LOCATION CRISTO                  UT

Established Series
Rev. LBC/DLT/KLS
11/2022

CRISTO SERIES

The Cristo series consists of moderately deep, well drained soils. These soils formed in material weathered from shale and limestone on mountain slopes. Slopes range from 10 to 60 percent. The mean annual precipitation is about 560 mm and the mean annual air temperature is about 6 degrees C.

TAXONOMIC CLASS: Fine, smectitic, frigid Pachic Argixerolls

TYPICAL PEDON: Cristo loam--rangeland. (Colors are for moist soil unless otherwise stated.)

Oi--0 to 5 cm; organic matter, leaves, stems, etc.

A1--5 to 18 cm; very dark grayish brown (10YR 3/2) loam, grayish brown (10YR 5/2) dry; weak fine and medium granular structure; friable, slightly sticky and plastic; many fine, very fine, and few medium roots; 5 percent gravel; slightly acid (pH 6.4); abrupt smooth boundary. (5 to 15 cm thick)

A2--18 to 38 cm; very dark grayish brown (10YR 3/2) loam, grayish brown (10YR 5/2) dry; weak medium subangular blocky structure that parts to weak fine and medium granular; hard, friable, slightly sticky and plastic; common fine, very fine, few medium and coarse roots; 10 percent gravel; slightly acid (pH 6.4); clear smooth boundary. (10 to 20 cm thick)

Bt--38 to 56 cm; dark brown (10YR 3/3) gravelly silty clay loam, grayish brown (10YR 5/2) dry; moderate medium subangular blocky structure; very hard, very firm, sticky and very plastic; common very fine, fine, few medium and coarse roots; common very fine and few fine pores; many moderately thick clay films of faces of peds; 25 percent gravel; slightly acid (pH 6.3); abrupt smooth boundary. (20 to 33 cm thick)

C/B--56 to 94 cm; dark brown (10YR 3/3) extremely gravelly silty clay loam, (pockets of silty clay loam adhering to soft shale fragments), grayish brown (10YR 5/2) dry; ped size and shape determined by space available between soft shale fragments but dominantly weak, medium subangular blocky structure; very hard, very firm, sticky and very plastic; few very fine and medium roots; many moderately thick clay films on faces of peds; 85 percent shale fragments; moderately calcareous; slightly alkaline (pH 7.4) boundary (18 to 36 cm thick).

Cr--94 to 156 cm; fractured shale.

TYPE LOCATION: Morgan County, Utah; head of Lost Creek, about 17 km north and 1600 meters east of Lost Creek Dam; about 115 meters east and 305 meters south of the northwest corner, sec. 23, T. 7 N., R. 5 E.

RANGE IN CHARACTERISTICS:
Mean annual soil temperature at depth of 50 cm--6 to 7 degrees C
Mean summer soil temperature--15 to 16 degrees C
The soils are usually moist but are dry for 50 to 70 consecutive days during the late summer.
Thickness of mollic epipedon--53 to 89 cm
Thickness of solum--53 to 89 cm
Depth to shale--50 to 100 cm
Rock fragment content--0 to 10 percent in the A horizon, 0 to 35 percent in the Bt horizon and 55 to 95 percent in the C horizon, consisting of angular limestone and shale lithology

A horizon
Hue--10YR
Value--4 or 5 dry, 2 or 3 moist
Chroma--2 and 3 dry and moist
Texture--loam
Clay content--18 to 27 percent
Horizon thickness--23 to 33 cm
Reaction--pH 6.1 to 7.3

Bt horizon
Value--4 or 5 dry, 2 or 3 moist
Chroma--2 or 3 dry
Texture--gravelly silty clay loam, gravelly clay loam to clay loam
Clay content--35 to 40 percent, with common to many, thin to moderately thick clay films on faces of peds and in pores
Structure--weak, coarse prismatic to moderate medium subangular blocky
Rock fragment content--15 to 30 percent
Reaction--pH 6.1 to 7.3

C/B or C horizon
Value--5 to 6 dry, 3 or 4 moist
Chroma--2 or 3 moist
Texture--extremely gravelly clay loam to very gravelly silty clay loam
Rock fragment content--60 to 80 percent
Calcium carbonate equivalent--1 to 15 percent, with slight to strong effervescence
Reaction--6.1 to 7.8

COMPETING SERIES: These are the Arcia, Arva (T), Broadhead, Henefer, Highwood (T), Rugar (T) and Sweitberg series. Arcia and Sweitberg, soils are noncalareous throughout. Arva, Broadhead, Henefer, Highwood and Rugar soils are more than 100 cm deep to bedrock. Rugar soils have iron manganese nodules in the Bt horizon.

GEOGRAPHIC SETTING:
Landform--all aspects of mountain slopes
Elevation--6,500 to 8,800 feet
Slope--10 to 60 percent
Parent material--residuum and colluvium weathered from shale and limestone
Climate--moist subhumid
Mean annual precipitation--405 to 635 mm
Mean annual air temperature--5 to 6 degrees C
Mean summer air temperature--14 to 15 degrees C
Frost-free period--60 to 70 days

GEOGRAPHICALLY ASSOCIATED SOILS: None listed

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

USE AND VEGETATION: These soils are used for watershed, range and wildlife habitat. The present native vegetation is big sagebrush, snowberry, yellowbrush, mountain bromegrass, slender wheatgrass and yarrow.

DISTRIBUTION AND EXTENT: Cristo soils are moderately extensive in the basin and range areas of central Utah; MLRA 28A and 47

SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Bozeman, Montana

SERIES ESTABLISHED: Morgan County, (Morgan Soil Survey Area), Utah, 1974

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon (pachic feature)--5 to 56 cm (A and Bt horizons)
Argillic horizon--38 to 56 cm (Bt horizon)
Secondary calcium carbonate accumulation--56 to 94 cm (C/B horizon)
Paralithic contact--94 cm to fractured shale

Converted to metric, updated formatting, and O horizons were updated to start at zero. Competing series section was not updated. 11/2022

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National Cooperative Soil Survey
U.S.A.