LOCATION GRAFFPOINT UT

Established Series
Rev. GCC/RSJ/MJD-JVC
11/2022

GRAFFPOINT SERIES

The Graffpoint series consists of very deep, well drained soils that formed in alluvium derived dominantly from sedimentary rocks. Graffpoint soils are on fan remnants. Slopes are 2 to 15 percent. The mean annual precipitation is about 11 inches and the mean annual temperature is about 49 degrees F.

TAXONOMIC CLASS: Loamy-skeletal, mixed, active, mesic Xeric Haplogypsids

TYPICAL PEDON: Graffpoint silt loam--rangeland. (Colors are for dry soil unless otherwise noted).

A--0 to 3 inches; brown (7.5YR 5/4) silt loam, dark brown (7.5YR 3/4) moist; weak medium platy structure; slightly hard, friable, slightly sticky, slightly plastic; common fine and very fine roots; many fine and very fine vesicular pores; strongly effervescent (18 percent calcium carbonate equivalent), carbonates are disseminated; (0.10 percent gypsum); slightly alkaline (pH 7.8); abrupt wavy boundary. (3 or 4 inches thick).

Bw--3 to 11 inches; brown (7.5YR 5/4) loam, brown (7.5YR 4/4) moist; weak medium and fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic, few medium, many fine and very fine roots; few medium, common fine and very fine tubular pores; strongly effervescent (19 percent calcium carbonate equivalent), carbonates are disseminated; (0.72 percent gypsum); moderately alkaline (pH 8.0); clear smooth boundary. (7 to 11 inches thick).

By1--11 to 22 inches; brown (7.5YR 5/4) very gravelly sandy clay loam, reddish brown (5YR 4/4) moist; massive; slightly hard, friable, slightly sticky and slightly plastic; common fine, few very fine roots; common medium and fine tubular pores; strongly effervescent (21 percent calcium carbonate equivalent), carbonates are disseminated; 50 percent gravels, 5 percent cobbles; (6 percent gypsum); slightly alkaline (pH 7.7); abrupt wavy boundary. (11 to 34 inches thick).

By2--22 to 56 inches; brown (7.5YR 5/4) very gravelly gypsiferous sandy clay loam, reddish brown (5YR 4/4) moist; massive; slightly hard, friable, slightly sticky and slightly plastic; common medium and fine interstitial pores; 5 percent cobbles and 50 percent gravel; common gypsum nodules and filaments (17 percent gypsum); strongly effervescent (17 percent calcium carbonate equivalent), carbonates are disseminated; slightly alkaline (pH 7.7); abrupt wavy boundary (26 to 43 inches thick).

By3--56 to 60 inches; light brown (7.5YR 6/4) gravelly gypsiferous loam, reddish brown (5YR 4/4) moist; massive; slightly hard, friable, slightly sticky and slightly plastic; common fine and very fine roots; common medium and fine tubular pores; strongly effervescent (16 percent calcium carbonate equivalent), carbonates are disseminated; 20 percent gravels, 2 percent cobbles; (gypsum 16.3 percent); visible as nodules, filaments, and weathered gypsiferous rocks; moderately alkaline (pH 8.0).

TYPE LOCATION: Iron County, Utah; in Cedar City; approximately 100 feet north of the southwest corner of the northeast 1/4 of section 23, T. 36 S, R. 11 W; USGS Cedar City 7.5 minute topographic quadrangle; 37 degrees 39 minutes 8 seconds north latitude and 113 degrees 03 minutes 31 seconds west longitude, NAD27.

RANGE IN CHARACTERISTICS:

Soil moisture - The soil is dry 50 to 75 percent of the time when the soil temperature is above 41 degrees F.; Aridic moisture regime that borders on xeric.

Mean annual soil temperature - 47 to 52 degrees F.

Mean summer soil temperature - 65 to 71 degrees F.

Particle-size control section - Clay content: Averages 18 to 27 percent;
Rock fragments: Averages 35 to 60 percent.

Effervescence - Strongly effervescent or violently effervescent.

Reaction - Slightly alkaline or moderately alkaline.

A horizon
Value: 5 or 6 dry, 3 or 4 moist.
Chroma: 4 through 6, dry or moist.
Texture: Silt loam or loam.

Bw horizon
Value: 5 or 6 dry, 4 through 6 moist.
Chroma: 4 through 6, dry or moist.
Texture: Loam or sandy clay loam.
Clay content: 18 to 27 percent.
Rock fragments: 0 to 15 percent.
Calcium carbonate equivalent: 15 to 25 percent.

By and BCy horizons
Hue: 5YR or 7.5YR.
Value: 5 or 6 dry, 4 or 5 moist.
Chroma: 4 through 6, dry or moist.
Texture: Very gravelly sandy clay loam, gravelly loam, or sandy clay loam; gypsiferous modifiers are present when gypsum content is 15 to 20 percent.
Clay content: 18 to 27 percent.
Calcium carbonate equivalent: 15 to 25 percent.
Gypsum content: 5 to 20 percent.

COMPETING SERIES: There are currently no other series in this family.

GEOGRAPHIC SETTING: Graffpoint soils are on fan remnants. These soils formed in alluvium derived dominantly from sedimentary rocks. Slopes are 2 to 15 percent. Elevations range from 5,500 to 6,000 feet. The climate semiarid. The mean annual precipitation is 10 to 12 inches, the mean annual air temperature is 45 to 50 degrees F., and the frost-free period is 120 to 140 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are Ashdown and Cavegulch soils. Ashdown soils are fine-loamy. Cavegulch soils are fine-silty.

DRAINAGE AND PERMEABILITY: Well drained; medium surface runoff; moderately slow permeability (moderately high saturated hydraulic conductivity).

USE AND VEGETATION: Graffpoint soils are used mainly for urban and recreational development.

DISTRIBUTION AND EXTENT: Southwestern Utah. These soils are not extensive with about 760 acres of the series mapped to date. MLRA 28A.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona.

SERIES ESTABLISHED: Iron County (Iron-Washington Area), Utah, 1997.

REMARKS: Diagnostic horizons and features recognized in this pedon are:

Ochric epipedon - The zone from the soil surface to 7 inches (A horizon and part of the Bw horizon).

Cambic horizon - The zone from 3 to 11 inches (Bw horizon).

Gypsic horizon - The zone from 11 to 60 inches (By1, By2, and By3 horizons).

Particle-size control section - The zone from 10 to 40 inches (By1 horizon and parts of the Bw and By2 horizons).

The revision of July 2007 updated the taxonomic class from Loamy-skeletal, mixed, superactive, mesic Xeric Haplogypsids and updated horizon designations. The change of the cation exchange activity class is an estimate based on NASIS data and similar soils in the major land resource area.

In Utah this series is correlated with semidesert range sites.

ADDITIONAL DATA: The typical pedon at the series type location has partial characterization data by the Soil Survey Laboratory (SSL) as soil survey sample number 71UT021007 (pedon # 72C0140).

National Cooperative Soil Survey
U.S.A.