LOCATION DOBROW                  CO+WY

Established Series
Rev. AJC/JEB/KLS
11/2022

DOBROW SERIES

The Dobrow series consists of poorly to very poorly drained soils formed in moderately coarse textured alluvial sediments overlying sand and gravel beds. Dobrow soils are on flood plains and slopes range from 0 to 6 percent. The mean annual precipitation is about 255 mm and the mean annual air temperature is about 2 degrees C.

TAXONOMIC CLASS: Coarse-loamy, mixed, superactive Cumulic Cryaquolls

TYPICAL PEDON: Dobrow loam - grassland. (Colors are for dry soil unless otherwise noted.)

Oi--0 to 3 cm; grass remains, roots, and leaves.

Oe--3 to 8 cm; partially decomposed organic materials like that of the horizon above.

Ag1--8 to 18 cm; dark grayish brown (10YR 4/2) loam, very dark brown (10YR 2/2) moist; strong fine granular and crumb structure; soft, very friable, slightly sticky, slightly plastic; common medium distinct mottles, dark reddish brown (5YR 3/4) and yellowish brown (10YR 5/8) moist; slightly alkaline (pH 7.6); clear smooth boundary. (8 to 15 cm thick)

Ag2--18 to 33 cm; dark gray (10YR 4/1) sandy loam, very dark gray (10YR 3/1) moist; weak coarse subangular blocky structure that parts to fine granules; slightly hard, very friable, nonsticky, nonplastic; common medium prominent mottles, dark reddish brown (5YR 3/4) and yellowish brown (10YR 5/8) moist; neutral (pH 7.0); clear smooth boundary. (10 to 30 cm thick)

Ag3--33 to 79 cm; gray (10YR 5/1) fine sandy loam, very dark gray (10YR 3/1) moist; weak coarse subangular blocky structure; slightly hard, very friable, nonsticky, nonplastic; common medium prominent mottles, dark reddish brown (5YR 3/4) and yellowish brown (10YR 5/8) moist; neutral (pH 7.0); clear smooth boundary. (36 to 84 cm thick)

2Cg--79 to 160 cm; light brownish gray (10YR 6/2) very gravelly sand, grayish brown (10YR 5/2) moist; single grained; loose; common medium distinct dark yellowish brown (10YR 4/4) and yellowish brown (10YR 5/8) moist mottles; 60 percent gravel; neutral (pH 7.2).

TYPE LOCATION: Jackson County, Colorado; near center of Sec. 5, T. 9 N., R. 79 W.

RANGE IN CHARACTERISTICS:
Mean annual soil temperature--6 degrees C
Mean summer soil temperature--13 degrees C
O horizons are usually present but are thin.
Mollic epipedon thickness--53 to 100 cm; typically, the mollic epipedon rests directly on the sandy-skeletal substratum, but mottled B2 horizons of low chroma may occur below the mollic epipedon in some pedons.
Base saturation--60 to 100 percent
Depth to noncontrasting 2C horizon--66 to 100 cm
Texture--sandy loam
Clay content--5 to 18 percent
Silt content--5 to 40 percent
Sand content--50 to 82 percent with more than 35 percent fine or coarser sand
Rock fragment content--0 to 35 percent in a major part of the control section above the 2C horizon and are mainly 0.5 cm to 25 cm in diameter

A horizon
Hue--5Y through 7.5YR
Value--4 or 5 dry, 2 or 3 moist
Chroma--1 or 2 and has common distinct to many prominent mottles
Reaction--pH 6.1 to 7.8

B horizon (if present)
Hue--5Y through 7.5YR
Value--5 through 7 dry, 4 through 6 moist
Chroma--1 or 2, and has common distinct to many prominent mottles
Reaction--pH 6.1 to 7.8

COMPETING SERIES: These are the Fleer, Mendenhall, New Fork, and Tepee series. Fleer soils are calcareous above a depth of 25 cm. Mendenhall soils are calcareous in all parts between depths of 25 and 50 cm. New Fork soils have a mollic epipedon less than 50 cm thick. Tepee soils have a fine-loamy control section.

GEOGRAPHIC SETTING:
Landform--flood plains
Elevation--2425 meters
Slope--0 to 6 percent
Parent material--moderately coarse textured alluvial sediments overlying sand and gravel beds
Mean annual precipitation--255 mm with peak periods of precipitation during the spring and early summer
Mean annual air temperature--2 degrees C
Frost-free period--65 to 110 days

GEOGRAPHICALLY ASSOCIATED SOILS: None listed

DRAINAGE AND PERMEABILITY: Poorly to very poorly drained; slow runoff to ponded; rapid permeability. Dobrow soils have high water tables that occur at or near the surface most of the year.

USE AND VEGETATION: These soils are used as native pastureland or for native hay meadow. Principal native vegetation is alpine timothy, Nebraska sedge, and willows.

DISTRIBUTION AND EXTENT: Dobrow soils are moderately extensive in the high mountain valleys of northcentral Colorado and southcentral Wyoming; MLRAs 48A and 48B

SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Bozeman, Montana

SERIES ESTABLISHED: Jackson County, Colorado, 1973

REMARKS:
The superactive cation exchange activity class was added in 03/2003 to the taxonomic classification by the National Soil Survey Center on request of the Lakewood office, without review of the soil series property data.

Converted to metric, updated formatting, and O horizons were updated to start at zero. Competing series section was not updated. 11/2022

---

National Cooperative Soil Survey
U.S.A.