LOCATION AGNESTON CO+WY
Established Series
Rev. AJC/LF/KLS
02/2022
AGNESTON SERIES
The Agneston series consists of moderately deep, well drained soils formed in moderately thin gravelly to very gravelly coarse textured, noncalcareous materials weathered from granite. Agneston soils are on hills, plateaus, ridges, and mountainsides. Slopes are 2 to 50 percent. The mean annual precipitation is about 640 mm and the mean annual temperature is about 2 degrees C.
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive Typic Haplocryalfs
TYPICAL PEDON: Agneston gravelly coarse sandy loam - forest. (Colors are for dry soil unless otherwise noted.)
Oi--0 to 3 cm; undecomposed organic material principally needles, bark, twigs, and the fleshy remains of scattered grasses.
Oe--3 to 6 cm; partially decomposed organic material like that of the horizon above.
E--6 to 21 cm; light brownish gray (10YR 6/2) gravelly coarse sandy loam, grayish brown (10YR 5/2) moist; weak thin platy structure parting to fine granular; soft, very friable; 20 percent pebbles, mostly fine and very fine angular pebbles; moderately acid (pH 5.8); clear smooth boundary. (10 to 25 cm thick)
Bt--21 to 57 cm; yellowish brown (10YR 5/4) very gravelly coarse sandy clay loam, dark yellowish brown (10YR 4/4) moist; moderate medium and fine subangular blocky structure; hard, very friable, slightly sticky and slightly plastic; peds are extremely hard; thin continuous wax-like coatings on faces of peds and wax-like coatings and fillings in root channels and pores; wax-like coatings on rock fragments; some wax-like bridging between sand grains; 40 percent pebbles, mostly fine and very fine angular pebbles; strongly acid (pH 5.2); gradual wavy boundary. (13 to 76 cm thick)
BC--57 to 70 cm; brown (7.5YR 5/4) extremely gravelly coarse sandy loam,d ark brown (7.5YR 4/4) moist; weak fine subangular blocky structure; very hard, very friable; peds are very hard; thin glossy patches on some faces of peds and glossy coatings on rock fragments; a small amount of wax-like bridging between some sand grains; 75 percent pebbles, mostly fine and very fine angular pebbles; strongly acid (pH 5.2); gradual irregular boundary. (0 to 25 cm thick)
R--70 cm; hard granite bedrock.
TYPE LOCATION: Jackson County, Colorado; approximately 30 meters south and 460 meters west of the northeast corner of Sec. 15, T. 11 N., R. 81 W.
RANGE IN CHARACTERISTICS: Mean annual soil temperature is about 5 degrees C, and mean summer soil temperature is about 11 degrees C. Thin A horizons are present in some pedons. Base saturation is less than 60 percent in at least some subhorizon of the argillic horizon. Depth to the lithic contact ranges from 50 to 100 cm. Depth to the top of the argillic horizon is less than 60 cm and depth to the base of the argillic horizon ranges from 43 to 100 cm. Transitional E/B horizons are absent in most pedons or are less than 8 cm in thickness. Rock fragments range from 25 to 250 mm in the B horizons and are mostly less than 75 mm in diameter and range from 25 to 250 mm in diameter. Within the sand fraction the content of medium and coarser angular sand having a large proportion of flat bearing surfaces between sand grains ranges from 15 to about 90 percent and horizons of low organic matter content have a differential between dry and moist consistence that is 1 to 3 times greater than soils of similar texture having finer and more rounded sand grains. These soils are dry in some part of the moisture control section for some period of nearly every year.
The A horizon, if present, has hue of 2.5Y through 7.5YR, value of 4 or 5 dry, 2 or 3 moist, and chroma of 1 through 3. It ranges from neutral to strongly acid.
The E horizon has hue of 2.5Y through 7.5YR, value of 5 through 8 dry, 4 through 7 moist, and chroma of 1 through 4. It ranges from slightly acid to very strongly acid.
The Bt horizon has hue of 2.5Y through 7.5YR, value of 5 through 7 dry, 4 through 6 moist, and chroma of 2 through 6. It is typically gravelly or very gravelly or very cobbly sandy clay loam, and less typically a clay loam. It averages 18 to 35 percent clay, 0 to 30 percent silt, and 40 to 75 percent sand with more than 35 percent fine or coarser sand. This horizon is moderately to very strongly acid.
The BC or C horizon, if present, has hue of 2.5Y through 7.5YR. It ranges from slightly acid to very strongly acid.
COMPETING SERIES: These are the
Angostura,
Cloud Peak,
Cundiyo,
Duchesne,
Frisco,
Gambler,
Granile,
Guffey,
Hollandlake,
Hyattville,
Kebler,
Lake Creek,
Lakehelen,
Larand,
Leadville,
Lulude, MacFarlane, (T)
Needleton,
Presa, (T)
Tamarron, (T)
Tenrag,
Tigeron,
Tolvar,
Trebor, and
Worock series. Angostura, Cundiyo, Duchesne, Frisco, Granile, Hollandlake, Larand, Leadville, MacFarlane, (T)Needleton, Presa, Tigeron, Tolvar, and Worock soils lack a lithic contact above a depth of 100 cm. Hyattville, Lakehelen, and (T)Tenrag soils all have hues that are predominantly 5YR or redder in a majority of subhorizons. Cloud Peak soils are calcareous in the lower part of the solum and C horizon and have consistent k horizons. Gambler, Lake Creek, and Lulude soils have more than 60 percent base saturation in all parts of the argillic horizon. Kebler soils have rock fragments that are dominantly more than 250 mm in diameter and have transitional A&B horizons. Guffey and (T)Tamarron soils have a paralithic contact above 100 cm.
GEOGRAPHIC SETTING:
Landform--hills, plateaus, ridges, and mountainsides
Elevation--2,500 to 3,600 meters
Slope--2 to 50 percent
Parent material--moderately thin, gravelly to very gravelly coarse textured, noncalcareous materials weathered from granite
Mean annual precipitation--510 to 760 mm with peak periods of precipitation in the spring and summer
Mean annual air temperature--1 to 3 degrees C
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Peeler and
Troutville soils. Peeler and Troutville soils lack bedrock within the 25- to 100-cm section.
DRAINAGE AND PERMEABILITY: Well drained; slow to medium runoff; moderate permeability.
USE AND VEGETATION: These soils are used principally for grazing land, recreation, and timber production. Native vegetation consists of lodgepole pine, spruce, fir, and juniper.
DISTRIBUTION AND EXTENT: Agneston soils are extensive in the mountainous areas of Colorado; MLRAs 43B, 48A
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Jackson County, Colorado, 1973.
REMARKS: Converted to metric and O horizons were updated to start at zero 2/2022
National Cooperative Soil Survey
U.S.A.