LOCATION MAWER SDEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, mesic Aridic Argiustolls
TYPICAL PEDON: Mawer fine sandy loam - on a plane slope of less than 1 percent in a cultivated field. When described the soil was moist throughout. (Colors are for dry soil unless otherwise stated.)
Ap1--0 to 4 inches; brown (10YR 5/3) fine sandy loam, very dark grayish brown (10YR 3/2) moist; weak fine granular structure; hard, very friable; many roots; few fine pebbles; slightly acid; abrupt smooth boundary.
Ap2--4 to 8 inches; brown (10YR 5/3) fine sandy loam, very dark grayish brown (10YR 3/2) moist; weak coarse and medium subangular blocky structure; hard, very friable; many roots; few fine pebbles; neutral; clear smooth boundary. (Combined thickness of the A horizons is 7 to 10 inches.)
Bt--8 to 22 inches; brown (10YR 5/3) fine sandy loam, dark grayish brown (10YR 4/2) moist; weak very coarse prismatic structure parting to moderate medium and coarse blocky; hard, very friable; common roots; few fine pebbles; neutral; abrupt wavy boundary. (8 to 20 inches thick)
2C--22 to 60 inches; light gray (10YR 7/2) sand and gravel, pale brown (10YR 6/3) moist; single grained; loose; violent effervescence; slightly alkaline.
TYPE LOCATION: Butte County, South Dakota; about 6 miles east and 1 mile north of Vale; 1500 feet west and 150 feet north of the southeast corner of sec. 20, T. 8 N., R. 7 E.
RANGE IN CHARACTERISTICS: Depth to sand and gravel ranges from 20 to 40 inches and depth to carbonate ranges from 15 to 25 inches. The mollic epipedon ranges from 7 to 16 inches in thickness.
The A horizon has hue of 7.5YR to 2.5Y, value of 4 or 5 and 3 moist, and chroma of 2 or 3. It is fine sandy loam or sandy loam. It is slightly acid or neutral.
The Bt horizon has hue of 7.5YR to 2.5Y, value of 4 to 6 and 3 to 5 moist, and chroma of 2 or 3. It typically is fine sandy loam with a clay content of 12 to 18 percent, but is sandy loam in some pedons. It is neutral or slightly alkaline.
Thin 2Bk, Bk, or BC horizons are in some pedons.
The 2C horizon has hue of 10YR or 2.5Y, value of 5 to 8 and 4 to 7 moist, and chroma of 2 to 4. It ranges from loose sand and gravel to gravelly loamy fine sand. It contains 15 to 45 percent by volume gravel. It is slightly alkaline or moderately alkaline.
COMPETING SERIES: These are the Julesburg, Manter, and Truckton series. Julesburg and Manter soils do not have a sandy skeletal 2C horizon within a depth of 40 inches. Truckton soils have extremely hard consistence when dry and formed in noncalcareous arkosic medium and coarse sands.
GEOGRAPHIC SETTING: Mawer soils are on nearly level to gently sloping terraces and fans. Slopes dominantly are plane and range from 0 to 6 percent. Mawer soils formed in loamy alluvium overlying sand and gravel. Mean annual temperature ranges from 45 to 48 degrees, and mean annual precipitation ranges from 14 to 16 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Manter soils and the Altvan and Dix soils. Altvan and Manter soils are on nearby higher landscapes. Altvan soils have more clay in the argillic horizon. Dix soils have sand and gravel substrata within depths of 20 inches and are on similar landscapes or on terrace escarpments.
DRAINAGE AND PERMEABILITY: Well drained. Runoff is low or medium. Permeability is moderately rapid in the upper part and rapid in the substratum.
USE AND VEGETATION: Most areas are irrigated and used principally for growing alfalfa, small grain, corn, and beans. Native vegetation is prairie sandreed, little bluestem, needleandthread, blue grama, western wheatgrass, sedges, and forbs.
DISTRIBUTION AND EXTENT: Western South Dakota. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado
SERIES ESTABLISHED: Butte County, South Dakota, 3/70.
REMARKS: Diagnostic horizons and features recognized in this pedon are: mollic epipedon - the zone from the surface of the soil to a depth of about 8 inches (Ap1 & Ap2 horizons); argillic horizon - the zone from a depth of about 8 to 22 inches (Bt horizon)