LOCATION MEDANO                  CO+ID

Established Series
Rev. GB/KLS
11/2022

MEDANO SERIES

The Medano series consist of deep, poorly drained soils formed in mixed alluvium. They are on low flood plains and the lower ends of alluvial fans with slopes of 0 to 6 percent. The mean annual precipitation is about 180 mm and the mean annual air temperature is about 6 degrees C.

TAXONOMIC CLASS: Sandy, mixed, frigid Typic Endoaquolls

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

Oi--0 to 5 cm; undecomposed organic material consisting mainly of grass roots and leaves. (0 to 5 cm thick)

A--5 to 25 cm; gray (10YR 5/1) fine sandy loam, black (10YR 2/1) moist; weak medium subangular blocky structure parting to very fine granular; soft, very friable; calcareous; moderately alkaline; gradual smooth boundary. (0 to 25 cm thick)

Ag--25 to 50 cm; grayish brown (10YR 5/2) loamy sand, very dark brown (10YR 2/2) moist; common medium distinct gray (2.5Y 5/1) and yellow (2.5Y 7/6) moist mottles; single grained; loose; slightly alkaline; gradual, wavy boundary. (13 to 51 cm thick)

Cg--50 to 157 cm; light brownish gray (10YR 6/2) loamy sand, dark grayish brown (10YR 4/2) moist; common medium distinct gray (2.5Y 5/1) and olive brown (2.5Y 4/4) moist mottles; single grained; loose; slightly alkaline.

TYPE LOCATION: Alamosa County, Colorado; about 490 meters south and 580 meters east of the NW corner of Sec. 17, T. 40 N., R. 12 E.

RANGE IN CHARACTERISTICS:
Mean annual soil temperature--6 to 7 degrees C
Mean summer soil temperature--16 to 17 degrees C
Medano soils are calcareous in the surface horizons but noncalcareous below depths of 50 cm.

Particle-size control section:
Texture--loamy fine sand, loamy sand, or sand, but exclude loamy very fine sands
Rock fragment content--0 to 15 percent, mainly less than 75 mm in diameter

A horizon
Hue--2.5Y through 7.5YR
Value--4 or 5, 2 or 3 moist
Chroma--1 through 3. It is
Reaction--pH 7.9 to 9.0

C horizon
Hue--5Y through 7.5YR
Value--5 or 6 dry, 3 through 6 moist
Chroma--2 through 4
Reaction--pH 6.6 to 7.8

COMPETING SERIES: These are the Fossum, Hamar, Hangaard, Isan, Isanti, and Venlo series. Fossum soils are calcareous throughout and have visible accumulation of calcium carbonate in the A horizon. Hamar, Hangaard, and Venlo series are noncalcareous in the upper part of the control section and become calcareous with increasing depth. Isan and Isanti soils are acid throughout the control section.

GEOGRAPHIC SETTING:
Landform--flood plains and alluvial fans
Elevation--2300 to 2550 meters
Slope--0 to 6 percent
Parent material--alluvium
Mean annual precipitation--180 mm to 230 mm with peak periods of precipitation in the spring and summer
Mean annual air temperature--5 to 7 degrees C
Mean summer air temperature--15 to 16 degrees C

GEOGRAPHICALLY ASSOCIATED SOILS: None listed

DRAINAGE AND PERMEABILITY: Poorly drained; slow runoff; rapid permeability but soil has a high water table that ranges within 0.5 to 1 meter of surface during spring seasons.

USE AND VEGETATION: These soils are used as native pastureland and for irrigated hay meadow or irrigated pasture. Native vegetation is mainly sedges, rushes, and other water-tolerant grasses and plants.

DISTRIBUTION AND EXTENT: Medano soils are moderately extensive in southcentral Colorado and eastern Idaho; MLRAs 11 and 51.

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

SERIES ESTABLISHED: Alamosa County, Colorado, 1974

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

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National Cooperative Soil Survey
U.S.A.