LOCATION HELLAKE IDEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Ultic Argixerolls
TYPICAL PEDON: Hellake loam -- on a 2 percent smooth south-facing slope at 3,050 feet elevation in pasture. When described on June 11, 1997, the soil was dry to 11 inches and slightly moist below. (Colors are for air-dry soil unless otherwise noted.)
A--0 to 3 inches; brown (10YR 5/3) loam, dark brown (10YR 3/3) moist; weak thin platy structure parting to moderate fine and medium granular; soft, very friable, slightly sticky and slightly plastic; many very fine and fine, common medium roots; many very fine and fine irregular pores; 5 percent gravel; slightly acid (pH 6.3); clear smooth boundary. (3 to 7 inches thick)
AB--3 to 10 inches; brown (10YR 5/3) loam, dark brown (10YR 3/3) moist; moderate thin platy structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine and fine, few medium roots; common very fine and fine tubular and irregular pores; 5 percent gravel; moderately acid (pH 6.0); clear smooth boundary. (0 to 8 inches thick)
Bt1--10 to 22 inches; yellowish brown (10YR 5/4) clay loam, dark yellowish brown (10YR 3/4) moist; moderate fine and medium subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; common very fine and fine roots; common very fine and fine tubular pores; common faint clay films on faces of peds and in pores; 5 percent gravel; strongly acid (pH 5.4); clear smooth boundary. (6 to 15 inches thick)
Bt2--22 to 36 inches; yellowish brown (10YR 5/4) clay loam, dark yellowish brown (10YR 3/4) moist; strong fine and medium subangular blocky structure; hard, firm, moderately sticky and moderately plastic; few very fine, fine and medium roots; common very fine and fine tubular pores; many distinct clay films on faces of peds and in pores; 5 percent gravel; strongly acid (pH 5.3); clear smooth boundary. (6 to 18 inches thick)
Bt3--36 to 43 inches; light yellowish brown (10YR 6/4) clay loam, dark yellowish brown (10YR 4/4) moist; strong fine and medium subangular blocky structure; hard, firm, moderately sticky and moderately plastic; few very fine and fine roots; common very fine and fine tubular pores; many distinct clay films on faces of peds and in pores; 5 percent gravel; strongly acid (pH 5.2); clear smooth boundary. (0 to 12 inches thick)
2BC--43 to 53 inches; light yellowish brown (10YR 6/4) very gravelly loam, dark yellowish brown (10YR 4/4) moist; weak fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few very fine and fine roots; common very fine and fine tubular pores; 35 percent gravel, 5 percent cobbles; strongly acid (pH 5.2); abrupt smooth boundary. (0 to 10 inches thick)
2C1--53 to 60 inches; brownish yellow (10YR 6/6) very gravelly sandy loam, dark yellowish brown (10YR 4/6) moist; massive; soft, very friable, nonsticky and nonplastic; few fine roots; 50 percent gravel, 5 percent cobbles; moderately acid (pH 6.0); abrupt smooth boundary.
2C2--60 to 66 inches; very pale brown (10YR 7/4) extremely gravelly loamy sand, yellowish brown (10YR 5/4) moist; single grain; loose, nonsticky and nonplastic; 60 percent gravel, 5 percent cobbles; moderately acid (pH 6.0).
TYPE LOCATION: Boise County, Idaho; about 2 miles west of Garden Valley; 1,450 feet north and 1,200 feet west of the southeast corner of section 21, T.9 N., R.4 E.; USGS Garden Valley Quadrangle; Latitude - 44 degrees, 05 minutes, 47 seconds N. and Longitude - 115 degrees, 58 minutes, 57 seconds W.; NAD 83.
RANGE IN CHARACTERISTICS:
Thickness of mollic epipedon - 10 to 15 inches
Depth to base of argillic horizon - 30 to 45 inches
Depth to discontinuity - 30 to 60 inches
Depth to bedrock - 60 inches or more
Base saturation - 50 to 75 percent in some part between 10 and 30 inches
Particle-size control section - 25 to 32 percent clay; 0 to 10 percent rock fragments; less than 25 percent medium or coarser sand
Moisture control section - dry 60 to 90 consecutive days following the summer solstice
Average annual soil temperature - 47 to 50 degrees F.
O horizons occur in some pedons
A horizon
Hue - 7.5YR or 10YR
Value - 4 or 5 dry, 2 or 3 moist
Chroma - 2 or 3 dry or moist
Rock fragments - 0 to 10 percent gravel
Reaction - moderately acid or slightly acid
Bt1 and Bt2 horizons
Hue - 7.5YR or 10YR
Value - 5 or 6 dry, 3 or 4 moist
Chroma - 3 or 4 dry or moist
Texture - L or CL
Clay content - 24 to 30 percent
Rock fragments - 0 to 10 percent fine gravel
Reaction - strongly acid or moderately acid
Bt3 horizon (when present)
Hue - 7.5YR or 10YR
Value - 6 or 7 dry, 4 or 5 moist
Chroma - 3 or 4 dry or moist
Clay content - 27 to 35 percent
Rock fragments - 0 to 15 percent fine gravel
Reaction - strongly acid or moderately acid
2C horizon
Hue - 7.5YR through 2.5Y
Value - 6 or 7 dry, 4 or 5 moist
Chroma - 2 through 6 dry or moist
Texture - SL or LS
Clay content - 4 to 18 percent
Rock fragments - 25 to 60 percent gravel, 0 to 15 percent cobbles and 25 to 75 percent total
Reaction - strongly acid or moderately acid
COMPETING SERIES: These are the Alderpoint (T), Annum, Brownlee, Chirpchatter, Dryfalls (T), Ebadlow, Felton, Fisherhill, Goldendale, Lompico, Lorena, Meland, Mendian (T), Meystre, Quiden, Rehfield, Robbscreek, Schumacher, Stacker, Stardust, Updegraff and Van Horn series. Alderpoint soils are not in the database and cannot be competed. Annum and Mendian soils have a mantle of loess and buried Bt horizons. Brownlee soils do not have a gravelly substratum discontinuity, have lamellae in the lower part and are typically 40 to 60 inches deep over weathered granite. Chirpchatter soils are dry 120 to 140 days. Lompico, Lorena, Meland, Robbscreek and Stacker soils are 20 to 40 inches deep. Dryfalls soils are 40 to 60 inches deep and have andic properties. Ebadlow soils have 10 to 30 percent rock fragments in the particle-size control section and are dry 90 to 105 days. Felton soils have more than 50 percent shale fragments in the C horizons. Fisherhill soils are dry 90 to 105 days and have an average annual soil temperature of 52 to 54 degrees F. Goldendale soils have argillic horizons that extend to depths below 60 inches and are slightly acid or neutral in the argillic horizon. Meystre soils are slightly acid or neutral throughout and lack a gravelly substratum discontinuity. Quiden soils have a mean annual soil temperature of 50 to 54 degrees F. Rehfield soils have an aridic soil moisture regime. Schumacher soils are 40 to 60 inches deep to bedrock and neutral throughout. Stardust soils have more than 25 percent medium and coarser sand, do not have a substratum discontinuity and depth to the base of the argillic horizon is over 45 inches. Updegraff soils are dry more than 90 consecutive days and are 40 to 60 inches deep. Van Horn soils have an average annual soil temperature of 51 to 54 degrees F.
GEOGRAPHIC SETTING: Hellake soils are level to steep on relict lakebed terraces, dissected fan remnants and landslides at elevations of 3,000 to 4,750 feet. These soils formed in lacustrine sediments over alluvium from igneous rocks. . Slopes range from 0 to 35 percent. Average annual precipitation is 20 to 26 inches. Average annual temperature is 45 to 48 degrees F. Frost-free period is 90 to 120 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Middlefork, Riverpoint, Staircase and the competing Stardust soils. Middlefork soils are frigid and occur on north-facing slopes. Riverpoint soils are loamy-skeletal and occur on risers and convex shoulders. Staircase soils are coarse-loamy, do not have an argillic horizon and occur on drainageways. Stardust soils occur on fan remnants and landslides.
DRAINAGE AND PERMEABILITY: Well drained; very slow to rapid runoff; moderately slow permeability. On nearly level areas all or part of the pedon is commonly saturated during the growing season due to flood irrigation.
USE AND VEGETATION: Hellake soils are used mainly for irrigated hayland/pasture and homesites. Native vegetation is ponderosa pine and common snowberry.
DISTRIBUTION AND EXTENT: West-central Idaho. MLRA 44 and 43. Hellake 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 pedon:
Mollic epipedon - zone from 0 to 10 inches (A and AB horizons)
Argillic horizon - zone from 10 to 43 inches ( Bt1, Bt2 and Bt3 horizons)
Particle-size control section - zone from 10 to 30 inches
Soil moisture regime - xeric
Significant Fe concentrations present in some pedons are due to continuous flood irrigation during the growing season and not related to natural drainage conditions.