LOCATION ALVARADO COEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive Aquic Argicryolls
TYPICAL PEDON: Alvarado very cobbly sandy loam - rangeland. (Colors are for dry soil unless otherwise noted.)
A1--0 to 7 inches; brown (7.5YR 5/2) very cobbly sandy loam, dark brown (7.5YR 3/2) moist; moderate fine granular structure; soft, very friable; 20 percent pebbles, 15 percent cobbles, 5 percent stones; slightly acid; clear smooth boundary. (6 to 15 inches thick)
A2--7 to 12 inches; dark brown (10YR 4/3) very cobbly sandy loam, dark brown (10YR 3/3) moist; weak very fine subangular blocky structure; slightly hard, friable; 20 percent pebbles, 15 percent cobbles, 5 percent stones; slightly acid; clear smooth boundary. (0 to 5 inches thick)
Bt1--12 to 31 inches; brown (7.5YR 5/4) very cobbly sandy clay loam, reddish brown (5YR 4/4) moist; common medium distinct yellowish red (5YR 5/8) and common fine prominent black (N 2/) redox features; moderate medium subangular blocky structure; very hard, friable, slightly sticky and plastic; common distinct clay films on faces of peds; 25 percent pebbles, 15 percent cobbles, 5 percent stones; neutral; gradual wavy boundary. (12 to 24 inches thick)
Bt2--31 to 41 inches; brown (7.5YR 5/4) very cobbly sandy clay loam, reddish brown (5YR 4/3) moist; common medium distinct yellowish red (5YR 5/6) and common fine prominent black (N2/) redox features; weak fine subangular blocky structure; very hard, friable, slightly sticky and slightly plastic; few distinct clay films on faces of peds; 25 percent pebbles, 15 percent cobbles, 5 percent stones; slightly alkaline.
C--41 to 60 inches; light brown (7.5YR 6/4) very cobbly sandy loam, reddish brown (5YR 4/3) moist; common medium distinct yellowish red (5YR 5/6) and common fine prominent black (N 2/) redox features; massive; very hard, friable, slightly sticky and slightly plastic; common large calcareous spots on bottom of cobbles; 20 percent pebbles, 15 percent cobbles, 5 percent stones; slightly alkaline.
TYPE LOCATION: Custer County, Colorado; approximately 5 miles west and 1 mile north of Westcliffe; 2,640 feet south and 1,140 feet west of the northeast corner of Sec. 8, T. 22 S., R. 73 W. U.S.G.S. Beckwith Mountain quad; Lat. 38 degrees, 9 minutes, 16 seconds N., and long. 105 degrees, 33 minutes, 48 seconds W.
RANGE IN CHARACTERISTICS: The mean annual soil temperature ranges from 40 to 44 degrees F; the mean summer soil temperature ranges from 55 to 59 degrees F. In most years a temporary water table in undrained soils is at a depth of two to four feet between March 1 and June 30, and is below four feet or absent the remainder of the year. The mollic epipedon ranges from 7 to 15 inches thick. Depth to bedrock is more than 60 inches. Rock fragments in the control section range from 35 to 75 percent. Rock fragments are rounded and dominantly less than 6 inches in diameter. Hue ranges from 5YR to 10YR in all horizons. Depth to any calcareous material is 30 inches or more.
The A horizon has value of 4 or 5 dry, 2 or 3 moist, and chroma of 1 through 3. It is slightly acid or neutral.
The Bt horizons have value of 5 or 6 dry, 4 or 5 moist, and chroma of 2 through 4. Mottles range from common to many and from distinct to prominent and chroma of mottles ranges from 0 through 8. These horizons are 20 to 35 percent clay. They are slightly acid or neutral.
The C horizon has value of 5 or 6 dry, 4 or 5 moist, and chroma of 2 through 6 and is mottled. It is neutral through moderately alkaline.
COMPETING SERIES: Currently there are no other series in this family.
GEOGRAPHIC SETTING: Alvardo soils are on fans and stream terraces and receive runoff from other soils. Slopes range from 2 to 5 percent. The soils formed in gravelly and cobbly outwash and alluvium. Average annual precipitation is 15 to 18 inches. Mean annual temperature ranges from 38 to 42 degrees F. Frost-free season is 60 to 80 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Ess and Norriston soils; each of these is well drained.
USE AND VEGETATION: Used for irrigated meadow hay, pasture and rangeland. Native vegetation is Arizona fescue, mountain muhly, western wheatgrass, needlegrasses, Baltic rush, and sun sedge.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained; slow to medium runoff; moderate permeability.
DISTRIBUTION AND EXTENT: Mountain valleys of southern central Colorado. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Custer County, Colorado, 1979.
REMARKS: Diagnostic features include a mollic epipedon from 0 to 12 inches; an argillic horizon from 12 to 41 inches; redox features in the Bt and C horizons; and a water table at 2 to 4 feet between March 1 and June 30, and is below 4 feet or absent the rest of the year. Last updated by the state 4/94.