a few subhorizons having hue redder than 7.5YR occur discontinuously in some pedons and occupy less than half the thickness of the control section.
COMPETING SERIES: These are the Clark Fork, Nemote, and Tinsley series. Clark Fork and Nemote soils are noncalcareous above depth of 40 inches. Tinsley soils are coarse textured throughout the control section and formed in parent materials that have only minor influence from basalt.
GEOGRAPHIC SETTING: Quamon soils are on broad, gently sloping alluvial fans and valley bottoms. Slope gradients range from 0 to about 6 percent. The soils formed in thick, very gravelly, calcareous, fan alluvium derived principally from basalt. At the type location the average annual precipitation is 7 inches with a sprlng and early summer rainfall pattern. Mean annual temperature is 41 degrees F; mean summer temperature is 62 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Dunul and Derrick soils. Dunul soils are less than 10 inches deep over sand and gravel and are moist less than 1/4 of the time the soil temperature is 41 degrees F or higher. Derrick soils have argillic horizons.
DRAINAGE AND PERMEABILITY: Moderately well drained, seasonal high water table at depths of 3 to 5 feet; slow runoff; rapid permeability to gravel substratum, and very rapid below.
USE AND VEGETATION: These soils are used for irrigated cropland, irrigated pasture, and as dry pasture land. Principal native plants are rabbitbrush and blue grama. Some irrigated crops are potatoes, barley, and alfalfa.
DISTRIBUTION AND EXTENT: San Luis Valley of south-central Colorado. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Rio Grande County, Colorado, 1972.
REMARKS: Last updated by the state 2/74.