LOCATION ALDAPE ID

Established Series
Rev. ALH/RWL
07/2011

ALDAPE SERIES

The Aldape series consists of deep to a duripan, well drained soils with moderately low saturated hydraulic conductivity that formed in alluvium from lacustrine deposits and volcanic ash. Slopes range from 3 to 35 percent in foothills and valleys. The average annual precipitation is about 13 inches and the average annual temperature is about 51 degrees F.

TAXONOMIC CLASS: Fine, smectitic, mesic Aridic Palexerolls

TYPICAL PEDON: Aldape loam -- on a convex northwest-facing slope of 9 percent, in rangeland at 2,750 feet elevation. When described on August 26, 1995, the soil was dry throughout. (Colors are for air-dry soil unless otherwise stated.)

A1--0 to 5 inches; grayish brown (10YR 5/2) loam, very dark grayish brown (10YR 3/2) moist; strong coarse platy structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine and fine, few medium roots; many very fine and fine, few medium tubular pores; neutral (pH 7.2); clear smooth boundary.

A2--5 to 11 inches; brown (10YR 5/3) loam, dark brown (10YR 3/3) moist; weak fine subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine and fine, few medium roots; common very fine and fine, few medium tubular pores; neutral (pH 7.2); clear wavy boundary. (combined A - 10 to 14 inches thick)

Bt/E--11 to 14 inches; (Bt material- 90 % of horizon) pale brown (10YR 6/3) clay loam, brown (10YR 4/3) moist; moderate fine and medium angular blocky structure; hard, firm, moderately sticky and moderately plastic; few very fine, fine and medium roots; common very fine and fine, few medium tubular pores; many faint clay films on faces of peds and in pores; neutral (pH 7.2); (E material) light gray (10YR 7/2) silt, prominent on all faces of peds and at lower boundary; abrupt smooth boundary. (1 to 3 inches thick)

Bt1--14 to 23 inches; pale brown (10YR 6/3) clay, brown (10YR 4/3) moist; moderate medium prismatic structure; very hard, very firm, very sticky and very plastic; few very fine, fine and medium roots; common very fine and fine tubular pores; many prominent clay films on faces of peds and in pores; common light gray (10YR 7/2) silt coats on ped faces at upper boundary; slightly alkaline (pH 7.5); clear wavy boundary.

Bt2--23 to 31 inches; pale brown (10YR 6/3) clay loam, brown (10YR 4/3) moist; strong medium angular blocky structure; hard, firm, moderately sticky and moderately plastic; few very fine and fine roots; common very fine and fine tubular pores; common distinct clay films on faces of peds and in pores; slightly alkaline (pH 7.4); gradual wavy boundary. (combined Bt - 8 to 24 inches thick)

Btk--31 to 36 inches; light yellowish brown (10YR 6/4) loam, dark yellowish brown (10YR 4/4) moist; moderate fine and medium subangular blocky structure; hard, friable, slightly sticky and slightly plastic; few very fine and fine roots; few very fine and fine tubular pores; few faint clay films on faces of peds and in pores; few fine slightly effervescent masses and seams of segregated calcium carbonates; slightly effervescent; moderately alkaline (pH 8.0); gradual wavy boundary. (0 to 24 inches thick)

Bk--36 to 47 inches; light yellowish brown (10YR 6/4) sandy loam, dark yellowish brown (10YR 4/4) moist; moderate medium subangular blocky structure; hard, friable, slightly sticky and nonplastic; few very fine and fine roots; few very fine and fine tubular pores; common fine strongly effervescent masses and seams of segregated calcium carbonates; moderately alkaline (pH 8.2); clear wavy boundary. (0 to 24 inches thick)

Bkq--47 to 53 inches; very pale brown (10YR 7/4) sandy loam, yellowish brown (10YR 5/4) moist; moderate fine subangular blocky structure; hard, friable, nonsticky and nonplastic; few very fine and fine roots; few very fine and fine tubular pores; 20 percent weakly cemented durinodes; violently effervescent, common fine and medium strongly effervescent masses and seams of segregated calcium carbonates; strongly alkaline (pH 8.6); abrupt wavy boundary. (6 to 24 inches thick)

Bkqm--53 to 60 inches; very pale brown (10YR 8/3) strongly cemented duripan with continuous indurated laminar cap 1 mm thick, light gray (10YR 7/2) moist; platy; extremely hard, slightly rigid; pink (7.5YR 8/4) sandy loam, single grain material between plates and in fractures; violently effervescent.

TYPE LOCATION: Ada County, Idaho; about 2 miles northeast of Eagle; 700 feet west and 150 feet south of the northeast corner of section 3, T.4 N., R.1 E.; USGS Eagle Quadrangle; Latitude - 43 degrees, 42 minutes, 57 seconds N. and Longitude - 116 degrees, 18 minutes, 53 seconds W., NAD 83.

RANGE IN CHARACTERISTICS:
Mollic epipedon thickness - 10 to 14 inches
Depth to abrupt textural change - 10 to 28 inches
Depth to base of argillic horizon - 20 to 50 inches
Depth to calcium carbonates - 20 to 36 inches
Depth to duripan - 40 to 60 inches
Particle-size control section - 35 to 45 percent clay; 0 to 15 percent rock fragments
Moisture control section - moist less than 90 consecutive days when the soil temperature is greater than 47 degrees F.
Average annual soil temperature - 51 to 54 degrees F.

A horizon
Value - 4 or 5 dry, 2 or 3 moist
Chroma - 2 or 3 dry or moist
Rock fragment content - 0 to 15 percent gravel
Reaction (pH) - slightly acid or neutral

Bt/E horizon
Clay content (wt. avg.) - 20 to 30 percent
Rock fragment content (wt. avg.) - 0 to 15 percent gravel
- Bt material (greater than 85 percent)
Chroma - 3 or 4 dry or moist
Texture - L, CL or SIL
- E material (silt coats) - few through very many

Bt horizon
Value - 5 or 6 dry, 3 or 4 moist
Chroma - 3 or 4 dry or moist
Texture - C, CL or SICL
Clay content (wt. avg.) - 35 to 45 percent
Rock fragment content - 0 to 15 percent gravel
Silt coats (upper boundary) - very few through many
Reaction (pH) - neutral or slightly alkaline

Bkq (or Bk) horizon
Value - 6 or 7 dry, 4 or 5 moist
Chroma - 3 or 4 dry or moist
Texture - SL or L
Clay content - 8 to 27 percent
Rock fragment content - 0 to 15 percent gravel
Durinodes - 0 to 20 percent
Calcium carbonate equivalent - 2 to 15 percent
Effervescence - slight through violent
Reaction (pH) - slightly through strongly alkaline

COMPETING SERIES: These are the Barshaad and Mahoon series. Barshaad and Mahoon soils are 20 to 40 inches deep to paralithic contact.

GEOGRAPHIC SETTING: Aldape soils are on southerly facing hill backslopes and footslopes, structural benches, fan remnants and landslides at elevations of 2,600 to 3,750 feet. Slopes range from 3 to 35 percent. These soils formed in alluvium from lacustrine deposits and volcanic ash. Average annual precipitation is 11 to 16 inches. Average annual temperature is 49 to 52 degrees F. Frost-free period is 125 to 155 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Adelmann , Chilcott, and Cranegulch soils. Adelmann soils have more than 35 percent rock fragments in the particle-size control section and are not abruptic. Cranegulch have a xeric soil moisture regime and are not abruptic. Chilcott soils are 20 to 40 inches deep to a duripan and have an ochric epipedon. These soils are on similar landscape positions.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; moderately low saturated hydraulic conductivity.

USE AND VEGETATION: Aldape soils are used mainly for rangeland and wildlife habitat. The dominant natural vegetation is basin big sagebrush and bluebunch wheatgrass. Some areas are used for irrigated hayland/pasture or homesites.

DISTRIBUTION AND EXTENT: Southwestern Idaho. MLRA 11. Aldape soils are not extensive.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon

SERIES ESTABLISHED: Boise Front Project, Ada County, Idaho, 1996.

REMARKS: The type location was moved due to cut and fill homesite development at the original site.
Diagnostic horizons and features recognized in this pedon:
Mollic epipedon - zone 0 to 11 inches (A1 and A2 horizons)
Argillic horizon - zone 11 to 35 inches (Bt/E, Bt1, Bt2 and Btk horizons)
Abrupt textural change - 11 to14 inches; est. 20% clay increase within 3 inches ( Bt/E horizon)
Duripan - at 53 inches (Bkqm horizon)
Linear extensibility - 4.0 to 6.0 cm (assumed) from 0 to 40 inches
Particle-size control section - zone 11 to 31 inches
Soil moisture regime - aridic bordering on xeric

These soils are drier than other Xerolls in the region under similar precipitation due to early runoff and extended period of high evapotranspiration.

National Cooperative Soil Survey
U.S.A.