LOCATION FOURMILEBENCH      UT
Established Series
Rev. JMS/KDS
10/2007

FOURMILEBENCH SERIES


The Fourmilebench series consists of very shallow and shallow, well drained, moderately rapid permeable soils that developed in residuum and colluvium from sandstone and mudstone deposits. Fourmilebench soils occur on structural benches and dipslopes of cuestas. Slopes range from 15 to 50 percent. Mean annual precipitation is about 11 inches. Mean annual air temperature is about 49 degrees F.

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, mesic Lithic Ustic Haplargids

TYPICAL PEDON: Fourmilebench extremely flaggy loamy sand - rangeland. (Colors are for dry soil unless otherwise noted) Surface is covered by 10 percent gravel, 10 percent cobbles, 15 percent channers, 15 percent flagstones and 5 percent stones.

A--0 to 2 inches; pale brown (10YR 6/3) extremely flaggy loamy sand, dark yellowish brown (10YR 4/4) moist; weak fine platy structure parting to weak fine granular; soft, very friable, nonsticky and nonplastic; few fine and medium roots; many very fine interstitial pores; 10 percent gravel, 10 percent cobbles, 15 percent channers, 20 percent flagstones, 10 percent stones; slightly effervescent; moderately alkaline (pH 8.2); clear wavy boundary. (1 to 3 inches thick)

Bt--2 to 7 inches; brown (7.5YR 5/3) very flaggy sandy loam, brown (7.5YR 4/3) moist; weak fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; few fine and medium roots; common very fine interstitial and few fine tubular pores; 5 percent gravel, 5 percent cobbles, 15 percent channers, 20 percent flagstones, 10 percent stones; few faint clay films on faces of peds; slightly effervescent; moderately alkaline (pH 8.2); abrupt smooth boundary. (3 to 14 inches thick)

R--7 inches; Wahweap Formation sandstone bedrock.

TYPE LOCATION: Kane County, Utah; Fourmile Bench Quadrangle; about 1500 feet east and 500 feet north of the southwest corner of sec. 17, T. 40 S. and R. 2 E.; 37 degrees 19 minutes 86 seconds north latitude and 111 degrees 43 minutes 21 seconds west longitude, NAD 83.

RANGE IN CHARACTERISTICS:

Soil Moisture: Ustic aridic soil moisture regime

Soil Temperature: 47 to 54 degrees F.

Depth to lithic contact: 4 to 20 inches

Depth to argillic: 1 to 14 inches

Reaction: slightly to moderately alkaline throughout

Calcium carbonate equivalent: 0 to 10 percent

Clay content: 12 to 20 percent

A horizon
Hue: 7.5YR, 10YR
Value: 4 to 6 dry, 3 to 5 moist
Chroma: 2 to 4, dry or moist
Rock fragments: 35 to 70 percent

Bt horizons
Hue: 5YR, 7.5YR, 10YR
Value: 4 to 6 dry, 3 to 5 moist
Chroma: 2 to 6, dry or moist
Clay content: 12 to 20 percent
Rock fragments: 35 to 70 percent

COMPETING SERIES: These are the Puertecito (NM), Quazo (UT), Roygorge (CO), and Wyva (NV) series. Puertecito, Roygorge, Quazo, and Wyva soils contain more than 20 percent clay.

GEOGRAPHIC SETTING:
Parent Material: colluvium over residuum of interbedded sandstone and mudstone
Landform: structural benches, dipslopes of cuestas
Elevation: 5,000 to 6,200 feet
Slope: 15 to 50 percent
Mean annual temperature: 45 to 52 degrees F
Mean annual precipitation: 9 to 12 inches
Frost-free period: 120 to 160 days

GEOGRAPHICALLY ASSOCIATED SOILS: This is the Daklos soil. Daklos soils do not have an argillic horizon.

DRAINAGE AND PERMEABILITY: Well drained; moderate runoff; moderately rapid permeability.

USE AND VEGETATION: Fourmilebench soils are used as for livestock grazing and wildlife habitat. Vegetation is Utah juniper, green mormontea, broom snakeweed, roundleaf buffaloberry, two-needle pinyon, Indian ricegrass, and galleta.

DISTRIBUTION AND EXTENT: Southern Utah. MLRA 35, LRR-D. This series is of small extent.

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

SERIES ESTABLISHED: Grand Staircase-Escalante National Monument Soil Survey Area, Utah, 2004.

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

Ochric epipedon - the zone from 0 to 2 inches (A horizon)

Argillic horizon - the zone from 2 to 7 inches (Bt horizon)

Lithic contact - the boundary with hard sandstone at 7 inches (R horizon)

Classified according to Soil Taxonomy Second Edition 1999; Keys to Soil Taxonomy Tenth Edition 2006


National Cooperative Soil Survey
U.S.A.