LOCATION APMAY COEstablished Series
TAXONOMIC CLASS: Fine-loamy over sandy or sandy-skeletal, mixed, superactive, frigid Cumulic Haplustolls
TYPICAL PEDON: Apmay sandy clay loam on an east facing 1 percent slope in irrigated hay at an elevation of 6,400 feet. (Colors are for dry soil unless otherwise noted.) When described on August, 7, 1979, the soil had free water at 33 inches.
A1--0 to 4 inches; dark grayish brown (10YR 4/2) sandy clay loam, very dark grayish brown (10YR 3/2) moist; weak medium granular structure; soft, very friable, slightly sticky and slightly plastic; many very fine and fine roots; 5 percent gravel; slightly alkaline (pH 7.4); abrupt smooth boundary. (3 to 12 inches thick)
A2--4 to 19 inches; dark grayish brown (10YR 4/2) sandy clay loam, very dark grayish brown (10YR 3/2) moist; weak coarse and medium granular structure; soft, very friable, slightly sticky and slightly plastic; many fine roots; 5 percent gravel; common fine prominent strong brown (7.5YR 5/6) moist redox concentrations; slightly alkaline (pH 7.4); clear smooth boundary. (10 to 24 inches thick)
Bw--19 to 23 inches; grayish brown (10YR 5/2) gravelly sandy loam, brown (10YR 4/3) moist; weak medium subangular blocky structure; nonsticky and nonplastic; common fine roots; 30 percent gravel; common fine prominent strong brown (7.5YR 5/6) moist redox concentrations slightly alkaline (pH 7.4); clear wavy boundary. (0 to 4 inches thick)
2C--23 to 60 inches; light brownish gray (10YR 6/2) extremely gravelly sand, yellowish brown (10YR 5/4) moist; single grain; loose, nonsticky and nonplastic; few fine roots; 60 percent gravel, 10 percent cobble; slightly alkaline (pH 7.4).
TYPE LOCATION: Routt County, Colorado; about 4 miles east of Hayden, about 2,300 feet east and 100 feet south of the NW corner of Sec. 8, T. 6 N., R. 87 W. Latitude 40 degrees, 29 minutes, 56 seconds north; longitude 107 degrees, 10 minutes, 21 seconds west, NAD27.
RANGE IN CHARACTERISTICS:
Soil Moisture: ustic moisture regime, typic subclass
Mean annual soil temperature is 41 to 45 degrees F.
Mean summer soil temperature is 59 to 64 degrees F.
Mollic epipedon thickness: 16 to 30 inches.
Depth to the 2C horizon: 20 to 40 inches.
Depth to seasonal endosaturation: 4 to 30 inches
Particle size control section (weighted average):
Upper part:
Clay content: 20 to 30 percent
Rock fragment content: 4 to 35 precent[this seems way hihg]
Lower part:
Clay content: 2 to 5 percent
Rock fragment content: 65 to 85 precent
A horizon(s):
Hue: 10YR, 2.5Y
Value: 3 through 5, 2 or 3 moist
Chroma: 2 or 3, dry or moist
Texture: gravelly sandy clay loam, sandy clay loam, clay loam, gravelly loam, loam, gravelly sandy loam.
Clay content: 15 to 35 percent
Coarse fragments: 0 to 10 percent mixed gravel, 0 to 10 percent mixed cobbles
Reaction: neutral or slightly alkaline (6.6 to 7.8).
Bw horizon(s)(An AC horizon in some pedons):
Hue: 10YR, 2.5Y
Value: 4 to 6, 3 to 5 moist
Chroma: 2 to 4.
Texture: sandy loam, gravelly sandy clay loam, gravelly loam, clay loam, loam, gravelly sandy loam.
Clay content: 13 to 35 percent
Coarse fragments: 0 to 30 percent mixed gravel, 0 to 5 percent mixed cobble.
Reaction: neutral or slightly alkaline (6.6 to 7.8).
C horizon(s)(present in some pedons)
Hue: 10YR, 2.5Y
Value: 4 to 6, 4 or 5 moist
Chroma: 2 to 4.
Texture: stratified loam, sandy clay loam, and clay loam.
Coarse fragments: 0 to 5 percent mixed gravel
Reaction: neutral or slightly alkaline (6.6 to 7.8).
2C horizon(s):
Hue: 10YR, 2.5Y
Value: 4 to 6 dry or moist
Chroma: 2 to 4 dry or moist
Texture: very gravelly sand, extremely gravelly sand
Clay content: 0 to 8 percent
Coarse fragments: 50 to 75 percent mixed gravel, 5 to 20 percent mixed cobble
Reaction: neutral or slightly alkaline (6.6 to 7.8).
COMPETING SERIES: This is the Sudworth (MT) series. Sudworth soils are calcareous in the 2C horizon.
GEOGRAPHIC SETTING:
Landform: flood plains
Elevation: 6,200 to 7,000 feet
Slopes: 0 to 5 percent
Parent material: mixed alluvium
Mean annual temperature: 40 to 45 degrees F
Mean summer temperature: 58 to 62 degrees F.
Mean annual precipitation: 13 to 20 inches.
Frost-free season: 75 to 110 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Homelake and Breezebasin soils. The Homelake soils do not have sandy-skeletal substratums above 40 inches and are on flood plains. The Breezebasin soils also do not have sandy skeletal substratums and are on flood plains and flood plain steps.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained. Runoff is negligible to medium or ponded. Permeability is moderate or moderately slow in the upper part and very rapid in the substratum. Depth to seasonal high water table is 4 to 30 inches in April, May, and June. The water table is between 30 and 72 inches the remainder of the year.
USE AND VEGETATION: Most of the acreage is irrigated grass hay land. A few areas are rangeland or nonirrigated pastureland and used for livestock grazing and wildlife habitat. Native vegetation consists of bluegrasses, needlegrasses, sedges, willows, and roses. A few narrowleaf cottonwood trees occur in some places.
DISTRIBUTION AND EXTENT: Northwest Colorado, LRR E, MLRA 48A, small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Moffat County (Moffat County Area), Colorado, 1991. The name Apmay is Yampa spelled backwards. The Indian word Yampa was originally applied to a common plant in northwest Colorado.
REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Particle size control section: The zone from 10 inches to 23 inches for the upper part (bottom of A2 and whole Bw horizon), and the zone from 23 to 40 inches for the lower part (upper part of 2C horizon)
Mollic epipedon: The zone from 0 to 19 inches (A1, A2, and Bw horizons)
Cumulic feature: An irregular carbon distribution with depth is inferred from the landscape position
Redoximorphic concentrations: In the zone from 4 to 23 inches (A2 and Bw horizons)
Lithologic discontinuity: At the upper boundary of the 2C horizon
Redoximorphic features in the surface layers are presumed to be induced by irrigation.
The 04/2005 version changed the classification from Aquic Cumulic Haplustolls to Cumulic Haplustolls because there is no clear evidence of a reducing regime.
Taxonomic version: Ninth Edition, 2003