LOCATION BLACKNOLL IDEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, frigid Calcic Haploxerolls
TYPICAL PEDON: Blacknoll fine sandy loam - on a 1 percent convex slope. (When described on September 4, 1980, it was slightly moist throughout. Colors are for dry soil unless otherwise noted.)
A--0 to 10 inches; brown (10YR 5/3) fine sandy loam, dark brown (10YR 3/3) moist; weak fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common fine and many very fine roots; common fine and many very fine tubular pores; 5 percent pebbles; neutral (pH 7.2); clear smooth boundary. (6 to 12 inches thick)
Bw--10 to 14 inches; brown (10YR 5/3) sandy clay loam, dark brown (10YR 3/3) moist; moderate medium subangular blocky structure; hard, friable, sticky and plastic; common fine and many very fine roots; common fine and many very fine tubular pores; 5 percent pebbles; neutral (pH 7.3); clear smooth boundary. (4 to 10 inches thick)
Bk--14 to 30 inches; light gray (10YR 7/2) fine sandy loam, dark brown (10YR 4/3) moist; weak fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few very fine roots; few very fine tubular pores; violent effervescence; 10 percent pebbles and cobbles; moderately alkaline (pH 8.4); clear smooth boundary. (8 to 18 inches thick)
2R--30 inches; unweathered vesicular basalt bedrock.
TYPE LOCATION: Fremont County, Idaho; about 14 miles northwest of St. Anthony; 2,220 feet south and 2,350 feet east of the northwest corner, sec. 28, T.9N., R.38E.
RANGE IN CHARACTERISTICS:
Depth to bedrock - 20 to 40 inches
Thickness of mollic epipedon - 10 to 16 inches
Average clay content of control section - 6 to 18 percent
Coarse fragments in control section - 5 to 15 percent
Depth to lime - 10 to 22 inches
Average annual soil temperature - 41 to 43 degrees F
Average summer soil temperature - 60 to 63 degrees F
A1 Horizon
Color value, dry - 4 or 5
chroma- 2 or 3 dry or moist
Bw horizon
Color value, dry - 5 or 6
value, moist - 3 or 4
chroma- 2 or 3 dry or moist Texture - SCL, FSL, L
Reaction - neutral to moderately alkaline
Bk horizon
Color value, dry - 6 or 7
value, moist - 4 or 5
chroma- 2 or 3 dry or moist Texture - FSL, L, VFSL
Reaction - neutral to moderately alkaline
Carbonates - 5 to 15 percent
COMPETING SERIES: These are the Arbone, Jacoby(T), and Kearl soils. Arbone soils are more than 40 inches deep to bedrock. Jacoby soils have a mollic epipedon that is less than 10 inches thick and average annual soil temperatures warmer than 43 degrees F. Kearl soils formed in materials weathered dominantly from limestone and have hues of 7.5YR through 2.5YR in the B and C horizons.
GEOGRAPHIC SETTING: Blacknoll soils are on undulating basalt plains with a mantle of eolian deposits. Average annual air temperature is 39 to 41 degrees F. Elevation is 5,000 to 5,600 feet. Average annual precipitation is 12 to 16 inches. Frost free season is about 80 to 100 days. Slopes range from 0 to 8 percent.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Jacoby(T), Jipper(T), Nayrib(T), Wolverine, Snowshoe(T), and Stipe soils. Jacoby soils have average annual soil temperatures greater than 43 degrees F. The Jipper soil is pachic and is deeper than 40 inches. Nayrib soils are very shallow to bedrock and have more than 35 percent rock fragments. Wolverine soils are very deep and lack B horizons. Snowshoe soils lack a mollic epipedon and are noneffervescent throughout. Stipe soils lack a calcic horizon. Jacoby, Jipper, and Stipe soils are on adjacent side slopes and swales. Nayrib soils are on pressure ridges and blowouts. Wolverine and Snowshoe soils are on stabilized dunes.
DRAINAGE AND PERMEABILITY: Well drained; slow or medium runoff; moderate permeability.
USE AND VEGETATION: Range and wildlife habitat. Principal vegetation consists of bluebunch wheatgrass, Idaho fescue, mountain big sagebrush, and arrowleaf balsamroot.
DISTRIBUTION AND EXTENT: Blacknoll soils are of small extent. They occur in eastern Idaho.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES PROPOSED: Fremont County, Idaho, 1981.
REMARKS: Diagnostic horizons and features recognized in this soil are:
Mollic epipedon - occurs from soil surface to approximately 14 inches (A and Bw horizons).
Calcic horizon - the zone from 14 to 30 inches (Bk horizon).
Lithic contact - is at 30 inches (2R horizon).