LOCATION GRECAN IDEstablished Series
TAXONOMIC CLASS: Fine, smectitic, frigid Calcic Pachic Argixerolls
TYPICAL PEDON: Grecan loam, rangeland (colors are for dry soil unless otherwise noted)
A1--0 to 8 cm; dark grayish brown (10YR 4/2) loam, very dark grayish brown (10YR 3/2) moist; moderate fine granular structure; soft, very friable, nonsticky and nonplastic; many very fine and fine roots, common medium roots; common very fine irregular pores; 5 percent gravel; slightly acid (pH 6.2); abrupt smooth boundary. (8 to 25 cm thick)
A2--8 to 23 cm; dark grayish brown (10YR 4/2) loam, very dark grayish brown (10YR 3/2) moist; moderate medium subangular blocky parting to moderate fine granular structure; soft, very friable, nonsticky and nonplastic; common very fine and fine roots, few medium roots; common very fine and fine irregular pores; 5 percent gravel; neutral (pH 6.6); clear smooth boundary. (0 to 25 cm thick)
BAt--23 to 56 cm; dark grayish brown (10YR 4/2) clay loam, very dark grayish brown (10YR 3/2) moist; strong medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common fine and few medium roots; common very fine and fine tubular pores; common distinct clay films on faces of peds; 10 percent gravel; neutral (pH 7.0); clear smooth boundary. (13 to 33 cm thick)
Bt--56 to 71 cm; pale brown (10YR 6/3) clay, brown (10YR 5/3) moist; strong medium subangular blocky structure; very hard, very firm, moderately sticky and moderately plastic; few fine and very fine roots; common very fine and fine tubular pores; many distinct clay films on faces of peds and in pores; 10 percent gravel; neutral (pH 7.2); clear smooth boundary. (15 to 61 cm thick)
Btk--71 to 81 cm; pale brown (10YR 6/3) clay, yellowish brown (10YR 5/4) moist; moderate medium subangular blocky; very hard, very firm, moderately sticky and moderately plastic; few very fine roots; common very fine and fine irregular pores; few distinct clay films on faces of peds and in pores; few fine soft masses of lime and disseminated lime; 10 percent gravel; slightly effervescent; moderately alkaline (pH 8.0); clear wavy boundary. (10 to 61 cm thick)
Bk1--81 to 104 cm; yellowish brown (10YR 5/4) clay loam, dark yellowish brown (10YR 4/4) moist; weak medium and coarse subangular blocky; hard, firm, slightly sticky and slightly plastic; few very fine roots; few very fine and fine irregular pores; common large soft masses of lime and few thin pendant lime coatings on the underside of rocks; 10 percent gravel; violently effervescent; moderately alkaline (pH 8.2); clear wavy boundary. (23 to 46 cm thick)
Bk2--104 to 152 cm; very pale brown (10YR 7/3) loam, light yellowish brown (10YR 6/4) moist; weak coarse subangular blocky; soft, friable, nonsticky and slightly plastic; few very fine and fine irregular pores; common large soft masses of lime and few thin pendant lime coatings on the underside of rocks; 10 percent gravel; violently effervescent; moderately alkaline (pH 8.2). (0 to 48 cm thick)
TYPE LOCATION: Bear Lake County, Idaho; 2200 feet south and 25 feet west of the NE corner of section 21, T. 15 S., R.43 E. St. Charles topographic quadrangle. UTM NAD 83 Zone 12: Northing 4661539, Easting 464862.
RANGE IN CHARACTERISTICS:
Soil temperature - 4 to 7 degrees C.
Soil moisture control section: between 10 and 30 centimeters; dry in all parts for 45 consecutive days or more in the four months following the summer solstice. Xeric moisture regime.
Thickness of the mollic epipedon - 50 to 71 cm
Depth to secondary carbonates: 41 to 81 cm
A horizons
Value: 3 or 4 dry, 2 or 3 moist
Chroma: 2 dry, 1 or 2 moist
Clay content: 15 to 25 percent
Rock fragments: 0 to 10 percent gravel
Reaction: pH 6.1 to 7.3
BAt horizon
Value: 3 or 4 dry; 2 or 3 moist
Chroma: 2 or 3, dry or moist
Clay content: 30 to 40 percent
Rock fragments: 0 to 10 percent gravel
Reaction: 6.6 to 7.8
Bt horizon
Hue: 10YR or 7.5YR
Value: 4 to 6 dry; 3 to 5 moist
Chroma: 2 or 3, dry or moist
Clay content: 35 to 45 percent
Texture: clay loam or clay
Rock fragments: 0 to 10 percent gravel
Reaction: 6.6 to 7.8
Btk horizon
Hue: 10YR or 7.5YR
Value: 4 to 6 dry; 3 to 5 moist
Chroma: 2 to 4, dry or moist
Clay content: 35 to 45 percent
Texture: clay loam or clay
Rock fragments: 0 to 10 percent gravel
Calcium carbonate equivalent: 2 to 10 percent
Reaction: 7.4 to 8.4
Bk horizons
Hue: 10YR or 7.5YR
Value: 5 to 8 dry; 4 to 7 moist
Chroma: 2 to 4, dry or moist
Clay content: 18 to 35 percent
Texture: loam or clay loam
Rock fragments: 0 to 15 percent gravel
Calcium carbonate equivalent: 5 to 15 percent
Reaction: 7.9 to 8.4
COMPETING SERIES: These are the Iwica and Siroco series. The Iwica series has a duripan at 107 to 152 cm. The Siroco series has greater than 15 percent rock fragments in the particle size control section.
GEOGRAPHIC SETTING: Grecan soils are on terraces and hillsides. Elevations are 1798 to 2175 m. Slopes are 4 to 20 percent. These soils formed in alluvium derived from sandstone, limestone, dolomite and conglomerate. The climate is characterized by long, cold winters; moist springs; and warm, dry summers. Mean annual precipitation is 381 to 508 mm, much of which falls as snow or spring rain. Mean annual temperature is 4 to 7 degrees C. Frost-free period is 70 to 90 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Clegg, Hagenbarth, Hutchley, and Swanpeak soils. Clegg and Hagenbarth soils have a fine-loamy particle size control section and occupy similar landform positions. Hutchley soils are shallow to lithic contact, have a loamy-skeletal particle size control section and are on summits and shoulders. Swanpeak soils have a clayey-skeletal particle size control section and occupy similar landform positions.
DRAINAGE AND PERMEABILITY: Well drained, slow permeability.
USE AND VEGETATION: Grecan soils are used for rangeland and wildlife habitat. Potential native vegetation is mountain big sagebrush, antelope bitterbrush, serviceberry, snowberry, bluebunch wheatgrass, and western wheatgrass.
DISTRIBUTION AND EXTENT: Grecan soils are of limited extent in southeastern Idaho. MLRA 43B.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Bear Lake County, Idaho 2008. The name is coined.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - from the soil surface to 56 cm (A1, A2, and BAt horizons)
Argillic horizon - from 23 to 81 cm (BAt, Bt, and Btk horizons)
Secondary carbonates - from 71 to 152 cm (Btk, Bk1 and Bk2 horizons)
Particle-size control section - upper 50 cm of the argillic horizon - from 23 to 73 cm (BAt, Bt, and part of the Btk horizons).
Grecan soils have a xeric moisture regime and a frigid temperature regime.