LOCATION MEC WY
Tentative Series
Rev. GEF/DJP/RJS
04/2016
MEC SERIES
The Mec series consists of very deep, well drained soils that formed in slope alluvium and colluvium weathered from sandstone. These soils are on hillslopes. Slopes are 15 to 35 percent. Mean annual precipitation is about 380 mm, and mean annual air temperature is about 4.0 degree C.
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, frigid Calcic Haplustalfs
TYPICAL PEDON: Mec fine sandy loam, in rangeland (colors are for dry soil unless otherwise noted).
A--0 to 11 cm; yellowish brown (10YR 5/4) fine sandy loam, brown (10YR 4/3), moist; weak fine granular structure; very friable, soft, moderately sticky, moderately plastic; many very fine and few medium roots; many very fine tubular pores; finely disseminated calcium carbonate; slightly effervescent; moderately alkaline (pH 8.0); clear wavy boundary. (7 to 15 cm thick)
Bt--11 to 45 cm; yellowish brown (10YR 5/4) sandy clay loam, brown (10YR 4/3), moist; moderate medium subangular blocky structure; friable, slightly hard, moderately sticky, moderately plastic; common very fine and few medium roots; common very fine tubular pores; 6 percent faint clay films on all faces of peds; 5 percent gravel; finely disseminated calcium carbonate; slightly effervescent; moderately alkaline (pH 8.0); clear wavy boundary. (30 to 50 cm thick)
Btk--45 to 125 cm; dark yellowish brown (10YR 4/6) sandy clay loam, dark yellowish brown (10YR 3/4), moist; moderate medium subangular blocky structure; friable, slightly hard, moderately sticky, moderately plastic; few fine and medium roots; common very fine irregular pores; 6 percent faint clay films on all faces of peds; 10 percent fine irregular carbonate masses in matrix; violently effervescent; moderately alkaline (pH 8.4); clear wavy boundary. (60 to 84 cm thick)
Bk--125 to 160 cm; reddish yellow (5YR 6/6) sandy clay loam, reddish brown (5YR 5/4), moist; weak medium angular blocky structure; firm, moderately hard, moderately sticky, moderately plastic; few fine roots; common very fine irregular pores; 5 percent fine irregular carbonate masses in matrix; violently effervescent; moderately alkaline, pH 8.4.
TYPE LOCATION: Lincoln County, Wyoming; USGS Windy Point, Wyoming topographic quadrangle; 41 degrees 39 minutes 26.52 seconds north latitude and 110 degrees 54 minutes 47.47.00 seconds west longitude.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature - 3.2 to 6.7 degrees C.
Ochric epipedon thickness - 7 to 15 cm
Depth to argillic horizon - 7 to 15 cm
Depth to calcic horizon - 40 to 60 cm
A horizon
Hue: 7.5YR or 10YR; dry or moist
Value: 4 or 5 dry; 3 or 4 moist
Chroma: 3 or 4; dry or moist
Texture: fine sandy loam, sandy loam, sandy clay loam
Clay content: 15 to 22 percent
Rock fragments: 0 to 5 percent gravel
Calcium carbonate equivalent: 2 to 10 percent
Reaction: pH 7.8 to 8.2
Bt horizon
Hue: 7.5 YR or 10YR; dry or moist
Value: 4 or 5; dry or moist
Chroma: 3 or 4; dry or moist
Clay content: 25 to 35 percent
Rock fragments: 0 to 20 percent gravel
Calcium carbonate equivalent: 5 to 10 percent
Reaction: pH 7.8 to 8.2
Btk horizon
Hue: 7.5YR or 10YR; dry or moist
Value: 4 to 6 dry; 3 to 5 moist
Chroma: 4 or 6; dry or moist
Clay content: 25 to 35 percent
Rock fragments: 0 to 5 percent gravel
Calcium carbonate equivalent: 15 to 25 percent
Reaction: pH 8.2 to 8.6
Bk horizon
Hue: 5YR to 10YR; dry or moist
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 4 or 6; dry or moist
Clay content: 20 to 30 percent
Rock fragments: 0 to 5 percent gravel
Calcium carbonate equivalent: 5 to 15 percent
Reaction: pH 8.0 to 8.6
COMPETING SERIES: None listed.
GEOGRAPHIC SETTING:
Landform - hillslopes
Elevation - 2,200 to 2,415 meters
Slope - 15 to 35 percent
Parent Material - slope alluvium and colluvium weathered from sandstone
Climate - long, cold winters; cool, moist springs; short, cool summers
Mean annual precipitation - 375 to 430 mm with peak periods of precipitation occurring during the spring
Mean annual air temperature - 2.2 to 5.7 degrees C.
Frost-free period - 30 to 80 days
GEOGRAPHICALLY ASSOCIATED SOILS: None listed.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained, Ksat in particle-size control section 1.5 to 15.0 um/sec.
USE AND VEGETATION: Mec soils are primarily used for rangeland. The potential native vegetation is mainly serviceberry, snowberry, antelope bitterbrush, Mountain big sagebrush, lupine and thickspike wheatgrass.
DISTRIBUTION AND EXTENT: Mec soils are of small extent in southwestern Wyoming. MLRA 46.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana.
SERIES PROPOSED: Sublette County, Wyoming, 2015. The series name is derived from a local landmark.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - 0 to 11 cm (A horizon)
Argillic horizon - 11 to 125 cm (Bt, Btk horizons)
Calcic horizon - 45 to 125 cm (Btk horizon)
Particle-size horizon control section - from 11 to 61 cm (Bt, part of Btk horizons)
Mec soils have a frigid temperature regime and an ustic moisture regime.
National Cooperative Soil Survey
U.S.A.