LOCATION WETTERDON WYEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Pachic Argiustolls
TYPICAL PEDON: Wetterdon silt loam-alfalfa, grass, hay, pasture. (Colors are for dry soil unless otherwise stated.)
Ap--0 to 5 inches; dark gray (10YR 4/1) silt loam, very dark brown (10YR 2/2) moist; moderate medium granular structure; slightly hard, very friable, slightly sticky and slightly plastic; many fine and very fine roots; common fine and very fine pores; mildly alkaline (pH 7.8); clear smooth boundary. (The Ap or A horizon is 1 to 9 inches thick)
BA--5 to 17 inches; gray (10YR 5/1) silt loam, very dark brown (10YR 2/2) moist; weak coarse prismatic structure parting to moderate coarse subangular blocky; slightly hard, very friable, slightly sticky and slightly plastic; common fine and very fine roots; many fine and very fine pores; few faint clay films on faces of peds; few bleached sand and silt grains on faces of peds; mildly alkaline (pH 7.6); clear smooth boundary. (0 to 14 inches thick)
Bt1--17 to 30 inches; grayish brown (10YR 5/2) silty clay loam, very dark grayish brown (10YR 3/2) moist; moderate medium prismatic structure parting to strong coarse angular blocky; slightly hard, very friable, sticky and slightly plastic; few very fine and fine roots; many fine and medium pores; common distinct clay films on all faces of peds; many bleached sand and silt grains on faces of peds; mildly alkaline (pH 7.4); clear smooth boundary.
Bt2--30 to 46 inches; pale brown (10YR 6/3) silty clay loam, dark yellowish brown (10YR 3/4) moist; strong medium prismatic structure parting to strong medium angular blocky; hard, very firm, sticky and plastic; few fine and very fine pores; many distinct clay films on faces of peds; common bleached sand and silt grains on faces of peds; neutral (pH 7.2); clear smooth boundary. (Combined thickness of the Bt horizons is 20 to 41 inches)
C--46 to 60 inches; brown (10YR 5/3) clay loam, dark yellowish brown (10YR 3/4) moist; weak coarse angular blocky structure; hard, firm, sticky and plastic; few fine pores; about 40 percent soft weathered porcelanite chips at angles in the ped faces; mildly alkaline (pH 7.4)
TYPE LOCATION: Sheridan County, Wyoming; about 200 yards southeast of gate in the SW1/4, NE1/4 of sec. 16, T. 54 N., R. 82 W.
RANGE IN CHARACTERISTICS: The mollic epipedon is 21 to over 40 inches thick. Depth to free carbonates is greater than 35 inches. Depth to the base of the argillic horizon is 27 to 50 inches. The mean annual soil temperature is 47 to 53 degrees F. These soils contain porcelanite chips. Most are soft, weathered chips but there may be up to 10 percent lithic chips less than one-half inch across. Colors may be variable depending upon the color of the baked shale parent material. The moisture control section is dry for 60 consecutive days between July 15 and October 25.
The A horizon has hue of 10YR, 7.5YR, or less commonly 5YR; value of 3 through 5 dry, 2 or 3 moist; and chroma of 1 through 3. Reaction is neutral or mildly alkaline. An AB or BA horizon is present in about half the pedons.
The Bt horizon has hue of 10YR, 7.5YR, and less commonly 5YR; value of 3 through 6 dry, 2 or 3 moist; and chroma of 1 through 4. The 4 chroma occurs only below 23 inches. Texture is silty clay loam, clay loam, silt loam, or loam with 18 to 35 percent clay and more than 15 percent but less than 35 percent fine or coarser sand. Individual horizons may exceed 35 percent clay but always occur too deep or when averaged have less than 35 percent clay in the upper 20 inches of this horizon. Reaction is neutral or mildly alkaline. Some pedons have a Btk horizon.
Some pedons have a Bk horizon which has hue of 10YR, 7.5YR, and 5YR; value of 5 through 7 dry, 3 through 6 moist; and chroma of 1 through 6. Texture is silt loam, clay loam, or loam with 12 to 30 percent clay. Secondary carbonates range from 3 to 8 percent. Reaction is moderately or strongly alkaline.
The C or BC horizon has the same color range as the Bk and lower Bt. Textures are loam, clay loam, or silt loam with 14 to 30 percent clay. Reaction is neutral through moderately alkaline.
COMPETING SERIES: These are the Albinas, Garrett, Haxtun, Jarita, Keya, Prosper, Renner, Sampson, Tracylee(T), Vosburg, Woodly, and Woonsocket soils. Albinas, Garrett, Sampson, and Woodly soils have more than 35 percent fine or coarser sand. Haxtun soils have a sandy clay loam Bt horizon. Jarita soils have a lithic contact at 30 to 40 inches. Prosper soils have a high watertable and are moderately well drained. Tracylee soils are non-calcareous throughout. Keya, Renner and Vosberg soils are not dry in the moisture control section for 60 consecutive days between July 15 and October 25. Woonsocket soils have loamy sand or sand substrata above 40 inches.
GEOGRAPHIC SETTING: Wetterdon soils are on undulating to sloping alluvial fans and hill slopes. They formed in alluvium derived from porcelanite. Elevations are 3,500 to 5,300 feet. Slopes are 0 to 16 percent. The mean annual precipitation ranges from 14 to 19 inches of which about half falls as snow and less commonly rain in April, May, and early June. The frost-free season is about 100 to 130 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Harlan, Nunn, Platner, and Recluse soils. All these soils have a thinner mollic epipedon. The Nunn and Platner soils are fine textured.
DRAINAGE AND PERMEABILITY: Well drained; slow or medium runoff; moderate permeability.
USE AND VEGETATION: Rangeland, wildlife habitat, and irrigated cropland or hayland. Native vegetation consists of western wheatgrass, Idaho fescue, prairie junegrass, spike fescue, and silver sagebrush.
DISTRIBUTION AND EXTENT: North central Wyoming. The series is not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado
SERIES ESTABLISHED: Sheridan County Area, Wyoming; 1987.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - 0 to 30 inches (Ap,BA,Bt1)
Argillic horizon - 17 to 46 inches (Bt1,Bt2)
SIR- WY0689