LOCATION MARYSTOWN IDEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, frigid Pachic Argixerolls
TYPICAL PEDON: Marystown silt loam--cropland. (Colors are for dry soil unless otherwise stated. When described on October 17, l983 the soil was moist to the surface.)
Ap--0 to 12 inches; dark brown (10YR 4/3) silt loam, very dark grayish brown (10YR 3/2) moist; moderate fine subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine and fine roots; common very fine tubular pores; about 2 percent pebbles; neutral (pH 7.2); clear smooth boundary. (8 to 22 inches thick)
BA--12 to 21 inches; dark brown (10YR 4/3) silt loam, dark brown (10YR 3/3) moist; moderate medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine and few fine roots; common very fine tubular pores; about 2 percent pebbles; neutral (pH 7.2); clear wavy boundary. (6 to 17 inches thick)
Bt--21 to 31 inches; yellowish brown (10YR 5/4) silt loam, dark brown (10YR 4/3) moist; moderate medium subangular blocky structure; hard, friable, slightly sticky and slightly plastic; few very fine roots; common very fine tubular pores; about 2 percent pebbles; uncoated silt grains on the faces of peds; few thin clay films on faces of peds; mildly alkaline (pH 7.4); gradual wavy boundary. (6 to 16 inches thick)
Btb1--31 to 40 inches; yellowish brown (10YR 5/4) silty clay loam, dark brown (10YR 4/3) moist; weak medium prismatic structure parting to strong medium subangular blocky; hard, firm, sticky, and plastic; few very fine roots; few very fine tubular pores; about 2 percent pebbles; uncoated silt grains on the faces of peds; clay nodules; common,moderately thick, clay films on faces of peds; mildly alkaline (pH 7.4); clear wavy boundary. (8 to 15 inches thick)
Btb2--40 to 60 inches; light yellowish brown (10YR 6/4) silty clay loam, yellowish brown (10YR 4/3) moist; moderate medium subangular blocky structure; hard, firm, sticky and plastic; few very fine roots; few very fine tubular pores; about 5 percent pebbles; few thin clay films on faces of peds; mildly alkaline (pH 7.5).
TYPE LOCATION: Fremont County, Idaho; about 6 miles east and 2 miles north of Marysville; 500 feet west and 75 feet south of the northeast corner of sec. 19, T.9N., R.44E. (5 percent northwesterly slope at 5,580 feet elevation)
RANGE IN CHARACTERISTICS:
Average annual soil temperature - 41 to 45 degrees F.
Thickness of Mollic epipedon - 20 to 40 inches
Clay content in the control section - 18 to 35 percent
Rock fragments - in the control section 0 to 10 percent
A horizon
Value - 4 or 5 dry, 2 or 3 moist
Chroma - 2 or 3, dry or moist
Clay content - 6 to 20 percent
BA horizon
Value - 4 or 5 dry, 2 or 3 moist
Chroma - 2 or 3, dry or moist
Clay content - 12 to 20 percent
Bt horizon
Value - 4 or 5 dry, 3 or 4 moist
Chroma - 3 or 4, dry or moist
Clay content - 18 to 30 percent
Rock fragments - 0 to 10 percent
Btb1 horizon
Value - 4 or 5 dry, 3 or 4 moist
Chroma - 3 or 4, dry or moist
Clay content - 23 to 35 percent
Structure - strong blocky, subangular blocky or prismatic
Rock fragments - 0 to 15 percent
Btb2 horizon
Hue - 7.5YR to 10YR
Value - 5 through 7 dry, 4 or 5 moist
Chroma - 3 or 4, dry or moist
Clay content - 20 to 35 percent
Rock fragments - 0 to 25 percent
In some pedons there is secondary lime as coatings or veins at 45 to 60 inches.
COMPETING SERIES: These are the Bothwell and Smelter series. Bothwell and Smelter soils do not have buried argillic horizons.
GEOGRAPHIC SETTING: Marystown soils are on undulating to hilly plains. Slopes range from 1 to 20 percent and elevation ranges from 5,300 to 5,700 feet. They formed in glacial drift influenced by loess. The average annual air temperature is 39 to 43 degrees F. The average annual precipitation is 16 to 22 inches. The frost-free period is 75 to 85 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These include the Kucera, Lostine, and Rin soils. Kucera and Lostine soils are found intermixed with Marystown soils and also at lower elevations. They have less than 18 percent clay in the particle-size control section and lack Bt horizons. Rin soils are formed near the upper elevation range of Marystown soils. They lack argillic horizons and have lower mean annual temperatures.
DRAINAGE AND PERMEABILITY: Well drained; medium runoff; slow permeability.
USE AND VEGETATION: Marystown soils are used for irrigated and nonirrigated cropland. The major crops include: seed potatoes (Irish), spring barley, peas, and alfalfa hay.
DISTRIBUTION AND EXTENT: These soils are inextensive in south east Idaho.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Fremont County, Idaho, l989.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - the zone from the surface to 21 inches (Ap and BA horizons).
Argillic horizon - the zone from 21 to more than 60 inches (Bt, Btb1, and Btb2 horizons).
Particle-size control section - the zone from 21 to 40 inches (Bt and Btbl horizons).