LOCATION BETHUNE COEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Aridic Argiustolls
TYPICAL PEDON: Bethune silty clay loam. (Colors are for dry soil unless otherwise noted.)
Ap--0 to 4 inches; brown (10YR 5/3) silty clay loam, dark brown (10YR 3/3) moist; moderate medium subangular blocky structure; slightly hard, friable, sticky and plastic; common very fine and fine roots; 34.0 percent clay; 7.4 Phenol red; 2 percent, by volume, subrounded gravel; slightly alkaline; abrupt smooth boundary. ( 4 to 6 inches)
Bt--4 to 11 inches; very dark grayish brown (10YR 3/2) silty clay, very dark brown (10YR 2/2) moist; strong medium prismatic structure parting to strong fine angular blocky; very hard, firm, very sticky and very plastic; common very fine and fine roots; common very fine tubular pores and common fine tubular pores; 45.0 percent clay; 7.6 Phenol red; many distinct clay films on faces of peds and distinct clay films in root channels and/or pores; slightly alkaline; clear smooth boundary. ( 4 to 7 inches)
BCk--11 to 17 inches; brown (10YR 5/3) silty clay, brown (10YR 4/3) moist; weak coarse subangular blocky structure; very hard, firm, sticky and plastic; few fine roots; few very fine tubular pores and few fine tubular pores; 24.0 percent calcium carbonate equivalent; 45.0 percent clay; 8.2 Thymol-blue; faint clay films on faces of peds; common fine and medium irregular soft masses of lime; strongly effervescent; 5 percent, by volume, subrounded gravel; moderately alkaline; gradual wavy boundary. ( 3 to 4 inches)
Ck--17 to 25 inches; pale brown (10YR 6/3) gravely clay loam, brown (10YR 5/3) moist; massive; hard, firm, slightly sticky and slightly plastic; few very fine and fine roots; few very fine tubular pores; 36.0 percent calcium carbonate equivalent; 35.0 percent clay; 8.2 Thymol-blue; many fine and medium irregular soft masses of lime; violently effervescent; 20 percent, by volume, subrounded gravel; moderately alkaline; abrupt wavy boundary. ( 8 to 9 inches)
Cr--25 inches; Weakly cemented soft calcareous sandstone.
TYPE LOCATION: Kit Carson County, approximately 11 miles south of Bethune; 750 feet south and 750 feet west of the northeast corner of sec. 35, T. 10 S., R. 45 W.; USGS Burlington 3 NW topographic quadrangle; lat. 39 degrees 8 minutes 32 seconds N. and long. 102 degrees 23 minutes 31 seconds W.
RANGE IN CHARACTERISTICS: Depth to weakly cemented soft calcareous sandstone ranges from 20 to 40 inches. Depth to the base of the argillic horizon is 8 to 11 inches. Depth to calcareous material is 8 to 11 inches.
The Ap horizon has hue of 10YR, value of 4 or 5 dry, and chroma of 2 or 3 dry or moist. It is silty clay loam. Clay content is 32 to 36 percent clay.
The Bt horizon has hue of 10YR, value of 3 or 4 dry, 2 or 3 moist, and chroma of 2 or 3 dry or moist. It is silty clay.
The clay content is 40 to 45 percent, silt 40 to 60 percent, and sand 5 to 15 percent.
The BCk horizon has hue of 10YR or 2.5Y, value of 5 to 7 dry, 4 to 6 moist, and chroma of 2 or 3 dry or moist. It is silty clay loam, clay loam, and silty clay. The clay content is 35 to 45 percent. The calcium carbonate equivalent ranges from 20 to 30 percent.
The Ck horizon has hue of 10YR or 2.5Y, value of 6 to 8 dry, 5 to 7 moist, and chroma of 1 to 3 dry, 2 or 3 moist. It is gravelly clay loam. The clay content is 30 to 35 percent. The rock fragments content ranges from 15 to 20 percent gravel. The calcium carbonate equivalent ranges from 30 to 40 percent. It is moderately or strongly alkaline.
COMPETING SERIES: Ashfork (AZ), Blackpipe (SD), Boneek (SD), Boquillas (AZ), Chapin (CO), Collbran (CO), Emigrant (WY), Huggins (SD), Kube (SD), Leyden (CO), Loma (CO), Nuncho (WY), Nunn (CO), Querc (WY), Rednun (CO), Richfield (KS), Ryus (KS), Savo (SD), Showlow (AZ), Sofia (MT), Standley (CO), Thunderbird (AZ), Torreon (NM), and Wormser (CO). Ashfork, Chapin, Thunderbird and Wormser soils have a lithic contact at a depth of 20 to 40 inches; Boneek, Collbran, Kube, Loma, Nuncho, Nunn, Rednun, Richfield, Ryus, Savo, Sofia, Showlow (AZ), Standley, and Torreon soils do not have a paralithic contact above a depth of 40 inches; in addition, Boneek, Boquillas, Chapin, Collbran, Loma, and Rednun soils have hue of 7.5 YR or redder; Blackpipe soils have free carbonates in the series control section or above 40 inches; Emigrant soils have greater than 15 percent fine sand or coarser; Huggins soils contain greater than 35 percent rock fragments in the BC horizon; Leyden soils formed in gravelly and cobbly alluvial material overlying shale; Querc soils are slightly or medium acid.
GEOGRAPHIC SETTING: The Bethune soils are on plains. Slope ranges from 0 to 2 percent. The elevation ranges from 4,300 to 4,410 feet. The soil formed in loess that overlies weakly cemented soft calcareous sandstone. The mean annual precipitation is about 15 inches with peak periods of precipitation in the spring and early summer months. Mean annual temperature is 50 degrees F. The frost-free period is 150 days.
GEOGRAPHICALLY ASSOCIATED SOILS: Richfield, Kimst, Rago, Weld, Iliff, and Canyon soils. Kimst, Richfield, Rago, and Weld soils are very deep. Iliff soils are moderately deep and have abrupt textural change between the A and Bt horizons. Kimst soils are fine-loamy and lack Bt horizons. Canyon soils are shallow to soft rock.
DRAINAGE AND PERMEABILITY: Well drained; runoff is low; slow permeability.
USE AND VEGETATION: Bethune soils are used primarily for nonirrigated cropland and rangeland. Vegetation is mainly blue grama, western wheatgrass, green needlegrass, and buffalograss.
DISTRIBUTION AND EXTENT: Eastern Colorado. This series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado
SERIES ESTABLISHED: Kit Carson County, Colorado, 1996.
REMARKS: The name is from a town in Kit Carson County. Diagnostic features recognized in this pedon are : mollic epipedon - from the zone 0 to 11 inches (Ap, Bt horizons); argillic horizon - the zone from 4 to 11 inches (Bt horizon); calcic horizon - 11 to 25 inches (BCk, Ck horizons).