LOCATION TURNBACK WYEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, mesic Ustic Haplocambids
TYPICAL PEDON: Turnback loamy fine sand-on an east facing slope of 3 percent: utilized as rangeland. (Colors are for dry soil unless otherwise stated)
A--0 to 4 inches; pale brown (10YR 6/3) loamy fine sand, brown (10YR 5/3) moist; weak fine granular structure; loose, nonsticky and nonplastic; slightly effervescent; moderately alkaline (pH 8.2); clear smooth boundary. (2 to 6 inches thick)
Bw1--4 to 8 inches; pale brown (10YR 6/3) sandy loam, yellowish brown (10YR 5/4) moist; weak medium and fine subangular blocky structure; loose, nonsticky and nonplastic; slightly effervescent, calcium carbonate disseminated; moderately alkaline (pH 8.4); clear smooth boundary. (0 to 6 inches thick)
Bw2--8 to 20 inches; light yellowish brown (2.5Y 6/4) sandy loam, light olive brown (2.5Y 5/4) moist; weak medium subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; strongly effervescent, calcium carbonate disseminated; moderately alkaline (pH 8.4); clear wavy boundary. (6 to 18 inches thick)
Bk--20 to 30 inches; pale yellow (2.5Y 7/4) loamy sand, light olive brown (2.5Y 5/4) moist; massive with some rock structure; soft, very friable, nonsticky and nonplastic; strongly effervescent, calcium carbonate as common medium and coarse soft masses and few fine filaments and seams; moderately alkaline (pH 8.4); gradual wavy boundary. (8 to 25 inches thick)
Cr--30 inches; yellow (10YR 7/8) soft, calcareous sandstone; moderately alkaline (pH 8.2); very slightly effervescent.
TYPE LOCATION: Converse County, Wyoming; 2,500 feet east and 1,900 feet north of the SW corner of sec. 19, T. 39 N., R. 74 W. Thompson Draw Quadrangle. 43 degrees 20 minutes 4 seconds north latitude and 105 degrees 47 minutes 24 seconds west longitude.
RANGE IN CHARACTERISTICS: Depth to bedrock ranges from 20 to 40 inches. These soils typically effervesce throughout the profile but may be leached as much as 8 inches in some pedons. The soil is dry in the moisture control section more than half the time cumulative that the soil temperature at a depth of 20 inches is 41 degrees F., which occurs about April 21-27, but is dry in all parts of the moisture control section for at least 60 consecutive days from July 15 to October 25 and for at least 90 cumulative days during this period. The mean annual soil temperature is 48 to 52 degrees F., and the soil temperature at a depth of 20 inches is 41 degrees F. or more for 175 to 192 days.
The A horizon has hue of 10YR or 2.5Y, value of 4 through 6 dry, 4 or 5 moist, and chroma of 2 through 4. It is loamy fine sand, fine sandy loam, or sandy loam. This horizon is mildly or moderately alkaline.
The Bw cambic horizon has hue of 10YR or 2.5Y, value of 5 through 7 dry, 4 through 6 moist, and chroma of 2 through 4. Texture is sandy loam or fine sandy loam. Clay ranges from 5 to 15 percent with total fines greater than 15 percent. Rock fragments range from 0 to 15 percent. Reaction is mildly or moderately alkaline. EC is 0 to 2 mmhos. Some pedons have few gypsum crystals in the lower part of this horizon.
The Bk horizon has hue of 10YR or 2.5Y, value of 5 through 7 dry, 4 through 6 moist, and chroma of 2 through 4. Texture is sandy loam, fine sandy loam, or loamy sand. Clay ranges from 5 to 15 percent with more than 15 percent total fines. Rock fragments range from 0 to 15 percent. Reaction ranges from moderately alkaline to strongly alkaline. EC is 0 to 2 mmhos. Carbonates range from 4 to 8 percent but do not qualify for a calcic. Some pedons have secondary accumulations of gypsum.
The Cr or material at the paralithic control is soft, calcareous sandstone. Some discontinuous horizons of hard sandstone may occur beneath some pedons.
COMPETING SERIES: These are the Begay, Ignacio, Parida, Remmit, and Sandspring(T) series. Begay and Remmit soils lack bedrock within 60 inches. Ignacio soils have lithic contacts at 20 to 40 inches. Parida soils have 15 to 35 percent rock fragments in the particle size control section. Sandspring soils are intermittently moist from July through September and have soil temperatures from 52 to 59 degrees F.
GEOGRAPHIC SETTING: Turnback soils are on partially stabilized hillslopes and summits. Slopes are 0 to 20 percent. The soils formed in moderately coarse textured alluvium, residuum and, eolian deposits derived from calcareous sandstone. Elevations are 4,500 to 6,000 feet. The average annual precipitation ranges from 10 to 14 inches with over half falling in April, May, and June and less than one inch falling in each month of July, August, September, and October. The mean annual temperature ranges from 44 to 49 degrees F. The frost-free season is about 110 to 130 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Keeline, Tassel, and Tullock soils. Keeline soils lack bedrock within 60 inches. Tassel soils have a paralithic contact at 20 inches or less. Tullock soils have sandy control sections.
DRAINAGE AND PERMEABILITY: Well or somewhat excessively drained; low runoff; moderately rapid permeability.
USE AND VEGETATION: These soils are dominantly used as rangeland. Potential native vegetation is needleandthread, prairie sandreed, Indian ricegrass, and little bluestem.
DISTRIBUTION AND EXTENT: Powder River Basin and adjacent areas of eastern Wyoming and Colorado. The series is of limited extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado
SERIES ESTABLISHED: Converse County, Wyoming, Northern Part; 1983.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - 0 to 4 inches (A)
Cambic horizon - 4 to 20 inches (Bw1,Bw2)
LRR- G
SIR- WY0517