LOCATION GIMMI IDEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Vertic Argixerolls
TYPICAL PEDON: Gimmi very gravelly loam -- on a southwest-facing slope of 25 percent at 2,950 feet elevation in rangeland. The surface has about 2 percent stone cover. When described on May 14, 1997, the soil was dry to 3 inches and slightly moist below. (Colors are for air-dry soil unless otherwise noted.)
A--0 to 3 inches; dark grayish brown (10YR 4/2) very gravelly loam, very dark brown (10YR 2/2) moist; weak thin and medium platy structure parting to weak fine granular; slightly hard, very friable, slightly sticky and slightly plastic; many very fine and fine, few medium and coarse roots; many very fine and fine, few medium tubular and irregular pores; 25 percent gravel, 10 percent cobbles, 5 percent stones; slightly acid (pH 6.3); clear smooth boundary. (1 to 4 inches thick)
BA--3 to 6 inches; grayish brown (10YR 5/2) very gravelly loam, very dark grayish brown (10YR 3/2) moist; moderate fine and medium subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; common very fine and fine, few medium roots; few very fine and fine, few medium tubular pores; 25 percent gravel, 10 percent cobbles, 5 percent stones; slightly acid (pH 6.4); clear smooth boundary. (0 to 3 inches thick)
Bt1--6 to 10 inches; brown (10YR 5/3) gravelly clay loam, dark brown (10YR 3/3) moist; moderate fine angular blocky structure; hard, firm, very sticky and very plastic; common very fine and fine roots; few very fine and fine tubular pores; many distinct clay films on faces of peds and in pores; 15 percent gravel, 10 percent cobbles, 5 percent stones; neutral (pH 6.7); clear wavy boundary. (4 to 10 inches thick)
Bt2--10 to 15 inches; yellowish brown (10YR 5/4) gravelly clay, dark yellowish brown (10YR 3/4) moist; moderate fine and medium prismatic structure; very hard, firm, very sticky and very plastic; common very fine and fine roots; few very fine and fine tubular pores; continuous prominent clay films on faces of peds and in pores; 15 percent gravel, 10 percent cobbles; cracks less than 5 mm wide; neutral (pH 6.8); clear wavy boundary. (5 to 12 inches thick)
Bt3--15 to 23 inches; light yellowish brown (10YR 6/4) gravelly clay, dark yellowish brown (10YR 4/4) moist; moderate fine and medium prismatic structure; very hard, very firm, very sticky and very plastic; few very fine and fine roots; few very fine and fine tubular pores; continuous prominent clay films on faces of peds and in pores; 15 percent gravel, 10 percent cobbles; neutral (pH 6.8); gradual smooth boundary. (0 to 10 inches thick)
2CBt--23 to 31 inches; very pale brown (10YR 7/3) extremely paragravelly silty clay loam, brown (10YR 5/3) moist; massive; very hard, firm, very sticky and very plastic; few very fine and fine roots; common distinct clay films on pararock fragments; 85 percent pararock; neutral (pH 6.9); abrupt smooth boundary. (0 to 8 inches thick)
2Cr--31 inches; stratified silty lacustrine deposits.
TYPE LOCATION: Boise County, Idaho; about 2 miles northeast of Horseshoe Bend; 1,900 feet north and 1,100 feet east of the southwest corner of section 13, T.7 N., R.2 E.; USGS Horseshoe Bend Quadrangle; Latitude - 43 degrees, 56 minutes, 31 seconds N. and Longitude - 116 degrees, 10 minutes, 17 seconds W.; NAD 83.
RANGE IN CHARACTERISTICS:
Mollic epipedon thickness - 8 to 15 inches
Depth to paralithic contact - 20 to 40 inches
Particle-size control section - 35 to 50 percent clay; 15 to 35 percent rock fragments
Moisture control section - dry 60 to 90 consecutive days following the summer solstice
Average annual soil temperature - 51 to 52 degrees F.
A horizon
Hue - 10YR or 7.5YR
Value - 4 or 5 dry, 2 or 3 moist
Rock fragments - 0 to 5 percent stones, 5 to 15 percent cobbles, 15 to 35 percent gravel and 35 to 50 percent total
Reaction - slightly acid or neutral
Bt1 horizon
Hue - 10YR or 7.5YR
Chroma - 2 or 3 dry or moist
Clay content - 27 to 35 percent
Rock fragments - 0 to 5 percent stones, 5 to 15 percent cobbles, 10 to 25 percent gravel and 15 to 35 percent total
Reaction - slightly acid or neutral
Bt2 and Bt3 horizons
Hue - 2.5Y through 7.5YR
Value - 4 or 5 dry, 3 or 4 moist
Chroma - 3 or 4 dry or moist
Texture - CL or C
Clay content - 35 to 50 percent
Rock fragments - 0 to 5 percent stones, 0 to 10 percent cobbles, 10 to 25 percent gravel and 15 to 35 percent total
Cracks - 0 to 5 mm wide
Reaction - neutral or slightly alkaline
COMPETING SERIES: These are the Ayette, Darow, Forsgren, Hann, Karney, Kuck, McDesh, Montour, Tub and Ukiah series. Ayette soils are deep to a paralithic contact. Darow soils have average annual soil temperature of 54 to 56 degrees F., are dry for 80 to 110 consecutive days, and have 0 to 15 percent paragravel in the Bt horizon. Forsgren soils are calcareous at depths of 40 to 55 inches. Hann soils are very deep and have mollic epipedons 20 to 40 inches thick. Karney soils are 40 to 60 inches deep to hard bedrock. Kuck soils have chroma of 1 or 2 dry in the Bt horizon, are over weathered andesite and dry from July 15 to October 15 (more than 90 days). McDesh soils are 20 to 40 inches deep to hard bedrock. Montour soils are calcareous at depths of 29 to 32 inches. Tub soils are very deep and are calcareous at depths of 18 to 37 inches. Ukiah soils have mollic epipedons 15 to 30 inches thick and 50 to 60 percent clay in the Bt horizon.
GEOGRAPHIC SETTING: Gimmi soils are moderately sloping to steep on landslides at elevations of 2,700 to 3,550 feet. These soils formed in mixed colluvium (landslide deposits) from basalt and silty lacustrine deposits. Slopes range from 5 to 35 percent. Average annual precipitation is 14 to 16 inches. Average annual temperature is 49 to 50 degrees F. Frost-free period is 130 to 140 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Ayette and Doubledia soils. Ayette and Doubledia soils are deep and have 0 to 5 percent rock fragments. These soils are on stable hillslope positions.
DRAINAGE AND PERMEABILITY: Well drained; medium to rapid runoff; slow permeability.
USE AND VEGETATION: Gimmi soils are used mainly for rangeland. Native vegetation is xeric big sagebrush and bluebunch wheatgrass.
DISTRIBUTION AND EXTENT: West-central Idaho. MLRA 10. Gimmi soils are not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Boise County Area, Idaho, Parts of Ada and Boise Counties, 2005.
REMARKS: Diagnostic horizons and features recognized in this soil:
Mollic epipedon - zone from the soil surface to 10 inches (A, BA and Bt1 horizons)
Argillic horizon - zone from 6 to 23 inches (Bt1, Bt2 and Bt3 horizons)
Paralithic contact - at 24 inches (2Cr horizon)
Particle-size control section - zone from 6 to 23 inches
Linear extensibility - 6.0 or more in the zone from the soil surface to the paralithic contact (assumed)
Soil moisture regime - xeric