LOCATION ULMET COEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Aridic Haplustalfs
TYPICAL PEDON: Ulmet loam - rangeland. (Colors are for dry soil unless otherwise noted.)
A--0 to 4 inches; brown (10YR 5/3) loam, very dark grayish brown (10YR 3/2) moist; moderate fine granular structure; soft, friable, slightly sticky and slightly plastic; common very fine and fine roots; neutral (pH 7.2); clear smooth boundary. (3 to 5 inches thick)
BAt--4 to 7 inches; brown (10YR 5/3) clay loam, brown (10YR 4/3) moist; weak medium prismatic structure parting to moderate fine subangular blocks; slightly hard, friable, sticky and slightly plastic; common very fine and fine roots; very few faint clay films on faces of peds; neutral (pH 7.2); clear smooth boundary. (0 to 4 inches thick)
Bt1--7 to 12 inches; brown (10YR 5/3) clay loam, brown (10YR 4/3) moist; moderate fine and medium prismatic structure parting to moderate fine subangular blocks; very hard, firm, very sticky and plastic; common very fine and fine roots; common distinct clay films on faces of peds; slightly alkaline (pH 7.4); clear smooth boundary. (5 to 14 inches thick)
Bt2--12 to 17 inches; brown (10YR 5/3) clay, brown (10YR 4/3) moist; moderate medium prismatic structure parting to moderate medium angular blocks; very hard, very firm, very sticky and very plastic; common very fine and fine roots; common distinct clay films on faces of peds; slightly alkaline (pH 7.4); clear smooth boundary. (0 to 11 inches thick)
Bk1--17 to 26 inches; pale brown (10YR 6/3) clay loam, light yellowish brown (10YR 6/4) moist; moderate medium prismatic structure parting to moderate medium subangular blocks; very hard, firm, very sticky and plastic; many very fine and fine roots; strongly effervescent, many soft carbonate nodules and masses; moderately alkaline (pH 8.2); gradual smooth boundary. (4 to 14 inches thick)
Bk2--26 to 37 inches; very pale brown (10YR 7/3) clay loam, light yellowish brown (10YR 6/4) moist; weak coarse prismatic structure parting to weak medium and coarse subangular blocks; hard, firm, sticky and plastic; many very fine and fine roots; many fine pores; violently effervescent; many soft carbonate nodules and masses; moderately alkaline (pH 8.4); gradual smooth boundary. (0 to 22 inches thick)
Bk3--37 to 60 inches; light gray (10YR 7/2) clay loam, very pale brown (10YR 7/3) moist; massive; slightly hard, friable, sticky and plastic; few fine roots; many fine pores; 2 percent fine pebbles; violently effervescent, few fine carbonate nodules; moderately alkaline (pH 8.4).
TYPE LOCATION: Kit Carson County, Colorado; approximately 14 miles south of Seibert; about 105 feet south and 796 feet east of the northwest corner of Sec. 16, T. 11 S., R. 49 W. U.S.G.S. quad Stratton CO 3 S.W. Lat. 39 degrees, 5 minutes, 50 seconds N., and long. 102 degrees, 54 minutes, 1 second W.
RANGE IN CHARACTERISTICS: Depth to calcareous material ranges from 13 to 24 inches. Organic carbon ranges from 1 to 3 percent in the upper 4 inches. Depth to the base of the argillic horizon ranges from 17 to 24 inches.
The A horizon has hue of 10YR, value of 5 or 6 dry, 3 or 4 moist, and chroma of 2 or 3. 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. Typically the horizon is loam or sandy clay loam. Clay content ranges from 18 to 25 percent. It is neutral or slightly alkaline.
The Bt horizons have hue of 10YR, value of 4 through 6 dry, 4 or 5 moist, and chroma of 2 or 3. Typically they are clay loam and clay, but the clay ranges from 35 to 45 percent clay, silt from 10 to 40 percent, and sand from 20 to 50 percent. There is 15 percent of more fine sand and coarser. They are neutral or slightly alkaline.
The Bk horizons have hue of 10YR, value of 6 or 7 dry, 5 to 7 moist, and chroma of 2 to 4. These horizons are typically clay loam, sandy clay loam, and loam, but clay ranges from 18 to 37 percent, silt from 10 to 60 percent, and sand from 30 to 70 percent. Rock fragments range from 0 to 5 percent pebbles. Calcium carbonates range from 5 to 15 percent.
COMPETING SERIES: These are the Baca (CO), Manzanst (CO), and Natank (AZ) series. Manzanst soils contain free carbonates in the A and Bt horizons and range to include silty clay loam in the Bt and Bk horizons. Natank soils are moderately deep and have a hue of 7.5YR or 5YR in the Bt and Bk horizons. Baca soils have less than 15 percent fine sand and coarser in the Bt horizon.
GEOGRAPHIC SETTING: The Ulmet soils are on plains. Slopes range from 0 to 3 percent. The elevation ranges from 4,500 to 5,200 feet. The soil formed in fine textured alluvium derived from the Ogallala Formation. The mean annual precipitation is about 13 to 16 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 140 to 150 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Stoneham, Fort Collins, Nunn, Olnest, Sampson, and Weld soils. Stoneham, Fort Collins, Olnest, and Sampson have a fine-loamy particle size control section. Nunn, Sampson, and Weld soils have a mollic epipedon. Weld soils have less than 15 percent fine sand in the particle size control section.
DRAINAGE AND PERMEABILITY: Well drained; runoff is slow; slow permeability.
USE AND VEGETATION: Ulmet soils are used primarily for nonirrigated cropland. Native vegetation is mainly blue grama, western wheatgrass, and green needlegrass.
DISTRIBUTION AND EXTENT: Eastern Colorado. This series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado
SERIES PROPOSED: Kit Carson County, Colorado, 1994.
REMARKS: The name is coined from the Ulm Series. Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - 0 to 4 inches (A)
Argillic horizon - 7 to 17 inches (Bt)