LOCATION MODKIN ID+OREstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, frigid Xeric Haplocambids
TYPICAL PEDON: Modkin sandy loam in rangeland at an elevation of 4920 feet. (Colors are for dry soil unless otherwise noted.)
A1--0 to 2 inches; brown (10YR 5/3) sandy loam, very dark grayish brown (10YR 3/2) moist; weak thin platy structure parting to weak fine granular; soft, very friable; many very fine, fine and medium roots; many very fine and fine interstitial pores; about 25 percent dark sand size basalt particles; neutral (pH 7.2); clear wavy boundary. (1 to 6 inches thick)
A2--2 to 6 inches; brown (10YR 5/3) sandy loam, dark brown (10YR 3/3) moist; weak thin platy structure parting to weak fine and medium subangular blocky; slightly hard, friable; many very fine, fine and medium roots; common very fine and fine tubular pores; about 25 percent dark sandsize basalt particles; mildly alkaline (pH 7.6); clear wavy boundary. (0 to 6 inches thick)
Bw1--6 to 20 inches; brown (10YR 5/3) sandy loam, dark brown (10YR 4/3) moist; moderate medium prismatic structure parting to weak fine and medium subangular blocky; hard, friable; few very fine, fine and medium roots; many very fine and fine tubular pores; about 25 percent dark sand size basalt particles; moderately alkaline (pH 8.0); clear wavy boundary. (6 to 24 inches thick)
Bw2--20 to 28 inches; light brownish gray (10YR 6/2) sandy loam, dark grayish brown (10YR 4/2) moist; weak medium prismatic structure parting to weak fine and medium subangular blocky; hard, friable; few very fine, fine and medium roots; many very fine and fine tubular pores; moderately alkaline (pH 8.0); clear wavy boundary. (0 to 10 inches thick)
Bk--28 to 32 inches; white (10YR 8/2) sandy loam, light brownish gray (10YR 6/2) moist; massive; hard, friable; few very fine and fine roots; 10 percent basalt pebbles; violent effervescence; moderately alkaline (pH 8.0); abrupt wavy boundary. (4 to 25 inches thick)
2R--32 inches; lime coated vesicular basalt bedrock.
TYPE LOCATION: Jefferson County, Idaho; about 6 miles south and 6 miles east of Hamer; about 150 feet west and 100 feet north of the southeast corner of section 14, T.6N., R.37E.
RANGE IN CHARACTERISTICS:
Average annual soil temperature - 41 to 47 degrees F.
Average summer soil temperature - 62 to 67 degrees F.
Soil moisture - Usually moist except for 45 or more consecutive days in late summer.
Depth to bedrock - 20 to 40 inches.
Depth to lime - 7 to 36 inches.
A horizons - Value: 5 or 6 dry.
Chroma: 2 or 3 dry or moist.
Dark color: due in part to basalt sand grains.
Bw horizons - Value: 5 or 6 dry, 3 or 4 moist.
Chroma: 2 or 3 dry or moist.
Texture: FSL or SL.
Structure: Weak or moderate, fine and medium angular or subangular blocky structure.
Bk horizon - Value: 5 through 8 dry, 4 through 7 moist.
Chroma: 2 or 3 dry or moist.
Texture: SL or FSL.
Structure: Some pedons have weak to strong subangular blocky, massive, or moderate to strong platy structure.
Nodules: Some Bk horizons have few to common cicada nodules.
COMPETING SERIES: These are the Granyon, Mathon and Ucopia series. Granyon soils have a paralithic contact at depth of less than 40 inches and hard bedrock at depths below 40 inches. Mathon and Ucopia soils are deeper than 40 inches.
GEOGRAPHIC SETTING: The Modkin soils are on basalt plains at elevations of 4,800 to 5,150. Slopes range from 0 to 30 percent. The soils formed in eolian deposits. The semiarid climate has a frost-free period of 80 to 115 days. The average annual precipitation is 8 to 11 inches. Maximum precipitation falls in June.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bondranch, Grassy Butte and the competing Mathon soils. Bondranch soils are less than 20 inches deep over bedrock on adjacent ridges, mounds and blowout areas. Grassy Butte soils have a sandy control section and occupy stabilized dunes and other more level very deep sites. Mathon soils are on basalt plains where the eolian material is over 40 inches thick.
DRAINAGE AND PERMEABILITY: Well drained; slow to rapid runoff; moderately rapid permeability.
USE AND VEGETATION: Rangeland and wildlife habitat. The natural plant community is bluebunch wheatgrass, Indian ricegrass, needleandthread,sand dropseed, western wheatgrass, arrowleaf balsamroot, basin big sagebrush and Wyoming big sagebrush.
DISTRIBUTION AND EXTENT: Southeastern Idaho and eastern Oregon. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Jefferson County, Idaho, 1975.
REMARKS: Diagnostic horizons and features recognized in this profile are:
Ochric epipedon - from the surface to 6 inches (A1 and A2 horizons).
Cambic horizon - from 6 to 28 inches. (All of the Bw1 and Bw2 horizons)
Calcic horizon - present except where truncated by basalt.
Particle-size control section - from 10 to 32 inches. (Part of the Bw1, all of the Bw2 and Bk horizons).