LOCATION AYETTE IDEstablished Series
The Ayette series consists of deep, well drained soils with slow permeability that formed in colluvium and residuum from lacustrine deposits. Slopes range from 8 to 50 percent in foothills. The average annual precipitation is about 15 inches and the average annual temperature is about 49 degrees F.
TAXONOMIC CLASS: Fine, smectitic, mesic Vertic Argixerolls
TYPICAL PEDON: Ayette loam -- on a slightly convex south-facing slope of 25 percent, in rangeland at 2,900 feet elevation. When described on July 2, 1996, the soil was dry to 10 inches and slightly moist below. (Colors are for air-dry soil unless otherwise stated.)
A--0 to 4 inches; gray (10YR 5/1) loam, very dark gray (10YR 3/1) moist; moderate fine and medium platy structure; slightly hard, friable, moderately sticky and moderately plastic; common very fine and fine, few medium roots; common very fine, fine and medium irregular pores; slightly acid (pH 6.2); clear smooth boundary. (3 to 10 inches thick)
Bt1--4 to 8 inches; dark grayish brown (10YR 4/2) clay loam, very dark brown (10YR 2/2) moist; weak medium platy structure parting to moderate fine and medium subangular blocky; hard, friable, very sticky and very plastic; common very fine and fine, few medium roots; many very fine and fine tubular pores; common faint clay films on faces of peds and in pores; slightly acid (pH 6.5); clear smooth boundary.
Bt2--8 to 12 inches; brown (10YR 5/3) clay loam, dark brown (10YR 3/3) moist; moderate fine and medium angular blocky structure; hard, firm, very sticky and very plastic; common very fine and fine, few medium roots; common very fine and fine tubular pores; many distinct clay films on faces of peds and in pores; neutral (pH 6.6); clear wavy boundary. (combined Bt horizon - 6 to 15 inches thick)
Btss1--12 to 30 inches; pale brown (10YR 6/3) clay, brown (10YR 4/3) moist; weak fine prismatic structure parting to moderate fine and medium angular blocky; very hard, firm, very sticky and very plastic; few very fine and fine roots; few very fine and fine tubular pores; many prominent clay films on faces of peds and in pores; common intersecting slickensides; cracks 1mm wide; slightly acid (pH 6.2); clear wavy boundary.
Btss2--30 to 43 inches; light yellowish brown (2.5Y 6/3) clay, olive brown (2.5Y 4/3) moist; moderate fine prismatic structure; very hard, 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; few intersecting slickensides; slightly acid (pH 6.5); clear wavy boundary. (combined Btss horizon - 24 to 40 inches thick)
2Cr--43 inches; partly consolidated sandy lacustrine deposits.
TYPE LOCATION: Boise County, Idaho; about 3 miles north of Horseshoe Bend; 50 feet south and 950 feet west of the northeast corner of section 14, T.7 N., R.2 E.; USGS Horseshoe Bend Quadrangle; Latitude - 43 degrees, 57 minutes, 03 seconds N. and Longitude - 116 degrees, 10 minutes, 45 seconds W.; NAD 83.
RANGE IN CHARACTERISTICS:
Mollic epipedon thickness - 10 to 20 inches
Depth to soft bedrock - 40 to 60 inches
Reaction - slightly acid or neutral
Particle-size control section - 0 to 5 percent rock fragments (mostly fine gravel); 35 to 45 percent clay
Moisture control section - dry 60 to 90 consecutive days following the summer solstice
Average annual soil temperature - 48 to 53 degrees F.
A horizon
Value - 4 or 5 dry, 2 or 3 moist
Chroma - 1 or 2 dry or moist
Rock fragments - 0 to 5 percent gravel
Bt horizon
Value - 4 or 5 dry, 2 or 3 moist
Chroma - 2 or 3 dry or moist
Clay content - 30 to 40 percent
Rock fragments - 0 to 5 percent gravel
Btss horizon
Hue - 2.5Y or 10YR
Value - 5 or 6 dry, 3 or 4 moist
Chroma - 3 or 4 dry or moist
Texture - C or CL
Clay content - 35 to 50 percent
Rock fragments - 0 to 5 percent gravel
Cracks - 0 to 5 mm wide
Slickensides - few or common
COMPETING SERIES: These are the Darow, Forsgren, Gimmi, Hann, Karney, Kuck, McDesh, Montour, Tub and Ukiah series. Darow, Gimmi, Karney, Kuck and Ukiah soils are moderately deep to a paralithic contact. Forsgren soils are calcareous at depths of 40 to 55 inches. Hann soils are very deep and have a mollic epipedon 20 to 40 inches thick. McDesh soils are 20 to 40 inches deep to a lithic contact. Montour soils are calcareous at depths of 29 to 32 inches. Tub soils have a mollic epipedon 20 to 25 inches thick and have secondary carbonates at a depth of 18 to 37 inches.
GEOGRAPHIC SETTING: Ayette soils are strongly sloping to steep on landslides, hill backslopes, shoulders and summits at elevations of 2,600 to 4,750 feet. Slopes range from 8 to 50 percent. These soils formed in colluvium and residuum from lacustrine deposits including fine pyroclastic sediments. Average annual precipitation ranges from 13 to 20 inches. Average annual temperature ranges from 46 to 51 degrees F. Frost-free period is 100 to 150 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Hann series and the Crawley, Hullsgulch and Yad soils. Crawley soils are loamy and shallow to paralithic contact on similar geomorphic positions. Hann soils are pachic and very deep on similar geomorphic positions. Hullsgulch soils are fine-loamy and very deep on similar geomorphic positions. Yad soils are cracked to the surface and very deep on footslopes and concave backslopes.
DRAINAGE AND PERMEABILITY: Well drained; medium to very rapid runoff; slow permeability.
USE AND VEGETATION: Ayette soils are used mainly for rangeland. Some areas are used for irrigated hayland/pasture. Native vegetation is xeric big sagebrush, bluebunch wheatgrass and Idaho fescue.
DISTRIBUTION AND EXTENT: West-central Idaho. MLRA 10. Ayette soils are of small extent.
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 0 to 12 inches (A, Bt1 and Bt2 horizons)
Argillic horizon - zone from 4 to 43 inches (Bt1, Bt2, Btss1 and Btss2 horizons)
Paralithic contact and lithologic discontinuity - at 43 inches (2Cr)
Particle-size control section - zone from 4 to 24 inches
Linear extensibility - 6.0 or more between the soil surface and 40 inches (assumed)
Soil moisture regime xeric