LOCATION NIELSEN ID+MT+WYEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive Lithic Argicryolls
TYPICAL PEDON: Nielsen loam, extremely stony rangeland. (Colors are for dry soil unless otherwise noted.)
A1--0 to 2 inches; dark grayish brown (10YR 4/2) loam, very dark brown (10YR 2/2) moist; very weak very fine platy structure parting to moderate very fine granular; soft, very friable, slightly sticky and slightly plastic; many very fine, fine, and medium roots; many very fine interstitial pores; 5 percent angular gravel and flagstones with 10 percent surface stones; neutral (pH 6.7); abrupt smooth boundary. (1 to 4 inches thick)
A2--2 to 6 inches; dark grayish brown (10YR 4/2) loam, very dark brown (10YR 2/2) moist; very weak fine and medium platy structure parting to moderate very fine and fine granular; slightly hard, friable, slightly sticky and slightly plastic; common very fine, fine, and medium roots; many very fine and common fine tubular pores; 8 percent angular gravel and flagstones; neutral (pH 6.8); clear wavy boundary. (2 to 6 inches thick)
A3--6 to 9 inches; dark grayish brown (10YR 4/2) (brown 10YR 5/3 crushed) channery loam, very dark brown (10YR 2/2) (very dark grayish brown 10YR 3/2 crushed) moist; weak fine and medium subangular blocky structure; hard, friable, slightly sticky and slightly plastic; common very fine, fine, and medium roots; common very fine and few fine tubular pores; 20 percent angular fragments of sandstone; faint patchy clay films in some pores; neutral (pH 6.8); clear wavy boundary. (0 to 5 inches thick)
Bt1--9 to 13 inches; brown (10YR 5/3) channery loam, dark brown (10YR 3/3) moist; moderate very fine and fine subangular blocky structure; hard, friable, slightly sticky and slightly plastic; few fine and very fine roots; many very fine and few fine tubular pores; faint patchy clay films on faces of peds and in pores; 40 percent angular fragments of sandstone; neutral (pH 6.9); abrupt irregular boundary. (3 to 7 inches thick)
Bt2--13 to 19 inches; yellowish brown (10YR 5/4) (light yellowish brown 10YR 6/4 crushed) extremely channery loam, dark yellowish brown (10YR 4/4) (yellowish brown 10YR 5/4 crushed) moist; moderate fine and very fine subangular blocky structure; hard, friable, moderately sticky and moderately plastic; few very fine, fine and medium roots; many very fine and few fine and medium tubular pores; faint patchy clay films on faces of peds and in pores; 75 percent angular fragments of sandstone; neutral (pH 6.7); abrupt irregular boundary. (2 to 8 inches thick)
R--19 inches; very pale brown (10YR 7/4) partly weathered and fractured sandstone bedrock, yellowish brown (10YR 5/4) moist; coated with 1 mm. of yellowish brown loam between the platy fragments.
TYPE LOCATION: Bingham County, Idaho; Wood Creek area of Fort Hall Indian Reservation, approximately 0.75 mile east of Red road-Wood Creek road junction, on trail off Red road; about 7 miles north and 20 miles east of Fort Hall Agency; in the NE1/4 sec. 29, T.3S., R.38E.
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 35 to 43 degrees F., and the mean summer temperature is 55 to 59 degrees F. cryic soil temperature regime. The depth to sandstone or quartzite bedrock is 10 to 20 inches. The mollic epipedon is 7 to 15 inches thick. It is neutral or slightly acid.
A horizons
Hue: 10YR or 7.5YR
Value: 4 or 5 dry, 2 or 3 moist
Chroma: 2 or 3
Texture (less than 2mm): loam, silt loam
Bt horizons
Hue: 10YR or 7.5YR
Value: 4 to 6 dry, 2 to 5 moist
Chroma: 2 to 4
Texture (less than 2mm): loam, silty clay loam, clay loam
Clay content: 18 to 35 percent
Rock fragments: 35 to 80 percent (flat or angular)
R horizon
Note: bedrock may be calcareous or noncalcareous, and in places there are laminated layers of each.
COMPETING SERIES: These are the Bushpark, Copenhaver, Donkehill, Hogmalat, Layview, Maygal, Mosroc, Mountpatterson, Nieman, Notstew and Thiefridge. Bushpart soils have a udic moisture regime. Copenhaver and Nieman soils are defined as having an ustic moisture regime. Donkehill soils have a mean summer soil temperature of 46 to 50 degrees F. and has secondary carbonates below the mollic epipedon. Hogmalat soils are strongly or moderately acid. Layview soils have a mean annual soil temperature of 43 to 47 degrees F. Maygal soils have rock fragments consisting of angular rhyolite and andesite. Mosroc soils formed in residuum and colluvium from granite with rock fragments consisting of angular granite. Mountpatterson soils have 15 to 30 percent glass and acid oxalate aluminum plus one-half the iron is 0.2 to 0.4 percent (Vitrandic). Notstew soils have rock fragments dominated by andesite and the surface horizons (a) contain 25 to 50 percent glass and have an abrupt boundary with a 15 percent clay increase between the A and Bt horizons. Thiefridge soils have a mollic epipedon 14 to 20 inches thick and have a mean summer soil temperature of 50 to 54 degrees F.
GEOGRAPHIC SETTING: These soils are on ridges and mountain sideslopes at elevations of 5,500 to 8,500 feet. Slopes are from 5 to 70 percent. The soil formed in residuum and colluvium from sandstone, quartzite or felsic volcanic rocks. The climate is continental subhumid with mean annual precipitation of 15 to 25 inches, including 5 to 10 feet of snowfall. The frost-free period is 30 to 90 days. The mean annual temperature is 35 to 41 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bush and Sessions soils, which are deeper than 40 inches. Sessions soils also have less than 35 percent rock fragments in the Bt horizon.
DRAINAGE AND PERMEABILITY: Well drained; medium to rapid runoff; moderate or moderately slow permeability.
USE AND VEGETATION: Used for range. The present natural vegetation is mainly Nevada bluegrass, Columbia needle grass, western wheatgrass, rabbitbrush, big sagebrush, and phlox.
DISTRIBUTION AND EXTENT: Southeastern Idaho and west-central Montana and Wyoming; moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Broadwater County Area, Montana, 1971.
REMARKS: Diagnostic horizons and other features:
Mollic epipedon - 0 to 13 inches
Argillic horizon - 9 to 19 inches
Particle-size control section - 9 to 19 inches
Xeric soil moisture regime