LOCATION LAS KS+CO NEEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, calcareous, mesic Aquic Ustifluvents
TYPICAL PEDON: Las clay loam - cultivated. (Colors are for dry soil unless otherwise stated.)
A--0 to 12 inches; grayish brown (10YR 5/2) clay loam, dark grayish brown (10YR 4/2) moist; weak granular structure; hard, firm; slight effervescence; mildly alkaline; gradual smooth boundary. (5 to 15 inches thick)
C1--12 to 24 inches; light brownish gray (10YR 6/2) clay loam, dark grayish brown (10YR 4/2) moist; few thin strata of sandy loam; massive; very hard, firm; strong effervescence; moderately alkaline; gradual smooth boundary. (8 to 20 inches thick)
C2--24 to 45 inches; light brownish gray (10YR 6/2) clay loam, grayish brown (10YR 5/2) moist; common medium distinct yellowish brown and strong brown mottles; massive; very hard, firm; stratified layers of sandy loam; coarser textured materials occur in lower part of horizon; strong effervescence; moderately alkaline; gradual smooth boundary. (10 to 30 inches thick)
2C3--45 to 75 inches; very pale brown (10YR 7/3) coarse sand and fine gravel; single grained; loose; slight effervescence; moderately alkaline.
TYPE LOCATION: Hamilton County, Kansas; about 5 3/4 miles west and 1 mile north of Syracuse; 1,200 feet east and 100 feet north of the southwest corner of sec. 31, T. 23 S., R. 41 W.
RANGE IN CHARACTERISTICS: The thickness of the solum ranges from 5 to 15 inches. These soils typically have free carbonates throughout; however, in some pedons the upper 6 inches are noncalcareous. Reaction is mildly alkaline or moderately alkaline throughout. The upper horizons may contain soluble salts.
The A horizon has hue of 10YR or 2.5Y, value of 5 or 6 and 3 to 5 moist, and chroma of 2 or 3. If value is 5 and 3 moist, the A horizon is less than 7 inches thick. It is loam, fine sandy loam, or clay loam.
The C horizon has hue of 10YR, value of 5 to 7 and 4 or 5 moist, and chroma of 2 or 3. It is loam, clay loam, sandy clay loam, or sandy loam and commonly contains thin sandy or clayey strata. The lower part of the C horizon is mottled with colors of higher chroma. Some pedons have AC horizons having color and texture like the C horizon.
The 2C horizon has hue of 10YR, value of 6 or 7 and 4 or 5 moist, and chroma of 2 to 4. It is loamy sand, fine sand, sand, or coarse sand, typically containing some gravel. Mottles are faint through prominent or lacking. Depth to the 2C horizon is more than 40 inches.
COMPETING SERIES: These are the Tefton and Werlog series in the same family and the Angelus, Caruso, Las Animas, Lesho, Sweetwater, and Uncompahgre soils. The Tefton soils have a mean annual soil temperature of less than 50 degrees F. The Werlog soils lack stratification above 40 inches. Angelus soils are fine-silty. Caruso, Lesho, Sweetwater, and Uncompahgre soils have mollic epipedons. In addition, Lesho and Sweetwater soils have contrasting textures and are thermic; Uncompahgre soils are wetter; and Wann soils are coarse-loamy. Las Animas soils are wetter and have coarse-loamy textures.
GEOGRAPHIC SETTING: Las soils are on nearly level flood plains and low stream terraces. The soil formed in light colored, calcareous, medium textured alluvium. Slope gradients are 0 to 1 percent. Mean annual precipitation ranges from 14 to 19 inches, and the mean annual temperature ranges from 52 to 57 degrees F. Thornthwaite Annual P-E Index ranges from 19 to 32.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Las Animas soils and the better drained Bridgeport and McCook soils on associated higher terraces.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained. Runoff is slow. Permeability is moderately slow. These soils flood occasionally. The water table generally fluctuates between 3 to 6 feet below the surface but comes within 2 to 3 feet of the surface in wet years.
USE AND VEGETATION: Mostly cropped to wheat and grain sorghum. Native vegetation is mid and tall grasses.
DISTRIBUTION AND EXTENT: Western Kansas and adjacent areas of Colorado and Nebraska. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado
SERIES ESTABLISHED: Hamilton County, Kansas, 1959.
REMARKS: The horizons and features diagnostic for the typical pedon are organic carbon content that decreases irregularly with depth.