LOCATION CHINOOK MT+ND SD WYEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, frigid Aridic Haplustolls
TYPICAL PEDON: Chinook fine sandy loam, cultivated. (Colors are for dry soil unless otherwise stated)
A1--0 to 4 inches; grayish brown (10YR 5/2) fine sandy loam, very dark grayish brown (10YR 3/2) moist; weak fine granular structure; soft, very friable, nonsticky and nonplastic; many fine roots; many very fine pores; neutral (pH 7.2); clear smooth boundary. (3 to 7 inches thick)
A2--4 to 11 inches; grayish brown (10YR 5/2) fine sandy loam, very dark grayish brown (10YR 3/2) moist; weak fine prismatic structure parting to moderate fine and medium subangular blocky; slightly hard, very friable, nonsticky and nonplastic; many fine roots; many very fine pores; slightly alkaline (pH 7.4); gradual smooth boundary. (0 to 8 inches thick)
Bw--11 to 21 inches; grayish brown (10YR 5/2) fine sandy loam, dark grayish brown (10YR 4/2) moist; weak fine prismatic structure parting to weak fine subangular blocky; slightly hard, very friable, nonsticky and nonplastic; few fine roots; few very fine pores; slightly alkaline (pH 7.6); gradual smooth boundary. (5 to 18 inches thick)
Bk1--21 to 31 inches; pale brown (10YR 6/3) fine sandy loam, dark brown (10YR 4/3) moist; weak coarse subangular blocky structure; slightly hard, very friable, nonsticky and nonplastic; few fine roots; few very fine pores; few fine threads lime; disseminated lime; strongly effervescent; moderately alkaline (pH 8.2); gradual smooth boundary.
Bk2--31 to 41 inches; pale brown (10YR 6/3) fine sandy loam, brown (10YR 5/3) moist; weak coarse subangular blocky structure; slightly hard, very friable, nonsticky and nonplastic; few fine roots; few very fine pores; few fine thread of lime; disseminated lime; strongly effervescent; moderately alkaline (pH 8.2); gradual smooth boundary. (Combined Bk horizons 15 to 45 inches thick)
BC--41 to 60 inches; pale brown (10YR 6/3) loamy fine sand, brown (10YR 5/3) moist; single grain; loose; nonsticky and nonplastic; strongly effervescent; moderately alkaline (pH 8.2). (0 to 18 inches thick)
TYPE LOCATION: Hill County, Montana; North Montana Branch Station; 1,300 feet north and 1,200 feet east of SW corner of sec. 27, T. 32 N, R. 15 E.
RANGE IN CHARACTERISTICS:
Soil temperature - 42 to 47 degrees F. Range to 40 degrees F. in MLRA 44.
Moisture control section - between 8 to 24 inches.
Mollic epipedon thickness - 7 to 15 inches thick.
Depth to Bk horizon - 10 to 35 inches.
A1 horizon - Hue: 10YR or 2.5Y
Value: 2 or 3 moist
Chroma: 2 or 3
Textures: fine sandy loam, loam, or sandy loam
Clay content: 5 to 27 percent
Rock fragments: 0 to 35 percent pebbles
Reaction: pH 6.6 to 8.4
A2 horizon - Hue: 10YR or 2.5Y
Value: 4 or 5 dry; 2, 3, or 4 moist
Chroma: 2, 3, or 4
Textures: fine sandy loam or sandy loam
Clay content: 5 to 18 percent and more than 50 percent medium, fine, and coarser sand
Rock fragments: 0 to 35 percent pebbles
Reaction: pH 6.6 to 9.0
Bw horizon - Hue: 10YR or 2.5Y
Value: 4, 5, or 6 dry; 3, 4 or 5 moist
Chroma: 2, 3, or 4
Textures: fine sandy loam or sandy loam
Clay content: 5 to 18 percent and more than 50 percent medium, fine, and coarser sand.
Rock fragments: 0 to 15 percent pebbles
Reaction: pH 6.6 to 9.0
Bk1 horizon - Hue: 10YR, 2.5Y, or 5Y
Value: 5, 6, or 7 dry; 4 or 5 moist
Chroma: 2, 3, or 4
Textures: fine sandy loam or sandy loam
Clay content: 5 to 18 percent and more than 50 percent medium, fine, and coarser sand.
Rock fragments: 0 to 15 percent pebbles
Calcium carbonate equivalent: 3 to 12 percent
Reaction: pH 6.6 to 9.0
Bk2 horizon - Hue: 10YR, 2.5Y, or 5Y
Value: 5, 6, or 7 dry; 4, 5, or 6 moist
Chroma: 2, 3, or 4
Texture: fine sandy loam or sandy loam
Clay content: 5 to 18 percent and more than 50 percent medium, fine, and coarser sand
Rock fragments: 0 to 15 percent pebbles
Calcium carbonate equivalent: 5 to 15 percent--few and common masses and threads of lime
Reaction: pH 6.6 to 9.0
BC and C horizons - Hue: 10YR, 2.5Y, or 5Y
Value: 5, 6, or 7 dry; 4, 5, or 6 moist
Chroma: 2, 3, or 4
Texture: fine sandy loam, sandy loam, loamy fine sand, or loamy sand
Clay content: 5 to 15 percent
Rock fragments: 0 to 15 percent pebbles
Reaction: pH 7.4 to 9.0
COMPETING SERIES:
Anaconda (MT) - has more than 15 percent calcium carbonate equivalent in the Bk horizon
Cozberg (MT) - noncalcareous above a depth of 20 inches; a lithological discontinuity between the depths of 20 and 40 inches; and lime is concentrated in the upper part of the discontinuity.
Lahood (MT) - has bedrock at depths of 20 to 40 inches
Pring (CO) - noncalcareous above a depth of 40 inches and are typically noncalcareous to 60 inches.
Rhame (ND) - soft bedrock at depths between 20 and 40 inches.
Tinytown (CO) - noncalcareous throughout the soil.
Ynot (T)(MT) - noncalcareous throughout the soil.
GEOGRAPHIC SETTING:
Landform - alluvial fans, hills, escarpments, stream terraces, drainageways, dunes, and till plains.
Elevations - 1,900 to 5,200 feet. Range elevation to 6000 feet in MLRA 44.
Slopes- 0 to 35 percent.
Parent material - alluvium from glaciofluvial material or in eolian deposits.
Climate - long, cold dry winters; moist springs; warm dry summers.
Mean annual precipitation - 10 to 16 inches, most of which falls as rain during spring and early summer.
Mean annual air temperature - 39 to 45 degrees F. Range mean annual air temperature to 38 degrees in MLRA 44.
Frost-free period - 90 to 135 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Rhame soils and the Archin, Kremlin, and Twilight soils. Kremlin and Archin soils are on similar landscapes as the Chinook soils. Kremlin soils are fine-loamy and Archin soils have a natric horizon. Rhame and Twilight soils have soft bedrock between 20 and 40 inches and are on sideslopes of uplands.
DRAINAGE AND PERMEABILITY: Well drained. Moderately rapid permeability. Runoff is negligible to medium depending on slope.
USE AND VEGETATION: Used for dry farmed crops and as rangeland. The potential native plant community is mainly bluebunch wheatgrass, prairie sandreed, needleandthread, little bluestem, forbs, and shrubs.
DISTRIBUTION AND EXTENT: Throughout the eastern plains of Montana and in the adjacent areas of the western parts of North Dakota and South Dakota. Chinook soils are extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: Butte County, South Dakota, 1970.
REMARKS: Soil interpretation records: MT0065, MT0794, MT0858.
Diagnostic horizons and features recognized in this pedon are: mollic epipedon - the zone from the surface of the soil to a depth of 11 inches (A1 and A2 horizons); cambic horizon - the zone from 11 to 21 inches (Bw horizon); accumulation of lime - the zone from 21 to 41 inches (Bk1 and Bk2 horizons); particle-size control section - the zone from 10 to 40 inches (A2, Bw, Bk1 and Bk2 horizons).
ADDITIONAL DATA: Laboratory data: S-74 MT-5-1