LOCATION GIRD               MT
Established Series
Rev. BDD-GLS-JAL
3/97

GIRD SERIES


The Gird series consists of very deep, well drained soils that formed in glaciofluvial deposits or alluvium. These soils are on dissected alluvial fans, stream terraces, and till plains. Slopes are 0 to 15 percent. Mean annual precipitation is about 15 inches, and mean annual temperature is about 42 degrees F.

TAXONOMIC CLASS: Coarse-silty, mixed, superactive, frigid Calcic Haploxerolls

TYPICAL PEDON: Gird silt loam, in cropland (colors are for dry soil unless otherwise noted).

Ap--0 to 10 inches; grayish brown (10YR 5/2) silt loam, very dark brown (10YR 2/2) moist; weak fine granular structure; soft, very friable, slightly sticky and slightly plastic; many very fine and fine roots; common very fine pores; neutral (pH 6.6); abrupt smooth boundary. (8 to 12 inches thick)

Bw--10 to 17 inches; brown (10YR 5/3) silt loam, dark brown (10YR 4/3) moist; moderate medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; many very fine and fine roots; common very fine pores; neutral (pH 6.8); clear smooth boundary. (4 to 17 inches thick)

Bk1--17 to 32 inches; pale brown (10YR 6/3) silt loam, brown (10YR 5/3) moist; weak coarse subangular blocky structure; soft, very friable, nonsticky and nonplastic; few very fine and fine roots; common very fine pores; disseminated lime; strongly effervescent; slightly alkaline (pH 7.8); gradual wavy boundary. (12 to 24 inches thick)

Bk2--32 to 60 inches; light gray (10YR 7/2) silt loam, pale brown (10YR 6/3) moist; massive; soft, very friable, nonsticky and nonplastic; few very fine roots; few very fine pores; disseminated lime, common fine masses of lime; strongly effervescent; moderately alkaline (pH 8.4).

TYPE LOCATION: Lake County, Montana; 300 feet east and 150 feet north of the SW corner of sec. 30, T. 21 N., R. 19 W.

RANGE IN CHARACTERISTICS:

Soil temperature - 42 to 47 degrees F.

Moisture control section - between 4 and 12 inches.

Mollic epipedon thickness - 10 to 17 inches.

Depth to Bk horizon: 12 to 21 inches.

Some pedons have a BC or C horizon between 40 and 60 inches.

Ap horizon - Value: 4 or 5 dry; 2 or 3 moist

Chroma: 2 or 3

Clay content: 10 to 18 percent

Reaction: pH 6.6 to 7.3

Bw horizon - Value: 4 or 5 dry; 3 or 4 moist

Clay content: 10 to 18 percent

Reaction: pH 6.6 to 7.8

All or part of this horizon may have mollic colors.

Bk1 horizon - Hue: 10YR, 7.5YR

Value: 6 or 7 dry; 4 or 5 moist

Chroma: 2 or 3

Clay content: 10 to 18 percent

Calcium carbonate equivalent: 5 to 10 percent

Reaction: pH 7.4 to 8.4

Bk2 horizon - Hue: 10YR, 7.5YR

Value: 6 or 7 dry; 4, 5, or 6 moist

Chroma: 2, 3 or 4

Texture: silt loam or very fine sandy loam

Clay content: 10 to 18 percent

Calcium carbonate equivalent: 3 to 10 percent

Reaction: pH 7.4 to 8.4

COMPETING SERIES:

Rexberg (ID) - have clay films in the Bw1, cicada knotovinas in the Bk horizons, and more than 15 percent calcium carbonate equivalent in the Bk horizons.

Ririe (ID) - have an AB transition horizon, dense rounded nodules in the Bk2 horizon, and a calcium carbonate equivalent of more than 15 percent in the Bk horizon.

GEOGRAPHIC SETTING:

Landform - dissected alluvial fans, stream terraces, and till plains.

Elevation - 2,400 to 3,500 feet.

Slope- 0 to 45 percent.

Parent material - glaciofluvial deposits or alluvium.

Climate - cold winters; moist springs and falls; warm, dry summers.

Mean annual precipitation - 14 to 19 inches.

Mean annual temperature - 40 to 45 degrees F.

Frost-free period - 105 to 125 days.

DRAINAGE AND PERMEABILITY: Well drained; moderate permeability.

USE AND VEGETATION: Gird soils are used for irrigated and dryland crops.

DISTRIBUTION AND EXTENT: Gird soils are moderately extensive in intermountain valleys in western Montana.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana

SERIES ESTABLISHED: Ravalli County (Bitterroot Valley Area), Montana, 1952. Classification changed from typic to calcic for Lake County, Montana final correlation, 1991.

REMARKS: Soil Interpretation Records: MT0661, MT0835, MT7048. Diagnostic horizons and features recognized in this pedon are: a mollic epipedon from the soil surface to 10 inches (Ap horizon); a cambic horizon from 10 to 17 inches (Bw horizon); a particle-size control section from 10 to 40 inches (Bw, Bk1, Bk2 horizons). Gird soils have a frigid temperature regime and a xeric moisture regime.

Additional Data: Reference pedon S65MT-81-2


National Cooperative Soil Survey
U.S.A.