LOCATION RIVERBEND AZ+CA NV
Established Series
Rev. RDV/RLB/PDC
12/2015
RIVERBEND SERIES
The Riverbend series consists of very deep, excessively drained soils that formed in stratified fan alluvium. Riverbend soils are on fan terraces and fan remnants and have slopes of 2 to 15 percent. The mean annual precipitation is about 4 inches and the mean annual air temperature is about 73 degrees F.
TAXONOMIC CLASS: Sandy-skeletal, mixed, hyperthermic Typic Haplocalcids
TYPICAL PEDON: Riverbend very cobbly sandy loam, rangeland and wildlife habitat. (Colors are for dry soil unless otherwise noted.)
A--0 to 2 inches; brown (7.5YR 5/4) very cobbly sandy loam, brown (7.5YR 4/4) moist; moderate medium platy structure; soft, friable, nonsticky and nonplastic; common fine roots; many fine irregular pores; 25 percent cobble and 30 percent gravel; strongly effervescent; moderately alkaline (pH 7.9); abrupt wavy boundary. (1 to 10 inches thick)
Bw--2 to 7 inches; brown (7.5YR 5/4) very gravelly sandy loam, brown (7.5YR 4/4) moist; weak medium subangular blocky structure; soft, friable, nonsticky and nonplastic; common fine roots; common fine tubular pores; 5 percent cobble and 30 percent gravel; strongly effervescent; moderately alkaline (pH 8.0); abrupt wavy boundary. (0 to 8 inches thick)
Bk1--7 to 18 inches; light brown (7.5YR 6/4) very cobbly loamy sand, brown (7.5YR 5/4) moist; massive; loose, nonsticky and nonplastic; common very fine roots; many fine irregular pores; 20 percent cobble and 30 percent calcium carbonate coated gravel; many large soft calcium carbonate accumulations; violently effervescent, 12 percent calcium carbonate equivalent; moderately alkaline (pH 8.0); clear wavy boundary.
Bk2--18 to 34 inches; light brown (7.5YR 6/4) very gravelly loamy sand, brown (7.5YR 5/4) moist; single grain; loose, nonsticky and nonplastic; few very fine roots; common fine irregular pores; 40 percent calcium carbonate coated gravel; common medium soft calcium carbonate accumulations; violently effervescent, 16 percent calcium carbonate equivalent; moderately alkaline (pH 8.2); clear wavy boundary.
Bk3--34 to 60 inches; brown (7.5YR 5/4) very gravelly sand, brown (7.5YR 4/4) moist; single grain; loose, nonsticky and nonplastic; few very fine roots; common fine irregular pores; 10 percent cobble and 45 percent calcium carbonate coated gravel; strongly effervescent, 10 percent calcium carbonate equivalent; moderately alkaline (pH 8.0). (Combined thickness of the Bk horizons is 40 to 56 inches.)
TYPE LOCATION: Mohave County, Arizona; about 4 miles southeast of Golden Shores; 680 feet west and 2,350 feet north of the southeast corner of Section 25, T. 16 1/2 N., R. 20 1/2 W.
RANGE IN CHARACTERISTICS:
Soil Moisture: Intermittently moist in some part of the soil moisture control section during December-February and for less than 20 days cumulative July - September. Driest during May and June. Typic aridic soil moisture regime.
Soil Temperature: 72 to 78 degrees F.
Depth to calcic horizon: 4 to 20 inches
Control Section - Rock fragments: 35 to 75 percent.
Clay content: Averages 0 to 10 percent.
Calcium carbonate equivalent: 7 to 20 percent
Reaction: Slightly alkaline to strongly alkaline
A horizon
- Hue: 7.5YR, 10YR
Value: 5, 6 or 7 dry, 4, 5 or 6 moist
Chroma: 2 or 4, dry or moist
Bw horizon (when present) -. Hue: 7.5YR, 10YR
Value: 5, 6 or 7 dry, 4, 5 or 6 moist
Chroma: 3 or 4, dry or moist
Bk horizons
- Hue: 7.5YR, 10YR
Value: 5, 6 or 7 dry, 4, 5 or 6 moist
Chroma: 3 or 4, dry or moist
Texture: Loamy sand, sand, coarse sand, loamy coarse sand;
Can range to include thin strata of sandy loam and loam
Structure: Single grain or massive.
Consistence: Loose or soft and loose or very friable.
Other features: Few to many soft calcium carbonate accumulations or coats on rock fragments.
COMPETING SERIES: This is the
Azsand (NV),
Mesabase (NV), and
Varwash (NV) series. Azsand soils have less than 20 percent rock fragments in subhorizons above 12 inches. Mesabase soils are 20 to 40 inches deep to sandstone bedrock. Varwash soils have accessory silica and cemented lenses with discontinuous cementation in the soil matrix.
GEOGRAPHIC SETTING: Riverbend soils are on fan terraces and fan remnants at elevations of 550 to 2,500 feet. These soils formed in mixed alluvium. Slopes range from 2 to 15 percent. The mean annual precipitation is 3 to 7 inches. The mean annual air temperature is 70 to 76 degrees F. The frost-free period is 250 to 360 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Carrizo,
Chuckawalla,
Hyder,
Quilotosa,
Rillito and
Gunsight soils. Carrizo soils do not have a calcic horizon. Chuckawalla soils have argillic horizons. Hyder and Quilotosa soils have bedrock at depths less than 20 inches. Rillito soils are coarse-loamy and Gunsight soils are loamy-skeletal.
DRAINAGE AND PERMEABILITY: Excessively drained; very low or low runoff; rapid permeability.
USE AND VEGETATION: Riverbend soils are used for recreation, livestock grazing, wildlife habitat and homesite development. The present vegetation is creosotebush, brittlebush, forbs, white bursage and range ratany.
DISTRIBUTION AND EXTENT: Mojave desert of Northwest Arizona, southeastern California and southern Nevada. MLRA 30. This series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: PHOENIX, ARIZONA
SERIES ESTABLISHED: Mohave County, Arizona; Soil survey of the Grand Canyon Area, Arizona, 2001.
REMARKS: Classified according to Keys to Soil Taxonomy Ninth Edition, 2003.
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - 0 to 7 inches (A and Bw horizons)
Calcic horizon - 7 to 60 inches (Bk1, Bk2 and Bk3 horizons)
Particle-size control section 10 to 40 inches (Part of the Bk1 and Bk3, and the Bk2 horizons).
Responsibility for this series was transferred from Davis to Phoenix 12/2015. The last revision to the series was 12/2006. ET
National Cooperative Soil Survey
U.S.A.