LOCATION NORTE CO+UT WYEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, calcareous, frigid Aquic Ustorthents
TYPICAL PEDON: Norte gravelly sandy loam - grassland. (Colors are for dry soil unless otherwise noted.)
A--0 to 4 inches; light brownish gray (10YR 6/2) gravelly sandy loam, dark grayish brown (10YR 4/2) moist; moderate fine granular structure; soft, very friable; 15 percent pebbles mostly basalt; many dark gray and red volcanic mineral grains in the sand and silt fractions; calcareous; moderately alkaline (pH 8.0); clear smooth boundary. (3 to 6 inches thick)
AC--4 to 12 inches; light brownish gray (10YR 6/2) gravelly sandy loam, dark grayish brown (10YR 4/2) moist; weak medium subangular blocky structure; slightly hard, very friable; 20 percent pebbles mostly basalt; many dark gray and red volcanic mineral grains in the sand and silt fractions; calcareous; moderately alkaline (pH 8.0); gradual wavy boundary. (4 to 10 inches thick)
C--12 to 30 inches; light brownish gray (10YR 6/2) gravelly sandy loam, dark grayish brown (10YR 4/2) moist; massive; slightly hard, very friable; 35 percent
pebbles mostly basalt; many dark gray and reddish brown volcanic mineral grains in sand and silt fractions, some discontinuous accumulation of visible secondary carbonate as concretions and as coatings on rock fragments; calcareous; moderately alkaline (pH 8.2); gradual wavy boundary. (4 to 33 inches thick)
2C--30 to 60 inches; very gravelly loamy sand; many dark gray and reddish brown volcanic mineral grains in the sand and silt fractions; content of basaltic pebbles and sand give this horizon a grayish cast on exposure; 45 percent pebbles and 10 percent cobbles.
TYPE LOCATION: Rio Grande County, Colorado; approximately 300 feet east and 300 feet south of the W1/4 corner of Sec. 18, T. 40 N., R. 8 E.
RANGE IN CHARACTERISTICS: Mean annual soil temperature ranges from 43 to 46 degrees F, and mean summer soil temperature ranges from 61 to 64 degrees F. Depth to calcareous material ranges from 0 to 10 inches. The soils range from neutral to strongly alkaline. Depth to the sandy-skeletal 2C horizon ranges from about 24 to 40 inches. It has 35 to 55 percent pebbles and 10 to 25 percent cobbles. 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 particle size control section averages about 5 to 18 percent clay, 35 to 80 percent fine or coarser sand, and 0 to 35 percent rock fragments. The rock fragments are mainly 1 to 10 inches in diameter. A seasonal high water table ranges from 2.5 to 4.5 feet.
The A horizon has hue of 5Y through 7.5YR, value of 5 or 6, 4 or 5 moist, and chroma of 2 or 3.
The C horizon above the 2C horizon has hue of 5Y through 6.5YR, value of 5 or 6, 4 or 5 moist, and chroma of 2 or 3.
The sandy-skeletal 2C horizon has varigated gray colors with hues similar to the A and C horizon.
COMPETING SERIES: There are no other known series in this family. The Clifterson, Mogote, and Mount Home series are closely related. Clifterson soils have mesic temperature. Mogote soils lack skeletal particle size control sections and Mount Home soils have an aridic moisture regime.
GEOGRAPHIC SETTING: Norte soils are on terraces and alluvial fans. Slopes range from 0 to 2 percent. These soils formed in calcareous, moderately coarse textured alluvium overlying beds of sand and gravel. The average annual precipitation is 7 inches with peak periods of precipitation in the spring and early summer months. These soils are underlain by a fluctuating water table that is highest in the summer which keeps the lower part of the moisture control section moist for periods much longer than is customary for the precipitation of the area. Mean annual temperature is 40 to 42 degrees F, and the mean summer temperature is 60 to 63 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Quamon and Monte soils. Quamon soils have a sandy-skeletal control section. Monte soils have an aridic moisture regime and a fine-loamy control section.
DRAINAGE AND PERMEABILITY: Moderately well drained to somewhat poorly drained; slow runoff; rapid permeability. These soils have a fluctuating water table that wets the lower part of the moisture control section for significant periods during most growing seasons.
USE AND VEGETATION: These soils are used principally as native pastureland or for irrigated cropland. Principal native plants are rabbitbrush, sage, and scattered grasses.
DISTRIBUTION AND EXTENT: San Luis Valley Area of south-central Colorado. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Rio Grande County Area, Colorado, 1972.
REMARKS: This soil is saturated with water above 1.5 meters for more than 1 month in most years and is an Aquic Ustorthent rather than Typic. This soil has been correlated only in the Rio Grande County Area Soil Survey of Colorado.
The superactive cation exchange activity class was added in 03/2003 to the taxonomic classification by the National Soil Survey Center on request of the Lakewood MLRA office, without review of the soil series property data. The remainder of this document has not been updated.