LOCATION SAVAR WY
Established Series
Rev. PJL/PSD/SJJ
01/2023
SAVAR SERIES
The Savar series consists of very deep, well drained soils that formed in colluvium and alluvium derived from shale. These soils are on alluvial fans, and hillslopes. Slopes are 3 to 35 percent. The average annual precipitation is 15 to 19 inches, and the average annual temperature is 43 to 45 degrees F.
TAXONOMIC CLASS: Fine, smectitic, frigid Pachic Argiustolls
TYPICAL PEDON: Savar clay loam-rangeland. (Colors are for dry soil unless otherwise stated.)
A--0 to 2 inches; grayish brown (2.5Y 5/2) clay loam, very dark grayish brown (2.5Y 3/2) moist; moderate very fine granular structure; slightly hard, friable, slightly sticky and slightly plastic; moderately alkaline (pH 7.9); clear smooth boundary. (1 to 4 inches thick)
Bt1--2 to 11 inches; dark grayish brown (2.5Y 4/2) clay, very dark grayish brown (2.5Y 3/2) moist; strong coarse prismatic structure parting to strong fine and medium angular blocky; extremely hard, firm, moderately sticky and moderately plastic; many prominent clay films on vertical and horizontal faces of peds; moderately alkaline (pH 8.1); clear smooth boundary. (6 to 13 inches thick)
Bt2--11 to 20 inches; grayish brown (2.5Y 5/2) clay, dark olive brown (2.5Y 3/3) moist; strong medium subangular blocky structure parting to strong fine angular blocky; extremely hard, firm, moderately sticky and moderately plastic; many prominent clay films on vertical and horizontal faces of peds; moderately alkaline (pH 8.2); clear smooth boundary. (6 to 18 inches thick)
Btk1--20 to 31 inches; light yellowish brown (2.5Y 6/4) clay, light olive brown (2.5Y 5/4) moist; strong medium subangular blocky structure; extremely hard, firm, moderately sticky and moderately plastic; many prominent clay films on faces of peds; strongly effervescent, calcium carbonate as common fine threads; strongly alkaline (pH 8.5); clear smooth boundary. (7 to 15 inches thick)
Btk2--31 to 60 inches; light gray (2.5Y 7/2) clay, light olive brown (2.5Y 5/3) moist; moderate coarse subangular blocky structure; extremely hard, firm, moderately sticky and moderately plastic; common distinct clay films on vertical and horizontal faces of peds; strongly effervescent, calcium carbonate as common fine threads and large soft masses; strongly alkaline (pH 8.6)
TYPE LOCATION: Sheridan County, Wyoming; SW1/4, SE1/4 of sec. 5, T. 57 N., R. 87 W.
RANGE IN CHARACTERISTICS: The mollic epipedon is 16 to 30 inches thick and typically includes the A and Bt horizons. Depth to free carbonates is 18 inches or more. The base of the argillic horizon is at 37 to 60 inches or more. In some pedons a C or Bk horizon is present. The mean annual soil temperature is 43 to 47 degrees F., and the mean summer soil temperature is 59 to 63 degrees F. These soils are dry in some part of the moisture control section for 60 consecutive days between July 15 and October 1. Coarse fragments are typically absent, but shale chips may range up to 15 percent.
The A horizon has hue of 2.5Y or 10YR, value of 3 through 5 dry, 2 or 3 moist, and chroma of 2 or 3. Some A horizons appear as a light colored vesicular crust that darkens when moistened. Reaction is slightly alkaline or moderately alkaline.
Th Bt horizon has hue of 2.5Y or 10YR, value of 3 through 5 dry, 2 or 3 moist, and chroma of 2 or 3. Texture is clay, clay loam, or silty clay. Clay content ranges from 35 to 50 percent. Sand content is less than 45 percent with over half being fine or very fine sand. Reaction is slightly alkaline or moderately alkaline.
The Btk horizon has hue of 2.5Y or 10YR, value of 5 through 7 dry, 4 through 6 moist, and chroma of 2 through 4. Texture is clay, clay loam, or silty clay with 35 to 50 percent clay. Calcium carbonate equivalent averages 5 to 15 percent. Some pedons have few discontinuous pockets exceeding 15 percent. Reaction is moderately alkaline or strongly alkaline.
COMPETING SERIES: These are the
Beaverdam,
Buckskin,
Cimarron,
Cucharas,
Gourley,
Heathcoat,
Slights,
Sudduth,
Toponce,
Wetopa, and
Youman series. The Beaverdam, Buckskin, Cimarron, Slights, Sudduth, Toponce, Wetopa, and Youman soils do not have horizons of secondary carbonate accumulation. The Cucharas soils are moderately deep to a paralithic contact and do not have horizons of secondary carbonate accumulation. The Gourley and Heathcoat series have mollic epipedons less than 16 inches thick. (This section needs to be re-written, after the classification was changed)
GEOGRAPHIC SETTING: Savar soils are on gently sloping to steep alluvial fans and hillslopes. Slopes range from 3 to 35 percent. Elevations range from 3,900 to 5,000 feet. The average annual precipitation is 15 to 19 inches. The average annual temperature is 40 to 45 degrees F. The frost-free season is 80 to 100 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Farnuf,
Hesperus,
Wyola,
Reget, and
Wayden soils. The Farnuf and Hesperus soils have less than 35 percent clay in the argillic horizons. Wyola soils have mollic epipedons less than 15 inches thick. The Reget soils have a paralithic contact at depths of 20 to 40 inches. The Waden soils have a paralithic contact at 10 to 20 inches.
DRAINAGE AND PERMEABILITY: Well drained; slow to rapid runoff; slow permeability.
USE AND VEGETATION: Irrigated and dryland crops, rangeland and wildlife habitat. Native vegetation consists of green needlegrass, western wheatgrass, Idaho fescue, sideoats grama, and big sagebrush.
DISTRIBUTION AND EXTENT: Northeastern Wyoming. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Sheridan County Area, Wyoming; 1987.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - 0 to 20 inches (A,Bt1,Bt2)
Argillic horizon - 2 to 60 inches (Bt1,Bt2,Btk1,Btk2)
The original soil classification concept was: fine, montmorillonitic Pachic Argiborolls. In the transition away from "borolls", the series was incorrectly placed with Argicryolls. The range in characteristics specifically states summer soil temperatures above 59F, which is clearly frigid criteria.
Previous classification: Fine, smectitic Vertic Argicryolls
Updated classification: Fine, smectitic, frigid Pachic Argiustolls
The soil temperature regime is frigid, and the soil moisture regime is Ustic.
National Cooperative Soil Survey
U.S.A.