LOCATION NORTONVILLE COEstablished Series
TAXONOMIC CLASS: Fine-loamy, frigid Typic Calciaquolls
TYPICAL PEDON: Nortonville loam - grassland. (Colors are for dry soil unless otherwise noted.)
A1ca--0 to 5 inches; grayish brown (10YR 5/2) loam, very dark brown (10YR 2/2) moist; weak medium subangular blocky structure that parts to weak fine granular; hard, firm; calcareous; some salt spots; abrupt wavy boundary. (3 to 8 inches)
ACcs--5 to 9 inches; grayish brown (10YR 5/2) light clay loam, very dark grayish brown (10YR 3/2) moist; weak fine granular structure; slightly hard, friable, slightly sticky, slightly plastic; calcareous; some salt and gypsum spots; clear smooth boundar. (2 to 7 inches thick)
C1cs--9 to 14 inches; light brownish gray (10YR 6/2) light clay loam, dark grayish brown (10YR 4/2) moist; weak coarse subangular blocky structure that parts to weak fine granular; slightly hard, friable, slightly sticky slightly plastic; large amount of gypsum crystals; calcareous; moderately alkaline; clear smooth boundary. (3 to 10 inches thick)
C3g--14 to 29 inches; grayish brown (10YR 5/2) loam, dark grayish brown (10YR 4/2) moist; common fine distinct yellowist brown (10YR 5/4 and 5/6) mottles, dark yellowish brown (10YR 4/4) moist; weak coarse prismatic structure that parts to weak medium subangular blocky; slightly lime spots; calcareous; moderately alkaline; clear smooth boundary. (10 to 20 inches thick)
C3--29 to 60 inches; pale brown (10YR 6/3) loam and fine sandy loam, dark brown (10YR 4/3) moist; many fine distinct yellowish brown (10YR 5/4 and 5/6) mottles, dark yellowish brown (10YR 4/4) moist; massive; slightly hard, friablek; noncalcareous; moderately alkaline.
TYPE LOCATION: Alamosa County, Colorado; 1,300 feet south and 600 feet east of the center of Sec. 7, T. 36 N., R. 11 E.
RANGE IN CHARACTERISTICS: The Nortonville soils are calcareous in the A and Ccs horizons but grade to noncalcareous C horizons at depths of less than 40 inches. Exchangeable sodium ranges from 10 to 35 percent in the upper part of the control section, and there are some subhorizons more than 4 inches thick above a depth of 20 inches that exceed 15 percent. Exchangeable sodium decreases as depth increases. Depth to the gypsic horizon ranges from 8 to 24 inches. Depth to skeletal materials ranges from 40 to more than 60 inches. The control section is usually loam or clay loam and has 18 to 35 percent clay, 20 to 55 percent silt, and 20 to 50 percent sand with less than 35 percent fine or coarser sand. Rock fragments range from 0 to 15 percent in a major part of the control section and are mainly less than 3 inches in diameter. The mean annual soil temperature is 45 degrees F., and the mean summer soil temperature is 62 degrees F.
The A horizon has hue of 5Y through 7.5YR, value of 4 or 5 dry, 2 or 3 moist, and chroma of 1 through 3. It ranges from moderately to very strongly alkaline.
The C horizon has hue of 5Y through 7.5YR. It ranges from moderately to very strongly alkaline in the upper part of the C horizon but grades to mildly or moderately alkaline in the lower part. A gypsic horizon occurs in the upper part of the C horizon, but content of calcium sulfate decreases as depth increases.
COMPETING SERIES: These are the Antler, Gilby, and Vallers series, all of which lack a gypsic horizon. Also, Antler and Gilby soils formed in 20 to 40 inches of loamy lacustrine sediments overlying firm loam or clay loam till.
GEOGRAPHIC SETTING: The Nortonville soils are on flood plains and low alluvial fans. Slope gradients range from 0 to about 6 percent. The soils formed in alluvial parent materials. At the type location the average annual precipitation is 7 inches, with peak periods of precipitation in the spring and summer.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the LaSauses and Zinzer soils. LaSauses soils lack gypsic horizons and have ochic epipedons. Zinzer soils have calcic rather than gypsic horizons and are well drained.
DRAINAGE AND PERMEABILITY: Poorly drained; slow runoff; moderately slow permeability.
USE AND VEGETATION: These soils are as native pastureland and for irrigated meadow. Occasionally they may be irrigated for barley. Native vegetation is mainly alkali sacaton, saltgrass, tall rabbitbrush, and greasewood.
DISTRIBUTION AND EXTENT: The 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: Alamosa Countuy, Colorado, 1974.
REMARKS: Last updated by the state 8/74.