LOCATION XEMA WYEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, mesic Aridic Haplustalfs
TYPICAL PEDON: Xema fine sandy loam -- on a southeast facing slope of 7 percent, utilized as rangeland. (Colors are for dry soil unless otherwise stated)
A--0 to 4 inches; brown (10YR 5/3) fine sandy loam, brown (10YR 4/3) moist; weak fine angular blocky structure parting to weak thin platy; soft, very friable, nonsticky and nonplastic; many very fine and fine roots throughout and common medium throughout; many fine low continuity vesicular and tubular pores; noneffervescent; neutral; clear smooth boundary. (2 to 6 inches thick)
Bt1--4 to 13 inches; brown (10YR 5/3) fine sandy loam, brown (10YR 4/3) moist; weak medium prismatic structure parting to weak fine angular blocky; soft, very friable, nonsticky and nonplastic; many very fine and fine roots throughout; many fine low continuity vesicular and tubular pores; common distinct continuous dark brown (10YR 3/3) clay bridging between sand grains; noneffervescent; neutral; clear wavy boundary.
Bt2--13 to 22 inches; yellowish brown (10YR 5/4) fine sandy loam, dark yellowish brown (10YR 4/4) moist; weak fine and medium angular blocky structure; soft, very friable, nonsticky and nonplastic; many very fine and fine roots throughout; many fine low continuity vesicular and tubular pores; few distinct discontinuous dark yellowish brown (10YR 3/4) clay bridging between sand grains; noneffervescent; slightly alkaline; clear wavy boundary. (Combined Bt horizons 6 to 25 inches thick)
Bk--22 to 31 inches; yellowish brown (10YR 5/4) fine sandy loam, dark yellowish brown (10YR 4/4) moist; weak fine and medium angular blocky structure parting to weak fine granular; soft, very friable, nonsticky and nonplastic; many very fine and fine roots throughout; common fine low continuity vesicular and tubular pores; carbonates are disseminated throughout; slightly effervescent; moderately alkaline; clear wavy boundary. (0 to 21 inches thick)
Cr--31 to 60 inches; slightly effervescent; moderately alkaline; soft calcareous sandstone.
TYPE LOCATION: Campbell County, Wyoming; about 300 feet east and 2350 feet north of the southwest corner of Sec. 26, T 55 N, R 69 W.; USGS Brislawn School, WY topographic quadrangle; lat. 44 degrees 43 minutes 14 seconds N. and long. 105 degrees 7 minutes 28 seconds W.
RANGE IN CHARACTERISTICS: Depth to bedrock ranges from 20 to 40 inches. Depth to the base of the Bt horizon is 12 to 30 inches. Depth to carbonates ranges from 12 to 30 inches. Rock fragments range from 0 to 10 percent throughout. The average annual soil temperature is 47 to 50 degrees F. The moisture control section is usually moist in March through early June. The soil temperature at 20 inches is 41 degrees F. or warmer for 175 to 195 days annually.
The A horizon has hue of 10YR, value of 5 to 7 dry and 3 to 5 moist, and chroma of 2 to 4. It is fine sandy loam, sandy loam, very fine sandy loam or loam. Reaction is slightly acid or neutral. Some pedons have an E horizon.
The Bt horizon has hue of 2.5Y, 10YR or 7.5YR, value of 5 to 7 dry and 3 to 5 moist, and chroma of 2 to 4. Texture is sandy loam or fine sandy loam with 10 to 18 percent clay. In some pedons the horizon has lamellae. Reaction is slightly acid through slightly alkaline. Some pedons have a Btk horizon.
The Bk horizon has hue of 2.5Y, 10YR or 7.5YR, value of 5 to 7 dry and 4 to 6 moist, and chroma of 2 to 4. Texture is sandy loam, loamy fine sand, loamy sand or fine sandy loam. Reaction is slightly alkaline to strongly alkaline.
The C horizon, where present, has hue of 2.5Y or 10YR, value of 5 or 6 dry, 4 or 5 moist, and chroma of 3 or 4. Texture is loamy sand, loamy fine sand, sandy loam or fine sandy loam. Reaction is slightly acid to moderately alkaline. Calcium carbonate is 0 to 4 percent.
The Cr horizon is soft sandstone that is often interbedded with shale. It can be calcareous or noncalcareous.
COMPETING SERIES: These are the Eva, Fragua, Fraguni, Vona and Vonalf series. It is presumed Eva soils are competing pending an update of the classification. Eva, Fraguni, Vona and Vonalf soils are very deep. Fragua and Fraguni soils are driest in the moisture control section during the months of May and June and receive more precipitation during July to October.
GEOGRAPHIC SETTING: Xema soils are on ridges, plateaus and hills. They formed in eolian or alluvium and residuum derived primarily from sandstone. Slopes are 0 to 30 percent. Elevations are 3,500 to 5,200 feet. The mean annual precipitation ranges from 15 to 17 inches, half of which falls as rain or snow from March through June. The mean annual air temperature ranges from 44 to 50 degrees F. The frost free period 105 to 30 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Vonalf and the Arwite, Elwop, Gateson, Fairburn and Mittenbutte soils. Fairburn and Mittenbutte soils are shallow. Arwite, Elwop and Gateson soils are fine-loamy. Arwite and Vonalf soils occur on footslopes. Elwop, Gateson, Fairburn and Mittenbutte soils occur on similar positions.
DRAINAGE AND PERMEABILITY: Well drained; low to medium runoff; moderately rapid permeability.
USE AND VEGETATION: These soils are utilized primarily as rangeland and wildlife habitat. The native vegetation is mainly needleandthread, prairie sandreed, little bluestem and threadleaf sedge.
DISTRIBUTION AND EXTENT: Xema soils occur in the Powder River Basin of north eastern Wyoming. The series is of limited extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado
SERIES ESTABLISHED: Campbell County, Wyoming Southern Part; 1995.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - 0 to 4 inches (A horizon)
Argillic horizon - 4 to 22 inches (Bt1 and Bt2 horizons)
Paralithic contact - 31 inches (Cr)
SIR- WY1410, WY1411
MLRR- G