LOCATION DACONO COEstablished Series
TAXONOMIC CLASS: Clayey over sandy or sandy-skeletal, smectitic, mesic Aridic Argiustolls
TYPICAL PEDON: Dacono clay loam, grassland. (Colors are for dry soil unless otherwise noted.)
A--0 to 5 inches; grayish brown (10YR 5/2) clay loam, very dark grayish brown (10YR 3/2) moist; moderate fine granular structure; soft, friable; approximately 5 percent pebbles; neutral; clear smooth boundary. (4 to 8 inches thick)
AB--5 to 9 inches; grayish brown (10YR 5/2) clay loam, very dark grayish brown (10YR 3/2) moist; weak medium subangular blocky structure parting to fine granules; slightly hard, very friable; individual aggregates are hard; 5 percent pebbles; neutral; clear smooth boundary. (3 to 6 inches thick)
Bt--9 to 20 inches; grayish brown (10YR 5/2) heavy clay loam or light clay, dark grayish brown (10YR 4/2) moist; moderate medium prismatic structure parting to strong fine angular and subangular blocks; slightly hard, friable; individual aggregates are extremely hard; sticky, plastic; thin nearly continuous clay films on peds; 10 percent pebbles; mildly alkaline; clear wavy boundary. (5 to 16 inches thick)
BCk--20 to 26 inches; brown (10YR 5/3) sandy clay loam, dark brown (10YR 4/3) moist; weak and moderate, medium subangular blocky structure; slightly hard, friable, individual aggregates are hard, slightly sticky, slightly plastic; thin patchy clay films on horizontal and vertical faces or peds; 10 percent pebbles; visible calcium carbonate occurring as concretions, and in thin seams and streaks; calcareous; moderately alkaline; gradual wavy boundary. (0 to 4 inches thick)
2Ck--26 to 60 inches; light yellowish brown (10YR 6/4) very gravelly sand, yellowish brown (10YR 4/4) moist; single grain; loose; visible secondary calcium carbonate as concretions, and as coatings on the sand and pebble fragments; calcareous; moderately alkaline.
TYPE LOCATION: Adams County, Colorado; 1,070 feet south and 150 feet west of the northeast corner of sec. 13, T. 1 S., R. 67 W.
RANGE IN CHARACTERISTICS: Mean annual soil temperature is about 52 degrees F. The thickness of the mollic epipedon ranges from 7 to 20 inches and depth to calcareous material typically ranges from 8 to 20 inches. Thickness of the solum commonly ranges from 15 to 40 inches, and depth to the contrasting gravel and sand substratum ranges from 20 to 35 inches. The soil is 80 to 100 percent base saturated. Cation exchange capacity of the Bt horizon ranges from approximately 60 to 80 milliequivalents per 100 grams of clay. Rock fragments range from 0 to 35 percent in the solum and range from 36 to 80 percent in the substratum and includes pebbles, cobble and a few stones.
The A horizon has hue of 2.5Y or 10YR, value of 4 or 5, 2 or 3 moist, and chroma of 1 through 3. Usually the horizon has a granular or crumb structure, but it has weak subangular blocky structure in some pedons. It ranges from soft to slightly hard. This horizon is neutral or mildly alkaline.
The Bt horizon has hue from 2.5Y through 7.5YR, value of 5 or 6, 3 or 4 moist, and chroma of 2 or 3. It is typically heavy clay loam or light clay and has 35 to 50 percent clay. This horizon ranges from prismatic to subangular and angular blocky. It is neutral in the upper part and moderately alkaline in the lower part.
The contrasting 2Ck horizon has hue of 2.5Y through 7.5YR. It has 6 to 14 percent calcium carbonate equivalent. The horizon is moderately alkaline or strongly alkaline.
COMPETING SERIES: This is the Valmont soil in another family. Valmont soils are clayey over loamy-skeletal.
GEOGRAPHIC SETTING: The Dacono soils are on high terraces and have slope gradients of 0 to 6 percent. The soils formed in alluvial parent materials which in places have had some loess modification in the upper part. At the type location the average annual precipitation is approximately 15 inches, 9 inches of which fall during the months of April through August. The average annual temperature is 50 degrees F., and the average summer temperature is 67 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Larimer, Nunn and Satanta soils. Larimer soils lack a mollic epipedon and have a fine-loamy Bt horizon. Nunn and Satanta soils have fine and fine-loamy particle size control sections.
DRAINAGE AND PERMEABILITY: Well-drained; slow runoff; moderately slow permeability.
USE AND VEGETATION: These soils are used principally as irrigated cropland, although they are used for native pastureland in places. Vegetable crops are the principal crops grown.
DISTRIBUTION AND EXTENT: High terraces along the front of the mountain ranges in east-central Colorado. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado
SERIES ESTABLISHED: Logan County, Colorado, 1974.