LOCATION CROYDON UT

Established Series
Rev. EJ/JAC/RLM/SJJ
01/2017

CROYDON SERIES

The Croydon series consists of deep, well drained, moderately slow permeable soils that formed in residuum and colluvium weathered from sandstone and shale. These soils are on east and north facing mountainsides. The average annual precipitation is about 30 inches and the mean annual temperature is about 38 degrees F.

TAXONOMIC CLASS: Fine-loamy, mixed, superactive Typic Argicryolls

TYPICAL PEDON: Croydon loam, woodland. (Colors are for moist soil unless otherwise noted.)

Oi--0 to 1 inches; leaves and other plant material. (1 to 4 inches thick)

A1--1 to 5 inches; very dark brown (10YR 2/2) loam, very dark grayish brown (10YR 3/2) dry; weak thick platy structure parting to moderate fine granular; soft, friable, and slightly plastic; many very fine, fine and coarse roots; slightly acid (pH 6.5); clear smooth boundary. (3 to 16 inches thick)

A2--5 to 17 inches; very dark brown (10YR 2/2) loam, very dark grayish brown (10YR 3/2) dry; moderate medium granular structure; soft, very friable and slightly plastic; many very fine through coarse roots; slightly acid (pH 6.5); abrupt broken boundary. (0 to 13 inches thick)

E--17 to 23 inches; brown (10YR 4/3) loam, pale brown (10YR 6/3) dry; weak coarse subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine through coarse roots; common fine pores; 20 percent pebbles; 35 percent of this horizon is animal burrow material from A1 horizon above; slightly acid (pH 6.4); clear wavy boundary. (3 to 11 inches thick)

Bt1--23 to 29 inches; light olive brown (2.5Y 5/4) silty clay loam, pale olive (5Y 6/3) dry; moderate medium subangular blocky structure; very hard, firm, sticky and plastic; few very fine, fine and medium roots; common fine pores; common thin and many moderately thick clay films on faces of peds; small pockets of A1 horizon from animal burrows; slightly acid (pH 6.2); clear smooth boundary. (3 to 10 inches thick)

Bt2--29 to 41 inches; light olive brown (2.5Y 5/4) silty clay loam, pale olive (5Y 6/3) dry; moderate coarse subangular blocky structure parting to moderate fine subangular blocky; very hard, firm, sticky and plastic; few very fine and fine roots; common fine pores; continuous thin clay films on faces of peds; slightly acid (pH 6.2); clear smooth boundary. (6 to 31 inches thick)

C--41 to 49 inches; light olive brown (2.5Y 5/4) heavy silt loam, pale olive (5Y 6/3) dry; weak medium subangular blocky structure; hard, friable, slightly sticky and plastic; few fine roots; slightly acid (pH 6.2); abrupt smooth boundary. (0 to 22 inches thick)

Cr--49 inches; weathered sandstone.

TYPE LOCATION: Morgan County, Utah; about 8.5 miles east, and 4 miles north of Croydon, Utah; 1,475 feet south and 200 feet east of the NW corner of section 34, T.5N., R.5E.

RANGE IN CHARACTERISTICS: The mollic epipedon is 11 to 16 inches thick. The combined thickness of the A, E and Bt horizons ranges from 39 to 60 inches. Soft weathered sandstone occurs at depths of 40 to 60 inches. The mean annual soil temperature at depth of 20 inches ranges from 39 to 42 degrees F. The mean summer soil temperature ranges from 56 to 59 degrees F. The soils are usually moist, but are dry for 30 to 45 consecutive days during late summer. Rock fragments consists of rounded pebbles and cobbles, and range from 0 to 20 percent in the A horizon, 0 to 30 percent in the E horizon, 0 to 20 percent in the Bt horizon and 0 to 20 percent in the C horizon.

The A horizon has value of 3 through 5 dry, 2 or 3 moist, and chroma of 2 to 4 dry. Reaction is medium acid to slightly acid.

The E horizon has hue of 10YR or 2.5Y, value of 5 through 8 dry, 4 through 6 moist, and chroma of 2 through 4 dry and moist. It ranges from loam or cobbly loam to cobbly sandy loam. Reaction is slightly acid or medium acid.

The Bt horizon has dominant hue of 10YR, 2.5Y or 5Y, value of 5 through 7 dry, 4 or 5 moist, and chroma of 2 through 4 dry and moist. It ranges from silty clay loam to clay loam. This horizon has weak to moderate, fine to coarse subangular blocky structure. Reaction is neutral to medium acid.

The C horizon has dominant hue of 2.5Y or 5Y (10YR in parts of some pedons), value of 5 through 7 dry, 4 or 5 moist, and chroma of 2 through 4 dry and moist. It ranges from silt loam to loam, gravelly loam, clay loam or silty clay loam. This horizon ranges from noncalcareous to moderately calcareous and is medium acid to neutral.

COMPETING SERIES: These are the Gillluly, Hourglass, Mult, Quietus, Sponsor, Swede and Wildcow series. Gilluly, Mult and Quietus series are moderately deep to a lithic contact. Hourglass, Sponsor, Swede and Wildcow series are very deep.

GEOGRAPHIC SETTING: Croydon soils are at elevations of 6,400 to 9,500 feet. They occur on east and north facing mountainsides. Slopes range from 8 to 60 percent. These soils formed in residuum and colluvium weathered from sandstone. The climate is humid and the average annual precipitation ranges from 20 to 34 inches. The mean annual temperature is 34 to 40 degrees F. and the mean summer temperature is 53 to 56 degrees F. The frost free season ranges from 40 to 75 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Hades, Isabell, Kilfoil, Lucky Star, and Scave soils. Hades soils have mollic epipedons more than 20 inches thick and lack E horizons. Isabell soils have summer soil temperature greater than 59 degrees F. and lack E horizons. Kilfoil soils lack a mollic epipedon and are 20 to 40 inches deep to bedrock. Lucky Star and Scave soils have more than 35 percent rock fragments in the particle size control section and have hue of 7.5YR, 5YR or 2.5YR.

DRAINAGE AND PERMEABILITY: Well drained; slow runoff; moderately slow permeability.

USE AND VEGETATION: These soils are used for watershed, range, wildlife habitat and timber production. The potential vegetation is aspen, white fir, Douglas fir, with an understory of snowberry, mountain bromegrass, ninebark, blue wildrye, peavine, sedges and willows.

DISTRIBUTION AND EXTENT: Northern and central Utah. The series is inextensive.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana

SERIES ESTABLISHED: Morgan County (Morgan Area), Utah, 1974.

REMARKS:
Diagnositc horizons and features recognized in this pedon are:
Mollic Epipedon:
Argillic Horizon:
Paralithic Contact:

The depth class was narrowed from deep and very deep, to only deep (40 to 60 inches), prior to 2000. The bedrock contact was changed in 2017 from "R" to "Cr" after researching the published manuscripts of Morgan Area, UT and Carbon Area, UT. In both manuscripts, the bedrock was described as soft and weathered, and the soil features table listed soft and rippable bedrock. This is more consistent with Cr material.

The classification of the series when first established was fine-loamy, mixed Argic Cryoborolls.
It was later changed to Pachic Argicryolls because the typical profile does marginally qualify as Pachic. However, the range in characteristics specifically describes a mollic epipedon with a thickness range less than 16 inches (40cm). This needs to be resolved in the future, either by finding a new typical profile, or by slightly reducing the current depths of this profile to support non-pachic, which I believe was the intent. SJJ.

National Cooperative Soil Survey
U.S.A.