LOCATION REDNUN CO+NMEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Aridic Argiustolls
TYPICAL PEDON: Rednun loam - cultivated. (Colors are for dry soil unless otherwise noted.)
Ap--O to 6 inches; 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. (4 to 8 inches thick)
B1--6 to 10 inches; 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; about 2 percent gravel; neutral (pH 7.0); clear smooth boundary. (3 to 5 inches thick)
B21t--10 to 20 inches; 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; about 2 percent gravel; mildly alkaline (pH 7.4); clear wavy boundary. (6 to 12 inches)
B22t--20 to 29 inches; reddish brown (5YR 5/4) heavy clay loam, 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; about 2 percent gravel; calcareous; moderately alkaline (pH 8.0); gradual smooth boundary. (6 to 10 inches thick)
B3ca--29 to 42 inches; 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; about 5 percent gravel; moderate amounts of visible secondary calcium carbonate in concretions and seams; moderately alkaline (pH 8.2) gradual wavy boundary. (10 to 15 inches thick)
Cca--42 to 60 inches; yellowish red (5YR 5/6) loam, yellowish red (5YR 4/6) moist, massive; hard, very friable; about 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; 1,500 feet west and 1,320 feet south of NE corner of Sec. 14, T. 9 S., R. 68 W.
RANGE IN CHARACTERISTICS: The mollic epipedon is 7 to 19 inches thick. Depth to calcareous material ranges from 10 to 30 inches. The solum is 15 to 42 inches thick. Organic carbon in the mollic epipedon ranges from 1 to 3 percent. Conductivity is usually less than 1 millimhos, and exchangeable sodium less than 1 percent. Cation exchange capacity ranges from 60 to 90 milliequivalents per 100 grams of clay. Mean annual soil temperature ranges from 47 to 58 degrees F., and mean summer soil temperature from 60 to 76 degrees F. These soils are usually dry in the moisture control section but are usually moist in some part of the soil above the lower boundary of the moisture control section. They are moist in all parts of the moisture control section less than 60 consecutive days in the 120 days following the winter solstice.
The A1 horizon has hue of 7.5YR to 2.5YR, value of 4 or 5 dry, 2 or 3 moist, and chroma of 2 or 3. It usually has fine granular primary structure, but it may be subangular blocky in plowed fields. It is usually slightly acid to mildly alkaline but moderately alkaline reaction is permitted, providing that the horizon is noncalcareous. It is soft to slightly hard.
The B2t horizon has hue of 5YR or 2.5YR, value of 5 or 6 dry, 3 through 5 moist, and chroma of 3 or 4. It is usually light clay, but clay ranges from 35 to 60 percent, silt from 15 to 45 percent, and sand from 15 to 45 percent with more than 15 percent but less than 35 percent fine or coarser sand. It is usually slightly acid to mildly alkaline in the upper part and mildly alkaline to moderately alkaline in the lower part, but may be moderately alkline in the upper part if that portion is noncalcareous.
The C horizon has hue of 5YR or 2.5YR. It is typically loam or light clay loam. It is mildly to strongly alkaline. Calcium carbonate equivalent ranges to 14 percent and visible accumulation of secondary carbonate occurs consistently in the form of concretions, seams, and streaks.
COMPETING SERIES: These are the Ashfork, Blackpipe, Boneek, Boquillas, Chapin, Collbran, Emigrant, Huggins, Kube, Leyden, Loma, Nunn, Querc, Richfield, Ryus, Savo, Showlow, Sofia, Standley, Thunderbird, Torreon, and Wormser series. Ashfork, Chapin, Thunderbird, and Wormser soils have lithic contacts at depths of 20 to 40 inches. Blackpipe, Boquillas, Emigrant, Huggins, Leyden, and Querc soils have paralithic contacts at depths of 20 to 40 inches. Boneek, Loma, Richfield, and Savo soils all have less than 15 percent fine sand and coarser in their particle-size control sections. Collbran soils have a high proportion of dark colored, magnetic, ferromagnesium minerals in the sand and silt fractions Ryus soils are calcareous throughout their solums. Showlow soils have calcic horizons. Standley soils have over 15 percent coarse fragments in the control section. Torreon soils have calcic horizons and solums thicker than 42 inches. Kube, Nunn, and Sofia soils have hues of 7.5YR and yellower.
GEOGRAPHIC SETTING: The Rednun soils are on alluvial fans and valley filling side slopes in areas of redbed shales and loamstones. Slope gradients usually range from 0 to 15 percent. The soils formed in thick, medium to moderately fine-textured, reddish brown to yellowish red calcareous alluvial fan sediments derived from redbed shales and loamstones. At the type location mean annual temperature is about 47 degrees F., mean summer temperature is about 63 degrees F., mean annual soil temperature is 49 degrees F.; and mean summer soil temperature is 62 degrees F. Average annual precipitation is about 17 inches with peak periods of precipitation occurring in the spring and early summer months.
GEOGRAPHICALLY ASSOCIATED SOILS: These are The Fondis and Renohill soils and the competing Nunn soils. Fondis soils have hue of 10YR or 2.5 and have overly thickened solums involving paleosols. Renohill soils have hue of 10YR or 2.5Y and have a paralithic contact at depths of less than 40 inches.
DRAINAGE AND PERMEABILITY: Well to moderately well drained; rapid runoff; slow permeability.
USE AND VEGETATION: Used as native pasture land or as cropland. Principal native vegetation is blue grama, oak brush, and cactus.
DISTRIBUTION AND EXTENT: Near foothills in central Colorado. The series is moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Sante Fe County (Area), New Mexico, 1970.
REMARKS: Last updated by the state 3/82.