LOCATION LAMANGA                 CO

Established Series
Rev. JMY/RHM
12/2022

LAMANGA SERIES

The Lamanga series consists of deep, somewhat poorly drained soils that formed in medium textured alluvial material. Lamanga soils are on flood plains and old alluvial fans and have slopes of 0 to 1 percent. The mean annual precipitation is about 7 inches and the mean annual air temperature is about 41 degrees F.

TAXONOMIC CLASS: Fine-loamy, mixed, superactive, frigid Aquic Haplargids

TYPICAL PEDON: Lamanga sandy clay loam, cultivated. (Colors are for dry soil unless otherwise noted.)

Ap--0 to 6 inches; brown (7.5YR 5/4) sandy clay loam, dark brown (7.5YR 4/4) moist; weak medium subangular blocky structure; hard, friable; neutral; clear smooth boundary. (4 to 8 inches thick)

B2t--6 to 13 inches; brown (7.5YR 5/4) clay loam, dark brown (7.5YR 4/4) moist; few medium faint mottles of dark reddish brown (5YR 3/4) and gray (5YR 5/1) moist; weak coarse prismatic structure that parts to moderate medium subangular blocks; hard, friable; clay films on peds; slightly acid; clear smooth boundary. (4 to 10 inches thick)

B3g--13 to 19 inches; light brownish gray (10YR 6/2) clay loam, dark grayish brown (10YR 4/2) moist; common fine faint mottles of dark reddish brown (5YR 3/4) and gray (5YR 5/1) moist; very weak medium subangular blocky structure; slightly hard, very friable; few large pebbles; slightly acid; clear wavy boundary. (6 to 12 inches thick)

IIC--19 to 60 inches; brown (7.5YR 5/4) gravelly sandy loam, dark brown (7.5YR 3/4) moist; very weak medium subangular blocky structure; soft, very friable; gravel content increases with depth; some lime coatings on pebbles; neutral.

TYPE LOCATION: Conejos County, Colorado; 100 feet south and 1,400 feet east of the NW corner of SW1/4 Sec. 11, T. 35 N., R. 8 E.

RANGE IN CHARACTERISTICS: Rock fragments range from 0 to 15 percent by volume in the solum and are mainly of gravel size. Content increases with depth and the IIC horizon contains as much as 35 percent gravel in some pedons.

The A horizon has hue of 7.5YR or 10YR, value of 5 to 6 dry, 4 or 5 moist, and chroma of 2 through 4. It is clay loam or sandy clay loam. Structure is weak to moderate coarse prismatic, or weak to moderate medium to coarse subangular blocky. ph ranges from 6.1 to 8.4.

The C horizon has hue of 7.5YR or 10YR.

COMPETING SERIES: This is the Paulmyers series. Paulmyers soils have mesic temperature.

GEOGRAPHIC SETTING: Lamanga soils are on bottom lands and old alluvial fans of mixed outwash material. Slopes range from 0 to 1 percent. At the type location the mean annual temperature is 41 degrees F. and the mean summer temperature is 56 degrees F. Average annual precipitation is 7 inches. The frost-free season is about 95 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Dunul, LaJara, and Mogote soils. Dunul soils have a sandy-skeletal control section. LaJara soils have a coarse-loamy control section. Mogote soils lack an argillic horizon.

DRAINAGE AND PERMEABILITY: Somewhat poorly drained; slow runoff; moderately slow permeability.

USE AND VEGETATION: Where drainage is established, these soils grow good crops of alfalfa and small grains. Native vegetation is mainly water-tolerant shrubs, grasses, and sedges, and is used for pasture and native hay meadows.

DISTRIBUTION AND EXTENT: San Luis Valley in south-central Colorado. The series is of small extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana

SERIES ESTABLISHED: Conejos County, Colorado, 1975.

REMARKS: Last updated by the state 7/75.

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 MLRA office, without review of the soil series property data. The remainder of this document has not been updated.

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National Cooperative Soil Survey
U.S.A.