LOCATION OLNEST COEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Aridic Haplustalfs
TYPICAL PEDON: Olnest loam - rangeland. (Colors are for dry soil unless otherwise noted.)
A--0 to 4 inches; brown (10YR 5/3) sandy loam, dark grayish brown (10YR 4/2) moist; moderate fine granular structure; soft, very friable, nonsticky and nonplastic; slightly alkaline (pH 7.4); abrupt smooth boundary. (3 to 5 inches thick)
BA--4 to 7 inches; brown (10YR 5/3) sandy loam, dark grayish brown (10YR 4/2) moist; weak medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; few fine tubular pores; 2 percent pebbles; slightly alkaline (pH 7.4); clear smooth boundary. (0 to 3 inches thick)
Bt--7 to 16 inches; brown (10YR 5/3) sandy clay loam, brown (10YR 4/3) moist; moderate medium prismatic structure parting to moderate medium subangular blocky; soft, friable, slightly sticky and slightly plastic; common fine tubular pores; few faint clay films on faces of peds; 2 percent pebbles; slightly alkaline (pH 7.6); clear smooth boundary. (9 to 16 inches thick)
Bk1--16 to 22 inches; pale brown (10YR 6/3) sandy clay loam, brown (10YR 5/3) moist; weak medium prismatic structure parting to moderate medium subangular blocky; slightly hard, firm, slightly sticky and slightly plastic; few very fine, fine pores; 1 percent pebbles; strongly effervescent; few calcium carbonate concretions; moderately alkaline (pH 8.4); gradual smooth boundary.
Bk2--22 to 35 inches; very pale brown (10YR 7/3) sandy clay loam, brown (10YR 5/3) moist; weak moderate medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine and fine tubular pores; violently effervescent; common fine soft masses of calcium carbonate; strongly alkaline (pH 8.6); gradual smooth boundary.
Bk3--35 to 49 inches; very pale brown (10YR 7/3) sandy clay loam, light yellowish brown (10YR 6/4) moist; massive; soft, friable, slightly sticky and slightly plastic; common very fine and fine pores; violently effervescent; common fine masses of calcium carbonate; strongly alkaline (pH 8.6); clear smooth boundary. (Combined thickness of the Bk horizons is 5 to 46 inches)
C--49 to 60 inches; pale brown (10YR 6/3) sandy loam, brown (10YR 5/3) moist; massive; 10 percent pebbles; strongly effervescent, carbonates are disseminated; strongly alkaline (pH 8.6).
TYPE LOCATION: Kit Carson County, Colorado; approximately 9 miles south of Flagler Lake; about 220 feet north and 2440 feet east of the southwest corner of Sec. 21, T. 10 S., R. 50 W. U.S.G.S. quad Stratton CO 3 N.W. Lat. 39 degrees, 9 minutes, 26 seconds N., and long. 102 degrees, 59 minutes, 45 seconds W.
RANGE IN CHARACTERISTICS:
Soil Moisture: control section is usually moist in some or all parts in May through June, intermittently July and August; ustic moisture regime bordering on aridic.
Depth to calcareous material: 12 to 23 inches.
Depth to the base of the argillic horizon: 9 to 25 inches.
Organic carbon: 1 to 2 percent in the upper 4 inches.
Rock fragment content: 0 to 10 by volume percent fine pebbles.
A horizon:
Hue: 10YR
Value: 4 or 5 dry, 3 or 4 moist
Chroma: 2 to 4
When the moist value and chroma is as dark as 3/3, the horizon is too thin; if mixed to 7 inches, or if it is too light colored or contains too little organic carbon, it fails to qualify as a mollic epipedon.
Texture: sandy loam, loam, loamy sand and sandy clay loam
Clay content: 5 to 26 percent
Silt content: 5 to 30 percent
Sand content: 45 to 90 percent
Rock fragment content: 0 to 5 percent
Reaction: neutral or slightly alkaline.
Bt horizon:
Hue: 7.5YR or 10YR
Value: 4 to 6 dry, 4 or 5 moist
Chroma: 3 or 4
Clay content: 20 to 32 percent
Silt content: from 10 to 30 percent
Sand content: 50 to 75 percent, with more than 35 percent being fine sand or coarser
Rock fragment content: 0 to 5 percent fine pebbles
Reaction: neutral to moderately alkaline.
Bk and C horizons:
Hue: 7.5YR or 10YR
Value: 5 to 8 dry, 4 to 6 moist
Chroma: 2 to 4
Texture: sandy clay loam, loam, fine sandy loam, very fine sandy loam, and sandy loam
Clay content: 5 to 30 percent
Silt content: 10 to 40 percent
Sand content: 40 to 75 percent
Rock fragment content: 0 to 10 percent, mainly fine pebbles.
Calcium carbonate equivalent: 4 to 15 percent
Reaction: slightly alkaline to strongly alkaline.
COMPETING SERIES: These are the
Arnor (NM), Arwhite (WY),
Augustine (NM),
Bigbow (KS),
Bosonoak (NM),
Carri (AZ),
Celacy (NM),
Celavar (NM),
Dalhart (OK),
Deekay (WY),
Dermala (NM),
Elwop (WY),
Evpark (NM),
Fort Collins (CO),
Flugle (NM),
Gateson (WY),
Iwela (NM),
Lykorly (AZ),
Navajita (NM),
Nyjack (NM),
Oldwolf (WY), Olnest (CO),
Orlie (NM),
Parkelei (NM),
Pinitos (NM),
Rauzi (WY),
Ribera (NM),
Rockybutte (WY),
Stoneham (CO),
Toluca (MT) and
Wagonhound series.
Potential competitors when reaction class is assigned are the Augustine (NM), Bigbow (KS), Celacy (NM), Carri (AZ), Dermala (NM),
Goesling (NM), Lykorly (AZ),
Maia (NM), Nyjack (NM), Pinitos (NM), and Ribera (NM) series.
Arnor, Iwela, Flugle, Lykorly, Maia, Navajita, Orlie, Parkelei, and Pinitos soils: are dry in
May and June.
Arwhite and Rauzi soils: are greater than 40 inches to secondary calcim carbonate.
Augustine soils: have 35 to 50 percent sand in the control section.
Bigbow soils: have a lithologic discontinuity at depths of 20 to 40 inches.
Bosonoak soils: have hues of 2.5YR or 5YR in the control section.
Carri, Celavar, Evpark, Carri, Nyjack and Ribera soils: have a lithic contact at depths of 20 to 40 inches.
Celacy soils: have a paralithic contact at depths of 20 to 40 inches.
Dalhart soils: are moist for longer periods of time and have 16 to 22 inches annual precipitation.
Deekay and Wagonhound soils: are dry for at least 45 consecutive days following the summer solstice.
Dermala soils: have 15 to 30 percent rock fragments in the control section.
Elwop, Gateson, Oldwolf, and Celacy soils: have a paralithic contact at depths of 20 to 40 inches.
Fort Collins soils: have less than 35 percent fine and coarser sand in the PSCS.
Stoneham soils: have secondary calcium carbonate at depths of less than 12 inches.
Toluca soils: have less than 50 percent sand in the control section.
GEOGRAPHIC SETTING:
Landform: hills, ridges, uplands and plains.
Slopes: 1 to 9 percent
Elevation: 4,000 to 6,000 feet
Parent material: eolian and alluvial material derived from the Ogallala Formation.
Mean annual precipitation: 13 to 16 inches with peak periods of precipitation in the spring and summer months.
Mean annual temperature: 45 to 53 degrees F.
The frost-free period: 130 to 155 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Ascalon, Kimst, Manter, Vona, Otero, Pleasant, Sampson, and the competing Fort Collins and Stoneham soils. Ascalon, Pleasant, Manter, and Sampson soils have a mollic epipedon. Kimst and Otero soils do not have Bt horizons and have free lime at the surface. Manter, Otero, and Vona soils have a coarse-loamy control section.
DRAINAGE AND PERMEABILITY: Well drained; runoff is low to medium; moderate or moderately slow permeability.
USE AND VEGETATION: Olnest soils are used primarily for range and nonirrigated cropland. Native vegetation is mainly blue grama, sideoats grama, needleandthread, prairie sandreed, sand bluestem, western wheatgrass, and green needlegrass.
DISTRIBUTION AND EXTENT: Eastern Colorado; LRR E, MLRA 67; This series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado
SERIES ESTABLISHED: Kit Carson County, Colorado, 1994.
REMARKS: The name is coined from the Olney Series. Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the zone from 0 to 4 inches (A horizon)
Argillic horizon - the zone from 7 to 16 inches (Bt horizon)
Remarks: Last updated by the state 4/94.
Modified by Lee Neve in January 2002 in order to make format changes.
2/2006 Updated competing series.
Taxonomic Version: Second Edition, 1999.