LOCATION REDNUN CO

Established Series
Rev. GB-KLS
05/2023

REDNUN SERIES

The Rednun series consists of deep, well to moderately well drained, slowly permeable soils formed in thick, medium to moderately fine textured, reddish brown to yellowish red calcareous alluvial fan sediments derived from redbed sandstone, shale and loamstone. Rednun soils are on alluvial fans, valley filling side slopes and strike valleys. Slopes are 0 to 15 percent. Mean annual percipitation is about 430 mm and mean annual air temperature is about 8 degrees C.

TAXONOMIC CLASS: Fine, smectitic, mesic Aridic Argiustolls

TYPICAL PEDON:Rednun loam - cultivated. (Colors are for dry soil unless otherwise noted.)

Ap--0 to 15 cm; reddish brown (5YR 5/3) loam, dark reddish brown (5YR 3/3) moist; moderate medium subangular blocky structure parting to medium granular; soft, very friable; neutral (pH 7.0); clear smooth boundary. (10 to 20 cm thick)

AB--15 to 25 cm; reddish brown (5YR 5/3) light clay loam, dark reddish brown (5YR 3/3) moist; moderate medium subangular blocky structure; slightly hard, very friable; few glossy patches on faces of peds; 2 percent gravel; neutral (pH 7.0); clear smooth boundary. (8 to 13 cm thick)

Bt1--25 to 51 cm; reddish brown (5YR 5/3) light clay, reddish brown (5YR 4/3) moist; moderate medium prismatic structure parting to strong medium angular blocky; very hard, very plastic; thin continuous glossy coatings on surfaces of peds; waxy fillings in pores and root channels; 2 percent gravel; slightly alkaline (pH 7.4); clear wavy boundary.

Bt2--51 to 74 cm; reddish brown (5YR 5/4) heavy clay loam, light reddish brown (5YR 6/4) moist; moderate medium prismatic structure parting to moderate medium angular blocky; very hard, very plastic; thin continuous glossy coatings on faces of peds; waxy fillings in voids; 2 percent gravel; calcareous; moderately alkaline (pH 8.0); gradual smooth boundary. (combined thickness of Bt1 and Bt2 horizons is 30 to 55 cm)

Bk--74 to 107 cm; yellowish red (5YR 5/6) light clay loam, yellowish red (5YR 4/6) moist; weak medium prismatic structure parting to weak medium subangular blocky; hard, friable; thin glossy patches on surfaces of peds; 5 percent gravel; moderate amounts of visible secondary calcium carbonate in concretions and seams; moderately alkaline (pH 8.2) gradual wavy boundary. (25 to 38 cm thick)

BCk--107 to 152 cm; yellowish red (5YR 5/6) loam, yellowish red (5YR 4/6) moist, massive; hard, very friable; 5 percent gravel; moderate amounts of visible secondary calcium carbonate in concretions and in finely divided forms; moderately alkaline (pH 8.2).

TYPE LOCATION:Douglas County, Colorado; 457 meters west and 402 meters south of the NE corner of sec. 14, T. 9 S., R. 68 W.

RANGE IN CHARACTERISTICS:
Mean annual soil temperature - 8 to 14 degrees C
Mean summer soil temperature - 16 to 24 degrees C
Mollic epipedon thickness - 18 to 48 cm
Depth to calcareous material - 25 to 75 cm
Solum thickness - 40 to 110 cm
Organic carbon content in the mollic epipedon - 1 to 3 percent

Particle-size control section:
Electrical conductivity - less than 1 millimhos
Exchangeable sodium - less than 1 percent
Cation exchange capacity - 60 to 90 milliequivalents per 100 grams of clay
Clay content: 35 to 60 percent
Silt content: 15 to 45 percent
Sand content: 15 to 45 percent, with 15 to 35 percent fine or coarser sand
Rock fragment content: typically less than 5 percent, but may range from 0 to 15 percent medium and fine gravel of sandstone and shale lithology

A horizon
Hue: 7.5YR to 2.5YR
Value: 4 or 5 dry, 2 or 3 moist
Chroma: 2 or 3
Reaction: typically, pH 6.1 to 7.8; however, some noncalcareous A horizons may have pH up to 8.0

Bt horizons
Hue: 5YR or 2.5YR
Value: 5 or 6 dry, 3 through 5 moist
Chroma: 3 or 4
Texture: clay, clay loam, sandy clay
Reaction: typically, pH 6.1 to 7.8; however, some noncalcareous B horizons may have pH up to 8.0

Bk and BCk horizons
Hue: 5YR or 2.5YR
Texture: loam, clay loam or sandy clay loam
Reaction: pH 7.4 to 8.4
Calcium carbonate equivalent: 1 to 14 percent; visible accumulation of secondary carbonate occurs consistently in the form of concretions, seams, and streaks.

COMPETING SERIES:
Bethune (CO) - have a calcic horizon
Blackpipe (SD) - moderately deep to paralithic contact; contain less than 15 percent fine sand or coarser in the particle-size control section
Boneek (SD) - contain less than 15 percent fine sand or coarser in the particle-size control section
Boquillas (AZ) - moderately deep to paralithic contact; are driest during May and June
Chapin (CO) - are moderately deep to lithic contact
Collbran (CO) - have more than 35 percent clay in horizons in the lower part of the series control section
Collide (CO) - have more than 35 percent clay in horizons in the lower part of the series control section
Emigrant (WY) - are moderately deep to paralithic contact
Huggins (SD) - are moderately deep to paralithic contact
Kube (SD) - contain less than 15 percent fine sand or coarser in the particle-size control section
Leyden (CO) - are moderately deep to paralithic contact; contain more than 15 percent rock fragments
Loma (CO) - contain less than 15 percent fine sand or coarser in the particle-size control section
Nuncho (WY) - have hue 7.5YR or yellower in the particle-size control section
Nunn (CO) - have hue 7.5YR or yellower in the particle-size control section Querc (WY) - contain less than 15 percent fine sand or coarser in the particle-size control section
Raku (CO) - have hue 7.5YR or yellower in the particle-size control section Richfield (KS) - contain less than 15 percent fine sand or coarser in the particle-size control section; have hue 10YR in the particle-size control section
Ryus (KS) - are calcareous throughout the solum
Savo (SD) - contain less than 15 percent fine sand or coarser in the particle-size control section; have hue 10YR or yellower in the particle-size control section
Showlow (AZ) - are driest in May and June
Standley (CO) - contain more than 15 percent rock fragments in the particle-size control section
Thunderbird (AZ) - are moderately deep to lithic contact
Weld (CO) - contain less than 15 percent fine sand or coarser in the particle-size control section; have hue 7.5YR or yellower in the particle-size control section
Wormser (CO) - are moderately deep to lithic contact

GEOGRAPHIC SETTING:
Landform - alluvial fans, strike valleys and valley filling side slopes
Elevation - calcareous alluvial fan sediments
Slope - 0 to 15 percent
Parent material - redbed sandstone, shale and loamstone
Mean annual air temperature - 7 to 10 degrees C
Mean annual precipitation - 380 to 480 mm
Precipitation pattern - peak periods of precipitation occur in the spring and early summer months
Frost-free period - 110 to 140 days

GEOGRAPHICALLY ASSOCIATED SOILS: None listed.

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

USE AND VEGETATION: Used as native pastureland or as cropland. Principal native vegetation is blue grama, oak brush, and cactus.

DISTRIBUTION AND EXTENT: Rednun soils are of small extent in the foothills along the eastern front of the Rocky Mountains in central Colorado; MLRA 49.

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

SERIES ESTABLISHED: Sante Fe County (Area), New Mexico, 1970.

REMARKS: Diagnostic horizons and features in this pedon are:
Mollic epipedon - 0 to 25 cm (Ap and AB horizons)
Argillic horizons - 25 to 74 cm (Bt1 and Bt2 horizons)
Secondary calcium carbonate accumulation - 74 to 152 cm (Bk and BCk horizons)
Particle-size control section - 25 to 74 cm (Bt1 and Bt2 horizons)

Rednun soils have a mesic soil temperature regime and have an ustic soil moisture regime bordering on aridic.

Converted to metric, formatting updated to current standards, and competing series section updated. 01/2021

National Cooperative Soil Survey
U.S.A.